### From: French.Chuck@epamail.epa.gov
To: King, Heidi R. Cc: Branning.Amy @epamail.epa.gov ; Higgins, Cortney; VanLare.Paula@epamail.epa.gov ; Fruh.Steve@epamail.epa.gov; Raymond, Gabrielle; Marinshaw, Richard Date: Thu 12/2/2010 12:36 PM Subject: Gold Mines MACT Standard

- costs documents, etc.... Hi Heidi, As we discussed, attached are the Cost and Impacts Document and the MACT Document (shows the MACT Floor and "beyond the floor" calculations). Also, as I mentioned, we made some edits to the preamble and rule to clarify/improve some things, make some minor corrections, and update the text on startup, shutdown and malfunctions. Attached is the revised preamble and rule (one version is a clean new version, and the other version sho ws the changes in "track changes"). We will also send you information on Title V very soon. Please let me know if you have comments or questions. Thank You.

Chuck (See attached file: Estimate of Impacts

- Final

- Draft

- 12
- 1
- 2010.doc) (See attached file: Gold Mine MACT Floor Document

- Final

- Draft

- 12
- 1
- 10.doc) (See attached file: Gold_Mine_Draft

- Preamble__Final_Rule_12

- 2
- 10
- clean.doc) (See attached file: Gold_Mine_Draft

- Preamble__Final_Rule_11

- 19
- 10
- edits

- track

changes.doc )

## ***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review***

ESTIMATES OF IMPACTS FOR THE FINAL MERCURY EMISSION STANDARDS FOR GOLD MINE ORE PROCESSING AND PRODUCTION

Metals and Minerals Group Sector Policies and Programs Division Office of Air Quality Planning and Standards U.S. E nvironmental Protection Agency Research Triangle Park, NC

Draft

- November 22 , 2010

## 2 Estimates o f Impacts f or t he Final Mercury Emission Standards f or Gold Mine Ore Processing a nd Production

1 . 0 Cost Estimates This section provides a summary of the estimate d costs of the final rule and background details on how these costs were developed. The cost components include both the cost of mercury emission controls and the costs associated with monitoring, reporting, and recordkeeping (MRR)

. The costs of mercury emission controls for each facility that we estimate will likely need to add controls to meet the emissions limits in the final MACT rule are summarized in Table 1. There were cases where facilities had installed new or additional controls on thermal proc ess units in 2008

– 2010 as a result of the Nevada Mercury Control Program (NMCP) . The costs of these newly

- installed controls are not included in the estimates presented here because the controls were installed prior to the final national standard. For example, mercury controls were installed at Round Mountain in 2008, at Cortez in 2008 and 2009, and at Jerritt Canyon (roasters) in 2009. Table 1. Estimate d Cost of Mercury Emission Control s for MACT Floor

No. Facility Name Location Hg reduction

(lb/y r) Estimates of mercury emission control costs Total capital

cost ($2008) Total O&M

cost ($/yr) Total annual

cost ($/yr) Cost effectiveness ($/lb) 1 Goldstrike Elko, NV 107 658,512 135,968 198,131 1,854 2 Denton

- Rawhide Fallon, NV 27 135,100 103,900 116,653 4,250 3 Florida Canyon Pershing Co., NV 87 367,868 165,382 200,109 2,305 4 Gold Quarry Carlin, NV 126 199,400 44,222 63,045 502 5 Jerritt Canyon Elko, NV 165 450,882 122,737 165,300 1,001 6 Lone Tree Valmy, NV 181 453,500 157,858 200,669 1,110 7 Midas Midas, NV 14 430,000 150,421 191,013 13,707 8 Twin Creeks Golconda, NV 636 30,064,551 2,413,109 5,239,483 8,232 Totals 1,343 32,759,813 3,293,597 6,374,404 4,746 

## Table 2 presents the costs of MRR and include s all of the gold mine ore proc essing and production facilities identified as having the thermal processes that would be subject to the final rule. All of these facilities will incur additional MRR costs. The final rule provides options for MRR; consequently, costs are presented for a range of these MRR options that includes the higher and lower costs options. Details for the MRR cost estimates are provided in Section 1.2.

## 3 Table 2. Estimates of Costs for Monitoring, Reporting, and Recordkeeping

No. Facility Name Facility Location Number of stacks a Higher estimates of MRR costs Lower estimates of MRR costs Roaste

r Other Not in NV b Monitoring capital Method 29 testing Monitoring O&M Monitoring total annual Monitoring capital Method 29 testing Monitoring O&M Monitoring total annu al 1 Goldstrike Elko, NV 2 15 120,000

- 182,061 199,149 200,668

- 78,619 107,194 2 Coeur Rochester Lovelock, NV 3 40,000

- 31,794 37,490

- - 11,299 11,299 3 Cortez Crescent Valley, NV 6 40,000

- 62,565 68,261

- - 21,576 21,576 4 Cripple Creek Victor, CO 3 3 40,000 28,260 31,794 65,750

- 28,260 11,299 39,559 5 Denton

- Rawhide Fallon, NV 4 40,000

- 42,051 47, 747

- - 14,725 14,725 6 Echo Bay/Kettle River Republic, WA 3 3 40,000 28,260 31,794 65,750

- 28,260 11,299 39,559 7 Florida Canyon Pershing County, NV 7 40,000

- 72,822 78,518

- - 25,001 25,001 8 Fort Knox Fairbanks, AK 2 2 40,000 18,840 21,537 46,073

- 18,840 7 ,873 26,713 9 Gold Quarry Carlin, NV 1 10 80,000

- 117,184 128,576 100,334

- 48,385 62,672 10 G olden Sunlight Whitehall, MT 3 3 40,000 28,260 31,794 65,750

- 28,260 11,299 39,559 11 Greens Creek Mine Greens Creek , AK 1 1 40,000 9,420 11,279 26,395

- 9,420 4,448 13,868 12 Bald Mountain Elko, NV 5 40,000

- 52,308 58,004

- - 18,150 18,150 13 Jerritt Canyon Elko, NV 2 3 120,000

- 58,976 76,064 200,668

- 37,512 66,087 14 Lone Tree Valmy, NV 5 40,000

- 52,308 58,0 04

- - 18,150 18,150 15 Marigold Valmy, NV 4 40,000

- 42,051 47,747

- - 14,725 14,725 16 Midas Midas, NV 3 40,000

- 31,794 37,490

- - 11,299 11,299 17 Ruby Hill Eureka, NV 4 40,000

- 42,051 47,747

- - 14,725 14,725 18 Round Mountain Round Mountain, NV 4 40,000

- 42,051 47,747

- - 14,725 14,725 19 Tw in Creeks Golconda, NV 13 40,000

- 134,365 140,061

- - 45,555 45,555 20 Western Mesquite Brawley, CA 3 3 40,000 28,260 31,794 65,750

- 28,260 11,299 39,559 21 Wharf Resources Lawrence County, SD 2 2 40,000 18,840 21,537 46,073

- 18,840 7,873 26,713 Totals 5 103 17 1,040,000 160,140 1,145,905 1,454,141 501,670 160,140 439,837 671, 414 a Number of stacks that must be monitored

. b Stacks at facilities outside of Nevada will incur additional costs for Method 29 testing (Method 29 testing is already requir ed in Nevada).

## 4 1 . 1 Cost of Mercury Emission Controls The primary basis for the cos t estimates are the estimates developed by the gold mine ore processing and production facilities in their Phase 2 applications for the NMCP

. 1 

## In these applications, individual facilities identified their process units that emit mercury and proposed addit ional controls for units that were not currently controlled. The cost estimates were based on applying carbon adsorbers to capture mercury emissions and were developed from the actual costs that had been incurred when installing th os e types of controls on other process units. Most of the facilities provided estimates of capital costs for the proposed emission control system s . For the few facilities that did not provide a capital cost estimate, a cost algorithm presented in the Phase 2 application for the Twins Creek facility was used. 1 

## This algorithm uses the total installed cost ($184,000) for a carbon adsorption system with a volumetric flow rate of 2,500 cubic feet per minute (cfm). The cost for applying carbon adsorbers to other process units was ba sed on the process unit’s exhaust flow rate ( cfm ) scaled with an exponent of 0.6 to account for economy of size: Total installed capital cost = $184,000 * (cfm/2,500) 0.6 

## Many facilities did not provide an estimate of the annual operating and maintenance (O&M) costs. However, when a facility estimated annual O&M costs in their Phase 2 application, those estimates were used in this analysis. For facilities without their own site

specific estimates, O&M cost estimates were developed based on the reported costs for other units that had already been equipped with carbon adsorbers. The Goldstrike facility estimated the annual labor costs for carbon adsorbers as $4,968/yr for operating labor, $4,752/yr for maintenance labor, and $106/yr for carbon replacement labor for a total of $9,826/yr. 2 

## The annual material and utility costs include the cost of replacement carbon and electricity for the additional fan capacity needed to move the vent stream through the carbon adsorber. The Goldstrike facility estimated c arbon replacement cost as $54,000/yr for a system designed for 4,400 cfm, or $12.27/cfm. 2 

## The Florida Canyon facility estimated carbon replacement costs as $23,541 for a 2,000 cfm system, or about $11.77/cfm. 3 

## Carbon replacement costs presented here are based on the average of these two values ($12/cfm of design capacity). For the fan, Florida Canyon estimated annual energy costs as $3,291/yr for a 2,000 cfm system or $1.65/cfm. 3 

## The combined O&M costs were then estimated based on the exhaust flow rate for each process unit using the following equation: O&M costs ($/yr) = $9,826 + $13.65 * cfm. The annualized cost of capital was estimated based on a 20

- year lifetime, an interest rate of 7 percent, and a capital recovery factor of 0.094. The total annu alized cost is estimated from the O&M costs plus the annualized cost of capital. Table 3 presents the estimated mercury emission control costs for each of the process units and provides references for the estimates

.

1 

### Cop ies of the Phase 2 applications are available at http://ndep.nv.gov/baqp/hg/clearinghouse.html

.

## 5 Table 3 . Breakdown of Estimated Cost of Mercury Emission Controls for Affected Process Units for MACT Floor

No. Facility Unit Control a Mercury reduction (lb/yr) Flow ( cfm ) b Total cap ital cost c Annual O&M cost e T otal annualized cost Cost effectiveness ( $/lb ) 1 Denton Rawhide Melt furnace CA 27.4 6,500 135,100 8 103,900 8 116,653 4,250 2 Florida Canyon Carbon kilns CA 80.9 1,000 183,934 7 82,691 7 100,054 1,237 3 Florida Canyon Electrowinning, preg tanks, melt furnace CA 5.9 1,000 183,934 2 82,691 7 100,054 16,962 4 Gold Quarry AARL carbon kiln CA 108.7 900 99,700 6 22,111 31,523 290 5 Gold Quarry Zadra carbon kiln CA 16.9 900 99,700 6 22,111 31,523 1,864 6 Goldstrike Carbon kilns WC, CA 106.9 4,406 658,512 d 135,968 198,131 1,854 7 Jerritt Canyon Melt furnace CA 131.3 1,622 141,933 d 31, 966 45,365 346 8 Jerritt Canyon Carbon kiln & retort CA 33.9 5,930 308,949 d 90,771 119,935 3,536 9 Lone Tree Electrowinning CA 24.3 10,000 423,000 9 146,326 186,257 7,662 10 Lone Tree Preg tanks CA 156.4 125 30,500 10 11,532 14,411 92 11 Twin Creeks Juni per preg tanks CA 94.5 3,085 209,000 4 51,936 71,666 758 12 Twin Creeks Electrowinning CA 52.4 7,311 434,000 5 109,621 150,591 2,871 13 Twin Creeks Melt furnace new CA 16.4 3,000 60,776 14 50,776 56,513 3,455 14 Twin Creeks Melt furnace old CA 42.5 3,000 6 0,776 14 50,776 56,513 1,329 15 Midas Furnace CA 13.9 10,300 430,000 15 150,421 191,013 13,707 16 Twin Creeks Autoclave WC, CA 430.6 11,300 29,300,000 19 2,150,000 4,904,200 11,390 Subtotal Carbon Group with Hg retorts (No. 1 through No. 14) 899 3,029,81 3 993,176 1,279,191 1,424 Subtotal Non - carbon Concentrate Group (No. 15) 14 430,000 150,421 191,013 13,707 Subtotal Ore Pretreatment Group (No. 16) 431 29,300,000 2,150,000 4,904,200 11,390 Total 1,343 32,759,813 3,293,597 6,374,404 4,746 a 

### CA = carbon adsorber, WC = water chiller (e.g., refrigeration unit or condenser) b 

### cfm = cubic feet per minute c 

### Capital costs estimates come primarily from the referenced NDEP Phase 2 applications (exceptions have footnotes). d 

### Estimated from : $184,000 * (cf m/2,500) 0.6 

### (see text). e 

### Unless a reference is given, estimated from : $9,826 + $13.65 * cfm (see text).


## 1 . 2 MRR Costs Th e final rule includes th ree monitoring options for roasters: a mercury continuous emission monitoring system (CEMS) , c ontinuous sor bent trap sampling , and periodic sorbent trap sampling. (Costs are not included for parametric monitoring of control devices because the facilities are already performing that monitoring as a result of State permit requirements.) The cost estimates for t he mercury CEMS were developed using EPA 's CEMS Cost Model for estimating CEMS costs and are summarized in Table 4

. Costs for the sorbent trap monitoring for roasters were obtained from EPA testing personnel and from vendor quotes for the cost of sorbent tubes and mercury analyses. The capital cost is estimated as $40,000 for the sampling probe, pump, mo is ture conditioner , metering console, and data logger . The paired traps cost $150 each with an analysis cost of $200 each. The estimated labor to instal l the traps, leak check, and set flow rates is 4 hours or $206/sample (at $51.51/hr). Sampling twice per month would be required, which results in an annual sampling cost of $13,335/yr per stack.

## 6 Table 4 . Cost Estimate for a Mercury CEMS Capital cost CEMS equipment (analyzer, sampling line data acquisition software, etc.) $90,000 Taxes and shipping $5,400 Install and check CEMS $4,320 Initial calibration $614 Total installed capital cost $100,334 Total annualized cost Daily operation of CEMS $4 ,608 Weekly checks of CEMS $2,938 Monthly checks of CEMS $2,765 Consumables $1,000 Annual QA $288 Recordkeeping and reporting $1.253 Subtotal $12,852 Capital recovery (10 years at 7%, CRF = 0.1424 ) $14,288 Total annualized cost $27,140 For proces s units other than roasters, the common mercury control device is a carbon adsorber. The final rule provides options for s am pling carbon adsorbers: monthly sorbent trap sampling (except going to weekly when the adsorber reaches 75 percent of the operatin g limit) or quarterly sampling of the carbon for mercury loading (going to monthly when 50 percent of capacity is reached). The capital cost for the sorbent trap sampling is the same as estimated above ($40,000). The annual cost is also estimated in a si milar manner except the lower frequency of sampling results in lower sampling costs. The annual costs for sorbent trap sampling and analysis of carbon adsorbers based on monthly sampling for 10 months and weekly sampling for 2 months is $10,000/yr per sta ck that is sampled. The carbon bed s am pling is much less e xp ensive because there is no capital cost, the analytical cost is less ($110/sample instead of $200/sample), and the sampling frequency is less. The carbon bed sampling is estimated as $3,170/yr p er carbon bed that is sampled. Reporting and recordkeeping costs are based on an estimate of 16 hours per plant plus 4 hours per stack that is monitored. The reporting costs for a facility were developed as shown in Table 5 ($ 1,022 + $ 256 × number of stac ks)

.

## 7 Table 5 . Estimate of Reporting and Recordkeeping Costs

General Description Mean Hourly

Rate a 

## Rate with overhead b 

## hr/plant $/plant hr/stack $/stack Environmental Engineer $ 35.24 $ 56.38 16 $ 902 4 $ 226 Management c 

## $ 57.27 $ 91.63 0.8 $ 73 0. 20 $ 18 Office/Admin. Support d 

## $ 18.31 $ 29.30 1.6 $ 47 0.40 $ 12 Total 18.4 $ 1,022 4.6 $ 256
a 

### Labor rates are for private industry workers in the mining industry (NAICS 212200) and were taken from the United States Department of Labor, Bureau of Labor Stati stics, May 200 9 , available at: http://www.bls.gov/oes/current/naics4_212200.htm

. b 

### Overhead at 60%. c 

### Estimated as 5% of technical hours

. d 

### Estimated as 10% of technical hours

. 

## The final ru le also require s annual stack sampling for mercury emissions (e.g., using EPA Method 29). However, most of the gold mine facilities are located in Nevada, and the Nevada Division of Environmental Protection already requires annual sampling using Method 29

. Consequently, only facilities outside of Nevada would incur additional costs for stack sampling. The cost of Method 29 testing is estimated as $9,420 per stack test as shown in Table 6 : Table 6 . Estimate of Costs for Method 29 Testing Cost Descripti on Cost Equipment rental $1,850 Travel and lodging $1,625 Testing cost $2,611 Laboratory analysis $2,650 Test report $680 TOTAL $9,420 The MRR costs were estimated for each facility and are presented in Table 2. The costs are estimated from the co st functions described in this section and the number of roaster stacks, number of other (no n - roaster process unit ) stacks , and stacks not located in Nevada (for Method 29 testing) that must be monitored and tested. 1.3 Beyond - the - Floor Costs T he affe cted sources with carbon processes with mercury retorts us e carbon to recover the gold and have one or more of the following process units: carbon kilns, electrowinning, preg tanks, mercury retorts, and melt furnaces. Approximately 7 of the 10 facilities for which data are available will need to improve control to meet the floor limits because these 7 plants have an average emission control performance that is above the Maximum Achievable Control Technology ( MACT ) floor average performance. We expect tha t the carbon process with mercury retorts units not currently controlled will have carbon adsorbers installed to effectively control mercury emissions at the MACT floor level. Considering the very low mercury

## 8 concentrations when the carbon processes with mercury retorts are performing at the MACT level of control, it is difficult to identify a technology that can obtain efficient additional percent reductions from low concentration streams. The final rule requires close monitoring of the carbon adsorber s o that the carbon can be replaced before breakthrough occurs and mercury is emitted. With careful monitoring, emission reductions on the order of 99 percent could be achieved by the carbon adsorbers installed to achieve the MACT floor level of control. F or a beyond

- the

- floor analysis, we assumed that theoretically a second carbon adsorption system could be installed in series with the first one and would get an additional 90 percent reduction (a lower reduction because of the very low mercury concentratio ns that result from the MACT floor level of control ) . We acknowledge that there is uncertainty as to the additional percent reduction the second control system might achieve. The cost estimates for a second carbon adsorption system in series with the fir st one for carbon processes with mercury retorts are presented in Table 7

. The capital cost was estimated as $3 million with a total annualized cost of about $ 1.3 million/yr and a cost effectiveness of about $ 150,000 /lb. The facilities with ore pretr eatment processes have installed , or would be required to install mercury scrubbers and carbon adsorbers on their roasters and autoclaves, to achieve the MACT floor for ore pretreatment processes. To achieve further reduction in mercury, one beyond

- the

- fl oor option is the installation of both a refrigeration unit and a carbon adsorber on the remaining facility with autoclaves. This additional control system would follow the existing venturi scrubbers, and , because autoclave exhaust is saturated with water , a refrigeration unit or condenser would be required to remove moisture that would otherwise adversely affect the adsorptive ca pacity of the carbon adsorber. We estimate the capital cost for the additional controls on the autoclaves would be $47,000,000, with a total annualized cost of $8,200,000/yr

. This option would reduce mercury emissions by 10 lbs/yr, resulting in an estimated cost effectiveness of $782,409/lb. We also identified as a beyond

- the

- floor option the installation of a carbon adsorber on ore preheater/dryer units. We estimated the capital cost for the additional controls as $2,962,000, with a total annualized cost of $1,622,000/yr. Based on an estimated control efficiency of 70 percent, m ercury emissions would be reduced by 118 lbs /yr , resulting in an estimated cost effectiveness of $13,784/lb

.

## 9 T able 7 . Estimate of Costs for a Second Carbon Adsorber for Carbon Processes with Mercury Retorts

No. Facility Unit Flow (cfm) Total capital

cost a 

### Annual O&M cost b 

### Total annualized cost Mercur y reduction

(lb/yr) 1 Twin Creeks Juniper P/B tanks 3,085 209,000 51,936 71,666 0.90 2 Twin Creeks Electrowinning 7,311 434,000 109,621 150,591 0.50 3 Goldstrike Carbon kilns 4,406 658,512 135,968 198,131 1.00 4 Gold Quarry AARL carbon kiln 900 99,700 22,111 31,523 1.03 5 Florida Canyon Carbon kilns 1,000 183,934 82,691 100,054 0.77 6 Florida Canyon Electrowinning, P/B tanks, melt furnace 1,000 183,934 82,691 100,054 0.06 7 Denton Rawhide Melt furnace 6,500 135,100 103,900 116,653 0.26 8 Lone Tree E lectrowinning 10,000 423,000 146,326 186,257 0.23 9 Lone Tree P/B tanks 125 30,500 11,532 14,411 1.48 10 Gold Quarry Zadra Carbon kiln 900 99,700 22,111 31,523 0.16 11 Twin Creeks Melt furnace new 3,000 60,776 50,776 56,513 0.15 12 Twin Creeks Melt fu rnace old 3,000 60,776 50,776 56,513 0.40 13 Jerritt Canyon Melt furnace 1,622 141,933 31,966 45,365 1.24 14 Jerritt Canyon Carbon kiln & retort 5,930 308,949 90,771 119,935 0.32 Totals 3,029,813 993,176 1,279,191 8.50 a 

### Estimated from : $184,000 * (c fm/2,500) 0.6 

### (see text). b 

### Operation and maintenance (O&M) costs estimated from : $9,826 + $13.65 × cfm (see text). 

## For the two facilities with carbon processes without retorts, we expect that Cortez will duct their uncontrolled P/B tank emissions in to the e lectrowinning control device. For a beyond

the

- floor analysis for carbon processes without mercury retorts , we estimated the costs and emissions reductions for installing a carbon adsorber to a unit at Round Mountain that is currently uncontrolled . For carbon processes without mercury retorts, t he capital cost for a carbon adsorber was estimated to be $ 0.2 million with a total annualized cost of $ 72,000 /yr . The mercury emission s reduction associated with this option would be 1.6 lbs /yr, resulting in an estimated cost effectiveness of $44,000/lb

. For the two facilities with non - carbon concentrate processes, we expect that Midas would need to add a carbon adsorber to its melt furnace to achieve the MACT floor level of control. For beyond

- the

- fl oor, we again assumed that the existing carbon adsorbers would be supplemented by adding a second control system of carbon adsorbers in series for all of the melt furnaces at both facilities

. Using the cost algorithms presented earlier as a function of sy stem flow rate, w e estimated the capital cost for the second set of carbon adsorber control systems as $ 430,000 , an annual operating cost of $ 150, 421 /yr, and a total annualized cost of $ 191,0 13 /year. Emissions would be reduced by 0.13 lb/year, which resul ts in a cost effectiveness of $ 1.4 million /lb. Table 8 summarizes the final mercury emission control costs including the beyond

- the

floor costs for ore pretreatment and the MACT floor costs for all the affected sources.

## 10 Table 8. Final Mercury Emission C ontrol Costs a



### No. Facility Name Location Hg reduction

(lb/yr) Estimates of mercury emission control costs Total capital cost ($2008) Total O&M cost ($/yr) Total annual cost ($/yr) Cost effectiveness ($/lb) 1 Goldstrike Elko, NV 141 858,512 1,335,968 1,417,131 10,016 2 Denton

- Rawhide Fallon, NV 27 135,100 103,900 116,653 4,250 3 Florida Canyon Pershing Co., NV 87 367,868 165,382 200,109 2,305 4 Gold Quarry Carlin, NV 189 2,451,400 74,672 305,045 1,617 5 Jerritt Canyon Elko, NV 185 960,882 235,737 326,300 1,761 6 Lone Tree Valmy, NV 181 453,500 157,858 200,669 1,110 7 Midas Midas, NV 14 430,000 150,421 191,013 13,707 8 Twin Creeks Golconda, NV 636 30,064,551 2,413,109 5,239,483 8,232 Totals 1,461 35,721,813 4,637,047 7,996,404 5,474 a 

### Inclu des b eyond

- the

- floor costs for ore pretreatment and MACT floor costs for all other affected sources

. 

## Table 9 summarizes the overall cost s of the final MACT rule. Table 9 . Overall Costs and Cost Effectiveness of the Final MACT Rule Capital Costs TAC Control Costs, $ million/yr 35,721,813 7,996,404 MRR, $ million/yr 770,835 1,062,778 Total Cost, $ million/yr 36,492,648 9,059,181 

## 2 . 0 Emission Estimates The emission estimates are based on mercury emission stack tests conducted in 2007 through 2009. 2 

## The data collected for the MACT floor analysis were used to estimate mercury emissions in pounds per year (lb/yr) for each process unit in each of the three groups of affected sources. The run

- by

- run data are presented in Appendix A , which also provide s t he details (emissions, operating hours, etc.) that were used in the calculations. When emissions were presented for different years for a single process unit, the emissions over the different years were averaged to estimate the average baseline emissions. Consequently, the emissions do not represent those reported for a given year, but the average of the years (2007

- 2009) for which data were avai lable . Emissions for the facil i ty were det ermined by summing emissions for each of the process units at the fa cility. A summary of the baseline emission estimates (i.e., emissions before MACT is effective) is given in Table 10 for the four groups of affected sources.

2 

### Copies of the emission test reports are available in the rulemaking docket: EPA

- HQ

- OAR 2010

- 02 39.

## 11 Emission reductions attributable to MACT for the carbon processes with mercury retorts, carbon p rocesses without mercury retorts, and non

- carbon processes group of units were estimated based on 95 percent and 99 percent control. The increased monitoring for carbon adsorbers is expected to result in continuing high reductions because the carbon would be replaced before complete breakthrough occurs. Table 11 presents the baseline emissions and emission reductions for the process units in the carbon processes with mercury retorts group that would be affected by MACT. For the carbon processes without retorts group, we expect that MACT would result in the installation of a carbon adsorber on the electrowinning cells at Round Mountain. Round Mountain electrowinning baseline emissions of 1.72 lb/yr would be reduced by 1.6 to 0.12 lb/yr. The overall carbo n processes without retorts baseline emissions of 3.52 lb/yr would be reduced by 1.6 to 1.89 lb/yr. The MACT reductions for the ore pretreatment group are based on the installation of carbon adsorbers on the autoclaves at Twin Creeks. No carbon adsorb ers have been installed on autoclaves, so there is some uncertainty in the emission reductions that would be achieved. A conservative estimate of 70 to 90 percent reduction is used here because the autoclaves have a much higher flow rate and higher temper ature than the exhaust streams typical of the carbon process units. The Twin Creeks autoclave baseline emissions of 615 lb/yr would be reduced by 431 to 184 lb/yr. The overall ore pretreatment baseline emissions of 1,451 lb/yr would be reduced by 431 lb/ yr from the controls on the autoclaves and 118 lb/yr from the beyond

- the

- floor control on the ore preheaters to 903 lb/yr. For the non

- carbon concentrate group, we expect that MACT would result in the installation of a carbon adsorber on the melt furnac e at Midas Operations. The Midas melt furnace baseline emissions of 14.67 lb/yr would be reduced by 13.94 to 0.73 lb/yr. The overall non - carbon concentrate baseline emissions of 25.79 lb/yr would be reduced by 13.94 to 11.85 lb/yr.

## 12 Table 10 . Baseline M ercury Emissions Estimates for the Four Groups of Affected Sources (based on data fo r 2007 - 2009) Ore Pretreatment Processes Facility Mercury Emissions (lb/yr) Gold Quarry 186 Goldstrike 538 Jerritt Canyon Mine 112 Twin Creeks Mine 615 Subtotal 1,45 1 Carbon Processes with Mercury Retorts Facility Mercury Emissions (lb/yr) Bald Mountain 2.8 Denton

- Rawhide 31 Florida Canyon Mine 93 Gold Quarry 231 Goldstrike 156 Jerritt Canyon 174 Lone Tree Mine 227 Marigold 5.7 Ruby Hill 5.9 Twin Creeks 23 0 Subtotal 1,155 Carbon Processes without Mercury Retorts Facility Mercury Emissions (lb/yr) Round Mountain 2.6 Cortez 2.3 Subtotal 4.9 Non - carbon Concentrate Processes Facility Mercury Emissions (lb/yr) Coeur Rochester 8.1 Midas Operations 18 S ubtotal 26 Grand Total 2,636

We estimate that in 2007 about 5 , 000 pounds of mercury were emitted from this source category based mainly on test data for year 2007. In 2008 and 2009 a few facilities added controls or modified their operations. Thus, u sing a combination of data from 2007 to 2009, we estimate that current emissions are about 2,63 6 lb/yr

. Overall, the proposed MACT limits are expected to reduce mercury emissions by about 1,46 1 to 1,17 4 lb/yr.

## 13 Table 11 . Mercury Emissions Reductions for the Carbon Processes with Mercury Retorts Group

No. Facility Unit Maximum concentrate usage (tpy) Unit average (lb/ton concentrate) Unit emissions

lb/yr Reductions @95% (lb/yr) Reductions @99% (lb/yr) 1 Twin Creeks Juniper PregTanks 104.57 0.95 99.50 94.52 98.50 2 Twin Creeks Electrowinning 104.57 0.53 55.21 52.45 54.66 3 Goldstrike Carbon Kiln #2

- Drum 105.93 1.05 110.94 105.40 109.83 4 Goldstrike Preg and Barren Tank A 105.93 0.01 0.92 0.88 0.91 5 Goldstrike Preg and Barren Tank B 105.93 0. 01 0.65 0.61 0.64 6 Gold Quarry AARL Carbon Kiln 62.10 1.84 114.43 108.71 113.28 7 Florida Canyon Carbon Kiln 11.35 7.50 85.16 80.90 84.31 8 Florida Canyon Electrowinning Cell A 11.35 0.55 6.21 5.90 6.15 9 Denton

- Rawhide Refinery Furnace 18.50 1.56 28.89 27.45 28.60 10 Lone Tree Mine Electrowinning Scavenger 11.00 2.33 25.59 24.31 25.33 11 Lone Tree Mine Pregnant & Barren Tanks 11.00 14.97 164.63 156.40 162.98 12 Gold Quarry Zadra Carbon Kiln 62.10 0.29 17.80 16.91 17.63 13 Twin Creeks Furnace ( New) 104.57 0.16 17.22 16.36 17.05 14 Twin Creeks Furnace (Old) 104.57 0.43 44.77 42.53 44.32 15 Jerritt Canyon Carbon Kiln & Retort 12.00 2.98 35.70 33.92 35.34 16 Jerritt Canyon Melt furnace 12.00 11.52 138.20 131.29 136.82 Totals 946 899 936


## 3. Secondary Impacts Secondary impacts include an increase in electricity consumption by fans and refrigeration units (in some cases) plus the generation of solid waste when the carbon in carbon adsorbers is replaced. The increase in electri city consumption was estimated from the following equation from the OAQPS Cost Manual 18 

## : kW

- hr/yr = 0.00081 * acfm * pressure drop (use 6 inches of water) * operating hr/yr

. The results are shown in Table 12 with a total increase of 12.6 million kW

- hr/y r. The estimated increase in spent carbon for regeneration or disposal assumes the carbon is replaced when half of its potential mercury capacity has been reached (a bout 0.1 lb mercury/lb carbon). For a mercury reduction of 1,461 lbs, approximately 14,60 0 lbs of carbon would be used and 16,060 lbs of spent loaded carbon would be generated.

## 14 Table 12 . Estimated Increase in Electricity Consumption

No. Facility Unit Operating hr/yr Flow (cfm) kw hr/yr 1 Denton

Rawhide Melt Furnace 347 6,500 10,962 2 Flo rida Canyon Electrowinning, P/B tanks, melt furnace 8,760 1,000 42,574 3 Florida Canyon Carbon Kiln 8,760 1,000 42,574 4 Gold Quarry Zadra Carbon Kiln 8,760 900 38,316 5 Gold Quarry AARL Carbon Kiln 6,471 900 28,304 6 Goldstrike Carbon Kiln 6,884 4,4 06 147,408 7 Jerritt Canyon Carbon Kiln & Retort 1,541 5,930 44,411 8 Jerritt Canyon Melt Furnace 872 1,622 6,874 9 Lone Tree Electrowinning 2,424 10,000 117,806 10 Lone Tree P/B Tanks 8,760 125 5,322 11 Midas Furnace 832 10,300 41,648 12 Twin Creeks Melt Furnace 2 (new) 8,760 3,000 127,721 13 Twin Creeks Melt Furnace 1 (old) 8,760 3,000 127,721 14 Twin Creeks Electrowinning 8,760 7,311 311,256 15 Twin Creeks Juniper P/B tanks 8,760 3,085 131,340 16 Twin Creeks Autoclave 11,300 11,389,107 a 

### Total 12,613,343 a 

## Electricity consumption for th e refrigeration unit taken from Phase 2 a pplication (Reference 19 ).

## 15 References 1

. Application for Phase 2 Operating Permit for Twin Creeks. Nevada Division of Environmental Protection. Page 3

- 21. 2008. 2

. Application for Phase 2 Operating Permit for Barrick Goldstrike. Nevada Division of Environmental Protection. Appendix 3, Table 3.4, Page 22. 2008. 3

. Application for Phase 2 Operating Permit for Florida Canyon. Nevada Division of Environmental Protect ion. Table 3.4, Page 19. 2008. 4

. Application for Phase 2 Operating Permit for Twin Creeks. Nevada Division of Environmental Protection. Table 14, Page 3

- 21. 2008. 5

. Application for Phase 2 Operating Permit for Twin Creeks. Nevada Division of Environment al Protection. Table 17, Page 3

- 24. 2008. 6

. Application for Phase 2 Operating Permit for Gold Quarry. Nevada Division of Environmental Protection. Table 20, Page 3

- 26. 2008. 7

. Application for Phase 2 Operating Permit for Florida Canyon. Nevada Division o f Environmental Protection. Table 3.4, Page 18. 2008. 8

. Application for Phase 2 Operating Permit for Denton

- Rawhide. Nevada Division of Environmental Protection. Table 3.4, Page 21. 2008. 9

. Application for Phase 2 Operating Permit for Lone Tree. Nevada Division of Environmental Protection. Page 3

- 10. 2008. 10

. Application for Phase 2 Operating Permit for Lone Tree. Nevada Division of Environmental Protection. Page 3

- 12. 2008. 11

. Application for Phase 2 Operating Permit for Bald Mountain . Nevada Divisio n of Environmental Protection. Appendix 3, Page 21 . 2008. 12

. Application for Phase 2 Operating Permit for Bald Mountain. Nevada Division of Environmental Protection. Appendix 3, Page 16. 2008. 13

. Application for Phase 2 Operating Permit for Ruby Hill. Ne vada Division of Environmental Protection. Appendix 3, Table 3.8, Page 31. 2008. 14

. Application for Phase 2 Operating Permit for Twin Creeks. Nevada Division of Environmental Protection. Page 3

- 21. 2008.

## 16 15

. Application for Phase 2 Operating Permit for Mi das. Nevada Division of Environmental Protection. Page 3

- 33. 2008. 16

. Application for Phase 2 Operating Permit for Twin Creeks. Nevada Division of Environmental Protection. Page 3

- 11. 2008. 17

. Application for Phase 2 Operating Permit for Twin Creeks. Nev ada Division of Environmental Protecti on. Pages 3

- 11 and 3

- 12. 18

. U.S. Environmental Protection Agency. EPA Air Pollution Control Cost Manual. Chapter 1. Baghouses and Filters. EPA/452/B

- 02

- 001. January 2002. 19

. Barrick Goldstrike Mines Inc. public comme nts (docket item EPA

- HQ

- OAR

- 2010

- 0239

- 0274 ) to proposed rule 75 Fed. Reg. 22470 (April 28, 2010)

## 17 Appendix A. Emission Test Results and Estimates of Baseline Emissions

## 18 TABLE A - 1. BASELINE MERCURY EMISSIONS FOR CARBON PROCESSES WITH MERCURY RETORTS

F acility Unit Run 1 (lb/hr) Run 2 (lb/hr) Run 3 (lb/hr) Run 1 (lb/ton) Run 2 (lb/ton) Run 3 (lb/ton) Year hr/yr Concentr ate (tpy) Max Concentr ate (tpy) Unit average (lb/ton) Per unit (lb/yr) Facility total (lb/ton) Facility total (lb/yr) Marigold EW, P/B 6.30E

- 04 9.30E

- 04 7.40E

- 04 3.68E

- 01 5.43E

- 01 4.32E

- 01 2008 6,281 10.75 10.75 4.48E

- 01 4.82E+00 Marigold Retort 6.30E

- 04 9.30E

- 04 7.40E

- 04 7.72E

- 02 1.14E

- 01 9.07E

- 02 2008 1,318 10.75 Marigold Retort 2.00E

- 05 9.20E

- 05 1.10E

- 05 2.48E

- 03 1.14E

- 02 1.37E

- 03 2009 1,142 9.20 10.75 4.95E

- 02 5.33E

- 01 Marigold Melt Furnace 4.54E

- 03 2.20E

- 03 1.35E

- 03 8.49E

- 02 4.11E

- 02 2.52E

- 02 2008 201 10.75 Marigold Melt Furnace 4.40E

- 04 4.81E

- 04 7.67E

- 04 1.00E

- 02 1.09E

- 02 1.74E

- 02 2009 209 9.20 10.75 3 .16E

- 02 3.40E

- 01 Marigold Carbon Kiln 1.41E

- 05 1.18E

- 05 1.31E

- 05 7.52E

- 03 6.29E

- 03 6.99E

- 03 2008 5,732 10.75 Marigold Carbon Kiln 1.50E

- 06 5.00E

- 07 8.00E

- 07 7.36E

- 04 2.45E

- 04 3.93E

- 04 2009 4,515 9.20 10.75 3.69E

- 03 3.97E

- 02 0.53 5.7 Denton

Rawhide Carbon Kiln 6.88E

- 06 7.55E

- 06 3.61E

- 05 3.16E

- 03 3.47E

- 03 1.66E

- 02 2007 8,497 18.5 Denton

Rawhide Carbon Kiln 1.35E

- 05 7.58E

- 06 2.42E

- 06 1.15E

- 02 6.48E

- 03 2.07E

- 03 2008 7,870 9.2 Denton

Rawhide Carbon Kiln 3.18E

- 04 1.85E

- 04 1 .63E

- 04 2.50E

- 01 1.45E

- 01 1.28E

- 01 2009 6,482 8.25 18.50 6.30E

- 02 1.16E+00 Denton

Rawhide Electrowinning 3.83E

- 06 1.44E

- 06 3.79E

- 05 6.46E

- 04 2.43E

- 04 6.39E

- 03 2007 3,120 18.5 Denton

Rawhide Electrowinning 2.27E

- 05 4.25E

- 06 5.27E

- 06 1.40E

- 02 2.62E

- 03 3.25E

- 03 2008 5,667 9.2 Denton

Rawhide Electrowinning 1.14E

- 05 8.10E

- 05 1.59E

- 04 9.14E

- 03 6.49E

- 02 1.27E

- 01 2009 6,612 8.25 18.50 2.54E

- 02 4.70E

- 01 Denton

Rawhide Melt Furnace 1.94E

- 01 8.31E

- 02 6.32E

- 02 3.64E+00 1.56E+00 1.19E+00 2007 347 18.5 Denton

Rawhide Melt Furnace 9.95E

- 02 2.07E

- 01 1.66E

- 01 8.90E

- 01 1.85E+00 1.48E+00 2008 82 9.2 Denton

Rawhide Melt Furnace 6.53E

- 02 1.95E

- 01 2.69E

- 02 7.84E

- 01 2.34E+00 3.23E

- 01 2009 99 8.25 18.50 1.56E+00 2.89E+01 Denton

Rawhide Retort 4.30E

- 07 4.66E

- 07 5.28E

- 07 5.84E

- 05 6.33E

- 05 7.17E

- 05 2007 2,513 18.5 Denton

Rawhide Retort 8.95E

- 07 2.93E

- 07 2.74E

- 07 4.59E

- 05 1.50E

- 05 1.40E

- 05 2008 472 9.2 Denton

Rawhide Retort 2.92E

- 04 2.05E

- 04 3.57E

- 04 6.2 4E

- 02 4.38E

- 02 7.62E

- 02 2009 1,762 8.25 18.50 2.03E

- 02 3.75E

- 01 1.67 31 Bald Mountain Carbon Kiln 8.23E

- 05 5.59E

- 05 6.30E

- 05 2.37E

- 02 1.61E

- 02 1.82E

- 02 2009 1,084 3.76 3.76 1.93E

- 02 7.27E

- 02 Bald Mountain Electrowinning & Barren Tank 5.57E

- 04 1.32E

- 0 4 8.14E

- 04 7.41E

- 01 1.76E

- 01 1.08E+00 2009 5,000 3.76 3.76 6.66E

- 01 2.51E+00 Bald Mountain Melt Furnace 1.80E

- 03 9.21E

- 04 1.21E

- 03 7.09E

- 02 3.63E

- 02 4.76E

- 02 2009 148 3.76 3.76 5.16E

- 02 1.94E

- 01 Bald Mountain Retort 6.68E

- 06 6.58E

- 06 2.88E

- 06 1.1 1E

- 03 1.09E

- 03 4.79E

- 04 2009 625 3.76 3.76 8.94E

- 04 3.36E

- 03 0.74 2.8 Ruby Hill Carbon Kiln 1.01E

- 03 9.49E

- 04 3.56E

- 04 2.30E

- 01 2.16E

- 01 8.08E

- 02 2009 1,274 5.61 5.61 1.75E

- 01 9.84E

- 01

## 19 F acility Unit Run 1 (lb/hr) Run 2 (lb/hr) Run 3 (lb/hr) Run 1 (lb/ton) Run 2 (lb/ton) Run 3 (lb/ton) Year hr/yr Concentr ate (tpy) Max Concentr ate (tpy) Unit average (lb/ton) Per unit (lb/yr) Facility total (lb/ton) Facility total (lb/yr)
Ruby Hill Electrowinning & Preg/Barren Tanks 9.64E

- 04 3.49E

- 04 3. 18E

- 04 1.51E+00 5.45E

- 01 4.97E

- 01 2009 8,760 5.61 5.61 8.49E

- 01 4.76E+00 Ruby Hill Melt Furnace 1.70E

- 03 2.04E

- 03 3.02E

- 02 3.63E

- 02 2009 100 5.61 5.61 3.33E

- 02 1.87E

- 01 Ruby Hill Retort 8.00E

- 07 8.00E

- 07 7.00E

- 07 1.30E

- 04 1.30E

- 04 1.14E

- 04 20 09 911 5.61 5.61 1.24E

- 04 6.98E

- 04 1.06 5.9 Goldstrike Carbon Kiln 8.38E

- 02 1.49E

- 02 8.62E

- 03 5.45E+00 9.68E

- 01 5.60E

- 01 2007 6,884 105.9 Goldstrike Carbon Kiln 6.03E

- 03 8.76E

- 03 5.92E

- 03 4.27E

- 01 6.21E

- 01 4.20E

- 01 2008 7,271 102.6 G oldstrike Carbon Kiln 1.81E

- 02 1.85E

- 02 2.21E

- 02 1.28E+00 1.31E+00 1.57E+00 2008 7,271 102.6 Goldstrike Carbon Kiln 1.97E

- 02 2.06E

- 02 1.90E

- 02 1.40E+00 1.46E+00 1.35E+00 2008 7,271 102.6 Goldstrike Carbon Kiln 9.04E

- 03 1.28E

- 02 5.71E

- 03 6.41E

- 01 9.07E

- 01 4.05E

- 01 2008 7,271 102.6 Goldstrike Carbon Kiln 3.10E

- 04 4.20E

- 04 4.90E

- 04 2.39E

- 02 3.23E

- 02 3.77E

- 02 2009 7,527 97.8 105.93 1.05E+00 1.11E+02 Goldstrike Electrowinning 2.38E

- 03 2.71E

- 03 3.03E

- 03 1.58E

- 01 1.80E

- 01 2.02 E

- 01 2007 7,053 105.9 Goldstrike Electrowinning 3.90E

- 03 5.60E

- 03 3.20E

- 03 2.74E

- 01 3.93E

- 01 2.25E

- 01 2008 7,202 102.6 Goldstrike Electrowinning 1.44E

- 03 9.60E

- 04 2.21E

- 03 1.06E

- 01 7.07E

- 02 1.63E

- 01 2009 7,202 97.8 105.93 1.97E

- 01 2.0 9E+01 Goldstrike Melt Furnace 4.95E

- 03 1.24E

- 02 3.96E

- 03 2.93E

- 02 7.35E

- 02 2.35E

- 02 2007 628 105.9 Goldstrike Melt Furnace 1.02E

- 02 2.88E

- 02 4.71E

- 02 4.56E

- 02 1.28E

- 01 2.10E

- 01 2009 436 97.8 105.93 8.50E

- 02 9.00E+00 Goldstrike Preg Tan k 3.27E

- 03 2.27E

- 03 1.16E

- 03 2.07E

- 02 1.43E

- 02 7.33E

- 03 2008 648 102.6 Goldstrike Preg Tank 4.20E

- 04 4.80E

- 04 6.10E

- 04 2.78E

- 03 3.18E

- 03 4.04E

- 03 2009 648 97.8 105.93 8.72E

- 03 9.24E

- 01 Goldstrike Preg Tank 6.28E

- 04 2.11E

- 03 1.89E

- 03 3.97E

- 0 3 1.33E

- 02 1.19E

- 02 2008 648 102.6 Goldstrike Preg Tank 4.80E

- 04 3.00E

- 04 3.30E

- 04 3.18E

- 03 1.99E

- 03 2.19E

- 03 2009 648 97.8 105.93 6.10E

- 03 6.46E

- 01 Goldstrike Retort 3.11E

- 03 2.51E

- 03 1.73E

- 03 5.91E

- 02 4.77E

- 02 3.29E

- 02 2009 1,858 97.8 105 .93 4.65E

- 02 4.93E+00 Goldstrike Retort 1.36E

- 03 6.90E

- 04 5.60E

- 04 3.00E

- 02 1.52E

- 02 1.23E

- 02 2009 2,154 97.8 105.93 1.92E

- 02 2.03E+00 Goldstrike Retort 3.08E

- 03 3.53E

- 03 3.34E

- 03 5.85E

- 02 6.70E

- 02 6.34E

- 02 2009 1,856 97.8 105.93 6.29E

- 02 6.67E+0 0 1.47 156 Twin Creeks Electrowinning 1.70E

- 04 9.00E

- 04 3.64E

- 03 2.29E

- 02 1.21E

- 01 4.91E

- 01 2007 8,760 64.9 Twin Creeks Electrowinning 1.30E

- 02 7.90E

- 03 8.80E

- 03 1.74E+00 1.06E+00 1.18E+00 2008 8,784 65.7 Twin Creeks Electrowinning 8.03E

- 04 5.15E

- 04 4.13E

- 04 6.73E

- 02 4.31E

- 02 3.46E

- 02 2009 8,760 104.57 104.57 5.28E

- 01 5.52E+01 Twin Creeks Melt Furnace 2 6.46E

- 02 1.85E

- 02 4.45E

- 02 4.20E

- 01 1.20E

- 01 2.89E

- 01 2007 422 64.9 Twin Creeks Melt Furnace 2 7.45E

- 02 2.12E

- 02 5.99E

- 02 4.85E

- 01 1.38E

- 01 3.90E

- 01 2007 422 64.9 Twin Creeks Melt Furnace 2 1.10E

- 02 3.10E

- 03 8.00E

- 03 6.60E

- 02 1.86E

- 02 4.80E

- 02 2008 394 65.7 Twin Creeks Melt Furnace 2 5.68E

- 05 7.99E

- 05 2.20E

- 04 1.77E

- 04 2.48E

- 04 6.84E

- 04 2009 32 5 104.57 104.57 1.65E

- 01 1.72E+01 Twin Creeks Melt Furnace 1 8.16E

- 02 3.28E

- 02 5.11E

- 02 1.04E+00 4.20E

- 01 6.54E

- 01 2007 831 64.9 Twin Creeks Melt Furnace 1 1.71E

- 01 6.65E

- 02 7.28E

- 02 2.19E+00 8.51E

- 01 9.32E

- 01 2007 831 64.9

## 20 F acility Unit Run 1 (lb/hr) Run 2 (lb/hr) Run 3 (lb/hr) Run 1 (lb/ton) Run 2 (lb/ton) Run 3 (lb/ton) Year hr/yr Concentr ate (tpy) Max Concentr ate (tpy) Unit average (lb/ton) Per unit (lb/yr) Facility total (lb/ton) Facility total (lb/yr) Twi n Creeks Melt Furnace 1 1.68E

- 03 4.99E

- 03 7.30E

- 03 2.15E

- 02 6.39E

- 02 9.35E

- 02 2007 831 64.9 Twin Creeks Melt Furnace 1 1.34E

- 02 7.00E

- 03 4.60E

- 03 7.79E

- 02 4.07E

- 02 2.67E

- 02 2008 382 65.7 Twin Creeks Melt Furnace 1 1.34E

- 04 1.14E

- 04 1.22E

- 04 5.36E

- 04 4.56E

- 04 4.88E

- 04 2009 418 104.57 104.57 4.28E

- 01 4.48E+01 Twin Creeks Carbon Kiln 1.88E

- 03 1.98E

- 04 8.21E

- 04 2.19E

- 01 2.30E

- 02 9.55E

- 02 2007 7,551 64.9 Twin Creeks Carbon Kiln 2.41E

- 03 9.20E

- 04 7.80E

- 04 2.80E

- 01 1.07E

- 0 1 9.08E

- 02 2007 7,551 64.9 Twin Creeks Carbon Kiln 6.50E

- 04 1.22E

- 03 1.20E

- 03 4.76E

- 02 8.89E

- 02 8.76E

- 02 2009 7,654 104.57 104.57 1.16E

- 01 1.21E+01 Twin Creeks Preg Tank 1.57E

- 02 1.41E

- 02 2.70E

- 03 2.12E+00 1.91E+00 3.64E

- 01 2007 8,760 64.9 Twin Creeks Preg Tank 6.10E

- 03 1.30E

- 02 5.80E

- 03 8.16E

- 01 1.74E+00 7.75E

- 01 2008 8,784 65.7 Twin Creeks Preg Tank 3.07E

- 03 3.08E

- 03 3.84E

- 03 2.57E

- 01 2.58E

- 01 3.22E

- 01 2009 8,760 104.57 104.57 9.52E

- 01 9.95E+01 Twin Creeks Reto rt 1.65E

- 06 1.43E

- 06 1.26E

- 06 8.80E

- 06 7.63E

- 06 6.72E

- 06 2009 558 104.57 104.57 7.72E

- 06 8.07E

- 04 Twin Creeks Retort 1.50E

- 05 2.20E

- 05 4.40E

- 05 8.13E

- 04 1.19E

- 03 2.39E

- 03 2007 3,519 64.9 Twin Creeks Retort 7.70E

- 05 9.20E

- 05 1.91E

- 04 4.18 E

- 03 4.99E

- 03 1.04E

- 02 2007 3,519 64.9 Twin Creeks Retort 5.00E

- 05 1.30E

- 05 2.10E

- 05 2.57E

- 03 6.68E

- 04 1.08E

- 03 2008 3,375 65.7 104.57 3.14E

- 03 3.28E

- 01 Twin Creeks Retort 7.20E

- 06 2.75E

- 05 2.82E

- 05 3.51E

- 04 1.34E

- 03 1.38E

- 03 2007 3,168 6 4.9 Twin Creeks Retort 3.20E

- 05 1.16E

- 04 5.70E

- 05 1.56E

- 03 5.66E

- 03 2.78E

- 03 2007 3,168 64.9 Twin Creeks Retort 1.20E

- 05 6.00E

- 05 1.20E

- 05 5.07E

- 04 2.54E

- 03 5.07E

- 04 2008 2,778 65.7 104.57 1.85E

- 03 1.93E

- 01 Twin Creeks Retort 1.91E

- 05 7.46E

- 05 1.36E

- 04 7.58E

- 04 2.96E

- 03 5.40E

- 03 2007 2,574 64.9 Twin Creeks Retort 1.90E

- 06 6.20E

- 06 7.80E

- 06 7.54E

- 05 2.46E

- 04 3.09E

- 04 2007 2,574 64.9 Twin Creeks Retort 1.30E

- 05 9.40E

- 05 1.11E

- 04 4.75E

- 04 3.43E

- 03 4.05E

- 03 2008 2,400 65.7 104.57 1.97E

- 03 2.06E

- 01 Twin Creeks Retort 5.00E

- 07 1.27E

- 04 4.76E

- 05 2.17E

- 05 5.49E

- 03 2.06E

- 03 2007 2,814 64.9 Twin Creeks Retort 1.50E

- 05 1.10E

- 05 4.00E

- 06 6.50E

- 04 4.77E

- 04 1.73E

- 04 2007 2,814 64.9 Twin Cre eks Retort 2.60E

- 06 6.10E

- 06 1.10E

- 05 1.17E

- 04 2.75E

- 04 4.95E

- 04 2008 2,958 65.7 104.57 1.09E

- 03 1.13E

- 01 2.20 230 Florida Canyon Carbon Kiln 1.31E

- 03 7.00E

- 04 8.50E

- 04 1.03E+00 5.52E

- 01 6.71E

- 01 2007 8,760 11.1 Florida Canyon Carbon Kiln 2. 38E

- 02 3.71E

- 02 3.64E

- 02 1.30E+01 2.03E+01 2.00E+01 2008 6,195 11.3 Florida Canyon Carbon Kiln 7.06E

- 03 7.74E

- 03 3.24E

- 02 3.87E+00 4.24E+00 1.78E+01 2008 6,195 11.3 Florida Canyon Carbon Kiln 5.83E

- 03 2.72E

- 03 6.90E

- 03 3.23E+00 1.51 E+00 3.83E+00 2009 6,292 11.4 11.35 7.50E+00 8.52E+01 Florida Canyon Melt Furnace 1.22E

- 02 3.20E

- 04 6.60E

- 04 3.17E

- 01 8.30E

- 03 1.71E

- 02 2007 288 11.1 Florida Canyon Melt Furnace 5.20E

- 04 7.20E

- 04 1.83E

- 03 1.45E

- 02 2.01E

- 02 5.11E

- 02 2008 3 16 11.3 Florida Canyon Melt Furnace 2.00E

- 04 2.80E

- 04 3.30E

- 04 5.76E

- 03 8.07E

- 03 9.51E

- 03 2009 327 11.4 11.35 5.02E

- 02 5.70E

- 01

## 21 F acility Unit Run 1 (lb/hr) Run 2 (lb/hr) Run 3 (lb/hr) Run 1 (lb/ton) Run 2 (lb/ton) Run 3 (lb/ton) Year hr/yr Concentr ate (tpy) Max Concentr ate (tpy) Unit average (lb/ton) Per unit (lb/yr) Facility total (lb/ton) Facility total (lb/yr) Florida Canyon Electrowinning 3.40E

- 04 1.80E

- 04 7.60E

- 04 2.68E

- 01 1.42E

- 01 6.00E

- 01 2007 8,760 11.1 Florida Canyon Electrowinning 1.33E

- 03 1.90E

- 04 1.05E

- 03 1.03E+00 1.47E

- 01 8.14E

- 01 2008 8,760 11.3 Florida Canyon Electrowinning 1.79E

- 04 9.00E

- 04 1.41E

- 03 1.38E

- 01 6.95E

- 01 1.09E+00 2009 8,760 11.4 11.35 5.47E

- 01 6.21E+00 Florida Canyo n Electrowinning 1.30E

- 04 1.30E

- 04 9.00E

- 05 1.03E

- 01 1.03E

- 01 7.10E

- 02 2007 8,760 11.1 Florida Canyon Electrowinning 9.80E

- 05 4.40E

- 05 5.90E

- 05 7.60E

- 02 3.41E

- 02 4.57E

- 02 2008 8,760 11.3 Florida Canyon Electrowinning 1.00E

- 04 1.00E

- 04 2.20E

- 05 7.72E

- 02 7.72E

- 02 1.70E

- 02 2009 8,760 11.4 11.35 6.70E

- 02 7.61E

- 01 Florida Canyon Retort 2.99E

- 05 1.42E

- 05 3.30E

- 06 2.63E

- 03 1.25E

- 03 2.90E

- 04 2008 992 11.3 Florida Canyon Retort 3.30E

- 07 2.20E

- 07 2.40E

- 07 2.30E

- 06 1.53E

- 06 1 .67E

- 06 2009 79 11.4 11.35 6.95E

- 04 7.89E

- 03 Florida Canyon Retort 6.70E

- 07 5.20E

- 07 6.00E

- 07 6.89E

- 05 5.35E

- 05 6.17E

- 05 2007 1,141 11.1 Florida Canyon Retort 3.00E

- 06 1.60E

- 06 1.30E

- 06 3.08E

- 05 1.65E

- 05 1.34E

- 05 2008 116 11.3 Florida Canyon Retort 6.20E

- 07 4.50E

- 08 5.90E

- 07 5.07E

- 05 3.68E

- 06 4.82E

- 05 2009 928 11.4 11.35 3.86E

- 05 4.38E

- 04 8.17 93 Lone Tree Electrowinning 1.96E

- 03 1.08E

- 03 1.63E

- 03 1.39E+00 7.68E

- 01 1.16E+00 2007 7,824 11.0 Lone Tree Electrowinning 6.60E

- 04 5.75E

- 03 7.30E

- 04 7.02E

- 01 6.11E+00 7.76E

- 01 2008 2,424 2.28 11.00 1.82E+00 2.00E+01 Lone Tree Elecrowinning 2.70E

- 04 1.01E

- 02 1.10E

- 04 1.92E

- 01 7.15E+00 7.82E

- 02 2007 7,824 11.0 Lone Tree Electrowinning 5.82E

- 03 2.38E

- 04 9.70E

- 05 6.18E+00 2.53E

- 01 1.03E

- 01 2008 2,424 2.28 11.00 2.33E+00 2.56E+01 Lone Tree Electrowinning 2.51E

- 03 1.22E

- 03 4.70E

- 04 2.67E+00 1.30E+00 5.00E

- 01 2008 2,424 2.28 11.00 1.49E+00 1.64E+01 Lone Tree Preg Tank 2.48E

- 03 4.13E

- 03 2.15E

- 02 1.97E+00 3.29E+00 1.72E+01 2007 8,760 11.0 Lone Tree Preg Tank 7.40E

- 03 1.73E

- 02 2.97E

- 02 9.17E+00 2.14E+01 3.68E+01 2008 2,824 2.28 11.00 1.50E+01 1.65E+02 20.60 227 Gold Quarry Carbon Kiln 3.31E

- 02 3.45E

- 02 3.77E

- 02 3.46E+00 3.60E+00 3.93E+00 2007 6 ,471 62.0 Gold Quarry Carbon Kiln 7.83E

- 03 4.07E

- 03 5.86E

- 03 7.47E

- 01 3.88E

- 01 5.59E

- 01 2008 5,920 62.1 Gold Quarry Carbon Kiln 1.01E

- 02 9.48E

- 03 1.11E

- 02 1.29E+00 1.21E+00 1.41E+00 2009 6,523 51.2 62.10 1.84E+00 1.14E+02 Gold Qu arry Electrowinning 3.67E

- 04 3.43E

- 04 3.75E

- 04 4.54E

- 02 4.24E

- 02 4.64E

- 02 2007 7,671 62.0 Gold Quarry Electrowinning 5.81E

- 04 5.32E

- 04 4.71E

- 04 7.32E

- 02 6.70E

- 02 5.94E

- 02 2008 7,826 62.1 Gold Quarry Electrowinning 3.12E

- 03 2.96E

- 03 5. 89E

- 04 4.48E

- 01 4.25E

- 01 8.46E

- 02 2009 7,356 51.2 62.10 1.44E

- 01 8.91E+00 Gold Quarry Preg Tank 1.63E

- 03 1.73E

- 03 2.63E

- 03 2.30E

- 01 2.44E

- 01 3.71E

- 01 2007 8,760 62.0 Gold Quarry Preg Tank 2.38E

- 03 4.31E

- 04 9.11E

- 03 3.36E

- 01 6.10E

- 02 1.29E+0 0 2008 8,784 62.1 Gold Quarry Preg Tank 2.70E

- 05 1.68E

- 03 3.83E

- 03 3.82E

- 03 2.38E

- 01 5.42E

- 01 2008 8,784 62.1

## 22 F acility Unit Run 1 (lb/hr) Run 2 (lb/hr) Run 3 (lb/hr) Run 1 (lb/ton) Run 2 (lb/ton) Run 3 (lb/ton) Year hr/yr Concentr ate (tpy) Max Concentr ate (tpy) Unit average (lb/ton) Per unit (lb/yr) Facility total (lb/ton) Facility total (lb/yr) Gold Quarry Preg Tank 1.89E

- 03 2.29E

- 04 6.04E

- 04 3.06E

- 01 3.71E

- 02 9.78E

- 02 2009 8,290 51.2 62.10 3.13E

- 01 1.94E+01 Gol d Quarry Melt Furnace 2.41E

- 01 5.46E

- 02 1.28E

- 01 2.35E+00 5.33E

- 01 1.25E+00 2007 605 62.0 Gold Quarry Melt Furnace 2.61E

- 03 6.67E

- 04 1.83E

- 02 2.59E

- 02 6.61E

- 03 1.81E

- 01 2008 615 62.1 Gold Quarry Melt Furnace 4.32E

- 02 9.55E

- 02 2.63E

- 01 4.76E

- 01 1.05E+00 2.90E+00 2009 564 51.2 62.10 9.75E

- 01 6.05E+01 Gold Quarry Retort 7.20E

- 04 1.58E

- 03 8.22E

- 04 3.73E

- 02 8.17E

- 02 4.26E

- 02 2007 3,216 62.0 Gold Quarry Retort 2.50E

- 03 1.89E

- 03 1.72E

- 03 1.30E

- 01 9.79E

- 02 8.90E

- 02 2007 3,216 6 2.0 Gold Quarry Retort 1.67E

- 01 1.80E

- 01 1.32E

- 01 2007 3,216 62.0 Gold Quarry Retort 2.94E

- 03 3.06E

- 03 1.69E

- 03 1.66E

- 01 1.72E

- 01 9.52E

- 02 2009 2,880 51.2 62.10 1.52E

- 01 9.43E+00 Gold Quarry Carbon Kiln 8.49E

- 03 5.47E

- 03 4. 54E

- 03 9.23E

- 01 5.95E

- 01 4.94E

- 01 2007 6,746 62.0 Gold Quarry Carbon Kiln 4.59E

- 04 5.16E

- 04 6.55E

- 04 5.56E

- 02 6.25E

- 02 7.94E

- 02 2008 7,527 62.1 Gold Quarry Carbon Kiln 1.17E

- 03 1.17E

- 03 1.42E

- 03 1.42E

- 01 1.41E

- 01 1.72E

- 01 2008 7,527 6 2.1 Gold Quarry Carbon Kiln 1.09E

- 03 2.17E

- 03 2.01E

- 03 1.60E

- 01 3.19E

- 01 2.96E

- 01 2009 7,529 51.2 62.10 2.87E

- 01 1.78E+01 3.71 231 Jerritt Canyon Mine Carbon Kiln & Retort 2.09E

- 02 9.14E

- 03 6.56E

- 03 5.10E+00 2.23E+00 1.60E+00 2007 2,930 12 12 2 .98E+00 3.57E+01 Jerritt Canyon Mine Melt Furnace 5.25E

- 03 2.27E

- 01 2.43E

- 01 3.82E

- 01 1.65E+01 1.76E+01 2007 872 12 12 1.15E+01 1.38E+02 14.49 174 Total 1,155 1,155

## 23 TABLE A - 2. BASELINE MERCURY EMISSIONS FOR CARBON PR OCES SES WITHOUT MERCURY RETORTS

Facility Unit Run 1 (lb/hr) Run 2 (lb/hr) Run 3 (lb/hr) Run 1 (lb/ton) Run 2 (lb/ton) Run 3 (lb/ton) Year hr/yr Concentrate (tpy) Max Concentrate (tpy) Unit average (lb/ton) Per unit (lb/yr) Facility total (lb/ton) Facility t otal (lb/yr) Round Mountain Electrowinning 9.17E

- 05 4.00E

- 04 9.59E

- 05 1.82E

- 02 7.93E

- 02 1.90E

- 02 2008 8760 44.2 44.2 3.88E

- 02 1.72E+00 Round Mountain Melt Furnace 1.07E

- 05 1.29E

- 04 1.27E

- 04 1.49E

- 04 1.80E

- 03 1.77E

- 03 2008 617 44.2 Round Mo untain Melt Furnace 2.62E

- 03 7.21E

- 04 1.39E

- 03 3.49E

- 02 9.59E

- 03 1.85E

- 02 2009 584 43.9 44.2 1.11E

- 02 4.91E

- 01 Round Mountain Carbon Kiln 1.32E

- 05 1.47E

- 05 8.05E

- 06 2.57E

- 03 2.86E

- 03 1.56E

- 03 2008 8,592 44.2 Round Mountain Carbon Kiln 7.73E

- 05 5.18E

- 05 8.05E

- 05 1.52E

- 02 1.02E

- 02 1.59E

- 02 2009 8,652 43.9 44.2 8.05E

- 03 3.56E

- 01 0.058 2.56 Cortez Pipeline Carbon Kiln 1.52E

- 05 8.70E

- 06 3.99E

- 05 1.12E

- 03 6.42E

- 04 2.94E

- 03 2008 1,748 23.7 Cortez Pipeline Carbon Kiln 2.38E

- 05 1.62E

- 05 1 .03E

- 05 2.59E

- 03 1.76E

- 03 1.12E

- 03 2009 2,341 21.50 23.7 1.70E

- 03 4.02E

- 02 Cortez Pipeline Carbon Kiln 1.57E

- 04 1.17E

- 04 4.59E

- 05 1.26E

- 02 9.36E

- 03 3.67E

- 03 2008 1,896 23.7 Cortez Pipeline Carbon Kiln 8.09E

- 05 3.48E

- 05 3.33E

- 05 6.13E

- 04 2.6 4E

- 04 2.52E

- 04 2009 163 21.50 23.7 4.45E

- 03 1.06E

- 01 Cortez Pipeline Electrowinning 6.99E

- 05 5.19E

- 05 8.08E

- 05 2.58E

- 02 1.92E

- 02 2.99E

- 02 2008 8,760 23.7 Cortez Pipeline Electrowinning 4.29E

- 05 1.09E

- 05 2.68E

- 05 1.41E

- 02 3.58E

- 03 8.79E

- 03 2009 7,055 21.50 23.7 1.69E

- 02 4.00E

- 01 Cortez Pipeline Electrowinning 3.79E

- 05 9.60E

- 06 1.71E

- 05 1.40E

- 02 3.55E

- 03 6.32E

- 03 2008 8,760 23.7 Cortez Pipeline Electrowinning 1.49E

- 05 1.58E

- 05 7.00E

- 06 5.30E

- 03 5.62E

- 03 2.49E

- 03 2009 7,641 21. 50 23.7 6.21E

- 03 1.47E

- 01 Cortez Pipeline Preg & Barren Tanks 2.72E

- 04 4.36E

- 04 2.38E

- 04 1.01E

- 01 1.61E

- 01 8.80E

- 02 2008 8,760 23.7 Cortez Pipeline Preg & Barren Tanks 9.56E

- 06 7.17E

- 06 7.36E

- 06 3.25E

- 03 2.44E

- 03 2.50E

- 03 2009 7,317 21.50 2 3.7 5.96E

- 02 1.41E+00 Cortez Pipeline Melt Furnace 2.19E

- 05 1.66E

- 05 2.57E

- 05 2009 385 21.50 Cortez Pipeline Melt Furnace 1.49E

- 04 6.74E

- 05 1.03E

- 04 2.67E

- 03 1.21E

- 03 1.84E

- 03 2009 385 21.50 23.7 1.91E

- 03 4.52E

- 02 Cortez Pipeline Melt Furnace 1.23E

- 04 1.54E

- 04 1.16E

- 04 1.43E

- 04 1.79E

- 04 1.35E

- 04 2009 25 21.50 23.7 1.52E

- 04 3.61E

- 03 Cortez Pipeline Fusion furnace 2.20E

- 05 5.78E

- 05 9.77E

- 06 5.23E

- 03 1.37E

- 02 2.32E

- 03 2009 5,107 21.50 23.7 7.09E

- 03 1.68E

- 01 0.098 2.32 Total 4.89 4.89

## 24 TABLE A - 3. BASELINE MERCURY EMISSIONS FOR ORE PRETREATMENT PROCESSES

Facility Unit Run 1 (lbs/hr) Run 2 (lbs/hr) Run 3 (lbs/hr) Run 1 (lb/ton) Run 2 (lb/ton) Run 3 (lb/ton) Year hr/yr Ore (tpy) Max Ore (tpy) Unit averag e (lb/ton) Per unit (lb/yr) Facility total (lb/ton) Facility total (lb/yr) Gold Quarry North Quench Circuit 5.67E

- 03 4.01E

- 03 5.76E

- 03 1.35E

- 05 9.56E

- 06 1.37E

- 05 2007 7,526 3,154,578 Gold Quarry North Quench Circuit 4.41E

- 03 5.55E

- 03 7.06E

- 03 1.05E

- 05 1.33E

- 05 1.69E

- 05 2008 7,973 3,336,226 Gold Quarry North Quench Circuit 3.57E

- 03 4.44E

- 03 4.09E

- 03 8.45E

- 06 1.05E

- 05 9.66E

- 06 2009 7,611 3,220,396 3,336,226 1.18E

- 05 3.93E+01 Gold Quarry Ore Preheater 5.32E

- 03 2.27E

- 03 1.90E

- 03 1. 27E

- 05 5.41E

- 06 4.53E

- 06 2007 7,526 3,154,578 Gold Quarry Ore Preheater 1.10E

- 02 1.05E

- 02 6.45E

- 02 2.63E

- 05 2.50E

- 05 1.54E

- 04 2008 7,973 3,336,226 Gold Quarry Ore Preheater 3.42E

- 03 1.46E

- 03 1.27E

- 03 8.18E

- 06 3.48E

- 06 3.03E

- 06 2009 7,692 3,220,396 3,336,226 2.70E

- 05 9.00E+01 Gold Quarry Ore Roaster 3.77E

- 04 2.92E

- 04 3.30E

- 04 8.99E

- 07 6.97E

- 07 7.87E

- 07 2007 7,526 3,154,578 Gold Quarry Ore Roaster 5.33E

- 04 6.72E

- 04 2.59E

- 04 1.27E

- 06 1.61E

- 06 6.19E

- 07 2008 7,973 3,336,22 6 Gold Quarry Ore Roaster 2.06E

- 04 1.15E

- 04 1.49E

- 04 4.92E

- 07 2.75E

- 07 3.56E

- 07 2009 7,692 3,220,396 3,336,226 7.78E

- 07 2.60E+00 Gold Quarry ROTP: Ore Dry Grind 7.01E

- 04 8.70E

- 04 6.25E

- 04 1.66E

- 06 2.06E

- 06 1.48E

- 06 2007 7,483 3,154,578 Gold Quarry ROTP: Ore Dry Grind 6.36E

- 04 2.04E

- 03 7.44E

- 04 1.50E

- 06 4.82E

- 06 1.75E

- 06 2008 7,868 3,336,226 3,336,226 2.21E

- 06 7.39E+00 Gold Quarry South Quench Circuit 7.10E

- 03 5.75E

- 03 4.05E

- 03 1.67E

- 05 1.36E

- 05 9.55E

- 06 2007 7,446 3,154,578 Gold Quarry South Quench Circuit 5.40E

- 03 6.20E

- 03 8.96E

- 03 1.27E

- 05 1.46E

- 05 2.11E

- 05 2008 7,862 3,336,226 Gold Quarry South Quench Circuit 4.33E

- 03 5.49E

- 03 5.51E

- 03 1.03E

- 05 1.31E

- 05 1.32E

- 05 2009 7,692 3,220,396 3,336,226 1.39E

- 0 5 4.63E+01 5.56E

- 05 186 Goldstrike Roaster Mill #1 4.30E

- 04 6.70E

- 04 4.80E

- 04 3.23E

- 07 5.03E

- 07 3.60E

- 07 2009 7,754 10,330,763

Goldstrike North Dry grinding process and pre

heater

- Mill 1 1.30E

- 03 9.00E

- 04 7.80E

- 04 8.61E

- 07 5.96E

- 07 5.17E

- 07 2 007 7,940 11,985,898

Goldstrike North Dry grinding process and pre

heater

- Mill 1 2.70E

- 03 2.10E

- 03 4.00E

- 04 1.79E

- 06 1.39E

- 06 2.65E

- 07 2007 7,940 11,985,898

Goldstrike North Dry grinding process and pre

heater

- Mill 1 3.30E

- 03 1.70 E

- 03 4.00E

- 04 2.19E

- 06 1.13E

- 06 2.65E

- 07 2007 7,940 11,985,898 11,985,898 8.48E

- 07 1.02E+01 Goldstrike Roaster Mill #2 1.14E

- 02 6.19E

- 03 2.25E

- 03 8.68E

- 06 4.71E

- 06 1.71E

- 06 2009 7,855 10,330,763

Goldstrike South Dry grinding process and pre

heater

- Mill 2 3.60E

- 02 7.70E

- 03 1.20E

- 03 2.36E

- 05 5.05E

- 06 7.86E

- 07 2007 7,854 11,985,898

Goldstrike South Dry grinding process and pre

heater

- Mill 2 1.30E

- 03 1.30E

- 03 6.00E

- 04 8.52E

- 07 8.52E

- 07 3.93E

- 07 2007 7,854 11,985,898

Gol dstrike South Dry grinding process and pre

heater

- Mill 2 2.50E

- 03 1.30E

- 03 6.00E

- 04 1.64E

- 06 8.52E

- 07 3.93E

- 07 2007 7,854 11,985,898 11,985,898 4.12E

- 06 4.94E+01

## 25 Facility Unit Run 1 (lbs/hr) Run 2 (lbs/hr) Run 3 (lbs/hr) Run 1 (lb/ton) Run 2 (lb/ton) Run 3 (lb/ton) Year hr/yr Ore (tpy) Max Ore (tpy) Unit averag e (lb/ton) Per unit (lb/yr) Facility total (lb/ton) Facility total (lb/yr) Goldstrike Roaster 1 & 2 1.10E

- 01 8.66E

- 02 7.98E

- 02 7.25E

- 05 5.71E

- 05 5.26E

- 05 2007 7,8 99 11,985,898 Goldstrike Roaster 1 & 2 1.90E

- 02 1.90E

- 02 2.60E

- 02 1.25E

- 05 1.25E

- 05 1.71E

- 05 2007 7,899 11,985,898 Goldstrike Roaster 1 & 2 2.56E

- 02 2.28E

- 02 1.73E

- 02 1.95E

- 05 1.73E

- 05 1.31E

- 05 2009 7,864 10,330,763 11,985,898 3.05E

- 0 5 3.65E+02 Goldstrike Roaster #1 Quench Tank 5.72E

- 03 3.89E

- 03 3.78E

- 03 4.35E

- 06 2.96E

- 06 2.87E

- 06 2009 7,851 10,330,763 11,985,898 3.39E

- 06 4.07E+01 Goldstrike Roaster #2 Quench Tank 4.65E

- 03 4.93E

- 03 4.36E

- 03 3.55E

- 06 3.76E

- 06 3.32E

- 06 2009 7,8 76 10,330,763 11,985,898 3.54E

- 06 4.25E+01 Goldstrike Autoclave 1 4.90E

- 04 7.60E

- 04 8.90E

- 04 2.59E

- 07 4.01E

- 07 4.70E

- 07 2009 5,457 10,330,763 11,985,898 3.77E

- 07 4.52E+00 Goldstrike Autoclave 2/3 8.60E

- 04 1.01E

- 03 7.20E

- 04 6.57E

- 07 7.71E

- 07 5.50E

- 07 2009 7,887 10,330,763 11,985,898 6.59E

- 07 7.90E+00 Goldstrike Autoclave 4 2.59E

- 03 3.00E

- 04 3.30E

- 04 1.42E

- 06 1.65E

- 07 1.81E

- 07 2009 5,679 10,330,763 11,985,898 5.90E

- 07 7.07E+00 Goldstrike Autoclave 5/6 1.84E

- 03 1.08E

- 03 6.00E

- 04 1.42E

- 06 8. 32E

- 07 4.62E

- 07 2009 7,954 10,330,763 11,985,898 9.03E

- 07 1.08E+01 4.49E

- 05 538 Jerritt Canyon Ore dryer 2.60E

- 03 5.50E

- 03 3.70E

- 03 1.35E

- 05 2.86E

- 05 1.92E

- 05 2007 5,033 967,727 Jerritt Canyon Ore dryer 5.94E

- 04 5.03E

- 03 1.77E

- 03 3.82E

- 06 3.2 4E

- 05 1.14E

- 05 2010 155.3 tph 1,576,800 1.82E

- 05 2.86E+01 Jerritt Canyon Roaster West 6.12E

- 03 6.20E

- 03 7.12E

- 03 4.42E

- 05 4.47E

- 05 5.14E

- 05 2010 138.6 tph Jerritt Canyon Roaster West 6.20E

- 03 2.86E

- 03 4.13E

- 03 4.48E

- 05 2.07E

- 05 2.99E

- 05 2010 138.3 tph Jerritt Canyon Roaster West 9.56E

- 04 1.08E

- 03 1.14E

- 03 7.01E

- 06 7.92E

- 06 8.36E

- 06 2010 136.3 tph 1,576,800 2.88E

- 05 4.54E+01 Jerritt Canyon Roaster East 7.62E

- 03 6.45E

- 03 3.91E

- 03 5.50E

- 05 4.65E

- 05 2.82E

- 05 2010 1 38.6 tph Jerritt Canyon Roaster East 7.91E

- 04 5.86E

- 04 6.34E

- 04 5.80E

- 06 4.30E

- 06 4.65E

- 06 2010 136.3 tph 1,576,800 2.41E

- 05 3.80E+01 7.10E

- 05 112 Twin Creeks Autoclave 1 2.38E

- 02 6.24E

- 02 4.40E

- 02 5.52E

- 05 1.45E

- 04 1.02E

- 04 2007 7,914 3,41 0,717 Twin Creeks Autoclave 1 3.37E

- 02 1.12E

- 01 1.25E

- 02 7.82E

- 05 2.59E

- 04 2.90E

- 05 2007 7,914 3,410,717 Twin Creeks Autoclave 1 1.02E

- 01 5.04E

- 02 4.67E

- 02 2.36E

- 04 1.17E

- 04 1.08E

- 04 2007 7,914 3,410,717 Twin Creeks Auto clave 1 9.20E

- 02 5.73E

- 02 4.73E

- 02 2.13E

- 04 1.33E

- 04 1.10E

- 04 2007 7,914 3,410,717 Twin Creeks Autoclave 1 4.50E

- 02 8.90E

- 02 1.20E

- 01 9.97E

- 05 1.97E

- 04 2.66E

- 04 2008 8,265 3,728,849 Twin Creeks Autoclave 1 4.58E

- 02 3.00E

- 02 2.68E

- 02 1.06E

- 04 6.95E

- 05 6.21E

- 05 2009 8,282 3,572,940 Twin Creeks Autoclave 1 3.73E

- 03 3.48E

- 03 3.29E

- 03 8.65E

- 06 8.07E

- 06 7.63E

- 06 2010 8,282 3,572,940 3,728,849 1.15E

- 04 4.28E+02 Twin Creeks Autoclave 2 5.09E

- 02 2.44E

- 02 2.38E

- 02 1.14E

- 04 5. 47E

- 05 5.33E

- 05 2007 7,644 3,410,717 Twin Creeks Autoclave 2 3.87E

- 02 2.22E

- 02 1.54E

- 02 8.67E

- 05 4.98E

- 05 3.45E

- 05 2007 7,644 3,410,717 Twin Creeks Autoclave 2 2.20E

- 02 4.10E

- 02 3.60E

- 02 4.87E

- 05 9.07E

- 05 7.96E

- 05 2008 8,250 3,728,8 49 Twin Creeks Autoclave 2 1.68E

- 02 1.19E

- 02 1.01E

- 02 3.53E

- 05 2.50E

- 05 2.12E

- 05 2009 7,502 3,572,940 Twin Creeks Autoclave 2 9.72E

- 03 9.11E

- 03 9.33E

- 03 2.04E

- 05 1.91E

- 05 1.96E

- 05 2010 7,502 3,572,940 3,728,849 5.02E

- 05 1.87E+02 1.6 5E

- 04 615 Total 1,451 1,451

## 26 TABLE A - 4. BASELINE MERCURY EMISSIONS FOR NON - CARBON CONCENTRATE PROCESSES

Facility Unit Run 1 (lbs/hr) Run 2 (lbs/hr) Run 3 (lbs/hr) Run 4 (lbs/hr) Run 5 (lbs/hr) Run 1 (lb/ton) Run 2 (lb/to n) Run 3 (lb/ton) Run 4 (lb/ton) Run 5 (lb/ton) Year hr/yr Conc (tpy) Max Conc (tpy) Unit average (lb/ton) Per unit (lb/yr) Facility total (lb/ton) Facility total (lb/yr) Coeur Rochester Refinery Furnace 2.23E

- 02 4.38E

- 02 8.54E

- 03 5.96E

- 02 1.17E

- 01 2.28E

- 02 2008 300 112 Coeur Rochester Refinery Furnace 1.01E

- 02 4.89E

- 03 1.20E

- 02 2.47E

- 02 1.20E

- 02 2.94E

- 02 2009 280 114 172 4.43E

- 02 7.61E+00 Coeur Rochester Retorts #1 & #2 9.60E

- 04 9.70E

- 04 2.60E

- 05 6.50E

- 04 5.50E

- 04 3.41E

- 03 3.45E

- 03 9.24E

- 05 2.31E

- 03 1.95E

- 03 2007 611 172 Coeur Rochester Retorts #1 & #2 8.65E

- 06 4.52E

- 04 1.24E

- 04 2.93E

- 04 1.53E

- 02 4.20E

- 03 2008 3 , 792 112 Coeur Rochester Retort 1.99E

- 06 8.76E

- 06 2.57E

- 06 4.17E

- 05 1.84E

- 0 4 5.39E

- 05 2009 2,400 114 172 2.84E

- 03 4.89E

- 01 0.047 8.10 Midas Melt Furnace 1 1.28E

- 03 4.15E

- 03 2.13E

- 03 5.58E

- 03 1.81E

- 02 9.29E

- 03 2009 994 228

Midas Refinery Furnace #1 7.50E

- 02 3.30E

- 02 1.50E

- 02 1.23E

- 01 5.41E

- 02 2.46E

- 02 2008 35 6 217 Midas Melt Furnace 2 2.12E

- 03 4.22E

- 03 3.14E

- 03 5.42E

- 03 1.08E

- 02 8.03E

- 03 2009 583 228

Midas Refinery Furnace #2 2.00E

- 02 6.50E

- 02 7.80E

- 03 5.01E

- 02 1.63E

- 01 1.95E

- 02 2008 543 217

Midas Refinery Furnace 1 & 2 2.62E

- 03 4.30E

- 03 7.43E

- 03 1.60E

- 02 2.63E

- 02 4.55E

- 02 2007 832 136

Midas Refinery Furnace 1 & 2 1.73E

- 01 2.17E

- 01 4.41E

- 02 2008

Midas Refinery Furnace 1 & 2 1.10E

- 02 2.89E

- 0 2 1.73E

- 02 2009 228 6.43E

- 02 1.47E+01 Midas Retort A 1.23E

- 04 9.51E

- 05 7.75E

- 05 2.32E

- 03 1.79E

- 03 1.46E

- 03 2007 2,565 136 Midas Retort A 7.70E

- 05 3.70E

- 03 2.10E

- 03 1.25E

- 03 6.01E

- 02 3.41E

- 02 2008 3524 217 Midas Retort A 2.64E

- 06 2.06E

- 06 2.41E

- 06 4.07E

- 05 3.18E

- 05 3.72E

- 05 2009 3,518 228 228 1.12E

- 02 2.56E+00 Midas Retort B 1.93E

- 05 7.46E

- 07 5.11E

- 07 2.78E

- 04 1.07E

- 05 7.36E

- 06 2007 1,959 136 Midas Retort B 3.10E

- 04 3.29E

- 04 4.15E

- 04 4.22E

- 03 4.48E

- 03 5.66E

- 03 2008 2957 217 Midas Retort B 6.96E

- 05 1.06E

- 04 7.49E

- 05 9.51E

- 04 1.45E

- 03 1.02E

- 03 2009 3,115 228 228 2.01E

- 03 4.58E

- 01 0.078 18 Total 25.79 25.79

## ***E.O. 12866 Review

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DEVELOPMENT OF THE MACT FLOORS AND MACT FOR THE FINAL NESHAP FOR GOLD MINE ORE PROCESSING AND PRODUCTION

Metals and Minerals Group Sector Policies and Programs Division Office of Air Quality Planning and Standards U.S. Environmental Protection Agency Research Triangle Park, NC

Draft

- November 10 , 20 10

## 1 Development of the MACT Floors and MACT for the Final NESHAP for Gold Mine Ore Processing and Production 1. Selection of Affected Source The Gold Mine Ore Processing and Productio n source category consists of facilities engaged in processing gold ore to recover gold using roasters, autoclaves, carbon kilns, melt furnaces, mercury retorts, electrowinning, and preg tanks. There were approximately 2 1 gold mine ore processing faciliti es operating these processes in the United States in 2008. Th e final rule appl ies to each new or existing affected source and specifies maximum achievable control technology ( MACT ) standards for mercury emissions for the following four affected sources in the G old M ine O re P rocessing and Production source category : ore pretreatment, carbon processes with mercury retorts, carbon processes without mercury retorts, and non

- carbon concentrate processes. These affected sources reflect the differences in proces s operations, the sources of mercury entering the processes, and the nature of the emissions

.
The ore pretreatment affected source includes roast ing operation s and autoclaves that pretreat refractory ore, which contains organic carbon an d sulfide mineral grains that prevent the initial use of cyanide leaching to effectively extract the gold from the ore. The refractory ore is oxidized in the roaster or autoclave, converting it to an “oxidized” ore, which can then be effectively leached w ith cyanide solution. Mercury enters these processes with the ore. Ore Pretreatment

There are four existing facilities that use ore pretreatment processes, and mercury emissions data are available for al l four of these facil i ties. The potential for mercury emissions f rom this affected source is directly related to the amount of ore processed in the autoclaves and roasters; consequently, the format selected for the standard for this affected source is pounds of mercury emissions (lb) per million ton of ore processed (lb / million ton of ore). In the 2007

- 2009 timeframe , the ore pretreatment sources accounted for approximately 55 percent of the mercury emissions from the source category.

The second affected source is carbon process es with mercury retorts , which includes those gold production operations that use carbon to collect (adsorb) the gold and mercury from solution and the process units that follow (i.e., carbon kilns, pregnant tanks, electrowinning cells, mercury retorts , an d melt furnaces) . Mercury emissions are subsequently generated by these Carbon Processes with Mercury Retorts

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2 process units. The primary intermediate product that is common to all of the facilities with these carbon processes with mercury retorts is the gold

- bearing concentrate, which is th e input to mercury retorts. Further, concentrate is closely related to the final product because it contains about 60 percent gold, and because of its value, it is carefully weighed and records of the quantities are kept. The amount of c oncentrate input to the mercury retort is also required to be reported under the Nevada Division of Environmental Protection ( NDEP ) program, so we had comparable and reliable data from the different gold mine facilities. Consequently, we decided that the most appropriate format of the emission limit for the carbon processes with mercury retorts is lb/ton of concentrate processed

. There are approximately 10 facilities with the carbon processes with mercury retorts , and we have mercury emissions data for 10 of these facili ties. In the 2007

- 2009 timeframe , the carbon process es with mercury retorts sources accounted for approximately 44 percent of the mercury emissions from the source category.

The third affected source is carbon proc esses without mercury retorts , which includes those gold production operations that use carbon to collect the gold and mercury from solution without the use of mercury retorts
. Several facilities have such low concentration s of mercury in their ore that t hey do not require a mercury retort to remove and recover mercury. In addition, the average mercury emissions from these types of facilities that do not have mercury retorts are a factor of 10 less than facilities that do have mercury retorts. For these reasons, the final rule differentiate s between carbon processes with and without mercury retorts
. Carbon Processes without Mercury Retorts

Mercury emissions are subsequently generated by the process units included in this affected source (i.e., carbon kilns, pregnant tanks, electrowinning cells, and melt furnaces)

. Similar to the reasons described previously for carbon processes with mercury retorts , the concentrate is the input to the melt furnace for carbon processes without mercury retorts ; we decided that the most appropriate format of the e mission limit for the carbon processes without mercury retorts is lb/ton of concentrate processed

. There are approximately eight facilities with the carbon processes without mercury retorts , and we have mercury emissions data for two of these facilities. In the 2007

- 2009 timeframe , the carbon process es without mercury retorts sources accounted for approximately 0.19 percent of the mercury emissions from the source category.

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3 Th is a ffected source includes facilities with g old ore processes that do not use carbon or ore pre - treatment. These facilities do not have roasters, autoclaves, or carbon kilns and instead only use mercury retorts and melt furnaces to recover the gold and liberate mercury from the concentrate. The am ount of mercury entering these processes and potential mercury emissions
are directly related to the amount of concentrate processed; consequently, the appropriate format for the final standard for this affected source is lb/ton of concentrate processed. There are about three gold mine ore processing facilities sources with non

- carbon concentrate affected sources, and we have mercury emissions data for two of these facilities. In the 2007

- 2009 timeframe , the
non - carbon concentrate sources accounted for ap proximately 0.98 percent of the mercury emissions from the source category. Non

- Carbon Concentrate Processes

2. Approach for Developing the MACT Floor Pursuant to Section 112(d) of the Clean Air Act, MACT standards for existing affected sources must be at least as stringent as the avera ge emissions limitation achieved by sources in the MACT pool ; that is, the best performing 12 percent of existing affected sources for which the Administrator has data for source categories with 30 or more sources or the best performing 5 sources for sourc e categories with fewer than 30 sources. This level of minimum stringency is called the MACT floor. For new sources, MACT standards must be at least as stringent as the control level achieved in practice by the best controlled similar affected source. The MACT floor limits for each of the four affected sources were calculated based on the performance of the lowest emitting (best performing) sources in each pool of sources with available data . We ranked all of the sources for which we had valid data re presenting current performance based on their emissions and identified the lowest emitting of the existing affected sources, which resulted in 4 facilities with ore pretreat ment processes, 10 facilities for those with carbon processes with mercury retorts , 2 facilities for those with carbon processes without mercury retorts, and 2 facilities with the non

- carbon concentrate processes. For new source s, MACT was based on the best performing source for each of the four aff ected source s . The run

- by

- run data an d the details of the statistical calculations for the MACT floor analyses are provided in Appendices A through E.

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4 2.1 Statistical Approach for Existing Sources To calculate the MACT floor limit for each of the affected sources, we established and ranke d sources’ emissions from lowest to highest. The data on which the limits are based are expressed in terms of pounds of mercury emitted per unit of mass of input, where millions of tons of gold mine ore is the input for the ore pretreatment processes and tons of concentrate is the input for the carbon processes with mercury retorts, carbon processes without mercury retorts, and the non

- carbon concentrate processes. T he emissions data for those best performing affected sources were used to determine the fi nal emission limits, with an accounting for variability. EPA must exercise its judgment, based on an evaluation of the relevant factors and available data, to determine the level of emissions control that has been achieved by the best performing sources u nder variable conditions. The Court has recognized that EPA may consider variability in estimating the degree of emission reduction achieved by best

- performing sources and in setting MACT floors. See Mossville Envt’l Action Now v. EPA, 370 F.3d 1232, 1241

– 42 (D.C. Cir 2004) (holding EPA may consider emission variability in estimating performance achieved by best

- performing sources and may set the floor at a level that a best

- performing source can expect to meet “every day and under all operating conditions” ). To calculate the achieved emission limit, including variability, we used upper prediction limit (UPL) approach, which is defined by the following equation :

T df T 

## v t x UPL **+ =** 
w here: UPL = upper prediction limit,

T 

## x = the avera ge total emission rate over the best performing affected sources , df 

## t 

## = the 99 th 

## percentile of the t distribution , and

T 

## v = the total variance for the top performing affected sources

. The degrees of freedom associa ted with df 

## t 

## is given by: 

# ( **) ∑**  **∑**

**= =**  

## − **=** N i M j ij

i 

## n df 1 1 

## 1

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5 where: N = number of best performing affected sources (2 to 4 for the four affected sources), M i 

## = number of mercury emitting processes at each affected source , and n ij 

## = number of merc ury emission test r u ns for each process unit. The average total emission rate ( T 

## x ) is calculated from : 

# ∑

**=** 

## = N

i Ti T 

## x N x 1 

## 1



## where: N = the number of top N affected sources ( N = 2 to 5),

Ti 

## x = t he total emis sion rate of an entire i th affected source

. To calculate Ti 

## x : 

# ∑

**=** 

## = i M
j ij Ti 

## x x 1 

## where: M i 

## = the number of distinct units within the i th affected source (i.e., we count all the distinct units in a n affected source , so if a p rocess type has two or more units, then each of those units must be counted),

ij 

## x 

## = the unit average for the j th unit within the i th affected source

. To calculate ij 

## x 

## : 

# ∑

**=** 

## = ij n

k ijk ij ij 

## x n x 1 

## 1

where:

n ij 

## = the number of runs within the j th unit of the i th affected source , x ijk 

## = the observation associated with the k th run within the j th unit and i th affected source

. T he total variance ( T 

## v ) consists of the following two variance components:

W B T 

## v v v **+ =** 

## ***E.O. 12866 Review

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6 The first variance component ( B 

## v ) is simply the variance of T 

## x ( the average total emission rate over all affected sources )

. Suppose 2 

## var( ) ij ijk 

## s x **=** is the variance of an individu al run in the j th unit and i th affected source , then th e variance of the unit average , ij 

## x 

## in the j th unit and i th affected source is

ij ij ij 

## n s x 2 

## ) var( **=** . If all units operate independently, then the unit variances, 2 ij 

## s , will be additive. Therefore, based on the assumption of variance additivity, the variance of the total emission rate of the i th affected
source is 

# ∑

**=** 

## = i M
j ij ij Ti 

## n s x 1 2 

## ) var( ,

and the variance of the average total emission rate over all affected s ources is 

# ∑ **∑**

**= =**  

## = **=** N

i M
j ij ij T B i 

## n s N x v 1 1 2
2 

## 1 ) var(

. The second variance component ( W 

## v ) is the variance of new T 

## x
, 

## , the total emission rate from new test runs at a n affected source in the future to determine compliance

. The theoretic al formulation of W 

## v based on thes e future runs is :

, , , 2 1 1 1 

## 1 var( ) var( ) var( ) M M m W T new j new jk new j j k 

## vx x x m **= = =**  

## = = **=** 

# ∑ ∑∑ ,

where

, jk new 

## x 

## refers to the k th run of the j th unit in the new affected source , and M is the number of units in the new affected source

. Also note that t he number of units, M , in the affected source to be tested in the future is unknown and may vary

. However, the theoretical formulation informs us how to derive an operational formula tion of W 

## v based on the data ava ilable from the runs already completed from the top N affected sources :

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7 2 2 1 11 1 1 

## 1 1 1 var( ) i i M M N m N W ijk ij i jk i j 

## v xs N m Nm
**= = = = =**  

##  

**= =**  **   **  

# ∑ ∑∑ ∑∑
Substituting into the equation provided for UPL earlier and rearranging yields:

2 1 1 

## 1 11 i M N T df ij i j ij 

## UPL x t s N Nn m
**= =** 

##  

**= + +**  **   **  

# ∑∑
The first term of the equa tion refers to the average total emission rate of the top N affected
sources . The second term accounts for the expected variability in future measurements due to variations resulting from system operation and measurement activities , and this variability
c onsists of two components

. The first component accounts for the variability of the average total emissions of the existing lowest emitting MACT pool sources , and the second component accounts for the variability of the average of m new test runs based on the observed variance of individual runs within test conditions from the lowest emitting MACT pool sources (the second component typically accounts for the major portion of the overall variability) . The variability factor assumes that variability from the individual best performing source s are independent, and thus are additive. This is a reasonable assumption because each individual best performing source has certain characteristics, such as material inputs, design and operation, etc. , that are unique to that process unit

. 2.2 Statistical Approach for New Sources MACT for new sources is based on the UPL for the best performing source for each of the four types of affected sources and is calculated from:

1 1 T df 

## v t x UPL **+ =**  where:

1 

## x = the average total emission rate of the best performing affected source,
df 

## t 

## = the 99 th 

## percentile of the t distribution with ( n

– 1) degrees of freedom, and

1 T 

## v = the total variance of the best performing source. The total variance of the best performing source is calculated from the formulas given in Section 2.1, except that in this case, N = 1 and the subscript i is replaced by the subscript 1 :

1 2 1 1 1 1 

## 1 1 M T j j j 

## v s n m **=** 

##   **= +  **  ** ** 

# ∑ ,

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8 where 2 1 j 

## s and 1 j 

## n 

## are the variance and number of runs, respectively, from the j th mercury emitting unit of the best performing source , 1 

## M is the number of distinct mercury

- emitting units in this source, and m is the n umber of future runs to determine compliance (typically 3). 3 . MACT Floor for Mercury Most of t he mercury emissions data used in the MACT floor analyses were obtained from annual testing that was required by the Nevada Division of Environmental Protectio n ( NDEP ) for 2007 through 2009

. 1



## The NDEP i nvalidated se veral mercury emission tests conducted in 2007 and 2008 because of failure s to follow the reference test method or the established testing protocol. As a result, none of the test data for Barrick Goldstrike’s roasters and autoclaves for 2008 were used in the analysis. However, 2007 and 2009 data for Goldstrike’s autoclaves and roasters
w ere use d in the analyses. The 2007 and 2008 tests for the mercury retorts at Goldstrike were also invalidated; however, test data for 200 9 w ere available for the mercury retort s and w ere used in the analysis for the carbon processes with mercury retorts . Other tests that were invalidated included the 2007 tests at Coeur Rochester , one of the October 2008 test s at Marigold , two of the August 2007 ore preheater tests at Gol dstrike, and one of the February 2010 roaster tests at Jerritt Canyon

. In addition, we excluded data from the October 2009 emission test on one of the m elt f urnace s for the Cortez Pipeline facility

. The NDEP reported that, for that test, the mercury cont ent of the concentrate was only 8 ppm, whereas the content However, 2010 test data were used for one facility that installed new mercury emission controls on its roasters and resumed operation in late 200 9

. The tests generally consist of three runs per test per process at each af fected source . Most of the measurements were made using EPA Method 29; however, Method 101A and the Ontario Hydro method were used in a few cases. There we re cases where 2007 and/or 2008 results represent emissions before a control device was installed, and 2008 and/or 2009 test results represent emissions after a mercury emission control device had been installed. In those cases, we used only the controlled test results to determine the top performing affected
sources . Emissions in lb/hr were multiplie d by the number of hours the process operated in 2007 , 2008, or 200 9 and then divided by the process input rate for the year (in tons or million tons ) to express mercury emissions in lbs per ton (or million tons) of input material.

1 

### A complete listing of the emission test data is provided in a spreadsheet in docket item “Mercury Emissions Test Data” in the rulemaking docket.

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9 for the December 2009 test was 1,557 ppm, and the content in 2007 and 2008 averaged 4,480 ppm and 4,250 ppm , respectively. Based on that information, we concluded that the mercury content was unus ually low for the October test , and the emissions data would not be representative of typical operations. The following paragraphs discuss the results of the MACT floor analyses for the four affected sources for the Gold Mine Ore Processing and Production source category
. Tables 1 through 4 summarize the results

.

V alid emissions d ata were available for all four o f the facilities with ore pretreatment processes . As shown in Table 1, the average emissions level achieved by these four f acilities is 84 lb Hg/million tons of ore. The MACT floor based on the UPL is 158 lb Hg/million tons of ore. For new sources, MACT corresponds to 84 lb Hg/million tons of ore. We estimate that requiring the MACT floor emission limit for th is affected so urce w ould reduce emissions of mercury by about 431 pounds per year ( lbs /yr) , a reduction of 30 percent from current levels. In addition, e nergy consumption would increase by about 11,400 megawatt

- hours per year (or 11.4 gigawatt

- hours per year ) . Solid w aste generation and disposal (spent carbon loaded with mercury) would increase by about 3 tons per year. Ore Pretreatment

Table 1. MACT Floor Results for Ore Pretreatment Affected Source Average performance (lb Hg /million tons ore) Goldstrike 45 Gold Quarry 56 Jerritt Canyon Mine 71 Twin Creeks Mine 165 Summary of Statistical Analysis Statistic Existing (top 4 ) New Average (lb/MM tons) 84 45 df 131 42 t 2.36 2.42 Vb 52 65 Vw 935 198 Vt 988 263 99% UPL (lb/MM tons) , MACT Floor 158 84

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10 Valid emissions data were available for 10 facilities that operate carbon processes with mercury retort s . Based on the MACT floor analysis, t he average emissions level achieved by the best performing five sources is 1.1 lb Hg/ton of concentrate. After accounting for the variability in emissions, t he MACT floor for this affected source is 2.2 lb Hg/ton of concentrate. For new sources, MACT is 0.8 lb Hg/ton concentrate. We estimate that the MACT floor limit for th is affected source w ould reduce emissions by about 899 lbs /yr , a reduction of 78 percent from current levels. Carbon Processes with Mercury Retorts

Table 2. MACT Floor Results for Carbon Processes with Mercury Retorts Affected Source Average performance (lb Hg /ton concentrate ) Marigold 0.53 Bald Mountain 0.74 Ruby Hill 1.06 Goldstrike 1.47 Denton

- Rawhide 1.67 Twin Creeks 2.20 Gold Quarry 3.71 Florida Canyon 8.17 Jerritt Canyon 14.49 Lone Tree 20.60 Summary of Statistical Analysis Statistic Existing (top 5) New Average (lb/tons) 1.1 0.53 D f 110 17 t 2.36 2.57 Vb 0.015 0.003 2 Vw 0.20 0.0037 Vt 0.2 2 0.0069 99% UPL (lb/ton) , MACT Floor 2.2 0. 8

Valid data were available for two facilities that operate carbon processes without mercury retorts
. As show n in Table 3, the average emissions level achieved by these two facilities is 0.078 lb Hg/ton of concentrate. The existing MACT floor based on the UPL is Carbon Processes without Mercury Retorts

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11 0.17 lb Hg/ton of concentrate. For new sources, MACT corresponds to 0.14 lb Hg/ton of concentrate. Table 3. MACT Floor Results for Carbon Processes without Mercury Retorts Affected Source Average performance (lb Hg /ton concentrate) Round Mountain 0.058 Cortez 0.098 Summary of Statistical Analysis Statistic Existing (top 2) New Average (lb/ton) 0 .078 0.058 df 4 3 12 t 2.42 2.68 Vb 0.00031 0.00045 Vw 0.0010 0.00048 Vt 0.0013 0.00093 99% UPL (lb/ton) , MACT Floor 0.1 7 0.14

For this affected source, valid emissions data were available for two facilities. The results of the analysis are summarized in Table 4. B ased on the MACT floor analysis, the average emissions level achieved by the se two facilities is 0.062 lb Hg/ton of concentrate. The MACT floor for this affected source is 0.2 Hg/ton of concentrate . For new sources, MACT is 0. 1 lb Hg/ton concentrate. We estimate that requiring the MACT floor emissions limit for non

- carbon concentrate processes would reduce emissions by about 14 lbs /yr , a reduction of 54 percent from current levels. Non

- Carbon Concentrate Processes

Table 4 . MACT Floor Results for Non - Carbon Concentrate Processes Affected Source Average performance (lb Hg /ton concentrate) Coeur Rochester Mine 0.047 Midas Operations 0.078 Summary of Statistical Analysis Statistic Existing (top 2) New Average (lb/ton) 0.062 0. 047 df 3 9 1 5 t 2.43 2.6 0 Vb 0.0002 4 0.0002 6 Vw 0.002 6 0.0005 2 Vt 0.0028 0.00077 99% UPL (lb/ton) , MACT Floor 0. 2 0.1

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12 4 . Beyond the Floor 2 

## To evaluate opportunities for emission reductions beyond those that would result from requiring facil ities to meet the MACT floor emissions limits , we typically identify control techniques that have the ability to achieve an emissions limit more stringent than the MACT floor. The following paragraphs summarize the results of th is " beyond

- the

- floor " analy sis for the four affected sources for the G old M ine O re P rocessing and P roduction source category.

Facilities with ore pretreatment processes either have installed, or would be required to install , calomel scrubbers and carbon adsorbers on their roasters and autoclaves, to achieve the MACT floor for ore pretreatment processes. W e identified as a beyond

- the

- floor option the installation of both a refrigeration unit and a carbon adsorber on the remaining facility with autoclaves . This add itional control system would follow the existing venturi scrubbers, and , because autoclave exhaust is saturated with water, a refrigeration unit or condenser would be required to remove moisture that would otherwise adversely affect the adsorptive
ca pacity of the carbon adsorber. We estimate the capital cost for the additional controls on the autoclaves would be $47,000,000 , with a total annualized cost of $8,200,000/yr

. This option would reduce m ercury emissions by 10 lbs /yr , resulting in an estimated co st effectiveness of $782,409/lb. Ore Pretreatment

We also identified as a beyond

- the

- floor option the installation of a carbon adsorber on ore preheater/dryer units. We estimate d the capital cost for the additional controls as $2,962,000 , with a total annualized cost of $1,622,000/yr. Based on an estimated control efficiency of 70 percent, m ercury emissions would be reduced by 118 lbs /yr , resulting in an estimated cost effectiveness of $13,784/lb

. Another assumption used in the beyond

- the

- floor calculations was th at one facility , which h as both roasters and autoclaves , would operat e only their roasters. With these additional control s , the average emissions level achieved by these
sources facilities would be 80 lb/million tons of ore. We estimate that requiring the MACT floor emissions limit and the beyond

- the

- floor options for ore pretreatment processes results in a total emissions reductions of 548 lbs/yr, a reduction of 38 percent from current levels.

2 

### Additional details and documentation for the estimat es of emissions, emission reductions, and costs are provided in the rulemaking docket (EPA

- HQ

- OAR

- 2010

- 0239)

.

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13 Applying the UPL formula to account for variability, the resulting beyond

- the

- floor emissions limit would be 127 lb/million tons of ore . Table 5 summarizes the beyond

- the

- floor analysis for ore pretreatment processes

. This emission limit was incorporated in the final rule. Table 5 . Beyond the Floor Results for Ore Pr etreatment
Affected Source Average performance (lb Hg/million tons ore) Gold Quarry (70% reduction) 37 Twin Creeks (70% reduction) 49 Jerritt Canyon (70% reduction) 58 Goldstrike (70% reduction) 80 Summary of Statistical Analysis Statistic Average achieved by all (lb/MM tons) 80 df 123 t 2.36 Vb 30 Vw 369 Vt 399 Affected Source 99% UPL (lb/MM tons) 127

For two of the other affected sources (carbon processes with mercury retorts and non

carbon concentrate proc esses), existing sources are equipped with efficient mercury emission controls, and it is difficult to identify a technology that might be applied to achieve further reductions in emissions , especially considering the very low mercury concentrations after the MACT floor level of control and the difficulty in obtaining efficient additional percent reductions for low concentration streams. For the beyond

- the

- floor analysis, we assumed that a second carbon adsorption system could be installed in series with t he first or existing adsorber and would get an additional reduction of 90 percent. (We acknowledge that there is significant uncertainty in the additional reduction s the redundant control system might achieve.) For carbon processes with mercury retorts, t he capital cost for the additional control was estimated to be $3 million , with a total annualized cost of $1. 3 million/ yr . The emission s reduction s for this control option would be 9 lbs /yr , resulting in an estimated cost effectiveness of $150,275/ lb

. For non

- carbon concentrate processes, w e estimated the capital cost for the additional adsorber to be $0. 4 million , with a total annualized cost of $ 191,000 /year. The mercury e missions reductions that would be achieved by this option Other Affected Sources

## ***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review***

14 would be 0.13 lb/year , resulting in an estimated cost effectiveness of $1,400,000/ lb

. Because of the uncertainties in the emissions reductions that could be achieved, and the high cost effectiveness values, beyond

- the

- floor limits for these three types of affected sources wer e not adopted in the final rule. For a beyond

- the

- floor analysis for carbon processes without mercury retorts , we estimated the costs and reductions for installing a carbon adsorber to a unit at Round Mountain that is currently uncontrolled. T he capital cost for a carbon adsorber was estimated to be $ 0.2 million with a total annualized cost of $ 72,000 /yr . The mercury emission s reduction associated with this option would be 1.6 lbs /yr, resulting in an estimated cost effectiveness of $44,000/lb

. For the s ame reasons described above for carbon processes with mercury retorts and non

- carbon concentrate processes, it was concluded that this option was not cost effective, and it was not adopted in the final rule. 4. Summary of Final Emission Standards Table 6 summarizes the mercury emission limits included in the final Gold Mine Ore Processing and Production Area Source NESHAP

.
Table 6 . Summary of Final Mercury Emission Limits
Affected Source Hg Emission Limit s Units Existing Source s New Source s Ore pretreatment processes 127 84 lb/million ton s of ore Carbon processes with mercury retorts 2.2 0.8 lb/ton of concentrate Carbon processes without mercury retorts 0.17 0.14 lb/ton of concentrate Non

- carbon concentrate processes 0.2 0.1 lb/ton of conc entrate

## ***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review***

15 Appendix A. Mercury Emissions Data for the Ore Pretreatment Affected Source (lb/ton of ore)

Facility Unit Run 1 (lb/ton) Run 2 (lb/ton) Run 3 (lb/ton) Unit sum (lb/ton) Unit average (lb/ton) Facility total (lb/ton) Unit variance No. of runs p er

unit DF (n - 1) per unit Variance of unit average Facility variance Vw (m = 3 per unit) Facility Vw Gold Quarry Roaster/Calcine quench 1.35E

- 05 9.56E

- 06 1.37E

- 05 Gold Quarry Roaster/Calcine quench 1.05E

- 05 1.33E

- 05 1.69E

- 05 Gold Quarry Roaster/Calcine quench 8.45E

- 06 1.05E

- 05 9.66E

- 06 1.06E

- 04 1.18E

- 05 7.33E

- 12 9 8 8.14E

- 13 2.44E

- 12 Gold Quarry Roaster Ore Preheater 1.27E

- 05 5.41E

- 06 4.53E

- 06 Gold Quarry Roaster Ore Preheater 2.63E

- 05 2 .50E

- 05 1.54E

- 04 Gold Quarry Roaster Ore Preheater 8.18E

- 06 3.48E

- 06 3.03E

- 06 2.43E

- 04 2.70E

- 05 2.35E

- 09 9 8 2.62E

- 10 7.85E

- 10 Gold Quarry Roaster 8.99E

- 07 6.97E

- 07 7.87E

- 07 Gold Quarry Roaster 1.27E

- 06 1.61 E

- 06 6.19E

- 07 Gold Quarry Roaster 4.92E

- 07 2.75E

- 07 3.56E

- 07 7.00E

- 06 7.78E

- 07 1.86E

- 13 9 8 2.07E

- 14 6.21E

- 14 Gold Quarry Roaster Ore Grinder 1.66E

- 06 2.06E

- 06 1.48E

- 06 Gold Quarry Roaster Ore Grinder 1.50E

- 06 4.82E

- 06 1.75E

- 06 1.33E

- 05 2.21E

- 06 1.67E

- 12 6 5 2.79E

- 13 5.58E

- 13 Gold Quarry Roaster/Calcine quench 1.67E

- 05 1.36E

- 05 9.55E

- 06 Gold Quarry Roaster/Calcine quench 1.27E

- 05 1.46E

- 05 2.11E

- 05 Gold Quarry R oaster/Calcine quench 1.03E

- 05 1.31E

- 05 1.32E

- 05 1.25E

- 04 1.39E

- 05 5.56E

- 05 1.19E

- 11 9 8 1.32E

- 12 2.64E

- 10 3.96E

- 12 7.92E

- 10 Goldstrike Roaster Ore Preheater 3.23E

- 07 5.03E

- 07 3.60E

- 07 Goldstrike Roaster Ore Preheater 8.61E

- 07 5.96E

- 0 7 5.17E

- 07 Goldstrike Roaster Ore Preheater 1.79E

- 06 1.39E

- 06 2.65E

- 07 Goldstrike Roaster Ore Preheater 2.19E

- 06 1.13E

- 06 2.65E

- 07 1.02E

- 05 8.48E

- 07 4.12E

- 13 12 11 3.43E

- 14 1.37E

- 13 Goldstrike Roaster Ore Pr eheater 8.68E

- 06 4.71E

- 06 1.71E

- 06 Goldstrike Roaster Ore Preheater 2.36E

- 05 5.05E

- 06 7.86E

- 07 Goldstrike Roaster Ore Preheater 8.52E

- 07 8.52E

- 07 3.93E

- 07 Goldstrike Roaster Ore Preheater 1.64E

- 06 8.52E

- 07 3.93E

- 07 4.95E

- 05 4.12E

- 06 4.40E

- 11 12 11 3.67E

- 12 1.47E

- 11

## ***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review***

16 Facility Unit Run 1 (lb/ton) Run 2 (lb/ton) Run 3 (lb/ton) Unit sum (lb/ton) Unit average (lb/ton) Facility total (lb/ton) Unit variance No. of runs p er

unit DF (n - 1) per unit Variance of unit average Facility variance Vw (m = 3 per unit) Facility Vw Goldstrike Roaster 7.25E

- 05 5.71E

- 05 5.26E

- 05 Goldstrike Roaster 1.25E

- 05 1.25E

- 05 1.71E

- 05 Goldstrike Roaster 1.95E

- 05 1.73E

- 05 1.31E

- 05 2.74E

- 04 3.05E

- 05 5.47E

- 10 9 8 6.08E

- 11 1.82E

- 10 Goldstrike Roaster/Calcine quench 4.35E

- 06 2.96E

- 06 2.87E

- 06 1.02E

- 05 3.39E

- 06 6.86E

- 13 3 2 2.29E

- 13 2.29E

- 13 Goldstrike Roaster/Calcine quench 3.55E

- 06 3.76E

- 06 3.32E

- 06 1.06E

- 05 3.54E

- 06 4.72E

- 14 3 2 1.57E

- 14 1.57E

- 14 Goldstrike Autoclave 2.59E

- 07 4.01E

- 07 4.70E

- 07 1.13E

- 06 3.77E

- 07 1.16E

- 14 3 2 3.87E

- 15 3.87E

- 15 Goldstrike Autoclave 6.57E

- 07 7.71E

- 07 5.50E

- 07 1.98E

- 06 6.59E

- 07 1.23E

- 14 3 2 4.09E

- 15 4.09E

- 15 Goldstrike Autoclave 1.42E

- 06 1.65E

- 07 1.81E

- 07 1.77E

- 06 5.90E

- 07 5.21E

- 13 3 2 1.74E

- 13 1.74E

- 13 Goldstrike Autoclave 1.42E

- 06 8.32E

- 07 4.62E

- 07 2.71E

- 06 9.03E

- 07 4.49E

- 05 2.32E

- 13 3 2 7.72E

- 14 6.50E

- 11 7.72E

- 14 1.98E

- 10 Jerritt Canyon Ore dryer 1.35E

- 05 2 .86E

- 05 1.92E

- 05 Jerritt Canyon Ore dryer 3.82E

- 06 3.24E

- 05 1.14E

- 05 1.09E

- 04 1.82E

- 05 1.17E

- 10 6 5 1.95E

- 11 3.90E

- 11 Jerritt Canyon Roaster 4.42E

- 05 4.47E

- 05 5.14E

- 05 Jerritt Canyon Roaster 4.48E

- 05 2.0 7E

- 05 2.99E

- 05 Jerritt Canyon Roaster 7.01E

- 06 7.92E

- 06 8.36E

- 06 2.59E

- 04 2.88E

- 05 3.31E

- 10 9 8 3.68E

- 11 1.10E

- 10 Jerritt Canyon Roaster 5.50E

- 05 4.65E

- 05 2.82E

- 05 Jerritt Canyon Roaster 5.80E

- 06 4.30E

- 06 4.65E

- 06 1.44E

- 04 2.41E

- 05 7.10E

- 05 5.16E

- 10 6 5 8.60E

- 11 1.42E

- 10 1.72E

- 10 3.21E

- 10 Twin Creeks Autoclave 5.52E

- 05 1.45E

- 04 1.02E

- 04 Twin Creeks Autoclave 7.82E

- 05 2.59E

- 04 2.90E

- 05 Twin Creeks Autoclave 2.36 E

- 04 1.17E

- 04 1.08E

- 04 Twin Creeks Autoclave 2.13E

- 04 1.33E

- 04 1.10E

- 04 Twin Creeks Autoclave 9.97E

- 05 1.97E

- 04 2.66E

- 04 Twin Creeks Autoclave 1.06E

- 04 6.95E

- 05 6.21E

- 05 Twin Creeks Autoclave 8.65E

- 06 8.07E

- 06 7.63E

- 06 2.41E

- 03 1.15E

- 04 6.39E

- 09 21 20 3.04E

- 10 2.13E

- 09 Twin Creeks Autoclave 1.14E

- 04 5.47E

- 05 5.33E

- 05 Twin Creeks Autoclave 8.67E

- 05 4.98E

- 05 3.45E

- 05 Twin Creeks Autoclave 4.87E

- 05 9.07E

- 05 7.96E

- 05 Twin Creeks Autoclave 3.53E

- 05 2.50E

- 05 2.12E

- 05 Twin Creeks Autoclave 2.04E

- 05 1.91E

- 05 1.96E

- 05 7.53E

- 04 5.02E

- 05 1.65E

- 04 9.06E

- 10 15 14 6.04E

- 11 3.65E

- 10 3.02E

- 10 2.43E

- 09
Average of top 4: 8.41E - 05 t DF: 131 Vb: 5.22E - 11 Vw (unpoole d): 9.35E - 10

## ***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review***

17 Facility Unit Run 1 (lb/ton) Run 2 (lb/ton) Run 3 (lb/ton) Unit sum (lb/ton) Unit average (lb/ton) Facility total (lb/ton) Unit variance No. of runs p er

unit DF (n - 1) per unit Variance of unit average Facility variance Vw (m = 3 per unit) Facility Vw t(.99): 2.36

## ***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review***

18 Appendix B . Mercury Emissions Data for the Carbon Processes with Mercury Retorts Aff ected Source (lb/ton concentrate)

Facility Unit Run 1 (lb/ton) Run 2 (lb/ton) Run 3 (lb/ton) Unit sum (lb/ton) Unit average (lb/ton) Facility total (lb/ton) Unit variance No. of runs per unit DF (n - 1) per unit Variance of unit average Facility variance Vw (m = 3 per unit) Facility Vw Marigold EW, P/B 3.68E

- 01 5.43E

- 01 4.32E

- 01 1.34E+00 4.48E

- 01 7.86E

- 03 3 2 2.62E

- 03 2.62E

- 03 Marigold Retort 7.72E

- 02 1.14E

- 01 9.07E

- 02 Marigold Retort 2.48E

- 03 1.14E

- 02 1.37E

- 03 2.97E

- 01 4.95E

- 02 2.52E

- 03 6 5 4.20E

- 04 8.41E

- 04 Marigold Furnace 8.49E

- 02 4.11E

- 02 2.52E

- 02 Marigold Melt Furnace 1.00E

- 02 1.09E

- 02 1.74E

- 02 1.90E

- 01 3.16E

- 02 8.13E

- 04 6 5 1.36E

- 04 2.71E

- 04 Marigold Carbon Kiln 7.52E

- 03 6.29E

- 03 6.99E

- 03 Marigold Carbon Kiln 7.36E

- 04 2.45E

- 04 3.93E

- 04 2.22E

- 02 3.69E

- 03 5.33E

- 01 1.27E

- 05 6 5 2.12E

- 06 3.18E

- 03 4.25E

- 06 3.74E

- 03 Bald Mountain Carbon Kiln 2.37E

- 02 1.61E

- 02 1.82E

- 02 5.80E

- 02 1.93E

- 02 1.55E

- 05 3 2 5.17E

- 06 5.17E

- 06 Bald Mountain EW, Barren Tank 7.41E

- 01 1.76E

- 01 1.08E+00 2.00E+00 6.66E

- 01 2.10E

- 01 3 2 6.99E

- 02 6.99E

- 02 Bald Mountain Melt Furnace 7.09E

- 02 3.63E

- 02 4.76E

- 02 1.55E

- 01 5.16E

- 02 3.11E

- 04 3 2 1.04E

- 04 1.04E

- 04 Bald Mountain Retort 1.11E

- 03 1.0 9E

- 03 4.79E

- 04 2.68E

- 03 8.94E

- 04 7.38E

- 01 1.30E

- 07 3 2 4.32E

- 08 7.00E

- 02 4.32E

- 08 7.00E

- 02 Ruby Hill Carbon Kiln 2.30E

- 01 2.16E

- 01 8.08E

- 02 5.26E

- 01 1.75E

- 01 6.77E

- 03 3 2 2.26E

- 03 2.26E

- 03 Ruby Hill EW, P/B 1.51E+00 5.45E

- 01 4.97E

- 01 2.55E+00 8.49E

- 01 3.24E

- 01 3 2 1.08E

- 01 1.08E

- 01 Ruby Hill Melt Furnace 3.02E

- 02 3.63E

- 02 6.65E

- 02 3.33E

- 02 1.83E

- 05 2 1 9.13E

- 06 6.09E

- 06 Ruby Hill Retort 1.30E

- 04 1.30E

- 04 1.14E

- 04 3.73E

- 04 1.24E

- 04 1.06E+00 8.79E

- 11 3 2 2.93E

- 11 1.10E

- 01 2.93E

- 11 1.10 E

- 01 Goldstrike Carbon Kiln 5.45E+00 9.68E

- 01 5.60E

- 01 Goldstrike Carbon Kiln 4.27E

- 01 6.21E

- 01 4.20E

- 01 Goldstrike Carbon Kiln 1.28E+00 1.31E+00 1.57E+00 Goldstrike Carbon Kiln 1.40E+00 1.46E +00 1.35E+00 Goldstrike Carbon Kiln 6.41E

- 01 9.07E

- 01 4.05E

- 01 Goldstrike Carbon Kiln 2.39E

- 02 3.23E

- 02 3.77E

- 02 1.89E+01 1.05E+00 1.47E+00 18 17 8.18E

- 02 4.91E

- 01 Goldstrike Electrowinning 1.58E

- 01 1.80E

- 01 2.02E

- 01 Goldstrike Electrowinning 2.74E

- 01 3.93E

- 01 2.25E

- 01 Goldstrike Electrowinning 1.06E

- 01 7.07E

- 02 1.63E

- 01 1.77E+00 1.97E

- 01 9.04E

- 03 9 8 1.00E

- 03 3.01E

- 03 Goldstrike Melt Furnace 2.93E

- 02 7.35E

- 02 2.35E

- 02 Goldstrike Melt Furnace Goldstrike Melt Furnace 4.56E

- 02 1.28E

- 01 2.10E

- 01 5.10E

- 01 8.50E

- 02 5.21E

- 03 6 5 8.68E

- 04 1.74E

- 03 Goldstrike Preg Tank 2.07E

- 02 1.43E

- 02 7.33E

- 03 Goldstrike Preg Tank 2.78E

- 03 3.18E

- 03 4.04E

- 03 5.23E

- 02 8.72E

- 03 5.28E

- 05 6 5 8.79E

- 06 1.76E

- 05 Goldstrike Preg Tank 3.97E

- 03 1.33E

- 02 1.19E

- 02 Goldstrike Preg Tank 3.18E

- 03 1.99E

- 03 2.19E

- 03 3.66E

- 02 6.10E

- 03 2.63E

- 05 6 5 4 .39E

- 06 8.77E

- 06 Goldstrike Retort Goldstrike Retort

## ***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review***

19 Facility Unit Run 1 (lb/ton) Run 2 (lb/ton) Run 3 (lb/ton) Unit sum (lb/ton) Unit average (lb/ton) Facility total (lb/ton) Unit variance No. of runs per unit DF (n - 1) per unit Variance of unit average Facility variance Vw (m = 3 per unit) Facility Vw Goldstrike Retort Goldstrike Retort Goldstrike Retort 5.91E

- 02 4.77E

- 02 3.29E

- 02 1.40E

- 01 4.65E

- 02 1.73E

- 04 3 2 5.76E

- 05 5.76E

- 05 Goldstrike Retort Goldstrike Retort Goldstrike Retort Goldstrike Retort 3.00E

- 02 1.52E

- 02 1.23E

- 02 5.75E

- 02 1.92E

- 02 8.94E

- 05 3 2 2.98E

- 05 2.98E

- 05 Goldstrike Retort Goldstrike Retort Goldstrike Retort Goldstrike Retort Goldstrike Retort 5.85E

- 02 6.70E

- 02 6.34E

- 02 1.89 E

- 01 6.29E

- 02 1.47E+00 1.84E

- 05 3 2 6.13E

- 06 8.38E

- 02 6.13E

- 06 4.95E

- 01 Denton

Rawhide Carbon Kiln 3.16E

- 03 3.47E

- 03 1.66E

- 02 Denton

Rawhide Carbon Kiln 1.15E

- 02 6.48E

- 03 2.07E

- 03 Denton

Rawhide Carbon Kiln 2.50E

- 01 1.45E

- 01 1.28E

- 01 5.67E

- 01 6.30E

- 02 8.10E

- 03 9 8 9.00E

- 04 2.70E

- 03 Denton

Rawhide Electrowinning 6.46E

- 04 2.43E

- 04 6.39E

- 03 Denton

Rawhide Electrowinning 1.40E

- 02 2.62E

- 03 3.25E

- 03 Denton

Rawhide Electrow inning 9.14E

- 03 6.49E

- 02 1.27E

- 01 2.29E

- 01 2.54E

- 02 1.87E

- 03 9 8 2.08E

- 04 6.24E

- 04 Denton

Rawhide Melt Furnace 3.64E+00 1.56E+00 1.19E+00 Denton

Rawhide Melt Furnace 8.90E

- 01 1.85E+00 1.48E+00 Denton

Rawhide Melt Furnace 7.84E

- 01 2.34E+00 3.23E

- 01 1.41E+01 1.56E+00 9.69E

- 01 9 8 1.08E

- 01 3.23E

- 01 Denton

Rawhide Retort 5.84E

- 05 6.33E

- 05 7.17E

- 05 Denton

Rawhide Retort 4.59E

- 05 1.50E

- 05 1.40E

- 05 Denton

Rawhide Reto rt 6.24E

- 02 4.38E

- 02 7.62E

- 02 1.83E

- 01 2.03E

- 02 1.67E+00 9.89E

- 04 9 8 1.10E

- 04 1.09E

- 01 3.30E

- 04 3.27E

- 01 Average of top 5: 1.09E+00 tDF: 110 Vb: 1.50E - 02 Vw (unpooled): 2.01E - 01 t(.99): 2.36 Twin Creeks Electrowinning 2.29E

- 02 1.21E

- 01 4.91E

- 01 Twin Creeks Electrowinning 1.74E+00 1.06E+00 1.18E+00

## ***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review***

20 Facility Unit Run 1 (lb/ton) Run 2 (lb/ton) Run 3 (lb/ton) Unit sum (lb/ton) Unit average (lb/ton) Facility total (lb/ton) Unit variance No. of runs per unit DF (n - 1) per unit Variance of unit average Facility variance Vw (m = 3 per unit) Facility Vw Twin Creeks Electrowinning 6.73E

- 02 4.31E

- 02 3.46E

- 02 4.75E+00 5.28E

- 01 4.10E

- 01 9 8 4.55E

- 02 1.37E

- 01 Twin Creeks Melt Furnace 2 (new) 4.20E

- 01 1.20E

- 01 2.89E

- 01 Twin Creeks Melt Furnace 2 (new) 4.85E

- 01 1.38E

- 01 3.90E

- 01 Twin Creeks Melt Furnace 2 (new) 6.60E

- 02 1.86E

- 02 4.80E

- 02 Twin Creeks Melt Furnace 2 (new) 1.77E

- 04 2.48E

- 04 6.84E

- 04 1.98E+00 1.65E

- 01 3.29E

- 02 12 11 2.74E

- 03 1.10E

- 02 Twin Creeks Melt Furnace 1 (old) 1.04E+00 4.20E

- 01 6.54E

- 01 Twin Creeks Melt Furnace 1 (old) 2.19E+00 8.51E

- 01 9.32E

- 01 Twin Creeks Melt Furnace 1 (old) 2.15E

- 02 6.39E

- 02 9.35E

- 02 Twin Creeks Melt Furnace 1 (old) 7.79E

- 02 4.07E

- 02 2.67E

- 02 Twin Creeks Melt Furnace 1 (old) 5.36E

- 04 4.56E

- 04 4.88E

- 04 6.42E+00 4.28E

- 01 3.84E

- 01 15 14 2.56E

- 02 1.28E

- 01 Twin Creeks Carbon Kiln 2.19E

- 01 2.30E

- 02 9.55E

- 02 Twin Creeks Carbon Kiln 2.80E

- 01 1.07E

- 01 9.08E

- 02 Twin Creeks Carbon Kiln 4.76E

- 02 8.89E

- 02 8.76E

- 02 1.04E+00 1.1 6E

- 01 6.70E

- 03 9 8 7.44E

- 04 2.23E

- 03 Twin Creeks Preg Tank 2.12E+00 1.91E+00 3.64E

- 01 Twin Creeks Preg Tank 8.16E

- 01 1.74E+00 7.75E

- 01 Twin Creeks Preg Tank 2.57E

- 01 2.58E

- 01 3.22E

- 01 8.56E+00 9.52E

- 01 5.8 3E

- 01 9 8 6.48E

- 02 1.94E

- 01 Twin Creeks Retort 8.80E

- 06 7.63E

- 06 6.72E

- 06 2.32E

- 05 7.72E

- 06 1.09E

- 12 3 2 3.63E

- 13 3.63E

- 13 Twin Creeks Retort 8.13E

- 04 1.19E

- 03 2.39E

- 03 Twin Creeks Retort 4.18E

- 03 4.99E

- 03 1.04E

- 02 Twin Creeks Retort 2.57E

- 03 6.68E

- 04 1.08E

- 03 2.82E

- 02 3.14E

- 03 9.63E

- 06 9 8 1.07E

- 06 3.21E

- 06 Twin Creeks Retort 3.51E

- 04 1.34E

- 03 1.38E

- 03 Twin Creeks Retort 1.56E

- 03 5.66E

- 03 2.78E

- 03 Twin C reeks Retort 5.07E

- 04 2.54E

- 03 5.07E

- 04 1.66E

- 02 1.85E

- 03 2.79E

- 06 9 8 3.10E

- 07 9.29E

- 07 Twin Creeks Retort 7.58E

- 04 2.96E

- 03 5.40E

- 03 Twin Creeks Retort 7.54E

- 05 2.46E

- 04 3.09E

- 04 Twin Creeks Retort 4.75E

- 0 4 3.43E

- 03 4.05E

- 03 1.77E

- 02 1.97E

- 03 4.03E

- 06 9 8 4.48E

- 07 1.34E

- 06 Twin Creeks Retort 2.17E

- 05 5.49E

- 03 2.06E

- 03 Twin Creeks Retort 6.50E

- 04 4.77E

- 04 1.73E

- 04 Twin Creeks Retort 1.17E

- 04 2.75E

- 04 4.95E

- 04 9.77E

- 03 1.09E

- 03 2.20E+00 3.11E

- 06 9 8 3.45E

- 07 1.39E

- 01 1.04E

- 06 4.72E

- 01 Gold Quarry Carbon Kiln 3.46E+00 3.60E+00 3.93E+00 Gold Quarry Carbon Kiln 7.47E

- 01 3.88E

- 01 5.59E

- 01

## ***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review***

21 Facility Unit Run 1 (lb/ton) Run 2 (lb/ton) Run 3 (lb/ton) Unit sum (lb/ton) Unit average (lb/ton) Facility total (lb/ton) Unit variance No. of runs per unit DF (n - 1) per unit Variance of unit average Facility variance Vw (m = 3 per unit) Facility Vw Gold Quarry Carbon Kiln 1.29E+00 1. 21E+00 1.41E+00 1.66E+01 1.84E+00 1.99E+00 9 8 2.21E

- 01 6.63E

- 01 Gold Quarry Electrowinning 4.54E

- 02 4.24E

- 02 4.64E

- 02 Gold Quarry Electrowinning 7.32E

- 02 6.70E

- 02 5.94E

- 02 Gold Quarry Electrowinning 4.48E

- 0 1 4.25E

- 01 8.46E

- 02 1.29E+00 1.44E

- 01 2.78E

- 02 9 8 3.09E

- 03 9.28E

- 03 Gold Quarry Preg Tank 2.30E

- 01 2.44E

- 01 3.71E

- 01 Gold Quarry Preg Tank 3.36E

- 01 6.10E

- 02 1.29E+00 Gold Quarry Preg Tank 3.82E

- 03 2.38E

- 01 5.42E

- 01 Gold Quarry Preg Tank 3.06E

- 01 3.71E

- 02 9.78E

- 02 3.76E+00 3.13E

- 01 1.19E

- 01 12 11 9.91E

- 03 3.96E

- 02 Gold Quarry Melt Furnace 2.35E+00 5.33E

- 01 1.25E+00 Gold Quarry Melt Furnace 2.59E

- 02 6.61E

- 03 1.8 1E

- 01 Gold Quarry Melt Furnace 4.76E

- 01 1.05E+00 2.90E+00 8.77E+00 9.75E

- 01 1.07E+00 9 8 1.19E

- 01 3.58E

- 01 Gold Quarry Retort Gold Quarry Retort 3.73E

- 02 8.17E

- 02 4.26E

- 02 Gold Qua rry Retort 1.30E

- 01 9.79E

- 02 8.90E

- 02 Gold Quarry Retort 1.67E

- 01 1.80E

- 01 1.32E

- 01 Gold Quarry Retort 1.66E

- 01 1.72E

- 01 9.52E

- 02 9.11E

- 01 1.52E

- 01 1.04E

- 03 6 5 1.74E

- 04 3.48E

- 04 Gold Quarry Carbon Kiln 9.23 E

- 01 5.95E

- 01 4.94E

- 01 Gold Quarry Carbon Kiln 5.56E

- 02 6.25E

- 02 7.94E

- 02 Gold Quarry Carbon Kiln 1.42E

- 01 1.41E

- 01 1.72E

- 01 Gold Quarry Carbon Kiln 1.60E

- 01 3.19E

- 01 2.96E

- 01 3.44E+00 2.87E

- 01 3.71E+00 6.93E

- 02 12 11 5.77E

- 03 3.59E

- 01 2.31E

- 02 1.09E+00 Florida Canyon Carbon Kiln 1.03E+00 5.52E

- 01 6.71E

- 01 Florida Canyon Carbon Kiln 1.30E+01 2.03E+01 2.00E+01 Florida Canyon Carbon Kiln 3.87E+00 4.24E +00 1.78E+01 Florida Canyon Carbon Kiln 3.23E+00 1.51E+00 3.83E+00 9.00E+01 7.50E+00 6.22E+01 12 11 5.18E+00 2.07E+01 Florida Canyon Melt Furnace 3.17E

- 01 8.30E

- 03 1.71E

- 02 Florida Canyon Melt Furnace 1.4 5E

- 02 2.01E

- 02 5.11E

- 02 Florida Canyon Melt Furnace 5.76E

- 03 8.07E

- 03 9.51E

- 03 4.52E

- 01 5.02E

- 02 1.02E

- 02 9 8 1.13E

- 03 3.40E

- 03 Florida Canyon Electrowinning 2.68E

- 01 1.42E

- 01 6.00E

- 01 Florida Canyon Elec trowinning 1.03E+00 1.47E

- 01 8.14E

- 01 Florida Canyon Electrowinning 1.38E

- 01 6.95E

- 01 1.09E+00 4.92E+00 5.47E

- 01 1.49E

- 01 9 8 1.66E

- 02 4.97E

- 02 Florida Canyon Electrowinning 1.03E

- 01 1.03E

- 01 7.10E

- 02

## ***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review***

22 Facility Unit Run 1 (lb/ton) Run 2 (lb/ton) Run 3 (lb/ton) Unit sum (lb/ton) Unit average (lb/ton) Facility total (lb/ton) Unit variance No. of runs per unit DF (n - 1) per unit Variance of unit average Facility variance Vw (m = 3 per unit) Facility Vw Flor ida Canyon Electrowinning 7.60E

- 02 3.41E

- 02 4.57E

- 02 Florida Canyon Electrowinning 7.72E

- 02 7.72E

- 02 1.70E

- 02 6.03E

- 01 6.70E

- 02 8.59E

- 04 9 8 9.55E

- 05 2.86E

- 04 Florida Canyon Retort 2.63E

- 03 1.25E

- 03 2.90E

- 04 Florida Canyon Retort 2.30E

- 06 1.53E

- 06 1.67E

- 06 4.17E

- 03 6.95E

- 04 1.13E

- 06 6 5 1.88E

- 07 3.76E

- 07 Florida Canyon Retort 6.89E

- 05 5.35E

- 05 6.17E

- 05 Florida Canyon Retort 3.08E

- 05 1.65E

- 05 1.34E

- 05 Flor ida Canyon Retort 5.07E

- 05 3.68E

- 06 4.82E

- 05 3.47E

- 04 3.86E

- 05 8.17E+00 5.39E

- 10 9 8 5.99E

- 11 5.20E+00 1.80E

- 10 2.08E+01 Jerritt Canyon Carbon Kiln 5.10E+00 2.23E+00 1.60E+00 8.93E+00 2.98E+00 3.48E+00 3 2 1.16E+00 1.16E+00 Jerritt Canyon Melt Furnace 3.82E

- 01 1.65E+01 1.76E+01 3.45E+01 1.15E+01 1.45E+01 9.32E+01 3 2 3.11E+01 3.22E+01 3.11E+01 3.22E+01 Lone Tree Electrowinning 1.39E+00 7.68E

- 01 1.16E+00 Lone Tree Electrowinning 7.02E

- 01 6.11E+00 7.76E

- 01 1.09E+01 1.82E+00 4.50E+00 6 5 7.50E

- 01 1.50E+00 Lone Tree Elecrowinning 1.92E

- 01 7.15E+00 7.82E

- 02 Lone Tree Electrowinning 6.18E+00 2.53E

- 01 1.03E

- 01 1.40E+01 2.33E+00 1.14E+01 6 5 1.90E+00 3.80E+00 Lone Tree Electrowinning 2.67E+00 1 .30E+00 5.00E

- 01 4.47E+00 1.49E+00 1.20E+00 3 2 4.01E

- 01 4.01E

- 01 Lone Tree Preg Tank 1.97E+00 3.29E+00 1.72E+01 Lone Tree Preg Tank 9.17E+00 2.14E+01 3.68E+01 8.98E+01 1.50E+01 2.06E+01 1.72E+02 6 5 2.87E+01 3.18E+01 5.74E+01 6.31E+01

## ***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review***

23 Appendix C . Mercury Emissions Data for the Carbon Processes without Mercury Retorts Affected Source (lb/ton concentrate)

Facility Process type Run 1 (lb/ton) Run 2 (lb/ton) Run 3 (lb/ton) Unit sum (lb/ton) Unit average (lb/ton) Facility total (lb/ton) Unit var No. of runs per unit DF (n - 1) per unit Var of unit average Facility var Vw (m = 3 per unit) Facility Vw Round Mountain Electrowinning 1.82E

- 02 7.93E

- 02 1.90E

- 02 1.16E

- 01 3.88E

- 02 1.23E

- 03 3 2 4.09E

- 04 4.09E

- 04 Round Mountain Melt Furnace 1.49E

- 04 1.80E

- 03 1.77E

- 03 Round Mountain Melt Furnace 3.49E

- 02 9.59E

- 03 1.85E

- 02 6.67E

- 02 1.11E

- 02 1.83E

- 04 6 5 3.05E

- 05 6.10E

- 05 Round Mountain Carbon Kiln 2.57E

- 03 2.86E

- 03 1.56E

- 03 Round Mountai n Carbon Kiln 1.52E

- 02 1.02E

- 02 1.59E

- 02 4.83E

- 02 8.05E

- 03 0.058 4.33E

- 05 6 5 7.22E

- 06 4.47E

- 04 1.44E

- 05 4.85E

- 04 Cortez Pipeline Carbon Kiln 1.12E

- 03 6.42E

- 04 2.94E

- 03 Cortez Pipeline Carbon Kiln 2.59E

- 03 1.76E

- 03 1.12E

- 03 1.02E

- 02 1 .70E

- 03 8.27E

- 07 6 5 1.38E

- 07 2.76E

- 07 Cortez Pipeline Carbon Kiln 1.26E

- 02 9.36E

- 03 3.67E

- 03 Cortez Pipeline Carbon Kiln 6.13E

- 04 2.64E

- 04 2.52E

- 04 2.67E

- 02 4.45E

- 03 2.81E

- 05 6 5 4.68E

- 06 9.36E

- 06 Cortez Pipeline Electro winning 2.58E

- 02 1.92E

- 02 2.99E

- 02 Cortez Pipeline Electro Winning System 1.41E

- 02 3.58E

- 03 8.79E

- 03 1.01E

- 01 1.69E

- 02 1.01E

- 04 6 5 1.68E

- 05 3.36E

- 05 Cortez Pipeline Electrowinning 1.40E

- 02 3.55E

- 03 6.32E

- 03 Cortez Pipeline Electro Winning System 5.30E

- 03 5.62E

- 03 2.49E

- 03 3.73E

- 02 6.21E

- 03 1.66E

- 05 6 5 2.77E

- 06 5.53E

- 06 Cortez Pipeline Preg Tank 1.01E

- 01 1.61E

- 01 8.80E

- 02 Cortez Pipeline Pregnant and Barren Tanks 3.25E

- 03 2.44E

- 03 2.50E

- 03 3.58E

- 01 5.96E

- 02 4.50E

- 03 6 5 7.50E

- 04 1.50E

- 03 Cortez Pipeline Melt Furnace 2.67E

- 03 1.21E

- 03 1.84E

- 03 5.72E

- 03 1.91E

- 03 5.37E

- 07 3 2 1.79E

- 07 1.79E

- 07 Cortez Pipeline Melt Furnace 1.43E

- 04 1.79E

- 04 1.35E

- 04 4.57E

- 04 1.52E

- 04 5. 53E

- 10 3 2 1.84E

- 10 1.84E

- 10 Cortez Pipeline Fusion furnace 5.23E

- 03 1.37E

- 02 2.32E

- 03 2.13E

- 02 7.09E

- 03 0.098 3.52E

- 05 3 2 1.17E

- 05 7.86E

- 04 1.17E

- 05 1.56E

- 03 Average of top 2: 0.078 tDF: 43 Vb: 3.08E - 04 Vw (unpooled): 1.02E - 03 t(.99): 2.42

## ***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review***

24 Appendix D . Mercury Emissions Data for the Non - Carbon Concentrate Affected Source (lb/ton concentrate)

Facility Unit Run 1 (lb/ton) Run 2 (lb/ton) Run 3 (lb/ton) Run 4 (lb/ton) Run 5 (lb/ ton) Unit sum (lb/ton) Unit average (lb/ton) Facility total (lb/ton) Unit variance No. of runs per

unit DF (n - 1) per unit Varianc e of unit average Facility variance Vw (m = 3 per unit) Facility Vw Coeur Rochester Refinery Furnace 5.96E

- 02 1.17E

- 01 2.28E

- 02 Coeur Rochester Refinery Furnace 2.47E

- 02 1.20E

- 02 2.94E

- 02 2.66E

- 01 4.43E

- 02 1.53E

- 03 6 5 2.55E

- 04 5.10E

- 04 Coeur Rochester Retorts #1 & #2 3.41E

- 03 3.45E

- 03 9.24E

- 05 2.31E

- 03 1.95E

- 03 Coeur R ochester Retorts #1 & #2 2.93E

- 04 1.53E

- 02 4.20E

- 03 Coeur Rochester Retorts #1 & #2 4.17E

- 05 1.84E

- 04 5.39E

- 05 3.13E

- 02 2.84E

- 03 0.047 1.96E

- 05 11 10 1.78E

- 06 2.57E

- 04 6.52E

- 06 5.17E

- 04 Midas Operations Refinery Furnace 1 & 2 1.60E

- 02 2.63E

- 02 4.55E

- 02 Midas Operations Refinery Furnace 1 & 2 1.73E

- 01 2.17E

- 01 4.41E

- 02 Midas Operations Refinery Furnace 1 & 2 1.10E

- 02 2.89E

- 02 1.73E

- 02 5.79E

- 01 6.43E

- 02 5.74E

- 03 9 8 6.38E

- 04 1.91E

- 03 Midas Operations Retort A 2.32E

- 03 1.79E

- 03 1.46E

- 03 Midas Operations Retort A 1.25E

- 03 6.01E

- 02 3.41E

- 02 Midas Operations Retort A 4.07E

- 05 3.18E

- 05 3.72E

- 05 1.01E

- 01 1.12E

- 02 4.56E

- 04 9 8 5.07E

- 05 1.52E

- 04 Midas Operations Retort B 2.78E

- 04 1.07E

- 05 7.36E

- 06 Midas Operations Retort B 4.22E

- 03 4.48E

- 03 5.66E

- 03 Midas Operations Retort B 9.51E

- 04 1.45E

- 03 1.02E

- 03 1.81E

- 02 2.01 E

- 03 0.078 4.72E

- 06 9 8 5.24E

- 07 6.89E

- 04 1.57E

- 06 2.07E

- 03
Average of top 2: 6.23E - 02 1.55E - 03 t DF: 39 Vb: 2.37E - 04 Vw (unpoole d): 2.58E - 03 t(.99): 2.43

## ***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review***

25 Appendix E . Ne w Source MACT Floors
Ore Pretreatment Processes

Facility Unit Run 1 (lb/ton) Run 2 (lb/ton) Run 3 (lb/ton) Unit sum (lb/ton) Unit average (lb/ton) Facility total (lb/ton) Unit variance No. of runs per

unit DF (n - 1) per unit Variance of unit average Fac ility variance Vw (m = 3 per unit) Facility Vw Goldstrike Roaster Ore Preheater 3.23E

- 07 5.03E

- 07 3.60E

- 07 Goldstrike Roaster Ore Preheater 8.61E

- 07 5.96E

- 07 5.17E

- 07 Goldstrike Roaster Ore Preheater 1.79E

- 06 1.39 E

- 06 2.65E

- 07 Goldstrike Roaster Ore Preheater 2.19E

- 06 1.13E

- 06 2.65E

- 07 1.02E

- 05 8.48E

- 07 4.12E

- 13 12 11 3.43E

- 14 1.37E

- 13 Goldstrike Roaster Ore Preheater 8.68E

- 06 4.71E

- 06 1.71E

- 06 Goldstrike Roaster Ore Preheater 2.36E

- 05 5.05E

- 06 7.86E

- 07 Goldstrike Roaster Ore Preheater 8.52E

- 07 8.52E

- 07 3.93E

- 07 Goldstrike Roaster Ore Preheater 1.64E

- 06 8.52E

- 07 3.93E

- 07 4.95E

- 05 4.12E

- 06 4.40E

- 11 12 11 3.67E

- 12 1.47E

- 11 Goldstrike Roaster 7.25E

- 05 5.71E

- 05 5.26E

- 05 Goldstrike Roaster 1.25E

- 05 1.25E

- 05 1.71E

- 05 Goldstrike Roaster 1.95E

- 05 1.73E

- 05 1.31E

- 05 2.74E

- 04 3.05E

- 05 5.47E

- 10 9 8 6.08E

- 11 1.82E

- 10 Goldstrike Roaster /Calcine quench 4.35E

- 06 2.96E

- 06 2.87E

- 06 1.02E

- 05 3.39E

- 06 6.86E

- 13 3 2 2.29E

- 13 2.29E

- 13 Goldstrike Roaster/Calcine quench 3.55E

- 06 3.76E

- 06 3.32E

- 06 1.06E

- 05 3.54E

- 06 4.72E

- 14 3 2 1.57E

- 14 1.57E

- 14 Goldstrike Autoclave 2.59E

- 07 4.01E

- 07 4 .70E

- 07 1.13E

- 06 3.77E

- 07 1.16E

- 14 3 2 3.87E

- 15 3.87E

- 15 Goldstrike Autoclave 6.57E

- 07 7.71E

- 07 5.50E

- 07 1.98E

- 06 6.59E

- 07 1.23E

- 14 3 2 4.09E

- 15 4.09E

- 15 Goldstrike Autoclave 1.42E

- 06 1.65E

- 07 1.81E

- 07 1.77E

- 06 5.90E

- 07 5.21E

- 13 3 2 1.74E

- 1 3 1.74E

- 13 Goldstrike Autoclave 1.42E

- 06 8.32E

- 07 4.62E

- 07 2.71E

- 06 9.03E

- 07 4.49E

- 05 2.32E

- 13 3 2 7.72E

- 14 6.50E

- 11 7.72E

- 14 1.98E

- 10 Average = 4.49E

- 05 DF = 42 t = 2.4 2 Vb = 6.50E

- 11 Vw = 1.98E

- 10 Vt = 2.63E

- 10 Facility 99% UPL = 8.41E

- 05

## ***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review***

26 Carbon Processes with Mercury Retorts

Facility Unit Run 1 (lb/ton) Ru n 2 (lb/ton) Run 3 (lb/ton) Unit sum (lb/ton) Unit average (lb/ton) Facility total (lb/ton) Unit variance No. of runs per

unit DF (n - 1) per unit Variance of unit average Facility variance Vw (m = 3 per unit) Facility Vw Marigold EW, P/B 3.68E

- 01 5.43E

- 0 1 4.32E

- 01 1.34E+00 4.48E

- 01 7.86E

- 03 3 2 2.62E

- 03 2.62E

- 03 Marigold Retort 7.72E

- 02 1.14E

- 01 9.07E

- 02 Marigold Retort 2.48E

- 03 1.14E

- 02 1.37E

- 03 2.97E

- 01 4.95E

- 02 2.52E

- 03 6 5 4.20E

- 04 8.41E

- 04 Marigold Furnace 8.49E

- 02 4.11E

- 02 2.52E

- 02 Marigold Melt Furnace 1.00E

- 02 1.09E

- 02 1.74E

- 02 1.90E

- 01 3.16E

- 02 8.13E

- 04 6 5 1.36E

- 04 2.71E

- 04 Marigold Carbon Kiln 7.52E

- 03 6.29E

- 03 6.99E

- 03 Marigold Carbon Kiln 7.36E

- 04 2.45E

- 04 3.9 3E

- 04 2.22E

- 02 3.69E

- 03 5.33E

- 01 1.27E

- 05 6 5 2.12E

- 06 3.18E

- 03 4.25E

- 06 3.74E

- 03 Average = 5.33E

- 01 DF = 17 t = 2.57 Vb = 3.18E

- 03 Vw = 3.74E

- 03 Vt = 6.92E

- 03 Facility 99% UPL = 7.46E

- 01

Carbon Processes without Mercury Retorts

Facility Unit Run 1 (lb/ton) Run 2 (lb/ton) Run 3 (lb/ton) Unit sum (lb/ton) Unit average (lb/ton) Facility total (lb/ton) Unit variance No. of runs per unit DF (n 1) per unit Variance of unit average Facility variance Vw (m = 3 per unit) Facility Vw Round Mountain Electrowinning 1.82E

- 02 7.93E

- 02 1.90E

- 02 1.16E

- 01 3.88E

- 02 1.23E

- 03 3 2 4. 09E

- 04 4.09E

- 04 Round Mountain Melt Furnace 1.49E

- 04 1.80E

- 03 1.77E

- 03 Round Mountain Melt Furnace 3.49E

- 02 9.59E

- 03 1.85E

- 02 6.67E

- 02 1.11E

- 02 1.83E

- 04 6 5 3.05E

- 05 6.10E

- 05 Round Mountain Carbon Kiln 2.57E

- 03 2.86E

- 03 1.5 6E

- 03 Round Mountain Carbon Kiln 1.52E

- 02 1.02E

- 02 1.59E

- 02 4.83E

- 02 8.05E

- 03 0.058 4.33E

- 05 6 5 7.22E

- 06 4.47E

- 04 1.44E

- 05 4.85E

- 04 Average = 5.80E

- 02 DF = 12 t = 2.68 Vb = 4.47E

- 04 Vw = 4.85E

- 04 Vt = 9.32E

- 04 Facility 99% UPL = 1.40E

- 01

## ***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review***

27 Non - Carbon Concentrate

Facility Unit Run 1 (lb/ton) Run 2 (lb/ton) Run 3 (lb/ton) Run 4 (lb/ton) Run 5 (lb/ton) Unit sum (lb/ton) Unit average (lb/ton) Facility total (lb/ton) Unit variance No. of runs per unit DF (n - 1) per unit Variance of unit average Facility variance Vw (m = 3

per unit) Facility Vw Coeu r Rochester Mine Refinery Furnace 5.96E

- 02 1.17E

- 01 2.28E

- 02 Coeur Rochester Mine Refinery Furnace 2.47E

- 02 1.20E

- 02 2.94E

- 02 2.66E

- 01 4.43E

- 02 1.53E

- 03 6 5 2.55E

- 04 5.10E

- 04 Coeur Rochester Mine Retorts #1 & #2 3.41E

- 03 3.45E

- 03 9.24E

- 05 2.31E

- 03 1.95E

- 03 Coeur Rochester Mine Retorts #1 & #2 2.93E

- 04 1.53E

- 02 4.20E

- 03 Coeur Rochester Mine Retort 4.17E

- 05 1.84E

- 04 5.39E

- 05 3.13E

- 02 2.84E

- 03 4.71E

- 02 1.96E

- 05 11 10 1.78E

- 06 2.57E

- 04 6.52E

- 06 5.17E

- 04 Average = 4.71E

- 02 DF = 15 t = 2.60 Vb = 2.57E

- 04 Vw = 5.17E

- 04 Vt = 7.74E

- 04 Facility 99% UPL = 1.19E

- 01

## ***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review***

28 Appendix F . Beyond the Floor

– Ore Pretreatment

Facility Unit Run 1 (lb/ton) Run 2 (lb/ton) Run 3 (lb/ton) Unit sum (lb/ton) Unit average (lb/ton) Facility total (lb/ton) Unit variance No. of runs per

unit DF (n - 1) per unit Variance of unit average Facility variance Vw (m = 3 per unit) Facility Vw Gold Quarry Roaster/Calcine quench 1.35E

- 05 9.56E

- 06 1.37E

- 05 Gold Quarry Roaster/Calcine quench 1.05E

- 05 1.33E

- 05 1.69E

- 05 Gold Quarry Roaster/Calcine quench 8.45E

- 06 1.05E

- 05 9.66E

- 06 1.06E

- 04 1.18E

- 05 7.33E

- 12 9 8 8.14E

- 13 2.44E

- 12 Gold Quarry Roaster Ore Preheater 3.81E

- 06 1.62E

- 06 1.36E

- 06 Gold Quarry Roaster Ore Preheater 7.90E

- 06 7.51E

- 06 4.63E

- 05 Gold Quarry Roaster Ore Preheater 2.45E

- 06 1.04E

- 06 9.09E

- 07 7.29E

- 05 8.10E

- 06 2.12E

- 10 9 8 2.35E

- 11 7.06E

- 11 Gold Quarry Roaster 8.99E

- 07 6.97E

- 07 7.87E

- 07 Gold Quarry Roaster 1.27E

- 06 1.61E

- 06 6.19E

- 07 Gold Quarry Roaster 4.92E

- 07 2.75E

- 07 3.56E

- 07 7.00E

- 06 7.78E

- 07 1.86E

- 13 9 8 2.07E

- 14 6.21E

- 14 Gold Quarry Roaster Ore Grinder 1.66E

- 06 2.06E

- 06 1.48E

- 06 Gold Quarry Roaster Ore Grinder 1.50E

- 06 4.82E

- 06 1.75E

- 06 1.33E

- 05 2.21E

- 06 1.67E

- 12 6 5 2.79E

- 13 5.58E

- 13 Gold Quarry Roaster/Calcine quench 1.67E

- 05 1.36E

- 05 9.55E

- 06 Gold Quarry Roaster/Calcine quench 1.27E

- 05 1.46E

- 05 2.11E

- 05 Gold Quarry Roaster/Calcine quench 1.03E

- 05 1.31E

- 05 1.32E

- 05 1.25E

- 04 1.39E

- 05 3.68E

- 05 1.19E

- 11 9 8 1.32E

- 12 2.60E

- 11 3.96E

- 12 7.77E

- 11 Goldstrike Roaster Ore Preheater 1.82E

- 07 2.84E

- 07 2.03E

- 07 Golds trike Roaster Ore Preheater 5.58E

- 07 3.86E

- 07 3.35E

- 07 Goldstrike Roaster Ore Preheater 1.16E

- 06 9.01E

- 07 1.72E

- 07 Goldstrike Roaster Ore Preheater 1.42E

- 06 7.29E

- 07 1.72E

- 07 6.49E

- 06 5.41E

- 07 1.78E

- 13 12 11 1.48 E

- 14 5.94E

- 14 Goldstrike Roaster Ore Preheater 4.90E

- 06 2.66E

- 06 9.66E

- 07 Goldstrike Roaster Ore Preheater 1.53E

- 05 3.27E

- 06 5.09E

- 07 Goldstrike Roaster Ore Preheater 5.52E

- 07 5.52E

- 07 2.55E

- 07 Goldstrike Roaster Ore Preheater 1.06E

- 06 5.52E

- 07 2.55E

- 07 3.08E

- 05 2.57E

- 06 1.81E

- 11 12 11 1.51E

- 12 6.04E

- 12

## ***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review***

29 Facility Unit Run 1 (lb/ton) Run 2 (lb/ton) Run 3 (lb/ton) Unit sum (lb/ton) Unit average (lb/ton) Facility total (lb/ton) Unit variance No. of runs per

unit DF (n - 1) per unit Variance of unit average Facility variance Vw (m = 3 per unit) Facility Vw Goldstrike Roaster 1.56E

- 04 1.23E

- 04 1.14E

- 04 Goldstrike Roaster 2.70E

- 05 2.70E

- 05 3.70E

- 05 Goldstrike Roaster 3.67E

- 05 3.26E

- 05 2.47E

- 05 5.78E

- 04 6.42E

- 05 2.65E

- 09 9 8 2.95E

- 10 8.85E

- 10 Goldstrike Roaster/Calcine quench 8.18E

- 06 5.56E

- 06 5.40E

- 06 1.91E

- 05 6.38E

- 06 2.43E

- 12 3 2 8.09E

- 13 8.09E

- 13 Goldstrike Roaster/Calcine quench 6 .67E

- 06 7.07E

- 06 6.25E

- 06 2.00E

- 05 6.66E

- 06 8.04E

- 05 1.67E

- 13 3 2 5.57E

- 14 2.97E

- 10 5.57E

- 14 8.92E

- 10 Jerritt Canyon Ore dryer 4.06E

- 06 8.58E

- 06 5.77E

- 06 Jerritt Canyon Ore dryer 1.15E

- 06 9.71E

- 06 3.42E

- 06 3.27E

- 05 5.45E

- 06 1.05 E

- 11 6 5 1.76E

- 12 3.51E

- 12 Jerritt Canyon Roaster 4.42E

- 05 4.47E

- 05 5.14E

- 05 Jerritt Canyon Roaster 4.48E

- 05 2.07E

- 05 2.99E

- 05 Jerritt Canyon Roaster 7.01E

- 06 7.92E

- 06 8.36E

- 06 2.59E

- 04 2.88E

- 05 3.31E

- 10 9 8 3.68E

- 11 1.10E

- 10 Jerritt Canyon Roaster 5.50E

- 05 4.65E

- 05 2.82E

- 05 Jerritt Canyon Roaster 5.80E

- 06 4.30E

- 06 4.65E

- 06 1.44E

- 04 2.41E

- 05 5.83E

- 05 5.16E

- 10 6 5 8.60E

- 11 1.25E

- 10 1.72E

- 10 2.86E

- 10 Twin Creeks Autoclave 1.66E

- 05 4.34E

- 05 3.06E

- 05 Twin Creeks Autoclave 2.35E

- 05 7.76E

- 05 8.70E

- 06 Twin Creeks Autoclave 7.07E

- 05 3.51E

- 05 3.25E

- 05 Twin Creeks Autoclave 6.40E

- 05 3.99E

- 05 3.29E

- 05 Tw in Creeks Autoclave 2.99E

- 05 5.92E

- 05 7.98E

- 05 Twin Creeks Autoclave 3.18E

- 05 2.09E

- 05 1.86E

- 05 Twin Creeks Autoclave 2.59E

- 06 2.42E

- 06 2.29E

- 06 7.23E

- 04 3.44E

- 05 5.75E

- 10 21 20 2.74E

- 11 1.92E

- 10 Twin Cre eks Autoclave 3.42E

- 05 1.64E

- 05 1.60E

- 05 Twin Creeks Autoclave 2.60E

- 05 1.49E

- 05 1.04E

- 05 Twin Creeks Autoclave 1.46E

- 05 2.72E

- 05 2.39E

- 05 Twin Creeks Autoclave 1.06E

- 05 7.50E

- 06 6.36E

- 06 Twin Creeks Autoclave 6.12E

- 06 5.74E

- 06 5.88E

- 06 2.26E

- 04 1.51E

- 05 4.95E

- 05 8.16E

- 11 15 14 5.44E

- 12 3.28E

- 11 2.72E

- 11 2.19E

- 10

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30 Facility Unit Run 1 (lb/ton) Run 2 (lb/ton) Run 3 (lb/ton) Unit sum (lb/ton) Unit average (lb/ton) Facility total (lb/ton) Unit variance No. of runs per

unit DF (n - 1) per unit Variance of unit average Facility variance Vw (m = 3 per unit) Facility Vw
Average of top 5: 5.62E - 05 t DF: 123 Vb: 3.00E 11 Vw (unpooled ): 3.69E - 10 56 t(.99): 2.36

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## 6560

- 50

- P

**ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part**  **s 9 and 63**  **[ EPA**  **- HQ**  **- OAR**  **- 20**  **10 -**  **0239 ; FRL**  **- 9140**  **- 7**  ] **RIN 2060**  **- AP48**  **National Emission Standards for Hazardous Air Pollutants: Gold Mine**  **Ore Processing and Production**  **Area Source Category ; and**  **Addition to Sour ce Category List for Standards**  **. AGENCY:**  Environmental Protection Agency (EPA).
**ACTION:** Final rule
. **SUMMARY:** EPA is adding the gold mine ore processing and production area source category to the list of source categories to be regulated under Section 1 12(c)(6) of the Clean Air Act due to its mercury emissions . EPA is also p romulgating national emission standards for hazardous air pollutants to regulate mercury emissions from this source category
. EPA proposed these actions on April 28, 2010 (75 FR 224 70).
**DATES:** This final rule is effective on [INSERT DATE OF PUBLICATION IN THE FEDERAL REGISTER].
**ADDRESSES:** EPA has established a docket for this action under Docket ID No. EPA

- HQ

- OAR

- 20 10

- 0239
. All documents in the docket are listed on the www.regul ations.gov w ebsite. Although listed in the index, some information is not publicly available, e.g., Confidential Business Information (CBI) or other information

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## whose disclosure is restricted by statute. Certain other material, such as copyrighted materi al, is not placed on the Internet and will be publicly available only in hard copy form. Publicly available docket materials are available either electronically through www.regulations.gov or in hard copy at the EPA Headquarters Library, Room Number 3334, EPA West Building, 1301 Constitution Ave., NW, Washington, DC. The EPA/DC Public Reading Room hours of operation are 8:30 a.m. to 4:30 p.m. Eastern Standard Time (EST), Monday through Friday. The telephone number for the Public Reading Room is (202) 566

- 1744, and the telephone number for the Air and Radiation Docket and Information Center is (202) 566

- 1742.
**FOR FURTHER INFORMATION CONTACT:** Mr. Chuck French , Sector Policies and Program Division, Office of Air Quality Planning and Standards (D243

- 02), En vironmental Protection Agency, Research Triangle Park, North Carolina 27711, telephone number (919) 541

- 7912; fax number (919) 541

- 3207, e

- mail address: french.chuck@epa.gov
**SUPPLEMENTARY INFORMATION:** .

The information presented in this preamble is organi zed as follows:
I. General Information A. Does this action apply to me?

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## B. Where can I get a copy of this document? C. Judicial Review II. Addition to Section 112(c)(6) Source Category List III
. Summary of Significant Changes Since Proposal A. Appli cability B. Final Emission Standards C. Compliance Dates D. Compliance Requirements E. Monitoring Requirements F. Definitions I V. Summary of Responses to Major Comments A. Statutory Requirements B. Applicability C. MACT Floors D. Compliance Deter minations E. Monitoring V. Summary of Environmental, Economic and Health Benefits? VI. S **tartup ,**  **Shutdown and Malfunctions** 
V II
. Statutory and Executive Order Reviews A. E xecutive Order 12866: Regulatory Planning and Review B. Paperwork Reduction Act C. Regulatory Flexibility Act D. Unfunded Mandates Reform Act E. Executive Order 13132: Federalism F. Executive Order 13175: Consultation and Coordination with Indian Tribal Governments G. Executive Order 13045: Protection of Children from Environm ental Health and Safety Risks H. Executive Order 13211: Actions Concerning Regulations that Significantly Affect Energy Supply, Distribution, or Use I. National Technology Transfer and Advancement Act J. Executive Order 12898: Federal Actions to Addre ss Environmental Justice in Minority Populations and Low

- Income Populations K. Congressional Review Act **I. General Information 60** 
A. Does this action apply to me The regulated categories and entities potentially affected by th is final rule include: ?

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## Ca tegory NAICS code 1 

## Examples of regulated E ntities Industry: Gold Ore Mining 212221 Establishments primarily engaged in developing the mine site, mining, and/or beneficiating (i.e., preparing) ores valued chiefly for their gold content. Establishments primarily engaged in transformation of the gold into bullion or dore bar in combination with mining activities are included in this industry.

1 

## North American Industry Classification System. This table is not intended to be exhaustive, but rather
pro vides a guide for readers regarding entities likely to be affected by this action. To determine whether your facility would be regulated by this action, you should examine the applicability criteria in 40 CFR 63. 11640 of subpart EEEEEEE (National Emission Standards for Hazardous Air Pollutants: Gold Mine Ore Pro c essing and Production Area Source Category ). If you have any questions regarding the applicability of this action to a particular entity, consult either the air permit authority for the entity or your EPA Regional representative, as listed in 40 CFR 63.13 of subpart A (General Provisions).
B
. Where can I get a copy of this document In addition to being available in the docket, an electronic copy of this final action will also be available on th e Worldwide Web (WWW) through the EPA Technology Transfer Network ?

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## (TTN). Following signature, a copy of th is final action will be posted on the TTN’s policy and guidance page for newly proposed or promulgated rules at the following address: www.epa.gov/ttn/oarpg/ . The TTN provides information and technology exchange in various areas of air pollution control.
C. Under section 307(b)(1) of the Clean Air Act (CAA), judicial review of this fin al rule is available only by filing a petition for review in the U.S. Court of Appeals for the District of Columbia Circuit by [INSERT DATE 60 DAYS AFTER PUBLICATION IN FEDERAL REGISTER]. Under section 307(d)(7)(B) of the CAA, only an objection to this fi nal rule that was raised with reasonable specificity during the period for public comment can be raised during judicial review. Moreover, under section Judicial Review

307(b)(2) of the CAA, the requirements established by this final rule may not be challenged separately in any civil or criminal proceedings brought by EPA to enforce these requirements. Section 307(d)(7)(B) also provides a mechanism for us to convene a proceeding for reconsideration, “[i]f the person raising an objection can demonstrate to EPA that it was impracticable to raise such objection within [the period for public comment] or if the grounds for such objection arose after

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## the period for public comment (but within the time specified for judicial review) and if such objection is of central relevance
to the outcome of the rule.” Any person seeking to make such a demonstration to us should submit a Petition for Reconsideration to the Office of the Administrator, U.S. EPA, Room 3000, Ariel Rios Building, 1200 Pennsylvania Ave., NW., Washington, DC 20460, with a copy to the person listed in the preceding
**FOR FURTHER INFORMATION CONTACT** section
. **II. Addition to**  **Section 112(c)(6) Source Category List**  For reasons stated in the preamble to the proposed rule ( 75
F R 22470, April 28, 2010 ) , we are adding the gol d mine ore processing and production area source category to the list of source categories under section 112(c)(6) on the basis of its mercury emissions.
**III .**  **Summary of Significant Changes Since Proposal** This section summarizes the significant changes t o the rule since proposal. Additional information on the basis for these changes and other changes can be found in the Summary of Responses to Major Comments in Section IV of this preamble.
A. We have clarified in §63.116 51 of the final r ule that the term "gold mine ore processing and production facility" does not Applicability

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## include laboratories (see CAA section 112(c)(7) ) , individual prospectors, and very small pilot scale mining operations. The se types of operations are very small and were not in cluded in the section 112(c)(6) inventory that was the basis for the listing of the gold mine ore processing and production source category
. B. We have made changes to all of the proposed emission standards a s the result of t he following developments: (1) inclusion of additional emission s test data received since proposal; (2) additional analyses in response to public comments on the proposed rule ; and (3) further review of the data used to develop the standards for the propo sed rule. The changes are summarized below and described in more detail in section IV of this preamble. Final emission standards

In the proposed rule, the proposed mercury emission standards for both existing and new ore pretreatment process es

were 14 9 pounds per million tons of ore processed ( lb /million tons of ore). In the final rule, the emission standard for existing sources is 12 7 lb/million tons of ore; for new sources the emission standard is 84 lb/million tons o f ore. The final Ore Pretreatment Processes

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## emission stand ards are based on several changes to the data set used in the MACT analysis. Since we issued the proposed rule,

w e collected emissions data from more recent tests that were not available at proposal
. Further , we learned that two emission s
test s that we u sed to develop the MACT floor in our proposed rule had been invalidated by the N evada D ivision of Environmental Protection (ND EP ) , and we removed those test results from the database. We also discovered that the test data for a unit within the ore pretrea tment affected source at a facility should have been included as part of a different unit at the same facility. Moreover, we conducted a dditional beyond

the

- floor analys e s for the ore pretreatment affected source
. The new information and analyses describ ed above are discussed in more detail in Section IV.C of this preamble and in the MACT Floor document in the docket for this rulemaking
. The resulting data set included emissions data for four facilities that ranged from 45 to 165 lb/million tons of ore. Based on these data, and using the same upper prediction limit (UPL) approach used for proposal to account for variability, we determined the MACT floor to be 158 lb/million tons o f ore for existing sources of ore pretreatment processes and 84 lb/million tons of ore for new sources
. As explained in the proposed rule

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## (75 FR at 22482), the technologies for achieving the MACT floor for existing ore pretreatment processes include calomel

- based mercury scrubbers on roasters and venturi scrubbers on autoclaves and ancillary roaster operations. After applying the beyond

- the

- floor analysis to the data, we determined the MACT limit for existing sources to be 12 7 lb/million tons of ore
. For new sources, t he MACT limit is 84 lb/million tons ( which is the same as th e MACT floor for new sources)
. Table 1 summarizes the MACT floor analysis for existing and new ore pretreatment
processes . Table 2 summarizes the results of the beyond

- the

floor analysis for these sources. Table 1

— MACT Floor Results for Ore Pretreatment Processes Facility Average performance (lb/million tons of ore ) A 45 C 56 E 71 D 165 Average of top 4 84 99% UPL existing (MACT Floor) 15 8 99% UPL new 1 

## (MACT Floor) 84 1 

## The MACT Floor for new sources i s based on the average performance of Facil ity A plus an amount to account for variability (i.e., 45 + 39 = 84)
.



## Table 2

— B eyond

- the

- F loor Results for Ore Pretreatment Processes Facility Average performance (lb/million tons of ore ) C 3 7 D 49 E 5 8 A 8 0

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## Highest Average 8 0 99% UPL existing ( BTF Floor) 12 7

Under the proposed rule, all carbon process es were subject to the same proposed mercury emissions limits of 2.6 pounds per ton of concentrate (lb/ton of concentrate) for existing sources and , for new sources, either 0.14 lb/ ton of concentrate or 97 percent reduction in uncontrolled mercury emissions . These limits would have applied to facilities that operate mercury retorts and facilities that do not operate mercury retorts. In the final rule, we distinguish between carbon processes with
mercury retorts and carbon processes without mercury retorts because we believe there are unique differences in these two types of processes
. Therefore, the final rule specifies separate emission standards for these two types of processes. Moreover, the final emission standards for carbon processes reflect inclusion of new test data that were not available at proposal. We also removed from the data set emissions data based on previously uncontrolled sources that installed controls in 2009; for those sources, only the controlled emissions data were used. (see section IV for further details). For carbon processes with mercury retorts, the emission standard in the Carbon Processes

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## final rule is 2.2 lb/ton of concentrate for existing sources and 0.8 lb/ton of concentrate for new sources. For carbon processes without mercury retorts, the emission standard in the final rule is 0.1 7 lb/ton of concentrate for existing sources and 0. 14 lb/ton of concentrate for new sources
. W e considered beyond

the

- floor options f or these affected sources ; however , we rejected those options because they were not cost effective. Additional information on the analyses performed can be found in the MACT Floor document in the docket for this rulemaking. We also eliminated in the final rule the compliance alternative of 97

- percent reduction for new carbon processes. After reviewing the comments received on this proposed alternative standard and giving further consideration to the practicality of how it would be measured, we concluded t hat this option would be difficult to implement , particularly when multiple processes that are operated at different times vent to a single control device and stack . In addition, we have limited data supporting this compliance alternative. In proposing t his alternative for comment, we had hoped to , but did not , receive additional data indicating that the 97 percent reduction option would be equivalent to the proposed new source limit of 0.14 pounds of mercury per ton of concentrate. For the reasons

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## state d above, we eliminated the 97 percent control efficiency option for new carbon processes in the final rule. Table 3 summarizes the results of the MACT floor analysis for carbon processes with mercury retorts, and Table 4 summarizes the analysis for car bon processes without mercury
retorts. Table 3

— MACT Floor Results for Carbon Processes with Mercury
Retort s Facility Average performance (lb/ton of concentrate ) N 0.53 J 0.74 I 1.06 A 1.47 H 1.67 D 2.20 C 3.71 G 8.17 B 20.60 Average of top 5 1.1 99% UPL existing (MACT Floor) 2.2 99% UPL new (MACT Floor) 0.8

Table 4

— MACT Floor Results for Carbon Processes without Mercury
Retort s Facility Average performance (lb/ton of concentrate ) M 0.0 58 F 0.0 9 8 Average of top 2 0.0 78 99% UPL existing (MA CT Floor) 0. 1 7 99% UPL new (MACT Floor) 0. 14

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## For carbon processes, regardless of whether the facility operates a mercury retort, the MACT floor is based on control of mercury emissions using mercury condensers and carbon adsorbers. For the beyond

- the

- f loor analysis, we considered adding a second carbon adsorber to the MACT floor level controls.

Under the proposed rule, the mercury emission standards for

non - carbon concentrate processes were 0.25 lb/ton of concentrate fo r existing sources and 0.2 lb/ton of concentrate for new

sources. In the final rule, t he emission standards for these sources are 0.2 lb/ton of concentrate for existing sources and 0.1 lb/ton of concentrate for new sources. The se standards are based on u sing new emissions data that were not available when we developed the proposal , along with most of the data that were used for the proposal
. We also considered beyond

- the

- floor controls for these sources, but concluded th ose controls would not be a cost

- e ffective option. Table 5 summarizes the results of the MACT floor analysis for non

- carbon concentrate processes. Non

- Carbon Concentrate Processes

Table 5

— MACT Floor Results for Non

- Carbon Concentrate Processes Facility Average performance (lb/ton of concentrate ) K 0.047 L 0.078 Avera ge of top 2 0.062 99% UPL existing (MACT Floor) 0. 2

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## 99% UPL new (MACT Floor) 0.1

For non

- carbon concentrate processes, the MACT floor is based on control of mercury emissions using mercury condensers and carbon adsorbers. For the beyond

- the

- floor anal ysis, we considered adding a second carbon adsorber to the MACT floor level controls.
C. In the final rule, we provide in §63.11641 that the compliance date for existing sources is 3 years after promulgation of the final rule as opposed to 2 years as proposed
. We review ed the information provided in public comments on the challenges of installing new controls, especially for autoclaves , which , although the controls have not yet been demonstrated , have been proposed by facilities with
aut oclaves in their Nevada Mercury Control Program ( NMCP ) permit applications ; and the consideration of installing new controls on the roaster preheaters , which also have not been demonstrated yet , but have been proposed by these facilities in their NMCP
perm it applications. W e concluded th at allowing 3 years for existing sources to comply is appropriate , given the complexity of the sources, the combinations of control devices that are needed in many cases, and the amount of time necessary for Compliance Dates

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## designing, inst all ing, testing, and commissioning addition al emission controls for mercury.
D. Section 63.11646(a)(1)(v) of the final rule does not include Method 30A , as was proposed, as an appropriate method for determining mercury concentrati on because it is not yet in general use. T his paragraph further clarifies that the use of ASTM D6784

- 02 and Method 30B are allowed for compliance tests only if approved by the permit authority
. The final rule also does not include the requirement to foll ow the acetone rinse procedures and the absence of cyclonic flow determination requirement, which were in subparagraph s (v) and (vi) respectively of our proposed §63.11646(a)(1). Method 29 already includes requirements for the acetone rinse, so there is n o need to specify those procedures in the rule; and Method 1, which is required by the rule, addresses the issue of cyclonic flow. Compliance Requirements

In §63.11646(a)(2) , we changed the minimum sample volume when Method 29 is used to determine compliance from the proposed 60 dry standard cubic feet ( dscf ) to 30 d s c f . We believe this volume is adequate for detecting mercury in the samples and determining mercury emissions for this industry . We have also expanded this section to address non

- detect values. If the

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## emission tes ting results for any of the emission points yield a

non - detect value, the final rule requires that the minimum detection limit (MDL) be used to calculate the mass emissions rate used to calculate the emissions factor (lb/ton) for that emission point and to calculate the sum of the emissions factors for all emission points subject to the emission standard. If the resulting mercury emissions factor is greater than the allowable emission standard , the owner or operator may repeat the mercury emissions testing one additional time for any emission point for which the measured result was below the MDL using procedures that produce lower MDL results. If this additional testing is performed, the results from that testing must be used to determine compliance.
For sources with multiple emission units (e.g., two roasters) ducted to a common control device and stack, we have clarified in §63.11646(a)(3) that compliance testing must be performed with all affected emissions units in operation , if this is possible . This same requirement applies to the establishment of operating limits for all process units. However, this requirement does not affect the frequency and schedule for monitoring , which are specified in the rule. If facilities have batch type processes that c annot be operated

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## simultaneously, then the facility can test some or all of the units individually.
In §63.11646(a)(6) and (7) , we clarify that the production data used in compliance determinations are based on full calendar months. For the initial compl iance test, data for all the full calendar months between publication of the final rule and the initial compliance test must be used. For subsequent annual compliance tests, data for the 12 full calendar months prior to the annual compliance test must be used to demonstrate compliance. In addition, we clarify in paragraphs §63.11646(a)(5), (6) and (7) that compliance determinations are based on the number of 1

- hour periods each process unit operates. By using the 1

- hour period terminology, the final rule language is consistent with the terminology used in the General Provisions to part 63.
Because the final rule does not include the 97 percent reduction option that was in §63.11645(e)(2) of the proposed rule , we have removed from the final rule the compl iance requir e ment for that option that was in §63.11646(b) of the proposed rule , which addressed testing the inlets and outlets for sources choosing that proposed option
. E. Monitoring Requirements

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## Section 63.11647(a) of the final rule include s an additi onal option for monitoring mercury emissions from roasters. The proposed rule specified two options for monitoring mercury emissions: paragraph (a)(1) specified weekly sampling using PS 12B, and paragraph (a)(2) specified continuous monitoring using a me rcury continuous emissions monitoring system ( CEMS ) . In the final rule, we added paragraph (a)(3) to provide a third option of continuous sampling using PS 12B. In addition, paragraph (a)(1) in the final rule was changed to require sampling at least twic e per month using either PS 12B or Method 30B rather than weekly
. W e believe that Method 30B is an acceptable alternative method for monitoring purposes and allows owners and operators more flexibility in how they monitor roaster emissions. We also belie ve that sampling twice per month coupled with extensive parametric monitoring of control devices (as explained below) is sufficient for th e monitoring option in paragraph (a)(1)
. Section 63.11647(a)(4)(iii) of the proposed rule would have required additio nal compliance testing if the mercury concentration in the ore fed to the roaster was higher than any concentration measured in the previous 12 months. We have removed this requirement from the final rule because it is not

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## clear that the mercury content o f the ore has a significant effect on the performance of mercury scrubbers applied to roasters, which are designed to handle and operate efficiently for a range of mercury inlet concentrations. In addition, condense rs are used to recover elemental mercury prior to the mercury scrubber, and any increase in mercury loading would likely result in an increase in the recovery of elemental
mercury. The final rule incorporates several changes to §63.11647(b), which addresses monitoring of calomel

- based
mercury scrubbers (i.e., mercury scrubbers) that are used to control emissions from roasters. The final r u le does not include the requirement to monitor pressure drop across calomel

based scrubber s because we conclude that pressure drop is not related to mercury emission control performance by this type of control device . In addition, the final rule allow s hourly monitoring of the line pressure in the scrubber liquid supply line as an alternative to hourly monitoring of scrubber liquid flow rate. Line pressure monitoring is already in practice at some facilities and provides the same type of information as does liquid flow rate. As was proposed, t he final rule allow s the operating limit for scrubber liquid flow rate (or line

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## pressure) to be based on the minimum flow rate ( or line
pressure ) established during the initial performance test . It also includes two additional options for setting the operating limit: (1) based on the manufacturer’s specifications if certain types of systems are designed to operate wit hin a specified range of flow rates; and (2) based on limits established by the permitting authority. I f the facility chooses the first option (to establish the limits during initial compliance) , the final rule requires the operating limit to be based on either the lowest value for any run of the initial compliance test or 10 percent less than the average value measured during the compliance test. This requirement takes into account the fact that, although initially the system may exhibit little variabili ty from test run to test run, the short

term variability in performance may increase with time. Additional discussion of these changes can be found in Section IV.E of this preamble and in the Summary of Public Comments and Responses document in the docket for this rulemaking. We have clarified the requirements for corrective action following control device monitoring parameter exceedances specified in §63.11647(d). Under the final rule, if the corrective actions taken following an exceedance do not resul t

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## in the parameter value (e.g. , liquid flow rate or line pressure ) being returned to within the parameter range or limit within 48 hours, a mercury concentration measurement must be made to determine if the operating limit for mercury concentration is bein g exceeded. The measurement must be performed and the concentration determined within 48 hours after the initial 48 hours , or a total of 96 hours from the time the parameter was exceeded . If the measured mercury concentration meets the operating limit fo r mercury concentration, the corrective actions are deemed successful. In addition, the owner or operator may request approval from the permitting authority to change the parameter range or limit based on measurements of the parameter at the time the merc ury concentration measurement was made. If , on the other hand, the measured mercury concentration indicates the operating limit for mercury concentration is exceeded, the exceedance must be reported as a deviation within 24 hours to the permit ting authori ty , and the facility must perform a compliance test (pursuant to §63.11647(d) ) within 40 days to determine whether the source is in compliance with the
MACT standard
. We believe 40 days is reasonable because it may take 3 to 4 weeks to schedule and have t he testing contractor on site, and, following completion of the test, another week to

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## receive the final test results. In §63.11647(a)(1)(ii) of the final rule, we require t hese

same corrective action s described above (i.e., measuring mercury concentration within 48 hours , reporting a deviation if the data show the operating limit was exceeded within 24 hours , and conducting a compliance test within 40 days ) for exceedances of mercury concentration operating limits indicated by the results of the twice month ly monitoring using PS 12B or Method 30B , CEMS, or continuous monitoring using PS 12B
. In such cases, the owner or operator must use the results of the compliance test to determine if the ore pretreatment process affected source is in compliance with the emission standard . If the source is determined to be in compliance , the owner or operator may use this compliance test to establish a new operating limit for mercury concentration for the roaster
. We also removed the requirement that roasters must be shu t down if a parameter is out of range. In the final rule, §63.11647(f)(1) require s monthly sampling of the exhaust stream of carbon adsorbers using Method 30B . The duration of sampling must be at least the minimum sampling time specified in Method 30B , u p to one week. The proposed rule required a full week of such sampling, but, as

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## pointed out by one of the commenters, breakthrough of the sampling trap from exhaust streams with high mercury concentrations could occur before a week had elapsed. Section 63.11647(f)(2) of the final rule clarif ies that sampling of the carbon bed must be collected from the inlet and outlet of the bed. T his paragraph also specifies that, for carbon adsorbers with multiple carbon columns or beds, the sampling should be perfor med in the first and last column or bed rather than at the inlet or outlet. We have deleted §63.11647(f)(3) in the proposed rule , which allowed the carbon bed change

- out rate to be determined based on historical data and the estimated life of the carbon. We have concluded that this method would not be adequate to ensure that breakthrough does not occur earlier than expected. We have clarified §63.11647(h) with respect to the monitoring of scrubber s (other than the calomel

- based mercury scrubbers descri bed above) . Under the final rule, owners or operat ors are required to monitor and record water flow rate (or line pressure) and scrubber pressure drop once per shift ; they also must record any occurrences when the pressure drop was outside the manufacture r’s recommended operating range , take corrective actions to return the pressure drop back in range,

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## and record the corrective actions taken. At proposal , the water flow rate and pressure drop were to be monitored continuously
. However , measuring pressure drop once per shift will provide two to three measurements per day, and we believe that is sufficient to assure proper operati ons of the wet scrubber, and thus assure compliance with the emission standards
. We have also added the option of monitoring the line pressure in the scrubber liquid supply line as an alternative to monitoring scrubber liquid flow
rate because l ine pressure monitoring is already in practice at some facilities and provides the same type of information as does liquid flow rate
. We h ave also clarified that , for scrubbers on autoclaves, the pressure drop parameter range should be established from manufacturer’s specifications only.
**F.** We have added a definition of carbon adsorber to §63.11651 to clarify that this term, as used in the final rule, includes control devices consisting of a single fixed carbon bed, multiple carbon beds or columns, carbon filter packs or modules, and other variations of carbon adsorber design
. **Definitions**

T he definition of "gold mine ore processing and production facility" in §63.116 51 of the rule has been clarif ied to state that operations, such as prospectors, laboratories, and very

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## small pilot scale mining operations, that process or produce less than 5 0 pounds of concentrate per year are excluded fr om the source category. These prospectors and very small pilot

scale operations (that process at or below th is cutoff) are orders of magnitude smaller than all the facilities in our database. These very small operations process far less material than the typical facility in our inventory. For example, the 21 facilities that are in our current inventory and that we expect will be subject to the final rule process or produce between 4,000 to 500,000 pounds of concentrate per year (i.e., at least 100 times the 5 0 lb/yr cut o ff). These types of very small operations were not intended to be subject to the final rule , and we do not expect any significant emissions from them. We also clarified that the source category does not include facilities at which 95 per cent or more of the metals produced are metals other than gold. For example, if other non

- ferrous metals (such as copper, lead, nickel, or zinc) comprise 95 percent or more of the product, the facility is not part of the gold ore processing and production source category. **IV. Summary of Responses to Major Comments** A. Statutory Requirements

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## 1. Listing of the Gold Mine Ore Processing and Production Source Category Under Section 112(c)(6)
**Comment :**  One commenter stated that adding the gold mine
ore pro cessing and production category to the list of categories required by Clean Air Act (CAA) section 112(c)(6) was correct and required because gold mines accounted for a significant portion of the aggregate emissions of mercury in the baseline year (1990) an d because they still do so today
. Several other commenters claimed that EPA did not provide the legal basis for listing gold mining as a source category under section 112(c)(6). The se commenters stat ed that EPA does not have the authority to list gold mi ning as a source category under section 112(c)(6) and noted that section 112(c)(6) requires EPA to list, by 1995, categories of sources that make up 90 percent of the 1990 emissions for a subset of hazardous air pollutants (HAP), including mercury. The co mmenters said that EPA concluded its statutory listing obligation for mercury in 1998 with the publication of a list of source categories constituting 90 percent of aggregate mercury emissions, and that gold mining was not included on that list in 1998. I n addition, the commenters said that the CAA requires EPA to list all categories under section 112(c)(6) by 1995 and complete issuance of standards for

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## all listed sources by 2000, a task that would be impossible if EPA had the authority to add source categ ories ad infinitum. **Response**

Some commenters questioned EPA’s estimated emission s of 4.4 tons from this sour ce category in the 1990 baseline year; however, they did not estimate or explain what the baseline emission should have been. EPA continues to believe that its baseline emission s estimate is reasonable and, as mentioned above, we have not received other e stimates. We disagree with the comment that , because EPA already completed this listing obligation when it published its section 112(c)(6) category list on April 10, 1998 (63 FR 17838), EPA has no authority to list gold mine ore processing and production as a category under section 112(c)(6) . Section 112(c)(6) requires that EPA list sufficient categories to ensure that sources accounting for not less than 90 percent of the aggregate emissions of each of the **:** Section 112(c)(6) does not prescribe any methodology that EPA must follow in listing source categories, thus giving EPA discretion on how to carry out this obligation. Therefore, unless sources from the gold mine ore proces sing and production area source category did not emit mercury in the 1990 baseline year, EPA has authority to list that category for regulation pursuant to section 112(c)(6).

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## HAP specified in section 112(c)(6) are subject t o standards. Although section 112(c)(6) requires that EPA list the categories by 1995, it contains no language prohibiting EPA from revising the list . In fact, i n order for EPA to regulate sufficient source categories to meet the 90 percent statutory req uirement,
EPA must have the authority to revise the category list, including adding categories , should it discover during the course of developing section 112(c)(6) standards that such revision is necessary to meet the statutory 90 percent obligation. Fur ther, were the section 112(c)(6) list of source categor ies that EPA published in 1998 considered final and unchangeable under the CAA , the CAA would have made the list judicial ly reviewable upon publication to ensure that EPA can later regulate sufficient categories to meet the statutory 90 percent requirement. To the contrary, CAA section 112(e)(4)
states that listing of a source category under section 112(c) is not a final agency action subject to judicial review , but such action may be reviewed when EPA issue s the standards. In l ight of section 112(e)(4), and were EPA prohibited from revising the category list, as the commenter claimed, it could potentially be impossible for EPA to meet the 90 percent requirement under section 112(c)(6). We do not beli eve that Congress would have

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## structured the CAA in a way that c ould potentially make it impossible for EPA to meet a statutory requirement. For the reasons stated above , w e believe that EPA has authority to revise the section 112(c)(6) category list as ne cessary to ensure that sufficient categories are subject to regulation under section 112(c)(6)
. W e also reject the comment that the task of completing standards by 2000 would be impossible if EPA had the authority to add source categories.
**Com ment**  **:** Several commenters stated that Phase 2 permits under the Nevada Mercury Control Program ( NMCP ) , which are scheduled for issuance by the end of 2010, will result in MACT

level controls on all thermal units at Nevada gold mines. According to the comm enters, these permits are the culmination of a 7

- year collaborative effort between NDEP and the gold mining industry to substantially reduce mercury emissions from gold mine processes
. The commenters said that the proposal does not address how the NESHAP will result in reductions in mercury at gold mines in areas of the country other than Nevada, where the mercury content of the ore in gold mines is non

- existent or only a fraction of the amount found in Nevada, and Nevada accounted for 99 percent of mercur y emissions associated with gold mining operations in the United States. According to the

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## commenters, this shows that if Nevada has an equivalent mercury control program for the gold mining industry, then there is nothing to be gained from imposing a fede ral program, and if EPA acknowledges that the mines in Nevada are already well controlled, then the listing of gold mining and the promulgation of an additional layer of regulation at substantial cost to industry , but with little environmental benefit, is both legally indefensible and practically unsupportable. **Response :**  We believe it is appropriate to promulgate MACT standards for mercury emissions for this industry. Based on our 1990 baseline inventory for 112(c)(6) and other emission information for subsequent years, w e estimate that this industry was among the top ten highest

- emitting categories of mercury emissions in the U.S. in 1990 and has remained in the top 10 since that time. Moreover, even though most emissions are from facilities located in Nevada, several commenters expressed serious concerns about the potential for mercury emissions from

new gold mines in other States (e.g., Alaska). We share these

concerns about potential emissions from new gold mine facilities
. In summary, we believe i t is necessary and appropriate to promulgate a federal NESHAP for existing and new gold mine ore processing and production facilities
.

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## 2 . Emission Standards for HAP Other t han Mercury
**Comment**

The commenter said that EPA appears to believe that because gold mines are needed only to reach the section 112(c)(6) requirement of 90 percent for mercury and not for the other pollutants enumerated in section 112(c)(6), EPA’s only obligation under section 112(c)(6) is to set section 112(d)(2) standards for mercury. The commenter said that section **:** One commenter stated that CAA section 112(c)(6) provides that EPA must “list categories and subcategories of sources assuring that sources accounting for not less than 90 percent of each [enumerated] pollutant are subject to standards under subsection (d)(2) or (d)(4) of this section.” The commenter also stated tha t the D.C. Circuit has held repeatedly that when EPA sets standards for a category or subcategory of sources under section 112(d)(2), EPA has a clear statutory duty to set emission standards for each HAP that the sources in that category or subcategory emi t (e.g., National Lime Ass’n v. EPA , 233 F.3d 625, 633

- 634 (D.C. Cir. 2000)). The commenter concluded that when EPA sets standards for gold mines under section 112(d)(2), as section 112(c)(6) requires it to do, EPA must set section 112(d)(2) emission stan dards for all the HAP that gold mines emit.

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## 112(c)(6) expressly requires EPA to issue section 112(d)(2) standards for the “sources” in the categories listed u nder section 112(c)(6), not some subset of the pollutants that those sources emit, and that section 112(d)(2) standards must include emission standards for each HAP that a source category emits. The commenter continued by stating that nothing in the CAA

e xempts EPA from this requirement. The commenter concluded that , had Congress wished to give EPA discretion to set standards for only some of the pollutants emitted by a category listed under section 112(c)(6), it would have done so expressly. **Response :**  E PA disagrees with the comment that , even though EPA lists a category under section 112(c)(6) due to the emissions of one or more HAP specified in that section, EPA must issue emission standards for all HAP (including HAP not listed in section 112(c)(6)) th at sources in that category emit
. The commenter cited in support the opinion by the United States Court of Appeals for the D.C. Circuit in National Lime Ass’n v.
EPA , 233 F.3d 625, 633

- 634 (D.C. Cir. 2000)). The part of the National Lime opinion referenc ed in the comment dealt with EPA’s failure to set emission standards for certain HAPs emitted by major sources of cement manufacturing because the Agency found

no sources using control technologies for those HAP. In

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## rejecting EPA’s argument , t he c ourt sta te d that EPA has “a statutory obligation to set emission standards for each listed
HAP.” Id
. at 634. T he Court noted the list of HAP in section 112(b) and stated that section 112(d)(1) require s that EPA

“ promulgate regulations establishing emission stand ards for each category or subcategory of major sources ... of hazardous air pollutants listed for regulation ..” Id. (Emphasis added). For the reasons stated below, we do not believe that today’s final rule conflicts with the National Lime decision. Ther e are several important distinctions between the National Lime case and this final rule for Gold Mine Ore Processing and Production area source category. T he relevant issue in the portion of the opinion referenced by the commenter was how EPA set standard s for a HAP where there are no control technologies being used to control that HAP . Accordingly, the
court’s statements described above in National Lime were made to address th is specific issue and in the context of a major source category. Today’s final rule applies to EPA’s obligation to issue emission standards for a listed area source category under CAA section 112(c)(6)
. On the other hand, t he National Lime

case addressed a major source category and not area source categories or EPA’s obligation und er section 112(c)(6).

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## We further note that the applicable lists of HAP under the CAA differ for major and area source categories
. Under CAA section 112(c) , a major source category must be listed for regulation if it emit s any of the HAP listed in sectio n 112(b)
. Accordingly, in National Lime , t he c ourt referenced the 112(b) HAP list in requiring that EPA “ promulgate regulations establishing emission standards for each category or subcategory of major sources ... of hazardous air pollutants listed for

re gulation.” Id. Unlike major source categories, the CAA does not require that EPA list an area source category for regulation if it emits a pollutant listed in section 112(b). Rather, an area source category may be listed for regulation under section
11 2 if EPA ma kes an adverse effect finding pursuant to Section 112(c)(3) or if that area source category emits an urban HAP listed under section 112(k) or a HAP listed in section 112(c)(6). T he gold mine ore processing and production area source category is listed for regulation under section 112(c)(6 ) because it emits mercury, one of the HAP listed in section 112(c)(6). Because the lis ted HAP at issue is only mercury , we have established in this final rule mercury emission standards for this area source ca tegory
. For the reasons stated above, EPA disagrees with the comment that it must set emission

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## standards for all HAP emitted by the gold mine ore processing and production area source category.
3 . Emission Standards for Fugitive Emissions
**Comment :**  One commenter stated that gold mines have significant fugitive emissions of mercury, but that EPA did not propose standards for these emissions or mention them in its proposal. The commenter said that EPA has a statutory obligation to set standards for gold m ine mercury emissions under section 112(d)(2) and (3), and must set emission standards for all the mercury emissions from the listed category
. The commenter described a recent preliminary study at two facilities in Nevada that found fugitive mercury air e missions from various

non - point sources at those two mining operations such as from leach pads and tailings ponds. One commenter stated that means to control fugitive emissions are available, such as enclosing their leaching operations. By enclosing the leaching process, the commenter believes that mines could eliminate this source of fugitive emissions. The commenter also stated that mines should not send tailings into open tailing ponds , but into closed treatment facilities that would remove mercury an d other HAP from the tailings and prevent their release to the air. The commenter recommended that EPA evaluate the use of sulfur

- based

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## complexing agents for removing mercury during cyanidization of gold. According to the commenter, research indicates th at these products appear useful for substantially reducing mercury in process solution during heap leaching. **Response**

Furthermore, we have very little information on how these fugitive mercury emissions might be controlled. A few

commenters suggested that certain compounds were available that may be useful for limiting these emissions. However, as far as **:** W e have not included fugitive mercury emissions at gold mine facilities in our 1990 baseline emission s estimate , or in our more recent emissions estimates, largely due to the lack of information about these emissions. Accordingly, these fugitive emissions are not part of the source category we are listing and regulating in this final rule. Other than the

r ecent preliminary research at t wo facilities , we have no data on fugitive mercury emissions from gold mine facilities. The recent preliminary research suggests that some fugitive emissions may be occurring at these facilities from large non

point sources such as tailings ponds, leach f ields, and waste rock piles
. However , it is our understanding that this preliminary research has not yet been published or peer

reviewed
.

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## we know, there has been no demonstration that these compounds would work effectively to limit the emissions, and we do not know the costs or potential adverse impacts of applying these chemicals. Therefore, we question the feasibility and practicality of applying these chemicals to limit fugitive mercury emissions from these non

- point sources. We also question the feasib ility and pr actical ity of enclos ing the leaching operations or the tailings ponds , as suggested by some
commenters
. As explained in the proposed rule, the gold mine ore processing and production area source category covers the thermal processes that occur after ore crushing, including roasting operations (i.e., ore dry grinding, ore preheating, roasting, and quenching), autoclaves, carbon kilns, electrowinning, preg tanks, retorts, and furnaces. T he data and calculations used to derive the estimate d 4.4 tons of merc ury emissions for this source category for the 1990 baseline inventory for section 112(c)(6) reflect emissions from the thermal processes described above, and t he final MACT standards address all of these processes
.

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## 4 . Major Source Determination
**Comment**

The commenter also stated that EPA’s failure to apply the

s ame variability analysis in calculating gold mines’ potential to emit that was used in setting floors was internally inconsistent, unexplained, and arbitrary and capricious. The commenter noted that the proposal requested comment on a certification proces s that would allow gold mines to avoid major source status whereby companies could certify that they are area sources by implementing certain “management practices” and then certifying to EPA that they had done so. The commenter stated **:** One commenter noted that the proposal state s t he following: “ data indicate that the gold mining processing and production category consists of only area sources ( i.e. facilities that emit less than 10 tons per year of any single HAP and less than 25 ton s per year of any combination of HAP).” 75 Fed. Reg. at 22479. The commenter also claimed that the proposal indicates that actual emissions of hydrogen cyanide at a few facilities are near the major source threshold. The commenter continued by saying tha t “b y basing its evaluation of whether gold mines are major sources on their actual emissions instead of their potential emissions, EPA violates both the Clean Air Act and its own regulations. ”

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## that such a certifi cation process would be unlawful in calculating a sources “potential to emit” because the management practices are not “control equipment,” “restrictions on hours of operation or on the type or amount of material combusted, stored, or processed,” and would not be “federally enforceable.” Other commenters supported EPA’s conclusion and determination t h at the gold mines are area sources of HAP. According to the commenters, EPA’s methodology in making this determination was extremely conservative and resulted in higher calculated HCN emissions than may actually be present. For instance, EPA did not apply what the commenters believe to be a key correction factor to account for the fact that much of the mass transfer of HCN for large surface areas is expected t o be gas phase limited. Application of this correction factor would have reduced the estimates for HCN emissions from the mines tested by about 40

- 50%. The commenters also stated that fence line testing at selected gold mine operations demonstrated that
t here was no concern with fenceline levels of HCN emissions , and that these levels of HCN were b elow all applicable public health standards. The commenters believe that , because the gold mines are

area sources o f HCN, they should not be subject to section 112

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## work practice standards or newly developed certification requirements. The commenters noted that it is not technically practical to set systematic work practice standards to reduce HCN emissions for every gold mining operation to follow because each m ine is unique in its mineralogy and cyanide leaching
processes , and different process solution pH values are necessary to enhance gold recovery. The commenters explained that for economic, health, and safety reasons, they already implement work practice standards designed to minimize HCN. The commenter concluded that the combination of these work practice standards and the annual TRI reporting more than adequately ensure that gold mining operations will remain area sources of HCN. **Response**

Nevertheless, in determining whether a source is a major source under CAA section 112, we must consider the source’s potential to emit as well as its actual emission s. See CAA **:** As explained above, some commenters believe that EPA’s estimates of hydrogen cyanide emissions are overly conservative (i.e., overestimated)
. O ther commenter s believe that EPA’s estimates do not reflect the “ potential to emit ” from these sources. However, t h ese comm enter s also incorrectly suggested that EPA’s estimates included only actual emissions.

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## section 112(a)(1) and 40 CFR 63.2. For each gold mine facility in our inventory we developed a range of estimated emissions, including an upper

- end estimate for each facility. B ased on these estimates the largest facility emits between 5 and 9 tons per year of hydrogen cyanide . A ll other facilities emit less than this level. Based on test data, a ll facilities emit less than 25 tons per year for the sum of all HAP. Our analysis of the test data include calculations for estimated emissions ba sed on facilities operating at full capacity. We understand that these facilities implement various management practices as part of their operations to minimize the use and emissions of cyanide to protect workers , to comply with Mine Safety and Health Ad ministration (MSHA) standards , to comply with their agreements to the International Cyanide Code , and for economic reasons (to reduce operational and supply costs)
. We currently do not have sufficient information to explicitly quantify emissions reduction s achieved through these management practices. Nevertheless, b ased on our current knowledge of these management practices and based on the results of the emission s testing, we believe that these facilities are

area sources. We have no information that wo uld indicate these facilities are major sources. Accordingly, we are taking final

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## action today to list the gold mine ore processing and production area source category and regulate its mercury emissions pursuant to CAA section 112(c)(6). In addition, we intend to send letters to various Gold Production companies pursuant to Section 114 of the Clean Air Act to obtain additional information which we will use to further evaluate the facilities’ potential to emit and to address any remaining questions regardi ng the ir area
source status
. 5 . Title V Permit Exemption
**Comment**

**•** EPA did not properly determine whether some or all sources in the category are major sources by determining each source’s potential to emit. **:** In the proposal preamble, EPA solicited comment on whether a title V exemption “is appropriate under section 502(a) for any particular sources in this category.” One commenter offered the following reasons for not exempting gold mines from title V permitting requirements:

**•** The CAA allows EPA to exemp t area sources from title V permitting only if it establishes that compliance with the title V permitting requirements would be “impracticable, infeasible or unnecessarily burdensome.” However, EPA does not claim that such requirements are “impracticable, ” “infeasible,” or “unnecessarily burdensome” for gold mines.

**•** It is feasible and within the gold mining companies’ financial means to comply with title V permitting requirements.

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## The commenter believes that the text and legislative history of the CAA ma ke plain that Congress intended ordinary citizens to be able to get emissions and compliance information about air toxics sources and to be able to use that information in enforcement actions and in public policy decisions on a State and local level. Acco rding to the commenter, Congress did not think that enforcement by States or other government entities was enough; if it had, Congress would not have enacted the citizen suit provisions. The commenter said that , if a source does not have a title V permit, it is difficult or impossible for a member of the public to obtain relevant information about its emissions and compliance status or to bring enforcement actions. The commenter stated that to the extent the informational and enforcement benefits provided by title V permits can be considered a burden, the se benefits far outweigh that burden. The commenter also noted that title V provides important monitoring benefits and that title V permits are necessary to provide adequate monitoring. The commenter con cluded by stating that the legislative history of the CAA shows that Congress did not intend EPA to exempt source categories from compliance with title V unless doing so would not adversely affect public

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## health, welfare, or the environment; however, exempt ing gold mines from title V would adversely affect public health, welfare and the environment by depriving the public of important informational and enforcement benefits. One State agency commented that additional title V permitting would subject both the source and the State agency to additional resource burdens. The commenter points out that major sources of criteria pollutant emissions are currently subject to title V permit requirements in Nevada and that sources not subject to major source permitting requirements are subject to Nevada’s minor source permitting program. In addition, the NMCP requires all mining sources to obtain
mercury - specific operating permits to construct. The commenter believes that these permit programs would provide a strong b asis for implementing and enforcing any F ederal MACT requirements for the gold mining industry, and there would be nothing gained by subjecting these sources to title V permitting. Several commenters stated that EPA should exercise its discretion and exemp t the gold mine ore processing and production industry from the title V requirements as impracticable, infeasible, and unnecessarily burdensome. The commenters said that, in light of EPA’s findings in other

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## similar rulemakings for area sources, the four f actors set forth in the Exemption Rule support a finding that title V permitting is “unnecessarily burdensome” for the gold mine ore processing and production area source category. In discussing the first factor of the Exemption Rule, whether title V woul d result in significant improvements to the compliance requirements, the commenters said that the proposed NESHAP for the gold mine ore processing and production area source category includes extensive monitoring, recordkeeping, and reporting requirements that are more comprehensive than title V requirements. The commenters believe that Nevada regulations and permits provide an additional layer of compliance assurance on the federal NESHAP that obviates the need for title V permitting. The commenters clai med that the additional layering of title V does not “significantly improve” upon the proposed and existing compliance requirements. Regarding the second factor in the Exemption Rule, whether title V permitting would impose significant burdens on the area source category and whether the burdens would be aggravated by any difficulty the sources may have in obtaining assistance from permitting agencies, the commenters said that there are extensive administrative burdens and costs associated with the

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## title V p ermitting process, including mandatory activities that have been previously identified by EPA. The commenters claimed that many of the area source gold mines are owned and operated by small entities that are already required to comply with comprehensive S tate permitting requirements for mercury emissions and that requiring title V permits for them would result in resources being redirected away from more useful and necessary efforts. The commenters explained that the third factor in the Exemption Rule exam ines whether the costs of title V permitting for the area source category would be justified, taking into consideration any potential gains in compliance likely to occur for such sources. The commenters claim that there do not appear to be any gains in co mpliance to justify the additional costs that would be imposed on these area sources from title V permitting based on the lack of significant improvements in compliance requirements and the substantial additional costs and burdens associated with title V c ompliance. The commenters noted that the fourth factor in the Exemption Rule analysis is whether there are implementation and enforcement programs in place that are sufficient to assure compliance with the NESHAP for the area source category, without

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## relyi ng on title V permits. The commenters claimed that the proposed rule includes all necessary monitoring to effectively implement its requirements, and the area sources for the gold mine ore processing and production are already permitted under State permit programs. According to the commenters, all non

title V sources in Nevada are required to hold “Class II” operating permits that must contain, among other things, all applicable emission limitations and standards. The commenters said that other States wh ere gold mine ore processing and production area source are located either would be covered by a comparable delegated State air program or by EPA. The commenters stated that EPA regularly provides title V exemptions for area sources similar to gold mine or e processing and production area sources and cited examples from the past
year. The commenters claim that the existing and proposed compliance and monitoring requirements for the gold mines are generally more stringent than those found in the other NESHA Ps for which EPA has granted a title V permit exemption. The commenters stated that exempting the gold mine ore processing and production area source category from title V permitting will not adversely affect public health, welfare, or the environment beca use title V permits do not generally impose

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## substantive air quality control requirements
. According to the commenters, requiring title V permits also carries the potential of adversely affecting public health, welfare, or the environment by shifting State agency resources away from ensuring compliance with a program that is reducing mercury emissions from gold mines. The commenters stated that EPA should exempt the gold mine ore processing and production area source category from title V permitting require ments, and at a minimum, should exempt area source gold mines that are subject to Nevada’s comprehensive mercury control program
. **Response :**  After reviewing the comments, w e continue to believe that it is appropriate that all gold mine ore processing and p roduction facilities be required to obtain title V permits. Most of the other area source categories for which we have provided title V permit exemption s have hundreds or thousands of facilities that are mostly owned by small businesses
. In contrast, t he re are an estimated 21 facilities that are subject to this final rule , and , based on our research and analyses , none of the facilities are owned by small business es ; most of these facilities a re owned by large, and i n some cases, multi

national , corporatio ns . Therefore, we do not believe that the

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## argument of financial burden, which has supported title V exemption for other source categories, applies to the gold mining industry. Currently, it is our understanding that 7 of the 21 facilities that will be s ubject to the final rule already have title V permits ( 5 in Nevada and 2 in other states )
. Further, there are approximately 5 facilities in all other States ( i.e., except Nevada) that do not have title V permits that will be subject to this final r ule , so title V permitting w ill apply to no more than a few facilities in any one of the se other States. Therefore, we do not believe the requirement for title V permitting will be overly burdensome to the permitting authorities in those States
. Although there are more facilities in Nevada that will be subject to the final rule, a s the commenters point out, Nevada already has an effective permitting system in place. Five of the 14 gold mine facilities in Nevada already have title V permits . Because of Nevada’s existing permitting system and experience with title V permitting , w e do not think that it is an undue burden on the State of Nevada to require title V permits from the other gold mine facilities located within the State. We also think it is important fo r the public in States where these facilities are located to have

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## access to emissions and monitoring data and the opportunity for public involvement in the permitting of these facilities that is provided by title V permitting
. 6 . Reconstruction
**Comment**

The commenters also noted that the definition of “reconstruction” authorizes EPA to establish special provisions in a particular standard for the app lication of the reconstruction criteria to the affected source. The commenters said that the “carbon processes” affected source illustrates that the affected source can consist of several pieces of interconnected equipment that together constitute the pro cess **:** Several commenters believe it is appropriate to group under each of the umbrella “affected sources” all the equipment associated with each particular process in order to ensure a reasonable application of the reconstruction provisions found in the General Provisions. The commenters asked that EPA reaffirm that the 50 percent fixed capital cost trigger for determining reconstruction would be measured against all equipment components needed for the defined processes, and that reconstruction at one affected source as defined in the standard will not affect or result in reconstruction at another affected

source.

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## line, and it can be anticipated that production needs will give rise to the need to add more pieces of equipment to an existing carbon process line or even to install a whole new carbon process line. The commenters provided three examples: adding a

n ew component to an existing carbon processes group , construction of a new carbon group due to expansion at a facility that has an existing carbon group ; and installation of new pollution control equipment . The commenter said that consideration of whether or where new MACT requirements should apply in these examples warrants the development of special reconstruction provisions in this standard, or EPA should clarify that the three examples would not be considered reconstruction under the proposed rule. The commenters asked that EPA either clarify that the three examples would not be considered reconstruction, or alternatively, add the following provisions to the proposed rule: (1) an addition of a new piece of equipment to address production requirements i s not considered a reconstruction, (2) the expansion of a facility by the construction of a completely new process line will not be considered a reconstruction of an existing process line, and (3) the installation of air pollution control equipment to comp ly with this standard is not considered

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## a reconstruction. **Response**

Re construction, unless otherwise defined in a relevant standard, means the replacement of components of an affected or a previously nonaffected source to such an extent that: **:** The determination of what constitutes a reconstruction is directly tied to the definition of the affected source and the definition of reconstruction in the p art 63 General Provisions:

(1) The fixed capital cost of the new components exceeds 50 percent of the fixed ca pital cost that would be required to construct a comparable new [affected] source; and (2) It is technologically and economically feasible for the reconstructed source to meet the relevant standard(s) established by the Administrator (or a State) pursuant to section 112 of the Act. Upon reconstruction, an affected source, or a stationary source that becomes an affected source, is subject to relevant standards for new sources, including compliance dates, irrespective of any change in emissions of hazardous a ir pollutants from that source. For each of the four affected sources in the final rule, we have defined the affected source as the collection of processes associated within each affected source. Consequently, if one process within the affected source is upgraded or replaced with a new process, the 50 percent fixed capital cost criterion would be based on the fixed capital cost of replacing all processes in the affected source, not just the capital cost of the process being upgraded or replaced. For examp le, if a new carbon kiln

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## is added to an existing group of carbon processes with mercury
retorts , the capital cost of the new carbon kiln would be divided by the fixed capital cost of constructing a comparable new affected source containing all of the proce sses within the existing affected source of carbon processes with mercury
retorts to calculate the percent for comparison to the 50 percent criterion. With regard to the scenario where a new carbon process with

a mercury retort is installed, t he affected source is defined as the collection of all applicable processes within the affected source, and because of this, a facility could not have two carbon processes with mercury retorts affected sources, such as the commenter suggested, where one group is new and the other is existing. For example, if a new group of carbon processes with
mercury retorts is installed at a facility in addition to existing group of carbon processes with mercury retorts , the two groups (all carbon processes with mercury retorts at the facility) collectively would be a single affected source. In this case, the fixed capital cost criterion would be based on the fixed capital cost of replacing the existing affected source with a comparable new affected source, and if the new processe s exceed 50 percent of that cost, all of the carbon processes with

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## mercury retorts would be subject to the new source limit for carbon processes. There would not be separate and different emission standards for the two sets of carbon sources with
mercury retorts (the older group and newer group) because the collection of all of these processes is the affected source. We do not see a necessity to provide criteria for this final rule that are different from the requirements in the General Provisions for det ermining what constitutes a reconstruction. We also think it is appropriate to exclude the cost of emission control equipment from the cost calculation for reconstruction determinations. B. Applicability
**Comment :**  Several commenters stated the rule shoul d exempt individuals (prospectors), laboratories, small mining operations, and non

- leaching operations. The commenters urged EPA to include in the final rule all of the following exemptions to avoid the problem of unintended regulation of sources that

wer e not meant to be included in the source category: gold mining operations that produce less than 100 pounds of concentrate per year, which would exempt analytical labs that perform small bench scale processing tests on gold ores; gold mining operations tha t do not leach or dissolve gold, which

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## would exempt placer and other non

- leaching operators, including both small commercial efforts as well as individual recreation

type prospectors; and gold mining operations that process less than 1,000 tons per year of gold ore, which would exempt certain small scale pilot plants and related testing operations. The commenters said that the exemptions suggested above will not reduce in any way the effectiveness of the proposed rule in controlling mercury emissions from the targeted larger mines, nor will they lead to increased mercury emissions, but they will exclude regulation of a large number of small operators who do not emit any significant mercury. **Response:** As mentioned above, we have clarified in this final rule that this area source category does not include laboratories (see CAA section 112(c)(7)) , individual prospectors and very small pilot scale mining operations. Prospectors and other very small pilot

- scale operations (e.g., operations that produce or proce ss less than 50 pounds of concentrate per year) are very small and were not included in the section 112(c)(6) inventory that was the basis for the listing of gold mine ore production and processing source category. A ll the facilities in our current invent ory, as well as the facilities considered in developing the 1990 baseline emissions inventory , process or

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## produce more than 4,000 lb/yr of concentrate. We believe that emissions from the very small scale operations described above to be very minimal, espe cially in comparison to the mercury emissions from operations that are regulated under this rule, which process or produce concentrate at amounts far above th i s threshold. However, we believe that the 100 pound s of concentrate cut

off suggested by the commenters is too high. We believe that 50 pounds of concentrate per year more appropriately reflect these very small operations. We are not making the suggested change of excluding operations that do not leach or dissolve gold because certain gold mine fa cilities in the source category use flotation or gravity flotation processes and perform thermal process ing of concentrate in melt furnace s, which can have significant emissions of mercury
. We are also not making the exemption of facilities that process l ess than 1 , 000 tons per year of ore because we believe this exemption is not necessary or appropriate. C. MACT Floors 1. Consideration of Variability in Determining Floors
**Comment :**  One commenter acknowledged that EPA may consider

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## variability in calcula ting the best sources’ performance, but stated that EPA’s method of considering variability seeks to assure that none of the sources among those identified as best performers would ever exceed the floor level. The commenter claims such an approach ignores the reality that sources’ emission levels are largely within their control, and although a great deal of variability may be statistically conceivable, that does not mean that a well

- operated source actually would experience such variability. The commente r said that one of the main points of having emission standards is to ensure that sources not only deploy the appropriate control measures, but also use those control measures consistently to minimize emissions. The commenter said that using an upper pr ediction limit to set standards reflecting the statistical worst performance these sources could have does not yield an accurate picture of the best sources performance, and it is especially arbitrary in the absence of any explanation of why EPA thinks tha t the relevant best sources’ performance would ever be so bad, other than the fact that it is statistically possible. **Response :**  It is EPA policy to allow for variance in test data, between units, and among facilities when developing the

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## MACT standard. F or this rule , we used the UPL analysis on the emissions data for the top five perform ing sources to account for the variance. We believe that this calculation method does yield an accurate picture of the best performers. It is an incorrect statement that no sources among the best performers (i.e., the top five performers for this final rule) would ever exceed the floor limit. The variability that is accounted for in the UPL analysis of historical data would apply to future data as well. Thus, although t he average of several data sets may show a top performing source meeting the emission standard by a wide margin, the variability in emissions inherent in any one compliance test could easily indicate much higher emissions, and, in some cases, an exceedance of the emission standard. The operating conditions under which emissions measurements are made for a given process unit will directly affect those measurements. For example, emissions obtained from a process that is operating poorly will almost certainl y be higher than when operating properly. Therefore, the process that is operating poorly will be less likely to be included in the pool of best performers than if it were operating properly.
We believe the data we use d to calculate the MACT limits are ba sed on representative and normal performance of the

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## source s for many reasons. First, the test results that we are using in our MACT database are tests conducted under Nevada’s mercury emission control program, and some of these tests are to determine whet her a facility is in compliance with State requirements . Facilities typically try to perform as well as they can during such tests. State (and often EPA) permitting authority staff are notified before a performance test is conducted to provide an opportu nity to attend and observe the test, and they often attend to ensure the source is operating properly and that the testing is performed according to the strict requirements in the codified test methods. Test reports are carefully reviewed by the permitting authority, and any failure to follow the test method or abnormal operation of a source is flagged. These data are usually invalidated, and invalidated tests are not used in our MACT floor calculations . For example, several tests from these facilities we re invalidated by the NDEP because the specified testing procedures were not followed or the emission control device was not operating properly, and we have not used those results in our analysis for those reasons. We have collected additional data from t est reports not available at the time of proposal, and one of those tests was invalidated because NDEP

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## representatives discovered that the emission control device was not operating properly during the test, therefore, we also did not use those test data
. T he commenter believes that floors must be set at the average emission level achieved by the best performers when they are operating properly. We agree that the performance data characterizing the emission level achieved by the top performers must be data obtained when they are operating properly, and we believe that is the case for our current database for this source category . The MACT floor is based on the average performance of the top performers, and we can and must develop a MACT floor limit from thi s average that accounts for variability. We accomplish this by calculating the MACT floor limit from this average performance and account for variability by using the 99 percent UPL, which is discussed in more detail in the Summary of Public Comments and Responses document in the docket for this rulemaking . It is not appropriate to ignore the variability in the data because that would be contrary to established statistical theory and practice, and it is also at odds with recent judicial decisions. Finall y, on a practical level and in terms of achievability, ignoring variability and using only the average performance would virtually guarantee

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## that some of even the best performers would exceed the floor limit.
**Comment**

The commenter also stated that the degree of variability allowed in the development of the new source limit for ore pretreatment appears to be out of line with the new source limits for carb on processes and non

- carbon processes. The commenter believes that ore pretreatment variability for new sources is higher than existing sources because low thermal units were included in the same category, high emissions were allowed in the data set, and variable emissions were allowed in data set. The commenter recommended that , if EPA continues to **:** Another commenter stated that conside ration should be given to defining the inherent range of measurement error and requiring more test runs in order to reduce variability due to process variation. The commenter said that this would also better clarify when variability was due to operational controls, which could be addressed, rather than due to factors that cannot be controlled, such as mercury content in the ore. The commenter asked for clarification on how inconsistent runs should be treated, what defines an acceptable set of runs, and at what point more runs would be required to provide reliable data.

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## use Goldstrike as the best performing source for new source MACT, then they should re

- evaluate and reduce the variability to be equal to or less than the vari ability for existing sources. **Response**

We agree with the commenter that the variability used in the development of the proposed new source MACT for the ore **:** We agree with the commenter that the testing process would be more accurate if the number of test runs was increased. However, we balance several factors in determining the minimum number of runs required, and be cause the compliance testing is supplemented by various types of continuous or periodic parametric monitoring, we have concluded that three test runs are appropriate for this final rule. Although we have not proposed a formal procedure to assess the consi stency of test runs, the permitting authority performs routine reviews of compliance test data to identify potential outliers and results that suggest further investigation is needed. For example, a routine review tracks trends in performance, and in part icular, flags any trends in deteriorating performance over time. An unusually high run among the three runs also attracts attention and would be examined to determine if it might have been caused by a problem with the process, control device, sampling, or analysis.

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## pretreatment group appeared to be inconsistent with other data , and it was due in part to two tests of the ore preheater/dry
g rinding process at Goldstrike that the commenter identified. As discussed in more detail below in this preamble, we have obtained new (additional) test data for the ore pretreatment group, including the ore preheater/dry grinding process at Goldstrike. W e have determined that the tests the commenter is referring to are not representative of normal operation, and those tests have been removed from our database because the NDEP invalidated the tests due to possible sample contamination. (See the MACT Floor D ocument in the docket for the final rulemaking). In addition, we have performed additional analyses using the newer test data, which show lower emissions and lower variability than the previous data available at the time of proposal. Also, we have cond ucted additional beyond

- the

- floor analyses. The variability associated with the new source MACT is now significantly lower than the estimate of variability at proposal, and the new source standard in the final rule is more stringent tha n the proposed stan dard . As discussed in more detail below, MACT for new sources for the ore pretreatment group has been reduced from 149 lb/million tons of ore at proposal to 84 lb/million tons in the final rule.

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## 2. General Comments on MACT
**Comment :**  Some commenters sta ted that the MACT floor already represents installation and operation of MACT controls, and the use of emissions data from facilities that are already controlling their mercury emissions creates an artificially low MACT floor. The commenters said that the low MACT floor penalizes facilities that voluntarily invested in pollution control technology and creates a substantial disincentive for industry and States to move ahead of EPA in reducing emissions of HAP. **Response :**  We acknowledged at proposal that ma ny gold mine facilities are already well controlled for many reasons, including participation in the NMCP . We also acknowledge that the top performing facilities that are the basis for the MACT floor calculation are the top performers because they have in stalled controls. CAA section 112(d)(3)(B) requires that, for a category with fewer than 30 sources, the MACT floor not be less stringent than “the average emission limitation achieved by the best performing 5 sources ( for which the Administrator has

or c ould reasonably obtain emission information ).” (Emphasis added). EPA has information on these well

- controlled facilities and use d the information to conduct MACT floor analysis, as

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## required by the CAA. Although the MACT floor may be considered more stri ngent in comparison to floors that would have been established if no facilities had mercury emission controls, we do not consider the floor to be “artificially low” because it has been demonstrated as achievable in practice by facilities that installed mer cury emission controls. 3. MACT for the Ore Pretreatment Group
**Comment :**  Several commenters supported EPA’s general approach to establish three groups of affected sources in the proposal. On the other hand, s everal commenters suggested that EPA develop separate emission standards for roasters and autoclaves for existing and new sources. One commenter stated that roaster and autoclave processes are different from each other based on the mercury species released, controls utilized, and their rates of merc ury emissions. The commenter said that roasters commonly reach temperatures of 400 ° to 700°C, releasing gaseous elemental mercury, whereas autoclaves commonly reach temperatures of 175 ° to 230°C producing reactive gaseous mercury and sulfate and forming m ercury sulfate. According to the commenter, autoclaves are expected to be able to improve efficiency over time. The commenter noted that roasters produce one to two orders of magnitude higher emissions than do

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## autoclaves. The commenter believes that fac ilities that only use autoclaves should not be allowed the leeway to emit at the rate that facilities employing roasters are allowed. The commenter recommends that the ore pretreatment group be divided into high temperature pretreatment processes (roaster s) and low temperature pretreatment processes (autoclaves and ancillary roaster processes, such as dry grinding, pre

- heating, and quenching). **Response :**  We discussed in Section V.A. of the preamble to the proposed rule our rationale for establishing the di fferent affected sources , including the ore pretreatment processes affected source. We believe it is appropriate to maintain the ore pretreatment group affected source, as we had proposed. We do not agree with the comment that roasters necessarily have h igher emissions that are one to two orders of magnitude higher than emission from autoclaves
. The available data show a wide range in emissions from autoclaves (from 0.4 to 115 lb/million tons of ore). This range overlaps the range for roasters and their ancillary equipment , which have combined emissions between 42 to 71 lb/million tons of ore. Moreover, autoclaves and roasters process that same input material (i.e., ore) and are intended for the same purpose (to oxidize the ore). Therefore,

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## we believe that it is appropriate to maintain the ore pretreatment affected source as we had proposed, keeping roasting operations and autoclaves together.
**Comment**

A commenter also stated that although EPA’s standard for new ore pretreatment facilities is as high as its standard for existing facili ties, EPA does not propose or discuss setting beyond

- the

- floor standards for new sources. The commenter claims that EPA has a statutory obligation to ensure that its new source standards reflect the maximum achievable reduction in emissions. **:** One commenter stated that EPA failed to consider beyond

- the

- floor standards for roasters and that if additional reductions are achievable at roasters, then EPA must set additional beyond

- the

- floor standards for roasters.

**Response :**  Following proposal, we continued to investigate the performance of facilities with ore pretreatment processes and opportunities for additional control. We collected data from more recent tests that were not available at proposal, and these new data show that emission control performance at these facilities has continued to improve. We identified two previous
test s in the proposal database that w ere suspect, and we confirmed with NDEP that th ese test s should be invalidated and

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## not used in the analysis bec ause of possible sample contamination. We have also dropped the data for one f acility from the analysis because their autoclave was shutdown in 2007 and dismantled, and we only had one test of the autoclave when it was operating in 2006. For these reason s, it is not appropriate to include data for that f acility in the analysis, which is now based on the only four facilities currently operating. Based on the addition and change described above with respect to our available data, we revised the MACT floor

a nalysis for the ore pretreatment processes. The revised MACT floor for existing sources decreased from 175 lb/million tons at proposal to 158 lb/million tons, and the new source MACT floor dropped from 163 lb/million tons to 84 lb/million tons. The MACT floor limit for existing ore pretreatment processes is based on the use of wet scrubbers, calomel scrubbers, and carbon adsorbers, depending on the specific processing unit included in the affected source . We conducted a beyond

- the

- floor analysis d uring the development of the proposed rule
. The roasters were already equipped with very good mercury controls, and we did not identify any beyond

- the

- floor options for the roasters. However, we identified as a beyond

- the

- floor

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## control for autoclaves the insta llation of both a refrigeration unit (or condenser) and a carbon adsorber. Since our proposal, we have identified a beyond

- the

- floor control option (carbon adsorption ) for the ore pre

- heaters /dryers that could achieve additional emissions reductions of ap proximately 70 percent (or more) for those units
. Two of the three facilities with roasters have already proposed in their NMCP Phase 2 permit applications to apply controls to their preheaters/ore dryers, and these two companies have submitted cost estim ates for applying a carbon adsorption system. Using the cost estimates submitted by the affected facilities, we estimate the capital costs for control of roaster preheaters/dryers for the three facilities with roasters as $3 million with a total annualize d cost of $1.6 million per year . We also estimate a reduction of 118 lb/yr of mercury emissions would be achieved at an overall cost effectiveness of about $13,800 per pound of mercury. We believe that the costs and cost effectiveness are reasonable
. As required under CAA section 112(d)(2), we have also considered

non - air quality health and environmental impacts and energy requirements of this additional control
. W e conclude that this is an acceptable beyond

- the

- floor control technology for existing roa ster preheaters/ore dryers. Therefore, we included

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## the beyond

- the

- floor control for ore preheaters/dryers , as well as the beyond

- the

- floor control for autoclaves, in determining the MACT standard in this final rule for existing sources of ore
pre - treatmen t processes . A fter applying the appropriate variability analyses to the data, we determined that the MACT standard for existing sources is 12 7 lb/million tons of ore
. Beyond

- the

- floor analyses have been included in the determination of the MACT limit f or existing ore pre

- treatment affected sources based on the emissions level achieved by the best controlled similar source
. We did not go beyond

- the

- floor the floor for new sources because we did not identify a feasible and cost

- effective technology that would achieve reduction greater than the new source floor. Therefore, for new sources of ore pretreatment processes, the MACT “ floor ” is the MACT standard for the affected source. T he final new source MACT standard is 84 lb/million tons of ore , which is considerably more stringent c ompared to the proposed standard of 149 lb/million tons o f ore . **Comment :**  One commenter stated that the proposed estimated capital costs of $890,000 and total annualized cost of $720,000 for beyond

- the

- floor autoclave controls are not representative of actual costs of installing a refrigeration unit (or

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## condenser) and a carbon adsorber on autoclaves. The commenter estimates that capital costs for autoclave controls will range from $18 million to at least $30 million, and annual operating costs could range from $2 million to $60 million, depending on which controls, if any, are determined to be technically feasible. The commenter believes that based on these cost estimates, beyond

- the

- floor MACT controls would be cost prohibitiv e and are not justified for the ore pretreatment affected source group. Another commenter estimated that for the installation of carbon adsorbers on their autoclaves to control mercury emissions, the capital costs w ould range from $30 million to $35 millio n, annual operating costs would be $2 million per year, and the annual energy requirements would be 11,400 megawatt

hours per year with an annual energy cost of $900,000. **Response :**  After reviewing the new cost estimates provided by the commenters, we agr ee that capital and total annualized cost estimates of the beyond

- the

- floor controls on autoclaves in the proposal w ere underestimated. We evaluated the detailed cost estimate based on an engineering study for a carbon adsorption system provided by one of the commenter s (see details in the comment above on capital , operating, and energy costs ),

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## and our review of these details indicates it to be a reasonable cost estimate. Therefore , we have used this estimate as the basis for our estimate of the costs of the beyond

- the

- floor mercury emission controls for autoclaves. Our revised estimate s are that the capital cost for install ing carbon adsorbers on autoclaves would be $29.3 million , with a total annualized cost of $4.9 million per year , which would result in an estimated reduction of 431 lb/yr of mercury emissions per year and an overall cost effectiveness of about $1 1 ,000 per pound of
mercury . Based on these new costs and estimated reductions we conclude that the beyond the floor controls are justified fo r the ore pretreatment affected source
. **Comment** : Several commenters noted that , at the proposed new source MACT limit of 149 pounds/million tons of ore, the proposed new source Donlin Creek Mine, located in Alaska, would be allowed to emit 3,200 lb /yr o f mercury based on a projected production rate of 22 million tons /yr of ore. **Response** : With respect to the proposed new gold mine in Alaska, the commenters’ estimate of 3,200 lb /yr of mercury emissions is inaccurate and a significant overestimate for

sev eral reasons. The two primary reasons are that , based on available information , if the facility is built, only an

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## estimated 15 percent of the ore mined will be processed in autoclaves (not 100 percent as assumed by the commenters), and that the commenters ’ estimate is based on assuming that the average emissions level for the facility throughout the year would be at the maximum allowed at the proposed new source limit (149 lb/million tons of ore )
. With the new source MACT standard in the final rule that is about two times more stringent than the proposed MACT standard , along with corrections described above, we estimate that far less than 3,200 lb/yr would be emitted from this new source if it is ever built. Assuming continuous operation for 365 days
pe r year, an estimated 21.5 million tons /yr of ore mined, about 3.2 million tons /yr processed in autoclaves (15 percent), and assuming the source would emit at the average emission level used to calculate the revised new source MACT (45 lb/million tons of or e), we calculate that mercury emissions would be about
144 lb/yr , which is about 5 percent of the estimate provided by the commenters. Considering that the facility has yet to go through the permitting process and that if they could not meet the new sourc e MACT limit, installation of carbon adsorbers would likely reduce the emissions below 45 lb/million tons, we believe that, if the facility is built, emissions w ould quite

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## likely be lower than 144 lb/yr
. 4. MACT for Carbon Processes
**Comment :**  Several com menters objected to including Facility M in the MACT floor determination for new and existing sources in the carbon processes affected source because it is not representative of , or similar to , other sources, because it has unusually low mercury concentrat ions in its ore, and no need for a retort to remove and recover mercury. They noted that , because the mercury content of the gold ore is fixed, the only way for other facilities to reduce emissions of mercury is to apply mercury emission controls, but , fo r many facilities, emission controls will not be enough to meet the proposed MACT standard. The commenters stated they were aware that the D.C. Circuit Court had constrained EPA’s discretion to set floors that fail to consider material inputs, but they sa id gold mines were different from the remanded source categories (brick kilns and cement kilns) because gold mining operations process very large quantities of ore, and the ore is the only material input that results in mercury emissions. The commenters s tated that , in adopting section 112, Congress expressly cautioned EPA against setting standards that would require mining operations to change the ore used as essential feedstock. The commenters

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## said that , by ignoring the mercury content in the ore being mined and processed at the facilities in the MACT floor determination, EPA is requiring facilities to consider the substitution of, or changes in, the ore that is processed because there is no other way to achieve the standard. The commenters recommended that EPA address, as a threshold matter, the differences in processing and emissions across facilities that result from the variable concentration of mercury in ore. The commenters recommended that Facility M not be considered the “best controlled similar source” for purposes of setting the new source MACT floor because the facility is not similar to other sources. The commenters stated that , if EPA does not exclude from the source category facilities that do not use retorts to process concentrate, then t hey should subcategorize them
. **Response :**  After consideration of comments and a re

examination of the emission controls and factors affecting emissions from the carbon processes at Facility M, we agree that this facility is quite different and unique compa red to most other gold mine ore processing and production facilities , including other facilities in Nevada, in its carbon process. The mercury emissions from carbon processes at this facility are a factor of 10 less than the next “best” performer ( F acilit y N)

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## and a factor of 23 less than the average of the top 5 performing facilities in the proposed rule . This level of emissions is due primarily to the very low levels of mercury in the ore rather than having better emission controls than those found at th e other top performing facilities. Facility M has good controls for mercury emissions from its carbon processes , but they are
not as effective as the controls at F acility N. Facility N has
state

- of

- the

- art controls. The difference is further manifested by the differences in the processing train for the carbon group in that mercury retorts are not needed or used at Facility M to recover mercury because the mercury levels are so low. As the commenter notes, t he CAA allows EPA to “distinguish among classes , types and sizes of sources within a category” in developing MACT emission standards , and gold mine facilities without mercury retorts are different in both class and type from those with mercury retorts
. Accordingly , in the final rule, we identify and s et separate MACT standards for two types of carbon processes: those that use mercury retorts ; and those , such as the carbon process at F acility M , that do not use
mercury retorts. As part of our re

- analysis of the MACT floor and MACT for sources that are in the carbon processes with mercury retorts

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## and those without mercury retorts, we considered new data that

w ere not available at the time of proposal. Over the past one to two years since our data collection effort for the proposal, facilities in Nevada have continued to add controls and improve emission control as part of the N MCP . The new data indicate that there were two facilities with carbon processes without
mercury retorts operating in 2009 . Using the data from these two facilities , we determine d that the MACT floor limits for carbon processes without mercury retorts are 0.1 7 lb/ton of concentrate for existing sources and 0. 14 lb/ton of concentrate for new sources (based on the best performing facility).
In our beyond

- the

- floor analysis , we con sidered the addition of a carbon adsorber on an uncontrolled emission unit within an existing affected source. We estimate the capital cost as $210,000 with a total annualized cost of $72,000 per year, an emission reduction of 1.63 lb/yr o f mercury, and a cost effectiveness of $44,000 /lb of mercury. In l ight of the small emission reduction and the high cost effectiveness of this beyond

- the

- floor option, we decided not to go beyond

- the

- floor. Therefore, for existing sources of carbon processes without

mer cury retorts, the MACT floor limit is the MACT standard for this affected source
.

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## As part of our re

- analysis for the carbon group processes with mercury retorts, we collected and evaluated additional data. As discussed above, several of the facilities have improved emission control over the levels observed in the database we used at proposal. Two facilities with newly

installed controls replaced two higher

- emitting facilities that were in the top 5 at proposal, and all three of the other facilities tha t remained in the top 5 had lower levels of emissions after considering the new data. The results are that the MACT floor limits for carbon processes with mercury retorts

are 2.2 lb/ton of concentrate for exi s ting sources and 0.8 lb/ton of concentrate for new sources (based on the best performing facility). In the beyond

- the

- floor analysis, we evaluated the impacts of adding a second carbon adsorber in series with the controls applied to achieve the MACT floor level of control. We estimate the capital co st would be $3 million with a total annualized cost of $1 .3 million per year, an emission reduction of 9 lb/yr or mercury, and a cost effectiveness of $150,000/lb of mercury. B ecause of the small emission reduction and high cost effectiveness associated w ith this additional control, we decided not to go beyond the floor. Therefore, for existing sources of carbon processes with mercury

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## retorts, the MACT floor limit is the MACT standard for this affected source
. 5. Compliance Alternative for New Carbon Pr ocess Sources
**Comment**

One commenter supported EPA’s use of the percent control alternative to the new source MACT for the carbon group. The commenter believes that the percent control alter native for new source carbon group MACT should also be available as an alternative to the existing source MACT for the carbon group. **:** One commenter noted that the compliance “alternative” of 97 percent would be unlawful unless EPA specified that carbon sources had to meet the more stringent of either the floor standard or a 97 percent reduction standard. The comm enter stated that because floors must reflect the emission level achieved by the best performing sources, allowing sources to meet a 97 percent reduction standard that was less stringent than the emission level actually achieved by the relevant best source s would contravene section 112(d)(3) and well

- established D.C. Circuit court precedent.

Another commenter stated that another facility, which has an average mercury reduction efficiency level of 99.995 percent , represents the “best controlled” similar source for the carbon

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## process group and should be the basis for the alternative limits for new carbon processes. Several commenters requested clarification of the way in which compliance with the alternative for p ercent reduction would be demonstrated for new sources when there are multiple control devices on an emission unit. **Response :**  We eliminated in the final rule the compliance alternative of 97

- percent reduction for new carbon processes. After reviewing the comments received on this standard and giving further consideration to the practicality of how it would be measured, we concluded that this option would be difficult to implement , particularly when multiple processes that are operated at different time s vent to a single control device and stack . In addition, we have limited data supporting this compliance alternative. In proposing this alternative for comment, we had hoped to but did not receive additional data indicating that the 97 percent reduction option would be equivalent to the proposed new source limit of 0.14 pounds of mercury per ton of concentrate. Largely due to the reasons stated above, we have eliminated the 97 percent control efficiency option for new carbon processes in the final rule.

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## D. Compliance Determinations 1. Timing for Compliance Determinations
**Comment :**  Several commenters requ ested that the compliance deadline for existing sources be 3 years after the effective date of the rule, rather than the 2 years proposed. The
comment ers noted that several facilities will have to install control devices to achieve the MACT floor limits that have been proposed. The commenters explained that the controls must be custom designed for the unique characteristics of each process and associat ed process streams at each facility and stated that it can be time consuming and difficult to design, procure, construct, and implement emission controls to ensure effective operation for the particular source. **Response :**  After reviewing the information provided in public comments on the challenges of retrofitting new controls , and the fact that these controls have not yet been demonstrated

on autoclaves and ore preheaters, w e believe th at allowing 3 years for existing sources to comply is appropriate . G iven the complexity of the sources, the combinations of control devices that are needed in many cases, and the amount of time necessary for designing, install ing, testing, and commissioning addition al emission controls for mercury , we conclude that 2 years may not

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## provide adequate time for existing sources to comply with the final emission standards
. **Comment**

Another commenter commented that the annual compliance testing should not be constrained to the same calendar quarter each year. The commenter stated that this can lead to testing during periods of operation that may not represen t normal production capacities. The commenter believes that mercury emissions testing should be scheduled for the most appropriate time interval throughout the calendar year. **:** Several commenters recommended that the rule specify that source testing results be used to determine compliance for the calendar year in which the t est was conducted rather than to determine compliance for the prior 12 months. The commenters suggested that the source test results be applied to the hours of operation at the end of the calendar year to determine the source’s compliance with the MACT st andard on an annual basis, as required in the NMCP. The commenters suggested that , if more than one source test is conducted in a year, the facility should average the mercury emission test results to determine compliance for the calendar year in which th e tests were conducted.

**Response :**  The permitting authority needs to be able to

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## determine compliance w ith the NESHAP as soon as possible after the tests are completed and test results are available. Consequently, the final rule requires that initial compliance be determined based on production data and operating hours for all full calendar months between the date the rule is published in the Federal Register and the date of the compliance test, and subsequently, annual compliance must be based on the 12 full calendar months preceding the compliance test. This allows the permitting authority to determine if the affected source is in compliance in a timely manner. (This is consistent with the way compliance determinations are made in another MACT rule that uses a similar format

- National Emission Standards for Hazardous Air Pollutants for Primary Lead Sme lting, 40 CFR part 63, subpart TTT.) If compliance was based on a calendar year, as suggested by the commenter, then we would not know if a source is in compliance until after December each year. For example, if a source conducted its compliance test in March, we would have to wait about 9 more months before we could determine if that source was actually in compliance. After those 9 months, if the source was not in compliance, it would mean that the source could have been out of compliance for the previo us 9 months.

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## Moreover, we do not believe that compliance with the NESHAP based on the production data from the 12 months prior to the compliance test would cause problems with reporting under the State program. It is our understanding that the emissions limits in the Nevada State phase 2 permits are (or will be) based on concentration in the stacks (e.g., micrograms per cubic meter (μg/m 3 

## )). The limits in this final rule are based either on pounds of mercury per million tons of ore or pounds of
mercury per tons of concentrate. Therefore, the companies can continue to report the annual emissions as required under the TRI program and the State program without conflict with this rule. If multiple compliance tests are conducted during the year, then a co mpliance determination must be made for each separate compliance test based on the production data for the 12 months preceding each test (i.e., the results of multiple compliance tests conducted throughout the year are not averaged to provide a single comp liance determination for the year). We understand that the rule , as proposed , may have required all existing sources to conduct their subsequent annual compliance tests in the same calendar quarter, and this may pose a scheduling problem because of the lar ge number of facilities

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## located in the same State (Nevada). Our concern was that subsequent annual compliance tests, if not separated in time, could be conducted for two different years with little time between the two tests (e.g., only a few days apart f or the extreme case where the first test is conducted in late December and the second one in early January of the following year). We are providing scheduling flexibility by requiring that annual compliance tests be at least 3 months apart and no more tha n 15 months apart, and we are providing a similar separation for the period between the initial compliance test and the first annual compliance test. We do not believe that tracking multiple compliance dates is a particular problem for the permitting auth ority because that is the case for many other source categories of sources subject to annual compliance testing. 2. Test Methods
**Comment :**  Several commenters supported EPA’s proposal of alternate Methods 30A and 30B for demonstrating compliance. One

comm enter supported EPA’s requirement to use Method 29 as an emission test method, but recommended two revisions: requiring a determination of the absence of cyclonic flow before sampling, and a minimum sampling time of 90 minutes for each test run. The comm enter also stated that they do not support the use of

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## the Ontario Hydro Method (ASTM D6784

- 02), Method 30A, or Method 30B as mercury test methods. The commenter believes that the methods of demonstrating compliance with the emissions standards should be c onsistent with the methods utilized to establish the emission standards , which were based on Method 29 data. The commenter said that the typical gas streams associated with the mining industry have high particulate loadings, high mercury concentrations, s ulfur dioxide (SO 2 

## ) , and contain particulate

bound mercury. The commenter also stated that the alternative methods were not developed specifically for the gold mining industry and their typical gas streams and concluded that the results from the various a lternative methods will yield varying results, will not be comparable, and will provide inconsistent reporting of overall mercury emissions. **Response**

When specifying the minimum requirements for compliance **:** Method 29 references Method 1, which requires cyclonic flow checks under certain circumstances. Consequ ently, in the final rule, we have removed the specific requirements for cyclonic flow checks prior to every stack test that were in the proposed rule. Owners or operators should follow the requirements in the applicable EPA reference method and any additi onal requirements specified by the permitting authority.

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## tests, it is more important to specify a minimum sampling volume than a minimum sampling time because the detection of a regulated pollutant is a function of the volume of the sample rather than the length of time taken to collect the sample
. Thus , the final rule does not specify a minimum sampling time
. We are also changing the required minimum sampling volume to be 30 dscf rather than the 6 0 dscf as proposed because we believe that 30 dscf generally will be adequate for detecting mercury emissions for this industry . Affected facilities should be aware, however, that the minimum sample volume may sometimes result in a failure to detect any m ercury (a non

- detect) emitted from a process unit subject to the emission standard (for the group of process units within the affected source) because of a mercury concentration at the outlet lower than expected. If the emission testing results for any of the emission points yield a

non - detect value, then the minimum detection limit (MDL) must be used in calculating the emissions for that emission point and, in turn, for calculating the sum of the mass emissions for all emission points subject to the emiss ion standard for determining compliance. If the resulting mercury mass emissions rate is greater than the allowable emission limit, the owner or operator
may use procedures that produce lower MDL results and repeat the

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## mercury emissions testing one additi onal time for any emission point for which the measured result was below the MDL. If this additional testing is performed, the results from that testing must be used to determine compliance (i.e., there are no additional opportunities allowed to lower the MDL). We agree with the commenter that M ethod 29 is the most appropriate method for compliance determinations for this source category because of the unique characteristics of these sources , however alternative methods (such as 30B and OHM) may prove to be more appropriate under certain circumstances . Therefore, w e are promulgating M ethod 29 as the main method for compliance in this rule . Alternative methods , such as 30B and the Ontario Hydro method (OHM), could be used to demonstrate compliance for thi s source category if approv ed by the permit ting authority. We have omitted Method 30A as an option in the final rule, as it is not yet in general use. E. Monitoring 1. Compliance Assurance
**Comment :**  One commenter noted that EPA’s proposed mercury
st andards are expressed in a format of pounds of mercury per million tons of ore processed and observed that the proposed rule requires stack testing only once a year. The commenter

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## claims that EPA’s proposed monitoring requirements would not demonstrate wh ether sources are in compliance with their emission standards, which renders the rule unenforceable. According to the commenter, the once

- a - year stack test would provide no indication as to what a mine’s emissions were the rest of the year. The commenter said that a source that failed its stack test would have only one violation of emission standards, even if that test showed that the source likely violated its emission standard throughout the year. The commenter believes that EPA’s proposed monitoring r equirements would not assure compliance with the proposed emission standards. The commenter also noted that EPA proposes to require sources to monitor their mercury emissions either with CEMs, sampling, or various types of parametric monitoring; however, these methods do not provide direct information about the pounds of mercury emitted. Consequently, none of these monitoring methods could be used to demonstrate whether a source is in or out of compliance with the proposed emission standards. Accordin g to another commenter, all three affected source categories should be required to use CEMS at all times and at all emission points. The commenter stated that the ore pretreatment group especially needs CEMS because of variable

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## levels of mercury in the or e and different operational measures within the control of the facility. Other commenters supported EPA’s decision to require continuous monitoring and said that the CEMS should be incorporated into the compliance regime as well. The commenters believe th at, if the monitoring results indicate that the mine is consistently out of compliance for a period of one week without correction, the process unit should be subject to compliance

- based penalties and/or shut down until corrections are made and the process unit is back in compliance. According to the commenters, quarterly stack testing should still be required to demonstrate that the CEMS is working. **Response** : We recognize the importance of requiring adequate monitoring to assure compliance with the emis sion standards . Because of the higher mercury emitting potential of the roaster, we proposed the option of mercury monitoring using CEMS or weekly monitoring with PS 12B with associated parametric monitoring as well
. We are including in the final rule th e option to perform continuous PS 12B monitoring, and, as with the CEMS, associated parametric monitoring would not be required. We are changing the frequency of the proposed weekly concentration monitoring approach for roasters to twice per

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## month (at lea st 1 1 days apart ) and would allow a facility to conduct a Method 30B test (as an alternative to a PS 12B test), supplemented with continuous parametric monitoring. We changed the frequency because we believe that sampling twice per month , coupled with con tinuous parametric monitoring , is sufficient for determining that the roaster control devices are operating properly. We added this alternative because Method 30B directly measures mercury concentration and is a valid means of determining whether the conc entration is below the operating limit established during t he initial performance test
. T he
t wice per month Method 30B measurements will provide a concentration value that can be compare d to that operating limit to determine if an exceedance of the operat ing limit has occurred
. Also, if the twice monthly sampling shows repeated deviations over time, EPA could decide at a later date that CEMs are appropriate and necessary for roasters. We believe that the mercury concentrations monitoring for
roasters along with the parametric monitoring of all control devices on all units is an acceptable approach to assure compliance with the emission standards
. Parametric monitoring of control devices assure s that the control devices are operating properly (and redu cing emissions ) on an ongoing basis.

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## We disagree with the commenter that the proposed monitoring requirements render the rule unenforceable. The mercury operating limits in both the proposed and final rules are enforceable, and any exceedance of these op erating limits triggers corrective action. If corrective action does not return the mercury concentration within the established limits, the plant must conduct a full compliance test and determine if the source is meeting the mass

- based (lb/million tons o f ore) emission standard. We disagree with commenters that CEMS should be required for the non

- roaster sources. These sources have less potential mercury emissions, and requiring CEMS on all these other units would be quite costly and burdensome. Moreov er, m ost of these other units are , or will be, controlled with carbon adsorbers, and the carbon adsorber monitoring required by the final rule is an effective means of ensuring the controls are working effectively on a contin uing basis . We consider that e ither frequent testing of carbon beds to monitor for breakthrough using Method 30B , or frequent adsorbent sampling for mercury
content , is an effective way to ensure these mercury control systems are operating properly on a continuing basis. With regard t o some of the units without carbon adsorbers, we believe

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## that annual tests coupled with appropriate parametric monitoring of the control devices are sufficient to ensure emissions are properly controlled on a continuing basis. With regard to the comment that quarterly stack testing should be required for facilities using a CEMS, we believe that following the Quality Assurance (QA) procedures detailed in 40
CFR 60 , Appendix F , are sufficient to ensure the CEMS continues to operate as designed, and in this case, additional stack sampling is not necessary. 2. Operating Limits
**Comment :**  One commenter stated that the operating limits for roasters and for carbon adsorbers are inappropriate and set up a second set of MACT standards. The commenter claimed that the operating limits do not take into account the effects of: hours of operation of a process unit on mercury emissions; reduction in performance of a process unit offset by an improvement in performance of another process unit; variability in the exhaus t gas flow rates with no appreciable effect on the corresponding mercury emission rate; and variability in the inlet mercury concentrations to a carbon adsorber . These factors all result in variability in the outlet mercury concentration. The commenter a lso noted that the proposed

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## operating limit for carbon adsorbers could result in premature carbon change out, resulting in the generation of more waste. The commenter recommended that EPA defer to the Nevada state monitoring requirements and only provide for monitoring of throughput and annual mercury emission testing to demonstrate compliance with the MACT emission standard. The commenter believes that any operating limit parameters must be established based on manufacturer specifications and recommendat ions in coordination with the permitting authority and not based on values measured during source compliance testing. **Response :**  We proposed the mercury operating limits as a monitoring tool to ensure that the processes within individual affected sources a nd their associated control devices are functioning properly on a continuing basis and not as a second set of MACT standards
. We developed emission standards for four affected sources, and the emission standard for an affected source applies to the sum of emissions from all process units within the affected source. One unit could have an upward fluctuation in mercury concentration, but the group of process units could still meet the limit. We see the value of the operating limit approach as sufficient to detect significant increases in emissions and as a valuable tool to ensure the

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## control devices are operating effectively and provide quick notification of a potential problem with controls or emissions
. The monitoring parameters are used as compliance in dicators , and the relevant mercury operating limits are the main “triggers” of a possible emissions increase and are set to alert facility operators when emissions are greater than the corresponding
mercury operating limit
. W e believe it is important to h ave such monitoring in the rule to ensure the control devices are working properly. Regarding specific comments about monitoring the carbon adsorber, the State of Nevada has had good results with conducting sampling of the carbon adsorber to maintain its performance. The final rule offers an additional option of measuring the mercury concentration exiting the carbon adsorber that also achieves the same objective of avoiding breakthrough of the bed. We do not expect sudden dramatic failures of this techn ology. Instead, we expect to obtain close control of performance by ensuring that the carbon is changed in a way that prevents breakthrough. This monitoring methodology should also prevent premature replacement of the bed. We disagree with the comments t hat only monitoring for throughput and annual emissions testing are sufficient to

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## demonstrate compliance for sources controlled with carbon adsorbers. Such an approach does not provide for continuous monitoring . The parametric monitoring and operating li mits specified in this final rule provide ongoing assurance that control devices are properly operated and maintained between emissions tests , and exceedances of the operating limit require corrective action. W e also reject the comment that all operating limits should be based solely on manufacturer specifications and/or in consultation with the permitting authority. Control device operating parameter values often are site

- specific and are associated with a level of emissions from the source. In order to ensure continuous compliance, certain parameter limits generally should be associated with an emissions test that demonstrates compliance with the emissions standards. However, we agree that certain parameters for mercury scrubbers applied to roasters, s uch as the ranges associated with ensuring the proper chemistry of the scrubber, are best provided by the system’s manufacturer. Guarantees of performance are usually conditioned by requiring that the system be operated as designed and specified by the ma nufacturer, and there is no assurance that a potentially narrow range that would be established during a short performance test reflects the full

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## applicable range of proper operation. A facility may request us to consider alternative procedures for settin g operating limits

on a case - by

- case basis under 40 CFR 63.8, if desired.
**Comment :**  Some commenters stated that their established parametric monitoring programs are sufficient to confirm that mercury emission controls are functioning properly for roasters
. The commenters also stated that the NMCP permits have required parametric limits and that additional CEMS for mercury would neither improve the operation of these current controls, nor reduce mercury emissions. The commenters concluded that the operat ing parameters monitored on a regular basis are key parameters for measuring the efficiency and operation of the mercury controls and that operating each of these units within the optimum ranges ensures that mercury emissions are being effectively controll ed. **Response :**  As discussed above, we do not believe parametric monitoring alone is sufficient for roasters because of the very high mercury emission potential , unless the facility has adequately demonstrated that the mercury emissions from the
roaster s are consistently very low (e.g., less than 10 pounds per million tons)
. Nevertheless, w e have concluded that the combined approach of annual stack compliance testing along with

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## the monitoring requirements and options outlined in this rule

are necessary to detect excess emissions and to ensu r e controls are working effectively on a continuous basis. 3. Mercury Concentration Monitoring for Roasters
**Comment :**  One commente r stated that the proposed provisions for monitoring mercury concentration s in roast er emissions are not based on roaster process and pollution control device operational parameters and would not yield reliable information that can be used for detecting and correcting problems. The commenter also stated that the formula for establishing the
mercury operation limit for roasters is not appropriate because it uses an emission limit that is based on emission test data from several process units in addition to the roaster. The commenter recommended using the methods proposed for parametric

mo nitoring of roaster emission control devices for all roasters. The commenter also has concerns about utilizing PS 12A (mercury CEMS) and PS 12B for emissions monitoring purposes because there are terms and conditions listed in the proposed rule that are

n ot fully defined. The commenter also recommended deleting the emissions monitoring requirements for mercury concentration for carbon adsorbers for the same reasons described above for
roasters.

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## Response **:** We disagree with the comment that monitoring the

m ercury concentration in roaster emissions would not yield reliable information that can be used for detecting and correcting problems. An elevated mercury concentration in the roaster stack gas indicates that there could be a problem with either the proce ss or the control device , which could result in excess mercury emissions from that unit . M onitoring the mercury concentration in roaster emissions provides a direct measure of the regulated pollutant (mercury). The commenter is correct that the formula f or establishing the mercury operating limit for roasters is based on emission tests performed on several processes units in addition to the roaster. However, f or the facilities with roasters that will be subject to the requirements to monitor mercury conc entration, the roaster is the biggest source of potential mercury emissions within the affected source. Therefore, we conclude that changes in the mercury concentration in the roaster exhaust gases provide a good indication of overall emissions from the a ffected source. In addition, the operating limit is not used directly to determine compliance with the MACT emission standard . As mentioned above, it is designed to detect elevated mercury concentrations in the roaster stack gas, which could indicate a

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## pr oblem with either the process or the control device. We continue to believe that it is necessary and appropriate to monitor mercury concentration for the largest source of potential mercury emissions in the source category (i.e., the roaster) to detect ex cursions in emissions that must be addressed when the operating limit is exceeded. By developing the mercury operating limit from the emission standard and compliance test results, an exceedance of the mercury operating limit will indicat e a potential inc rease in emissions and that corrective actions are need ed
. As described above, we believe that either continuous mercury sampling or mercury sampling twice per month, coupled with continuous parametric monitoring of the control device , should be require d for the roaster emissions. If a CEMS is used, the daily average mercury concentration is calculated by averaging the hourly emissions concentrations during that day. If PS 12B is used for continuous integrated sampling (i.e., without parametric monitor ing), the daily average concentration is determined by assigning the mercury concentration measured by the sorbent trap monitoring system (total mass of mercury collected during the sampling period divided by the sample volume) as the daily average value t o each of the days covered

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## by the integrated sample. As discussed above, the final rule include s continuous sampling with PS 12B as a second option for monitoring roasters. A third option is based on short

- term sampling twice per month (at least 1 1 days a part) for mercury concentration using either PS 12B or Method 30B, and if this option is chosen, parametric monitoring of the mercury scrubber must also be performed. For the third option (twice per month sampling) each measured mercury concentration must be compared to the operating limit to determine if an exceedance has occurred. For the contents of the monitoring plan, see 40 FR 63.8(d)(3) and 40 CFR 60, Appendix F.
W e also disagree that parametric monitoring alone is sufficient for carbon adsorbers. For carbon adsorbers, measuring the mercury concentration exiting the carbon bed is also a direct measure of the pollutant of interest. (The other option as established for years in NDEP operating permits involves sampling the carbon for mercury content .) An elevated mercury concentration indicates that there could be a problem with either the process or the control device , which could result in excess mercury emissions from that unit
. We have established exit concentration monitoring requirements in m any

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## rules for emissions of organic compounds exiting carbon adsorbers . T hat monitoring has proven to be effective to prevent or detect breakthrough, and the same principles apply here for mercury . **Comment :**  Commenters stated that CEMS for gold mining
op erations are not capable of accurately measuring mercury emissions and that there are three major challenges with the feasibility of mercury CEMS for the gold mining industry: mercury CEMS calibration, sample transport, and system operability and reliabil ity. The commenters are concerned with the unavailability of a means to calibrate the CEMS for roasters because existing calibrator designs are simply not capable of generating mercury concentrations high enough to provide meaningful upscale calibration p oints that correspond to gold mining source characteristics. The commenters noted the unavailability of National Institute of Standards and Technology (NIST) traceable calibration gas es and stated that the current calibration standards traceable to NIST d o not apply to the full range of mercury concentrations that can be present in the exhaust gases of roasters. The commenters concluded that the lack of a NIST

- traceable standard is a fatal flaw that precludes using mercury CEMS to monitor roaster emission s. Regarding

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## sample transport, the commenters said that current designs of mercury CEMS for coal

- fired electric generating units require high temperature umbilical lines to transport the sample from the stack to the analyzer and that CEMS on coal

- fired el ectric generating units have seen umbilical failures occur, representing another challenge to having CEMS function consistently for the continuous monitoring of mercury from industrial sources. The commenters were also concerned with the CEMS operability and reliability because mercury CEMS must contain some type of converter to reduce oxidized mercury to elemental mercury and premature catalytic failures periodically occur in these units resulting in several days of missing data. The commenters continued by stating that users reported mercury CEMS to be unavailable as much as 30 to 40 percent of the electric generating unit operating time. The commenters believe the amount of downtime to be expected from these systems on roasters would likely be even hig her. The commenter concluded that the breakdown events, combined with the other types of failures, result in data availability that is substantially inferior to parametric monitoring and cannot justify the significant cost and resource investment necessar y to install, operate, and maintain these devices.

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## The commenters are concerned that continuous data reports of mercury emissions that are not accurate, reliable, or credible could be offered as “credible evidence” to assert a violation. The commenter con cluded by stating that this concern was particularly troubling in Nevada, where there are separate mercury limits established pursuant to State law. **Response**

In addition, the NIST has recently completed certification of a ‘NIST Prime’ elemental m ercury gas generator at concentrations of 41, 68, 85, 105, 140, 185, 230, 287, and 353 μg/m 3 

## . Mercury gas generator vendors may now submit elemental mercury gas generators for certification to serve as ‘Vendor Primes’ in a wide range of concentrations. T herefore NIST traceable mercury gas standards can now be made available in **:** Regarding the feasibility of using CEMS to monitor mercury emissions from roasters, CEMS have be en demonstrated for process units similar to roasters (e.g., coal

fired power plants ), and we believe there is no technical reason why they will not work for the roasters . Many of the issues with mercury CEMS have been resolved as facilities have gained

e xperience with their use. As we discussed in the proposal preamble, CEMS manufacturers supply calibration standards for the ranges of concentrations seen at roasters.

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## concentrations that exceed the concentrations typically seen from roasters. After consideration of public comments, we continue to believe CEMS are a valuable tool and a reasonable option for monitor ing mercury concentration and comparing those concentrations to the operating limit that is established by CEMS measurements made during the compliance test. In addition, we are promulgating a second option for continuous monitoring usin g PS 12B, and a third option of twice per month sampling using PS 12B or Method 30B coupled with parametric monitoring. We also point out that the final rule does not require the use of CEMS ; instead, the final rule includes CEMS as one of the three monit oring option s to ensure that emissions from the
roasters are not exceed operating limits, or if they do exceed the operating limits, that corrective actions are taken in a timely manner to bring the emissions down to within the operating limits. The CEMs can also be used to help identify problems with control systems and ensure that corrective actions are taken immediately to fix such problems
. We understand the commenter ’s concerns regarding the transport of samples and converter failures. We have revise d the final rule to give facilities 3 years to successfully

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## operate controls and monitoring equipment to be able to comply with the MACT standards.
**Comment :**  One commenter stated that the regulated industry has no experience with direct measurements of mercury concentrations at the roaster exhaust gas stream. As a result, the commenter believes that there will be problems in collecting data, establishing appropriate timeframes for sampling under PS 12B, maintaining instrument reliability for CEMS, and i n establishing confidence in the accuracy of the results reported by these methods. The commenter claimed that the calculated operating limit based on source testing and simultaneous direct measurements may not be reflective of the future daily operations of all the stack emissions. The commenter noted that flow rate measurements are critical in verifying compliance with actual emission limits because sometimes lower flow rates of the stack exhaust gas flow can artificially elevate the mercury concentrati on in the gas stream with no real effect on emissions. The commenter concluded that any exceed a nce in mercury concentration should be verified first with a compliance test before halting the roaster production. **Response :**  W e have learned from the comments received that there may be a learning curve for facilities to implement the

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## concentration monitoring procedures. As described in section
IV. D. of this preamble , w e have established in the final rule a compliance date that is 3 years after the effective d ate of the final rule for existing sources, part ly to allow sources time to ensure they can successfully comply with the monitoring requirements, but mainly to allow time to install new mercury emission controls that we believe will be necessary to meet th e emission standards in the final rule. We agree that mercury concentration measurements are not direct measure ments of the emissions rate from the affected source and that flow rate, production, and other factors need to be considered. These are some of the reasons that the operating limit is not being used as a direct measure of compliance with the MACT limit. However, concentration measure ments above the operating limit should indicate that either controls are not working effectively or other problems are occurring . In either case, exceedances of the operating limit require investigation and may require corrective actions.
**Comment :**  One commenter requested that EPA reduce the weekly Method 12B monitoring frequency to quarterly or at most monthly. The c ommenter also requested that EPA include a provision that allows for a source to demonstrate a correlation

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## or consistency of performance such that the Method 12B sampling frequency can be further reduced based on the permitting authority’s acceptance of th e demonstration. The commenter suggested that if multiple Method 12B samples are collected in a single day or over multiple days in the calendar week, then the samples should be averaged, and this average concentration sh ould be compared to the operating limit. The commenter said that , for stacks with high mercury concentration, the sample collection time may be only an hour or two, and in this case, it may be important to collect more than one sample in a single day or over multiple days to obtain a repr esentative mercury concentration measurement. **Response :**  After taking into consideration the commenter’s rationale , the final rule requires monitoring mercury concentration twice per month (at least 1 1 days apart ) . If multiple samples are taken during the twice per month period , each result must be compared to the operating limit separately (i.e., not averaged). Otherwise, a high result from a sample taken near the end of the sampling period might not trigger corrective actions to correct a problem that d eveloped at that time if the results are averaged with previous samples during periods of good performance. We do not agree with the

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## suggestion to allow the monitoring frequency to be reduced if the monitoring results demonstrate consistency over the long term. We believe that monitoring the mercury concentration at least twice per month is necessary to ensure that potential problems with control systems are identified quickly and corrective actions are taken in a timely manner. 4. Parametric Monitoring of Control Device for Roasters
**Comment :**  Some commenters recommended that EPA remove the provisions requiring monitoring of the mercury scrubber liquor flow rate and scrubber pressure drop because each facility that has a roaster has a unique sequence of a ir pollution control devices, and monitoring parameters that may be appropriate for one roaster may not be applicable to another. One of the commenters said that the scrubber liquor flow rate is not currently monitored, nor is it considered a critical par ameter in the daily operation of the scrubber mercury removal tower associated with roasters at their facility . The commenter further explained that the scrubber is not a spray tower, but instead the liquor is recirculated in the tower, so the pump is

mon itored to insure it is operational. The commenter stated that the pressure drop across the mercury removal tower at its roasters is monitored, but is not considered a critical

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## parameter and that the mercuric ion and chloride ion concentrations that they m onitor are the critical parameters that define the effectiveness of the mercury scrubber. Another commenter added that , for the calomel

- based mercury scrubbers, the key parameter is the reagent concentration in the solution exiting the scrubber and that maintaining the exit reagent concentration ensures there is sufficient reagent to react with the mercury vapor. The commenter noted that low exit concentrations indicate that either the liquor flow rate is too low, or the fresh reagent addition rate is to o low. Thus, liquor flow rate does not need to be monitored in addition to reagent exit concentration. The commenter stated that if EPA continues to require them, the ranges should be based on the manufacturer’s specification or an alternative value appr oved by the permitting authority, as opposed to three test runs. One commenter recommended that the corresponding range or limit for parametric deviations be applied to a daily average value rather than continuous instantaneous values or single samples. Another commenter also stated that the requirement to establish the minimum water flow rate and pressure drop of the wet scrubber on readings taken during the performance test should not apply to scrubbers on roasters. The commenter noted

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## that these para meters were intended to monitor for physical processes, and the scrubbers on roasters often include chemical reaction s , which are not monitored. One commenter believes that establishing a maximum operating temperature for inlet gas concentrations by arti ficially increasing this temperature during compliance testing may destroy the control equipment, conflict with recommended operating temperatures, and artificially increase the reported mercury emissions. The commenter concluded that these parameters are not deemed critical in the effective operation of a mercury calomel scrubber. Another commenter added that their Compliance Assurance Monitoring (CAM) plan provides for an inlet gas temperature range of 32 ° to 134°F to prevent water freezing problems or extremely hot gas temperatures that could damage the mercury scrubber. The commenter stated that mercury scrubbers remove mercury from the gas stream through a chemical reaction and not a condensation mechanism and that lower temperatures will not remove (via condensation) additional mercury. The commenter explained that , although mercury scrubber inlet gas temperature is not a relevant control performance parameter, their facility maintains the inlet gas temperature below 134°F and monitors the

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## temperatu re daily to prevent damage to the controls system from excessively low or high gas temperatures
. **Response :**  After additional review of operating permits and consideration of public comments, we have found that the inlet temperature is monitored and maintai ned within a range to provide operational flexibility with the lower end bounded to prevent freezing and the upper end bounded to prevent damage to equipment, which in turn could lead to excess emissions. In addition, we have learned that this temperature is dependent on the cooling tower water temperature used in the process, and this water temperature can vary quite widely from winter to

summer. Facilities may not be able to address the issues described above if they can only use initial compliance test ing to establish the inlet temperature operating range, as we proposed. Consequently, the final rule provides the following three ways for a facility with a roaster to establish an operating range for inlet temperature : (1) based on the maximum inlet tem perature during the initial compliance test ; (2) from the manufacturer’s specifications ; or (3) based on the limits established by the permitting authority . The facility must monitor the temperature hourly, and any exceedance of the upper limit for temper ature would trigger corrective action.

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## We agree that pressure drop is not relevant to mercury scrubbers because, unlike venturi scrubbers applied to control
PM emissions, it is not related to its mercury emission control performance. We have removed pre ssure drop monitoring from the final rule for mercury scrubbers. However, we continue to believe that it is important to monitor the scrubber flow rate to ensure the scrubber solution is being delivered to the system and that the flow is adequate, which i s related to the system’s performance. We understand that some facilities monitor mercury scrubber solution line pressure (solution header pressure) as an indicator of flow rate, and we agree this is adequate to ensure proper flow. Consequently, the fina l rule requires hourly monitoring of scrubber flow rate (or line pressure) for mercury scrubbers on roasters. As with the inlet temperature operating range, t he minimum flow rate or line pressure must be established by one of the following three ways: (1) during the initial compliance test, (2) from the manufacturer’s specifications, or (3) based on the limits established by the permitting authority . The final rule requires hourly monitoring and that corrective action is triggered if the flow rate or line
pressure falls below the established parameters
. Regarding the acceptability of parameter values that were

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## approved by permitting a uthorities prior to this final r ule , such values must be established as specified in the final rule and are not presumed in advance to be acceptable. 5. Exceeding the Operating Limits for Roasters
**Comment**

One commenter recommended that the corrective action response time be extended minimally to 48 hours after daily
average values are processed, plus an additional 24 hours to verify the daily average parametric value was within limits. For **:** One commenter was concerned about the consequences of exceeding a parametric monitoring limit . The commenter remarked that shutting down the roaster for exceeding a monito ring parameter without evidence of an ongoing emission limit exceedance is arbitrary and capricious, unnecessarily punitive, and threatens the economic viability of the regulated sources. The commenter pointed out that the ranges of parameters measured du ring source testing are not necessarily the only ranges within which the unit can operate effectively
. The parameters proposed by EPA are not the best parameters for monitoring roaster emissions and do not directly correlate to mercury emissions or proper control system operation. The commenter also objected to the period of only 45 minutes to investigate and take corrective action.

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## facilities that conduct PS 12B sampling and a daily average parametric deviation persists for 96 hours, the commenter recommended requirin g sampling of the roaster’s exhaust using PS 12B within the next 24 hours, then evaluating the mercury concentration results. If the mercury concentration is below the operating limit, then , within 10 days of receiving the analytical results , the facility sho uld be required to either petition the permitting authority for a change in the parametric limits, or provide the permitting authority with a compliance plan that details corrective actions taken to date and the plan and schedule for bringing the param eter back within range. The commenter said that , if the mercury concentration is above the operating limit, the facility will be required to schedule an independent source testing firm to perform a compliance test within 45 days using one of the approved methods described in the rule. The commenter noted that the Nevada State agency requires 30 days to review the testing protocol, and source testing companies typically require 30 days or more advanced notice. For roasters where direct concentration measu rements are not required and a daily average parametric deviation persists for 96 hours, the commenter recommended that within 48 hours,

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## the facility sh ould : (1) provide the permitting authority with a compliance plan that details corrective actions taken to date and the plan and schedule for bringing the parameter back within the limits ; or (2) schedule an independent source testing firm to perform a compliance test within 45 days using one of the approved methods described in the rule. The commenter con cluded that , if the test results show that the source has exceeded the threshold of 10 lb/million tons of ore, the facility would be required to implement direct mercury concentration measurements. One commenter requested that EPA provide an exception from the shutdown requirement when it can be demonstrated that, notwithstanding an exceedance of the parametric operating range, the roaster mercury emissions are less than the operating limit for mercury concentration. The commenter stated that the
mercury c oncentration measurement is a more direct indication of the ultimate mercury emissions that the parametric monitors are designed to address. **Response :**  We have investigated in greater detail the issues associated with monitoring roasters, and we have

con sulted with NDEP and the owners and operators of roasters to learn more about appropriate roaster monitoring. We believe the requirements of th is final rule provide assurance that timely

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## corrective actions are taken when a monitoring parameter is exceeded , and we have included requirements for testing for mercury concentration s to determine if the corrective actions were successful or if a deviation has occurred. The final rule includes parametric monitoring of the mercury scrubbers applied
to roasters to control mercury. If a parameter is outside of the established range or limit, corrective actions are triggered. If corrective actions do not result in the parameter reading being corrected and verified within 48 hours, a mercury concentration measuremen t (using method 30B, 12B, 29, or OHM) must be made to determine if the operating limit for mercury concentration is being exceeded. The measurement must be performed and the concentration determined within 48 hours (after the initial 48 hours , or a total of 96 hours ). If the measured mercury concentration meets the operating limit for mercury concentration, the corrective actions are deemed successful. In addition, the owner or operator may request approval from the permitting authority to change the par ameter range or limit based on measurements of the parameter at the time the mercury concentration measurement was made. If the operating limit is exceeded, the exceedance must be reported as a deviation and the facility must conduct a full compliance tes t

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## within 4 0 days to determine if the source is in compliance with the MACT limit
. **Comment**

For facilities that choose PS 12B monitoring, the commenter recommended that a deviation be considered an exceedance of the operating limit if the a verage of three consecutive sampling results (three weeks) were above the established limit. The commenter proposed that the facility sh ould then have one week to take corrective actions, an additional week to take the verification sample using PS 12B, wi th receipt of results the following week (three weeks total). The commenter stated that if the exceedance persists, the facility sh ould be required to schedule an independent source testing firm to perform a compliance test within 45 days using one of the approved methods **:** For facilities that monitor roasters with a CEMS, one commenter proposed that corrective action be required within 48 hours of receiving and processing the result s from the CEMS data, plus an additional 24 hours sh ould be allowed to collect verification data to see if the daily average concentration was restored below the operating limit. The commenter recommended that , if the exceedance persists, the facility sh o uld be required to schedule an independent source testing firm to perform a compliance test within 45 days.

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## described in the proposed rule. **Response :**  After consider ing these comments on the mercury concentration operating limit and the above discussion on parametric monitoring of roasters , we have made several clarifications in the final rule
. If a mercury concentration operating limit is exceeded from either daily average measurements from a CEMS , continuous sampling using PS 12B, or from sampling twice per month (at least 1 1 days apart) using PS 12B or Method 30B, the exceedance must be repo rted to the permit authority as a deviation and corrective actions must be implemented within 48 hours upon receipt of the sampling results that show the deviation. Moreover, w ithin 96 hours of the exceedance, the owner or operator must measure the concen tration again (with the CEMS or Method 12B or 30B) and demonstrate to the permit authority that the operating limit for mercury concentration has been met, or inform the permit authority that the limit continues to be exceeded
. If the operating limit is

s till exceeded after these 96 hours, t he owner or operator m ust conduct a full compliance test for the ore pretreatment affected source within 40 days to determine if the affected source is in compliance with the MACT emission standard . If the source is de termined to be in compliance, the compliance test may also be

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## used to establish a new operating limit for mercury concentration.
**Comment :**  One commenter requested that EPA provide an exception to the shutdown requirement for facilities that have well

- contr olled roasters and elect to monitor under the proposed Option 3. The commenter believes a facility should have time (45 days) to demonstrate that the roaster’s mercury emissions remain less than 10 lbs of mercury per million tons of ore. The
commenter sta ted that this would be achieved by scheduling an independent source testing firm to perform a compliance test using methods described in the rule, and calculations that demonstrate compliance with the limit of 10 lbs per million tons of ore. **Response :**  As we have discussed above, the final rule relies in part on parametric monitoring of mercury scrubbers used on roasters to assure compliance with the applicable emission standards , and when the measured parametric values are out of the established operating range, corrective actions must be taken. This is no different f or facilities that qualify for the exemption described in §63.11647(a)(5) (i.e., facilities exempt from mercury concentration monitoring by having demonstrated that their roaster emissions ar e less than 10

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## lb/million tons of ore ). For these facilities , the final rule similarly requires that corrective actions be taken to restore the scrubber operating parameters to the established operating range. If the parameters are not restored to the es tablished range within 48 hours of triggering the corrective actions, the owner or operator must perform mercury concentration sampling of the roaster emissions using PS 12B or Method 30B or Method 29 and determine the mercury concentration within 48 hours following the initial 48 hours (or a total of 96 hours from the time the parameter range was exceeded) . The measured concentration must be compared to a mercury concentration operating limit that is based on Equation 3 in the final rule, where the value for “C trap 

## ” in Equation 3 is based on the mercury concentration for the roaster measured during the most recent compliance test. If the measured mercury concentration meets the operating limit for mercury concentration, the corrective actions are deemed s uccessful. In addition, the owner or operator may request approval from the permitting authority to change the parameter range or limit based on measurements of the parameter at the time the mercury concentration measurement was made. If the operating li mit is exceeded, the facility must take corrective actions and report it to the permit authority as

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## a deviation. The owner or operator m ust also conduct a compliance test within 40 days to determine if the roaster operations are in compliance with the emi ssion standard
. **Comment**

One commenter noted that continuous readings on wet scrubbers are unreliable and proposed monitoring the water flow rate and pressure drop once per shift. The commenter noted that if any water flow rate or pressure drop reading exceeds the operating limit, the facility should follow the procedures for operating limit exceedances. The commenter stated that many f acilities do not have d ata a cquisition s ystems capable of recording continuous data and that wet scrubbers are primarily **:** One commenter proposed that only the scrubber water flow rate monitoring be required for wet scrubbers on the quenching circuits associated with the roaster. The commenter wanted to confirm that wet scrubber monitoring does not apply to wet scrubbers or condensers on roasters. Another commenter asked that EPA confirm that the term “wet scrubbers” does not include condensers, which are used throughout the mining processes for gas cooling to condense water or (in the case of
retor ts) mercury. Another commenter asked EPA to confirm that wet scrubber monitoring does not apply to wet scrubbers associated with ore preheaters.

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## used to control particulates. The commenter concluded by stating that wet scrubbers are not key mercury controls and monitoring once p er shift is sufficient to maintain control performance on a continuing basis. One commenter wanted to confirm that the limits established during testing would not be more stringent than the requirements set forth in the Standards of Performance for New S tationary Sources for Metallic Mineral Processing Plants, which allows for plus or minus 30 percent. Another commenter recommended that the operating limit for wet scrubber monitoring be based on either the lowest average value during any test run or no l ower than 10 percent below the average value measured during the
test. **Response :**  As discussed above, the scrubber monitoring for roasters applies to the mercury scrubber (located at or near the end of the exhaust gas treatment train) and does not apply to the additional scrubbers that are used to remove PM and SO 2 

## prior to the mercury scrubber. We are also clarifying in the final rule that when the primary mercury emission control device is a carbon adsorber, which is the last stage of the exhaust gas cle aning treatment train, it is necessary to monitor the carbon adsorber to ensure it is operating properly and controlling

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## mercury emissions, and the rule does not require that scrubbers in the gas treatment train (typically used for control of PM and/or SO 2 

## ) prior to the carbon adsorber be monitored under this rule for mercury emissions. However, if there is no carbon adsorber or mercury scrubber , and the scrubber in question is the only control device for mercury emissions, the final rule requires that it be monitored once per shift per operating day (e.g., minimum of two times) for pressure drop and flow rate with operating limits that either are established during the initial compliance test, from the manufacturer’s specifications,

or based on approval fr om the permitting authority (except for pressure drop for autoclaves as discussed above). This applies to scrubbers on ore preheaters and quenching if there is no carbon adsorber or mercury scrubber in the exhaust gas treatment train. We are clarifying i n the final rule that condensers, such as those found at roasters and retorts, are not wet scrubbers. We agree that monitoring and recording the pressure drop once per shift is adequate for monitoring these wet scrubbers to ensure they are operating prope rly. We disagree that a buffer of +/

- 30 percent based on a certain NSPS subpart is appropriate for this NESHAP for mercury. The comment suggesting an option

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## of a +/

- 10 percent buffer around the average value during the performance test has merit as an o ption to only using the lowest value during any individual run as the operating limit. If the system is so stable that it shows very minimal variability during the performance test, we agree that it is appropriate to add +/

- 10 percent to account for poten tial future variability
. Consequently, we are incorporating the option in the final rule , as suggested by the commenter.
6 . Carbon Adsorber Temperature Monitoring
**Comment :**  Several commenters stated their concern with the proposed requirement of monitori ng gas st r eam temperature at the inlet to the carbon adsorber and maintaining the inlet temperature below the maximum temperature established during the compliance test. They noted that the primary purpose for monitoring the inlet gas stream temperature o f carbon adsorbers is to prevent spontaneous combustion of the sulfidized carbon in the adsorber, not to detect excursions in mercury emissions. The commenters also stated that some carbon adsorption systems heat the gas stream prior to the carbon adsorbe r to prevent moisture buildup and/or subsequent condensation in the carbon. The commenters explained that the NMCP already requires that the exit gas temperature of condensers prior to the carbon adsorbers

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## be established to minimize mercury emissions from the condenser. The commenters believe that an increase in inlet gas temperature to a carbon adsorption unit is not indicative of an increase in inlet gas stream mercury emissions because the high operating temperatures of the processes volatilize approxi mately 100 percent of mercury. The commenters stated that establishing a maximum operating temperature for inlet gas concentrations by artificially increasing this temperature during compliance testing may destroy mercury control equipment; conflict with NMCP requirements and/or manufacturer’s recommended operating temperatures; artificially increase the reported mercury emissions; or artificially decrease the allowable operating limit for mercury concentration. The commenters continued by stating that, if EPA persisted in requiring the monitoring of the gas stream inlet temperature, the maximum inlet temperature limit should be established by either the manufacturer’s recommendation and/or concurrence with the permitting authority. The commenters proposed monitoring the inlet temperature once per shift as an option to continuously monitoring the inlet temperature and comparing the daily averages rather than the hourly averages to the operating limit. The commenters noted that many facilities do not have

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## d igital a cquisition s ystems capable of recording continuous data, and monitoring once per shift is sufficient to maintain control performance. The commenters suggested that , if corrective action is needed, the facility should be allowed to sample the carbo n loading to demonstrate that the effectiveness of the carbon adsorber has not been adversely impacted. **Response :**  The purpose of monitoring the inlet temperature to carbon adsorbers is not to provide an indication of higher mercury concentrations in the inlet stream as suggested by the commenters. The purpose is related to the fact that temperature is a fundamental parameter that affects the efficiency and capacity of carbon adsorbers. Generally, higher temperature s result in lower capacity and earlier breakthrough and , in fact, high temperatures are used to desorb adsorbed pollutants to regenerate carbon. In the extreme of temperature, the carbon adsorber might actually be desorbing rather than acting as a control device. This is particularly importan t for those carbon adsorbers applied to high temperature thermal processes, such as carbon kilns and melt furnaces, where it is possible for the exhaust temperature to rise above the normal operating temperature or above the temperature at which the carbon adsorber was designed to operate. For high temperature

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## processes ( such as furnaces) , and not those such as electrowinning where the temperature may be near ambient conditions), we continue to require monitoring the inlet temperature . Owners or operators must establish an operating limit for temperature based on one of the following : (1) the maximum temperature during the initial compliance test ; (2) from the manufacturer’s specifications ; or (3) based on limits established by the permitting authority . I f this established operating limit is exceeded corrective action must be taken and the exceedance reported as a deviation to the permit authority
. Further , the final rule requires facilities to monitor inlet temperature once per shift rather than continuo usly, as was proposed. Because inlet temperatures should not vary greatly over the course of an 8 to 12

- hour period, we believe monitoring once per shift is adequate. We also conclude that if a temperature exceedance has occurred, the carbon bed should b e sampled or the outlet concentration determined, depending on the monitoring option chosen, within 48 hours to ensure no permanent damage to the carbon adsorber occurred as a result of the deviation. We believe the temperature exceedance should be report ed as a deviation even if the subsequent monitoring shows that the carbon bed is operating properly because the subsequent

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## monitoring would not necessarily detect if mercury had been desorbed and excess emissions occurred.
7 . Monitoring of Multiple Units Ducted to One Stack
**Comment**

Commenters also requested clarification that , for facilities with multiple process units ducted together through a shared carbon adsorber, the mercury concentration monitoring would be conducted on the combined exhaust stream. T he commenters also requested clarification that the mercury concentration operating limit for a carbon adsorber for multiple units that share the carbon adsorber would be established during the simultaneous operations of all process units in order to

accou nt for the combined mercury emissions. **:** Commenters requested clarification that , for facilities that have two roasters ducted together through a shared mercury control system, the mercury concentration monitoring would be conducted on the combined exhaust stream.
T he commenters also requested clarification that the mercury concentration operating limit for two roasters that share a control system would be established during the simultaneous operation of the roasters in order to account for the combined mercury emiss ions from both roasters.

**Response :**  We agree with the commenters in general and have

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## made the following clarifications in the final rule. If two roasters share a common control device and stack, the mercury concentration operating limit , a s well as stack testing for compliance w ill be based on both roasters operating. However, monitoring for mercury concentration must be performed at the frequency specified in the final rule whether only one or both roasters are operating. We also have cl arified that , for multiple process units vented to a common carbon adsorber, the mercury concentration operating limit and the stack testing for compliance must be based on all units operating if possible
. However, the ongoing mercury concentration monito ring must be performed at the frequency specified in the final rule for whatever units are operating at the time.
8 . Monitoring Mercury Concentration in Roaster Ore
**Comment :**  One commenter objected to the proposed requirement to conduct additional complia nce testing if the mercury concentration in the ore fed to the roaster is higher than any concentration measured in the previous 12 months. The commenter stated that there would not be an increase in the mercury emissions from their roasters because of th e extensive series of mercury controls, some of which operate more efficiently at higher mercury loadings with unchanged stack

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## emissions. In addition, the commenter noted that the rule does not provide details on how to measure the mercury ore concentrati on or what threshold of significance would be used to show an increase in ore mercury content occurred. The commenter concluded that the requirement would only provide extra cost and burden without any environmental benefit. **Response**

**V. Summary of Environmental, Economic and Health Benefits? :**  We agree with the c ommenter and have removed this requirement from the final rule. We have no data showing that the mercury content of the ore has a significant effect on the performance of mercury scrubbers applied to roasters, which are designed to handle and operate effi ciently for a range of mercury inlet concentrations. In addition, roasters condense and recover elemental mercury prior to the mercury scrubber, and any increase in mercury loading would likely result in an increase in the recovery of elemental mercury. We have identified and require the monitoring of parameters associated with the scrubber chemistry, and maintaining these parameters within the established range for which the mercury scrubber was designed . This monitoring approach helps ensure th at the

m ercury scrubbers are controlling mercury emission independent of variations in ore mercury content
.

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## For proposal, we estimated baseline mercury emissions to be 3,119 lb/yr based on the available emissions data and average process data for the period 2007 to 2009. To estimate the impacts of the final rule, we have revised our baseline mercury emissions estimate to account for the recent installation of new mercury emission controls at two faciliti es and additional test data received since proposal. As a result of these changes, we now estimate baseline mercury emissions to be 2,636 lb/yr. We estimate the final MACT standard will reduce mercury emissions from gold mine ore processing and productio n by 1,461 lb/yr from the baseline emissions levels of 2,636 lb/yr down to a level of 1,176 lb/yr post

- MACT. The annual emissions expected after MACT ( 1,176 lb /yr ) represent a n estimated 77 percent reduction from 2007 emissions (5,000 lb /yr ), a 95 percent reduction from the emissions level in 2001 (about 23,000 lb /yr ), and more than 97 percent reduction from uncontrolled emissions levels (more than 37,000 lb /yr ). The capital cost of emission controls is estimated as $36 million with a total annualized cos t of $8 million per year. The capital costs for monitoring, reporting, and recordkeeping are estimated as $0.5 to $1.0 million with a total annualized cost of $ 0.7 to $1.5 million per year, depending on the monitoring option that is chosen. The overall

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## c ost effectiveness is estimated to be about $6,300 per pound of mercury reduced. The cost of compliance is estimated to be less than 0. 8 percent of sales for all affected firms . We therefore believe that the economic impact on an affected company would be insignificant. Electricity consumption is expected to increase by about 12,600 megawatt

- hours per year due to increased fan capacity for carbon adsorbers and the installation of refrigeration units or condensers on a few process units. Non

hazardous sol id waste (spent carbon containing mercury that must be regenerated or disposed of) would increase by about 7 tons
per ye ar. VI. Startup , Shutdown , and Malfunctions The United States Court of Appeals for the District of Columbia Circuit vacated portions o f two provisions in EPA’s CAA Section 112 regulations governing the emissions of HAP during periods of startup, shutdown, and malfunction (SSM). S ierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 2008), cert. denied, 130 S. Ct. 1735 (U.S. 2010) . Specifically, the Court vacated the SSM exemption contained in 40 CFR 63.6(f)(1) and 40 CFR 63.6(h)(1), that are part of a regulation, commonly referred to as the “General Provisions Rule,” that EPA promulgated under section 112 of the CAA. When incorporated into CAA S ection

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## 112(d) regulations for specific source categories, these two provisions exempt sources from the requirement to comply with the otherwise applicable CAA section 112(d) emission standard during periods of SSM. Consistent with Sierra Club v. EPA, EPA h as established standards in this rule that apply at all times. In establishing the standards in this rule, EPA has taken into account startup and shutdown periods and, for the reasons explained below, has not established different standards for those peri ods. We have no reason to believe that emissions are different during startup or shutdown. The mercury emissions from significant emissions points are, or will be, controlled by condensers, carbon bed filters , or mercury scrubbers. The carbon beds, whic h are applied to most types of process units to control mercury emissions, will capture mercury as well, or better, during periods of startup and shutdown as compared to normal operations. Condensers also capture mercury as well, or better, during periods of startup and shutdown as compared to normal operations. Mercury scrubbers are applied only to roasters, and roasters operate continuously for most of the year. Roasters are normally shutdown purposely only about once per year ( typically for a few week s) for maint e n an ce and repair. The

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## facilities that have roasters ensure that the control devices (including the mercury scrubbers) are fully operational before the roasters are started. Also, the controls stay operational throughout the shutdown period. Th erefore , no increase s in emissions are expected during the startup and shutdown periods
. Moreover, the MACT limit is based on pounds of mercury emissions
per rate of input or production over a 12

- month rolling average ( e.g., pounds of mercury per milli on tons of input ore ).
T herefore, no change in the emissions standard s are needed for periods of startup and shutdown
. Periods of startup, normal operations, and shutdown are all predictable and routine aspects of a source’s operations. However, by con trast, malfunction is defined as a “sudden, infrequent, and not reasonably preventable failure of air pollution control and monitoring equipment, process equipment or a process to operate in a normal or usual manner ” (40 CFR 63.2). EPA has determined that malfunctions should not be viewed as a distinct operating mode and, therefore, any emissions that occur at such times do not need to be factored into development of CAA section 112(d) standards, which, once promulgated, apply at all times. In Mossville E nvironmental Action Now v. EPA , 370 F.3d 1232, 1242 (D.C. Cir. 2004), the court upheld as reasonable

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## standards that had factored in variability of emissions under all operating conditions. However, nothing in section 112(d) or in caselaw requires that EPA anticipate and account for the innumerable types of potential malfunction events in setting emission standards. See , Weyerhaeuser v Costle

Further, i t is reasonable to interpret section 112(d) as not requiring EPA to account for malfunctions in setting emissions standards. For example, we note that Section 112 uses the concept of “best performing” sources in defining MACT. Applying the concept of “best performing” to a source that is malfunctioning presents significant difficulties. The goal of best performing sources is to operate in such a way as to avoid malfunctions of their units. , 590 F.2d 1011, 1058 (D.C. Cir. 1978) (“ In the nature of things, no general limit, individual permit, or even any upset provision can anticipate all upset situations. After a certain point, the transgression of regulatory limits caused by ‘uncontrollable acts of third parties,’ such as strikes, sabotage, operator intoxication or insanity, and a variety of other event ualities, must be a matter for the administrative exercise of case

- by

- case enforcement discretion, not for specification in advance by regulation.”)

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## Moreover, even if malfunctions were considered a distinct operating mode, we believe it would be impracticable to take malfunctions into account in setting CA A section 112(d) standards for the gold mine ore processing and production source category. As noted above, by definition, malfunctions are sudden and u nexpected events and it would be difficult to set a standard that takes into account the myriad differe nt types of malfunctions that can occur across all sources in the category. Moreover, malfunctions can vary in frequency, degree, and duration, further complicating standard setting. We believe it un likely that malfunction s w ould result in violation s of the standard s in this rule
. The primary pollution control devices used in this industry to control mercury emissions ( condensers, carbon bed filters and mercury scrubbers) are not expected to be significantly affected by SSM events. Moreover, the standar ds in this rule are expressed in terms of long

- term averages (e.g., pounds of mercury emitted per rate of production over a 12

- month period ) . We believe that malfunctions (which are expected to occur quite infrequently over that period ) are not likely to result in an exceedance of the standard s . In the unlikely event that a source fails to comply with

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## the applicable CAA section 112(d) standards as a result of a malfunction event, EPA would determine an appropriate response based on, among other things, the good faith efforts of the source to minimize emissions during malfunction periods, including preventative and corrective actions, as well as root cause analyses to ascertain and rectify excess emissions. EPA would also consider whether the source's failu re to comply with the CAA section 112(d) standard was, in fact, “sudden, infrequent, not reasonably preventable” and was not instead “caused in part by poor maintenance or careless operation.” 40 C.F.R. § 63.2 (definition of malfunction). Finally, EPA re cognizes that even equipment that is properly designed and maintained can sometimes fail and that such failure can sometimes cause an exceedance of the relevant emission standard. ( See, e.g., State Implementation Plans: Policy Regarding Excessive Emission s During Malfunctions, Startup, and Shutdown (Sept. 20, 1999); Policy on Excess Emissions During Startup, Shutdown, Maintenance, and Malfunctions (Feb. 15, 1983)). EPA is therefore adding to the final rule an affirmative defense to civil penalties for

exc eedances of emission limits that are caused by malfunctions. See 40 CFR 63. 11651 (defining “affirmative defense” to mean, in

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## the context of an enforcement proceeding, a response or defense put forward by a defendant, regarding which the defendant has the burden of proof, and the merits of which are independently and objectively evaluated in a judicial or administrative proceeding.). We also have added other regulatory provisions to specify the elements that are necessary to establish this affirmative defe nse; the source must prove by a preponderance of the evidence that it has met all of the elements set forth in 63. 11648 . (See 40 C.F.R. 22.24). The criteria ensure that the affirmative defense is available only where the event that causes an exceedance of the emission limit meets the narrow definition of malfunction in 40 C.F.R. 63.2 (sudden, infrequent, not reasonable preventable and not caused by poor maintenance and / or careless operation). For example, to successfully assert the affirmative defense, the source must prove by a preponderance of the evidence that excess emissions “[w]ere caused by a sudden, short, infrequent, and unavoidable failure of air pollution control and monitoring equipment, process equipment, or a process to operate in a normal or usual manner....” The criteria also are designed to ensure that steps are taken to correct the malfunction, to minimize emissions in accordance with section 63. 1164 6(b) and to prevent future

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## malfunctions. For example, the source must prove by a preponde rance of the evidence that “[r]epairs were made as expeditiously as possible when the applicable emission limitations were being exceeded...” and that “[a]ll possible steps were taken to minimize the impact of the excess emissions on ambient air quality, the environment and human health....” In any judicial or administrative proceeding, the Administrator may challenge the assertion of the affirmative defense and, if the respondent has not met its burden of proving all of the requirements in the affirmative def ense, appropriate penalties may be assessed in accordance with Section 113 of the Clean Air Act (see also 40 C.F.R. Part 22.77).
**VI I**  **. Statutory and Executive Order Reviews**
A. This action is a “signi ficant regulatory action” under the terms of Executive Order 12866 (58 FR 51735, October 4, 1993) because it may raise novel legal or policy issues. Accordingly, EPA submitted this action to the Office of Management and Budget (OMB) for review under Execu tive Order 12866, and any changes made in response to OMB recommendations have been documented in the docket for this action. Executive Order 12866: Regulatory Planning and Review

B. Paperwork Reduction Act

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## The information collection requirements in this final rule have been submitted for approval to OMB u nder the Paperwork Reduction Act, 44 U.S.C. 3501 et s eq

The recordkeeping and reporting requirements in this final rule are based , in large part, on the information collection requirements in EPA’s NESHAP General Provisions (40 CFR part 63, subpart A). The recordkeeping and reporting requirements in the General Provisions are specifically authorized by section 114 of the CAA (42 U.S.C. 7414). All in formation other than emissions data submitted to EPA pursuant to the information collection requirements for which a claim of confidentiality is made is safeguarded according to CAA section 114(c) and EPA’s implementing regulations at 40 CFR part 2, subpar t B. . The Information Collection Request (ICR) document prepared by EPA has been assigned EPA ICR No. 2383.01
.

This final NESHAP will require applicable one

- time notifications according to the NESHAP General Provisions. In addition, owners or operators must submit annual notifications of compliance status and report any deviations in each semiannual reportin g period. Records of all performance tests, measurements of feed input rates, monitoring data, and corrective actions w ill be required.

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## The average annual burden for this information collection averaged over the first 3 years of this ICR is estimated to total 483 labor hours per year at a cost of approximately $ 26,847 per year for the 2 1 facilities that w ill be subject to th is final rule, or approximately 23 hours per year per facility. Capital costs are estimated as $ 1.0 million , operation and maintenan ce costs are estimated as $ 52,000 per year, and total annualized cost (including capital recovery) is estimated as $ 360,210 per year for th is final rule ’s information collection requirements. No costs or burden hours are estimated for new sources because none is projected for the next 3 years. Burden is defined at 5 CFR 1320.3(b). An agency may not conduct or sponsor, and a person is not required to respond to, a collection of information unless the collection displays a currently valid OMB control numbe r. The OMB control numbers for EPA’s regulations in 40 CFR part 63 are listed in 40 CFR part 9. In addition, EPA is amending the table in 40 CFR part 9 of currently approved OMB control numbers for various regulations to list the regulatory citations for the information requirements contained in this final rule.
C. The Regulatory Flexibility Act generally requires an agency Regulatory Flexibility Act

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## to prepare a regulatory flexibility analysis of any rule subject to notice and comment rulemaking requi rements under the Administrative Procedure Act or any other statute unless the agency certifies that th is rule would not have a significant economic impact on a substantial number of small entities. Small entities include small businesses, small not

- for

- p rofit enterprises, and small governmental jurisdictions. For the purposes of assessing the impacts of th is final NESHAP on small entities, a small entity is defined as: (1) a small business whose parent company meets the Small Business Administration size standards for small businesses found at 13 CFR 121.201 (less than 500 employees for gold mine ore processing and production facil i ties

– NAICS 212221 ); (2) a small governmental jurisdiction that is a government of a city, county, town, school district , or special district with a population of less than 50,000; and (3) a small organization that is any not

- for

- profit enterprise that is independently owned and operated and is not dominant in its field. After considering the economic impacts of this final rule on small entities, I certify that this action will not have a significant economic impact on a substantial number of small entities. This final rule is estimated to impact about 2 1 gold

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## mine ore processing and production facilities, none of which ar e owned by small entities. T hus, there are no impacts to small entities from this final rule. Although this final rule will contain requirements for new sources, EPA expect s few, if any , new sources to be constructed in the next several years.
T herefore , EPA did not estimate the impacts for new affected

sources for this final rule
. Although this final rule will not have a significant economic impact on a substantial number of small entities, EPA nonetheless has tried to reduce the impact of this final rule on small and large entities. The se standards establish emission limits that reflect practices and controls that are used throughout the industry and in many cases are already required by State operating permits. The se standards also require only the essential monitoring, recordkeeping, and reporting needed to verify compliance. The se final standards were developed based on information obtained from industry representatives in our surveys, consultation with business representatives and their trade as sociation and other stakeholders
. D. This final rule does not contain a federal mandate that may result in expenditures of $100 million or more for state, local, Unfunded Mandates Reform Act

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## and tribal governments, in the aggregate, or to the private

s ector in any one year. This final rule is not expected to impact state, local, or tribal governments. The total nationwide annualized cost of this final rule for affected industrial sources is $9.1 million/yr. Thus, this final rule is not subject to the requirements of sections 202 and 205 of the Unfunded Mandates Reform Act (UMRA). This final rule is also not subject to the requirements of section 203 of UMRA because it contains no regulatory requirements that might significantly or uniquely affect sma ll governments. This final rule will not apply to such governments and will not impose any obligations upon them.
E. This action does not have federalism implications. It will not have substantial direct effects on th e States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government, as specified in Executive Order 13132
. This final rule does not impose any requireme nts on state and local governments. Thus, Executive Order 13132 does not apply to this action
. Executive Order 13132: Federalism

In the spirit of Executive Order 13132, and consistent with

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## EPA policy to promote communications between EPA and State and local governments, EPA specifically solicit ed comment on this proposed action from State and local officials.
F.

This action does not have tribal implications, as specified in Executive Order 13175 (65 FR 67249, November 9, 2000). This final rule imposes no requirements on tribal governments; thus, Executive Order 13175 does not apply to this action. Although EPA requested comment from tribal officials in developing this action , no comments on the propo sal were received from tribal governments
. However, the reductions in mercury emissions to the environment, which will be achieved by this final rule, will certainly benefit tribal populations within the vicinity of affected gold mine ore processing and p roduction facilities. Executive Order 13175: Consultation and Coordination with Indian Tribal Governments

G.

EPA interprets Executive Order 13045 (62 F.R. 19885, April 22, 1997) as applying only to those regulatory actions that are based on health or safety risks, such that the analysis required under section 5

- 501 of the Executive Order has the potential to influence the regulation. This action is not subject to Executive Order 13045: Protection of Children from Environmental Health and Safety Risks

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## Executive Order 13045 because it is based solely on technology performance. However, we note that the final rule will result in significant reductions in emissions of mercury, and thus will provide benefits to children's health.
H.

This action is not a “significant energy action” as defined in Executive Order 13211 (66 FR 28355, May 22, 2001) because it is not likely to have a significant adverse effect on the supply, distribution, or use of energy. We have concluded that this final rule will not likely have any significant adverse energy effects because energy consumption would increase by only 12,600 megawatt

- hours per year. Executive Order 13211: Actions Concerning Regulations That Significantly Affect Energy Supply, Distributio n, or Use

I. Section 12(d) of the National Technology T ransfer and Advancement Act of 1995 (“NTTAA”), Public Law No. 104

- 113 (15 U.S.C. 272 note), directs EPA to use voluntary consensus standards (VCS) in its regulatory activities unless to do so would be inconsistent with applicable law or otherwise impractic al. VCS are technical standards (e.g., materials specifications, test methods, sampling procedures, business practices) that are developed or adopted by voluntary consensus National Technology Transfer and Advancement Act

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## standards bodies. NTTAA directs EPA to provide Congress, through OMB, explanation s when the Agency decides not to use available and applicable VCS. This final rulemaking involves technical standards. EPA decided to use ASME PTC 19.10

- 1981, “Flue and Exhaust Gas Analyses,” for its manual methods of measuring the oxygen or carbon diox ide content of the exhaust gas. These parts of ASME PTC 19.10

- 1981 are acceptable alternatives to EPA Method 3B. This standard is available from the American Society of Mechanical Engineers (ASME), Three Park Avenue, New York, NY 10016

– 5990. Another VCS, ASTM D6784

- 02, “Standard Test Method for Elemental, Oxidized, Particle

- Bound and Total Mercury in Flue Gas Generated from Coal

- Fired Stationary Sources (Ontario Hydro Method)” is an acceptable alternative to EPA Method 29. This performance test method is available from ASTM International. See http://www.astm.org/. EPA has also decided to use EPA Methods 1, 1A, 2, 2A, 2C, 2D, 2F, 2G, 3, 3A, 3B, 4, 29 , 30B, Method 7471A, “Mercury in Solid or Semisolid Waste (Manual Cold

- Vapor Technique),” and ASTM D6784

– 0 2, “Standard Test Method for Elemental, Oxidized, Particle

- Bound and Total Mercury in Flue Gas Generated from

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## Coal

- Fired Stationary Sources,” (incorporated by reference

– see 63.14). Although the Agency has identified 14 VCS as being potentially applicabl e to these methods cited in this rule, we have decided not to use these standards in this final rulemaking. The use of these VCS would have been impractical because they do not meet the objectives of the standards cited in this rule. The search and revie w results are in the docket for this final rule. Under section 63.7(f) and section 63.8(f) of Subpart A of the General Provisions, a source may apply to EPA for permission to use alternative test methods or alternative monitoring requirements in place of any required testing methods, performance specifications, or procedures in the final rule.
J.

Executive Order 12898 (59 FR 7629, F ebruary 16, 1994) establishes federal executive policy on environmental justice. Its main provision directs federal agencies, to the greatest extent practicable and permitted by law, to make environmental justice part of their mission by identifying and a ddressing, as appropriate, disproportionately high and adverse human health or Executive Order 12898: Federal Actions to Address Environmental Justice in Minority Populations and Low

- Income Populations

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## environmental effects of their programs, policies, and activities on minority populations and low

- income populations in the United States. EPA has determined that this final ru le will not have disproportionately high and adverse human health or environmental effects on minority or low

- income populations because it will increase the level of environmental protection for all affected populations without having any disproportionate ly high and adverse human health or environmental effects on any population, including any minority or low

- income population. This final rule is expected to reduce mercury emissions from gold mine ore processing and production facilities and thus decrease the amount of such emissions to which all affected populations are exposed
. K. The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the Small Business Regulatory Enforcement Fairness Act of 1996, generally provides tha t before a rule may take effect, the agency promulgating the rule must submit a rule report, which includes a copy of the rule, to each House of the Congress and to the Comptroller General of the United States. EPA will submit a report containing this fin al rule and other required Congressional Review Act

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## information to the U.S. Senate, the U.S. House of Representatives, and the Comptroller General of the United States prior to publication of this final rule in the Federal Register . A major rule cannot take effect until 60 days a fter it is published in the Federal Register . This action is not a “major rule” as defined by 5 U.S.C. 804(2). This final rule will be effective on [INSERT DATE OF PUBLICATION IN THE FEDERAL REGISTER].

## National Emission Standards for Hazardous Air Pollutants: **Gold Mine Ore Processing and Production**  **Area Source Category; and Addition to Source Category List for Standards**  **Page 152**  **of 203** 



## List of Subjects in 40 CFR Part **s 9 and 63**  Environm ental protection, Air pollution control, Hazardous substances, Incorporations by reference, Reporting and recordkeeping requirements.

___________ Dated:

____________________________ Lisa P. Jackson, Administrator.

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## For the reasons stated in the preamb le, title 40, chapter I, of the Code of Federal Regulations is amended as follows: **PART 9 —**  **[AMENDED]** 1. The authority citation for part 9 continues to read as follows: **Authority:** 7 U.S.C. 135, et seq ., 136

– 136y; 15 U.S.C. 2001, 2003, 2005, 2006, 2601

– 2671 ; 21 U.S.C. 331j, 346a, 348; 31 U.S.C. 9701; 33 U.S.C. 1251, et seq ., 1311, 1313d, 1314, 1318, 1321, 1326, 1330, 1342, 1344, 1345(d) and (e), 1361; E.O. 11735, 38 FR 21243, 3 CFR, 1971

– 1975 Comp. p. 973; 42 U.S.C. 241, 242b, 243, 246, 300f, 300g, 300g

– 1, 3 00g

– 2, 300g

– 3, 300g

– 4, 300g

– 5, 300g

– 6, 300j

– 1, 300j

– 2, 300j

– 3, 300j

– 4, 300j

– 9, 1857, et seq

**Subpart A —**  **[Amended]** ., 6901

– 6992k, 7401

– 7671q, 7542, 9601

– 9657, 11023, 11048.

* * * * * 2. The table in § 9.1 is amended by adding an entry in numerical order for “ 6 3.11647

– 63.11648 ” under the heading “National Emission Standards for Hazardous Air Pollutants for Source Categories” to read as follows: **§9.1 OMB Approvals under the Paperwork Reduction Act.**
* * * * *
40 CFR citation OMB control No. * * * * *

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## National E mission Standards for Hazardous Air Pollutants for Source Categories 3 

## * * * * * 63.11647

– 63.11648 2060

– NEW * * * * * * * * * *

3 

## The ICRs referenced in this section of the table encompass the applicable general provisions contained in 40 CFR part 63, s ubpart A, which are not independent information collection requirements.
* * * * * **PART 63 —**  **[AMENDED]** 3 . The authority citation for part 63 continues to read as follows: **Authority** : 42 U.S.C. 7401 et seq **Subpart A —**  **[Amended]** .

4 . Section 63.14 is amende d by revising paragraph s (b)(35) and (i)(1) and by adding paragraph (k)(1)(v) to read as follows: **§63.14 Incorporation by reference.**
* * * * * (b) * * * (35) ASTM D6784

– 02, Standard Test Method for Elemental, Oxidized, Particle

- Bound and Total Mercury in Flue Gas Generated from Coal

- Fired Stationary Sources (Ontario Hydro Method), IBR approved for §63.11646(a)(1)(v) and table 5 to subpart DDDDD of this part.

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## * * * * * (i) * * * (1) ANSI/ASME PTC 19.10

– 1981, “Flue and Exhaust Gas Analyses [Part 10, Instru ments and Apparatus],” IBR approved for §§63.309(k)(1)(iii), 63.865(b), 63.3166(a)(3), 63.3360(e)(1)(iii), 63.3545(a)(3), 63.3555(a)(3), 63.4166(a)(3), 63.4362(a)(3), 63.4766(a)(3), 63.4965(a)(3), 63.5160(d)(1)(iii), 63.9307(c)(2), 63.9323(a)(3), 63.11148( e)(3)(iii), 63.11155(e)(3), 63.11162(f)(3)(iii) and (f)(4), 63.11163(g)(1)(iii) and (g)(2), 63.11410(j)(1)(iii), 63.11551(a)(2)(i)(C), 63.11646(a)(1)(iii), table 5 to subpart DDDDD of this part, and table 1 to subpart ZZZZZ of this part.
* * * * * (k) * * * (1) * * * (v) Method 7471A, “Mercury in Solid or Semisolid Waste (Manual Cold

- Vapor Technique),” IBR approved for §63.11647( f )(2).
* * * * * 5 . Part 63 is amended by adding subpart EEEEEEE to read as follows: **Subpart EEEEEEE —**  **National Emission Standa rds for Hazardous Air**  **Pollutants: Gold Mine Ore Processing and Production Area Source** 

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## Category

**Applicability and Compliance Dates** Sec. 63.11640 Am I subject to this subpart? 63.11641 What are my compliance dates? **Standards and Compliance Requirements** 6 3.11645 What are my mercury emission standards? 63.11646 What are my compliance requirements? 63.11647 What are my monitoring requirements? 63.11648 Affirmative Defense for Exceedance of Emission Limit s During Malfunction. 63.1164 9 What are my notificatio n, reporting, and recordkeeping requirements? **Other Requirements and Information** 63.11650 What General Provisions apply to this subpart? 63.11651 What definitions apply to this subpart? 63.11652 Who implements and enforces this subpart? 63.11653 [Reserve d] **Tables to Subpart EEEEEEE of Part 63** Table 1 to Subpart EEEEEEE of Part 63

— Applicability of General Provisions to Subpart EEEEEEE **Subpart EEEEEEE —**  **National Emission Standards for Hazardous Air Pollutants: Gold Mine Ore Processing and Production**  **Area Source**  **Category Applicability and Compliance Dates**  §63.11640 Am I subject to this subpart (a) You are subject to this subpart if you own or operate a gold mine ore processing and production facility as defined in §63.11651 , that is an area source
. ?

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## (b) This subpart applies to each new or existing affected

source. The affected sources are each collection of “ore pretreatment processes” at a gold mine ore processing and production facility, each collection of “carbon processes with
mercury retorts ” at a gold mine ore processing and production facility, each collection of “carbon processes without mercury retorts” at a gold mine ore processing and production facility, and each collection of “non

- carbon concentrate processes" at a gold mine ore processing and production facility, as defined in §63.11651. (1) An affected source is existing if you commenced construction or reconstruction of the affected source on or before April 28, 2010
. (2) An affected source is new if you commenced construction or reco nstruction of the affected source after April 28, 2010
. (c) This subpart does not apply to research and development facilities, as defined in section 112(c)(7) of the Clean Air Act (CAA). (d) If you own or operate a source subject to this subpart, you must have or you must obtain a permit under 40 CFR part 70 or 40 CFR part 71. §63.11641 What are my compliance dates ?

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## (a) If you own or operate an existing affected source, you
must comply with the applicable provisions of this subpart no later than [IN SERT DATE 3 YEARS AFTER PUBLICATION OF THIS FINAL RULE IN THE FEDERAL REGISTER]
. (b) If you own or operate a new affected source , and the initial startup of your affected source is on or before [INSERT
DATE OF PUBLICATION OF THIS FINAL RULE IN THE FEDERA L REGISTER] , you must comply with the provisions of this subpart no later than [INSERT DATE OF PUBLICATION OF THIS FINAL RULE IN THE FEDERAL REGISTER]
. (c) If you own or operate a new affected source , and the initial startup of your affected source is af ter [INSERT DATE OF PUBLICATION OF THIS FINAL RULE IN THE FEDERAL REGISTER] , you
must comply with the provisions of this subpart upon startup of your affected source. **Standards and Compliance Requirements**
§ 63.11645 What are my mercury emission standards (a) For existing ore pretreatment processes, you must emit no more than 12 7 pounds of mercury per million tons of ore processed
. ?

(b) For existing carbon processes with mercury retorts , you must emit no more than 2.2 pounds of mercury per ton of
concent rate processed
.

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## (c) For existing carbon processes without mercury retorts, you must emit no more than 0.1 7 pounds of mercury per ton of concentrate processed. ( d ) For existing non

- carbon concentrate processes, you must emit no more than 0. 2 pounds of m ercury per ton of
concentrate processed
. ( e ) For new ore pretreatment processes, you must emit no more than 84 pounds of mercury per million tons of ore processed
. ( f ) For new carbon processes with mercury retorts , you
must emit no more than 0.8 pounds of mercury per ton of concentrate processed. (g) For new carbon processes without mercury retorts, you must emit no more than 0. 14 pounds of mercury per ton of concentrate processed. ( h ) For new non

- carbon concentrate processes, you must emit no mor e than 0.1 pounds of mercury per ton of concentrate processed
. ( i ) The standards set forth in this section apply at all times.
§ 63.11646 What are my compliance requirements (a) Except as provided in paragraph (b) of this section, you must conduct a mercury compliance emission test within 180 ?

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## days of the compliance date for all process units at new and existing affected sources according to the requirements in paragraphs (a)(1) through (1 3 ) of this section. This compliance testing must be repeated a nnually thereafter , with no two consecutive annual compliance tests occurring less than 3 months apart or more than 15 months apart
. (1) You must determine the concentration of mercury and the volumetric flow rate of the stack gas according to the followi ng test methods and procedures: (i) Method 1 or 1A (40 CFR part 60, appendix A

- 1) to select sampling port locations and the number of traverse points in each stack or duct. Sampling sites must be located at the outlet of the control device (or at the out let of the emissions source if no control device is present) and prior to any releases to the atmosphere. (ii) Method 2, 2A, 2C, 2D, 2F (40 CFR part 60, appendix A

1), or Method 2G (40 CFR part 60, appendix A

- 2) to determine the volumetric flow rate of the stack gas. (iii) Method 3, 3A, or 3B (40 CFR part 60, appendix A

- 2) to determine the dry molecular weight of the stack gas. You may use ANSI/ASME PTC 19.10

- 1981, “Flue and Exhaust Gas Analyses” (incorporated by reference

- see §63.14) as an alternativ e to EPA Method 3B.

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## (iv) Method 4 (40 CFR part 60, appendix A

- 3) to determine the moisture content of the stack gas. (v) Method 29 (40 CFR part 60, appendix A

- 8) to determine the concentration of mercury, except as provided in paragraphs (a)(1)(vi) and ( vii) of this section. (vi) Upon approval by the permitting authority , ASTM D6784

– 02 ; “Standard Test Method for Elemental, Oxidized, Particle

- Bound and Total Mercury in Flue Gas Generated from Coal

- Fired Stationary Sources (Ontario Hydro Method)” (incorpor ated by reference

– see §63.14) may be used as an alternative to Method 29 to determine the concentration of
mercury. (vii) Upon approval by the permitting authority, Method 30B (40 CFR part 60, appendix A

- 8 ) may be used as an alternative to Method 29 to determine the concentration of mercury for those process units with relatively low particulate

- bound mercury as specified in Section 1.2 of Method 30B
. (2) A minimum of three test runs must be conducted for each performance test of each process unit . E ach test run conducted with Method 29 must collect a minimum sample volume of 0.85 dry standard cubic meters ( 30 dry standard cubic feet)
. If conducted with Method 30B or Ontario Hydro Method, determine sample time and volume according to the testing crit eria set

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## forth in the relevant method. If the emission testing results for any of the emission points yields a non

- detect value, then the minimum detection limit (MDL) must be used in calculating the emissions for that emission point and, in turn, for cal culating the sum of the mass emissions for all emission points subject to the emission standard for determining compliance. If the resulting mercury mass emissions rate is greater than the allowable emission standard , the owner or operator may use procedu res that produce lower MDL results and repeat the mercury emissions testing one additional time for any emission p o int for which the measured result was below the MDL. If this additional testing is performed, the results from that testing must be used to determine compliance (i.e., ther e are no additional opportunities allowed to lower the MDL). (3) Performance tests shall be conducted under such conditions as the Administrator specifies to the owner or operator based on representative performance of the affected source for the period being tested. Upon request, the owner or operator shall make available to the Administrator such records as may be necessary to determine the conditions of performance tests. Performance t ests must be conducted under o perating conditions (including process or production throughputs) that are based on representative performance. Record and report to

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## the permit authority the process throughput for each test run. For sources with multiple emission units (e.g., two roaste rs) ducted to a common control device and stack, c ompliance testing must be performed with all affected emissions units in operation if possible
. If it is not possible to test all sources ducted to a common control device simultaneously, the sources can b e tested separately. In such cases, any source that is not tested initially must be tested as soon as is practicable. (4) Calculate the mercury emission rate , based on the average of 3 test run values, for each process unit using Equation (1) of this sec tion: E = Cs * Qs * K (Eq. 1) Where:
E = mercury emissions in lb/hr; Cs = concentration of mercury in the stack gas, in grains per dry standard cubic foot (gr/dscf) ; Qs = volumetric flow rate of the stack gas, in dry standard cubic feet per hour; an d K = conversion factor f or grains (gr) to pounds (lb), 1.43 x 10 - 4



## . (5) Monitor and report to the permit authority the number of one - hour periods each process unit operates during each month. (6) For the initial compliance determination for both new

an d existing sources, determine the total mercury emissions for all the full calendar month s between the compliance date and the date of the initial compliance test by multiplying the emission

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## rate in lb/hr for each process unit by the number of hours each
p rocess unit operated during t h ose full calendar month s prior to the initial compliance test
. After the initial compliance test , for subsequent compliance tests, determine the mercury mass emissions for the 12 month period prior to the compliance test in a ccordance with the procedures in paragraph (a)(7) of this section. Existing sources may use a previous emission test for their initial compliance determination in lieu of conducting a new test if the test was conducted within one year of the compliance da te using the methods specified in paragraphs (a)(1) through (4) of this section, and the tests were representative of current operating processes and conditions. ( 7 ) For compliance determinations following the initial compliance test for new and existing sources, d etermine the total mercury mass emissions for each process unit for the 12

- month period preceding the performance test by multiplying the emission rate in lb/hr for each process unit by the number of hours each process unit operated during the 1 2 full calendar months preceding the completion of the performance tests. ( 8 ) You must install, calibrate, maintain and operate an appropriate weight measurement device , mass flow meter, or densitometer and volumetric flow meter to measure ore throughpu t for each roast ing operation and autoclave and calculate hourly,

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## daily and monthly totals in tons of ore according to paragraphs (a)(8)(i) and (ii) of this section
. (i) Measure the weight or the density and volumetric flow rate of the oxidized ore slurry as it exits the roaster oxidation circuit and before the carbon

- in

- leach tanks. (ii) Measure the weight or the density and volumetric flow rate of the ore slurry as it is fed to the autoclave(s). ( 9 ) Measure the weight of concentrate ( produced by electr owinning, Mer r ill Crowe process, gravity feed, or other methods) using weigh scales for each batch prior to processing in mercury retort s or melt furnaces . The concentrate must be weighed in the same state and condition as it is when fed to the
mercury re tort. F or facilities without mercury retorts, the concentrate must be weighed prior to being fed to the melt furnace before drying in any ovens. For facilities that ship concentrate offsite , measure the weight of concentrate as shipped offsite. You must keep accurate records of the weights of each batch of concentrate processed and calculate , record , and report to the permit authority the total weight of concentrate processed each month. ( 10 ) You must maintain the systems for measuring density, volumet ric flow rate, and weight within ±5 percent accuracy. You must describe the specific equipment used to make

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## measurements at your facility and how that equipment is periodically calibrated. You must also explain, document, and maintain written procedures for determining the accuracy of the measurements and make these written procedures available to your permitting authority upon request. You must determine, record, and maintain a record of the accuracy of the measuring systems before the beginning of your initial compliance test and during each subsequent quarter of affected source operation. (1 1 ) R ecord the weight in tons of ore for ore pretreatment processes and concentrate for carbon processes with mercury retorts, carbon processes without mercury reto rts, and for non

carbon concentrate processes on a daily and monthly basis and report the monthly values to the permit authority
. (1 2 ) Calculate the emissions from each new and existing affected source for the sum of all full month s between the compliance date and the date of the initial compliance test in pounds of mercury per ton of process input using the procedures in paragraphs (a)(1 2 )(i) through (i v ) of this section to determine initial compliance with the emission standards in §63.11645. After th is initial compliance test period, d etermine annual compliance using the procedures in paragraph (a)(13) of this section for existing sources. (i) For o re pretreatment processes, divide the sum of

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## mercury mass emissions from all roasting operations and
aut oclaves during the number of full months between the compliance date and the initial compliance test by the sum of the total amount of gold mine ore processed in these process units during th ose same full month s following the compliance date
. (ii) For c arbon processes with mercury retorts , divide the sum of mercury mass emissions from all carbon kilns, preg tanks, electrowinning, mercury retorts, and melt furnaces during the initial number of full months between the compliance date and the initial compli ance tests by the total amount of concentrate processed in these process units during those same full months following the compliance date. (iii) For carbon processes without mercury retorts, divide the sum of mercury mass emissions from all carbon kilns, preg tanks, electrowinning, and melt furnaces during the initial number of full months between the compliance date and the initial compliance tests by the total amount of concentrate processed in these process units during those same full months following the compliance date
. (i v ) For non

- carbon concentrate processes, divide the sum of mercury mass emissions from mercury retorts and melt furnaces during the initial number of full months between the compliance

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## date and the initial compliance tests by the t otal amount of concentrate processed in these process units during those same full months fol lowing the compliance date
. (13) After the initial compliance test, c alculate the emissions from each new and existing affected source for each
12

- month period pr eceding each subsequent compliance test in pounds of mercury per ton of process input using the procedures in paragraphs (a)(13)(i) through (i v ) of this section to determine c ompliance with the emission standards in §63.11645. (i) For ore pretreatment p rocesses, divide the sum of
mercury mass emissions from all roasting operations and autoclaves in the 12

- month period preceding a compliance test by the sum of the total amount of gold mine ore processed in th at 12

- month period
. (ii) For carbon processes with mercury retorts , divide the sum of mercury mass emissions from all carbon kilns, preg tanks, electrowinning, mercury retorts, and melt furnaces in the 12

- month period preceding a compliance test by the total amount of concentrate processed in these pr ocess units in that 12

- month period
. (iii) For carbon processes without mercury retorts, divide the sum of mercury mass emissions from all carbon kilns, preg tanks, electrowinning, and melt furnaces in the 12

- month period

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## preceding a compliance test by th e total amount of concentrate processed in these process units in that 12

- month period. (i v ) For non

- carbon concentrate processes, divide the sum of mercury mass emissions from mercury retorts and melt furnaces in the 12

- month period preceding a complianc e test by the total amount of concentrate processed in these process units in that 12

- month period
. ( b ) At all times, you must operate and maintain any affected source, including associated air pollution control equipment and monitoring equipment, in a ma nner consistent with safety and good air pollution control practices for minimizing emissions. Determination of whether such operation and maintenance procedures are being used will be based on information available to the Administrator which may include, but is not limited to, monitoring results, review of operation and maintenance procedures, review of operation and maintenance records, and inspection of the source.

(a) Except as provided in paragraph (a)( 5 ) of this section, you must monitor each roaster for mercury emissions using one of the procedures in paragraphs (a)(1) , (2) , or (3) of this section and establish operating limits for mercury concentration as described in paragraph (a)( 4 ) of this section. §63.11647 What are my monitoring requirements?

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## ( 1 ) Perform sampling and analysis of the roaster’s exhaust for mercury concentration using EPA Performance Specification
12B or EPA Method 30B at least twice per month . A minimum of two measurements must be taken per month that are at least 11 days apar t from other consecutive tests. T he mercury concentration must be maintained below the operating limit established in paragraph (a)( 4 ) of this section. The results of the sampling must be obtained within 72 hours of the time the sample is taken. (i) To determine the appropriate sampling duration, you must review the available data from previous stack tests to determine the upper 99th percentile of the range of mercury concentrations in the exit stack gas. Based on this upper end of expected concentratio ns, select an appropriate sampling duration that is likely to provide a valid sample and not result in breakthrough of the sampling tubes. If breakthrough of the sampling tubes occurs, you must re - sample within 30 days using a shorter sampling duration. (ii) If the any mercury concentration measurement from the twice per month sampling with method 12B or 30B is higher than the operating limit, the exceedance must be reported to the permit authority as a deviation and corrective actions must be implemente d within 48 hours upon receipt of the sampling

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## results. Moreover, within 96 hours of the exceedance, the owner or operator must measure the concentration again (with method 12B or 30B) and demonstrate to the permit authority that the mercury concentration is no higher than the operating limit, or inform the permit authority that the limit continues to be exceeded. If the operating limit is still exceeded after these 96 hours, the owner or operator must conduct a full compliance test for the ore

- pretreatme nt affected source within 40 days to determine if the affected source is in compliance with the MACT emission standard . If the source is determined to be in compliance, the compliance test may also be used to establish a new operating limit for mercury co ncentration ( in accordance with paragraph (e) of this section )
. (2) Install, operate, calibrate, and maintain a continuous emissions monitoring system (CEMS) to continuously measure the mercury concentration in the final exhaust stream from each
roaster a ccording to the requirements of Performance Specification 12A (40 CFR part 60, appendix B) except that calibration standards traceable to the National Institute of Standards and Technology are not required. You must perform a data accuracy assessment of t he CEMS according to section 5 of Appendix F in part 60 and follow the monitoring requirements in §63.8 , e xcept that 63.8 (c ) (1) (i) and (iii) no longer apply
.

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## Moreover, 63.8(d) (3) applies except the last sentence, which refers to an SSM plan. SSM plan s ar e no longer required. (i) You must continuously monitor the daily average mercury concentration from the roaster and maintain the daily average concentration below the operating limit established in paragraph (a)( 4 ) of this section. (ii) If the dail y average mercury concentration from the CEMs is higher than the operating limit, the exceedance must be reported to the permit authority as a deviation and corrective actions must be implemented within 48 hours upon receipt of the sampling results. Moreo ver, within 96 hours of the exceedance, the owner or operator must measure the concentration again (with the CEMs) and demonstrate to the permit authority that the mercury concentration is no higher than the operating limit, or inform the permit authority that the limit continues to be exceeded. If the operating limit is still exceeded after these 96 hours, the owner or operator must conduct a full compliance test for the ore

- pretreatment affected source within 40 days to determine if the affected source i s in compliance with the MACT emission standard . If the source is determined to be in compliance, the compliance test results may also be used to establish a new operating limit for mercury concentration ( in accordance with paragraph (e) of this section )
.

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## (ii i ) You must submit a monitoring plan that includes quality assurance and quality control (QA/QC) procedures sufficient to demonstrate the accuracy of the CEMS to your permitting authority for approval 180 days prior to your initial compliance test. At a minimum, the QA/QC procedures must include daily calibrations and an annual accuracy test for the
CEMS. (3) Continuously measure the mercury concentration in the final exhaust stream from each roaster using EPA Performance Specification 12B. (i) You must continuously measure the mercury concentration in the roaster exhaust and maintain the average daily mercury concentration below the operating limit established in paragraph (a)(4) of this section. To determine the appropriate sampling duration, you must review the available data from previous stack tests to determine the upper 99th percentile of the range of mercury concentrations in the exit stack gas. Based on this upper end of expected concentrations, select an appropriate sampling duration that is likely to provide a valid sample and not result in breakthrough of the sampling tubes. If breakthrough of the sampling tubes occurs, you must re

- sample within 30 days using a shorter sampling duration.

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## (ii) If the daily average mercury concentration is higher than the operating limit, the exceedance must be reported to the permit authority as a deviation and corrective actions must be implemented within 48 hours upon receipt of the sampling results. Moreover, within 96 hours of the exceedance, the ow ner or operator must measure the concentration again with method 12B or 30B and demonstrate to the permit authority that the mercury concentration is no higher than the operating limit, or inform the permit authority that the limit continues to be exceeded
. If the operating limit is still exceeded after these 96 hours, the owner or operator must conduct a full compliance test for the ore

- pretreatment affected source within 40 days to determine if the affected source is in compliance with the MACT emission standard . If the source is determined to be in compliance, the compliance test results may also be used to establish a new operating limit for mercury concentration ( in accordance with paragraph (e) of this section )
. ( 4 ) Use Equation (2) of this secti on to establish an upper operating limit for mercury concentration as determined by using the procedures in paragraphs (a)(1) , (2) , or (3) of this section concurrently while you are conducting your annual compliance performance stack test according to the procedures in §63.11646(a)
.

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## OLR = C test 

## * ( EL /CT) (Eq 2) where
OLR = mercury concentration operating limit for the roaster ( in micrograms per cubic meter); C test 

## = average mercury concentration measured by the monitoring procedures (PS 12A or PS 12B or 30B ) during the annual performance stack test ( in micrograms per cubic meter); EL = emission standard for ore pretreatment processes ( in lb/ million tons of ore); CT = compliance test results for ore pretreatment processes ( in lb/ million tons of ore). ( 5 ) For r oaster s that utilize calomel

- based mercury control systems for emissions controls , y ou are not required to perform the monitoring for mercury emissions in paragraphs (a)(1) , (2) , or (3) of this section if you demonstrate to the satisfaction of your permitting authority that mercury emissions from the roaster are less than 10 pounds of mercury per million tons of ore throughput. If you make this demonstration , you must conduct the parametric monitoring as described below in paragraphs (b) and (c ) of this section. (i) The initial demonstration must include three or more consecutive independent stack tests for mercury at least one month apart on the roaster exhaust stacks . Subsequent demonstrations may be based upon the single stack test require d in paragraph (a) of section §63.11646 . The results of each of the tests must be less than 10 pounds of mercury per million tons of ore. The testing must be performed according to the

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## procedures in §63.11646(a)(1) through (4) to determine mercury emissi ons in pounds per hour. (ii) Divide the mercury emission rate in pounds per hour by the ore throughput rate during the test expressed in millions of tons per hour to determine the emissions in pounds per million tons of ore. (b) For facilities with r oasters and a calomel

- based mercury control system that choose to monitor for mercury emissions using the procedures in paragraph (a)( 1 ) of this section or that qualify for and choose to follow the requirements in paragraph (a)( 5 ) of this section , you must establish operating parameter limit s for scrubber liquor flow (or line pressure) and scrubber inlet gas temperature and monitor these parameters. You may establish your operating parameter limit s from the initial compliance test, according to the manufac turer’s specifications, or based on limits established by the permitting authority. If you choose to establish your operating parameter limit s from the initial compliance test, m onitor the scrubber liquor flow (or line pressure) and scrubber inlet gas tem perature during each run of your initial compliance test. The minimum operating limit for scrubber liquor flow rate (or line pressure) is the lowest value during any run of the initial compliance test, and your maximum

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## scrubber inlet temperature limit is the highest measured during any run of the initial compliance test. Y ou must monitor the scrubber liquor flow rate (or line pressure) and scrubber inlet gas temperature hourly and maintain the scrubber liquor flow (or line pressure) at or above the establ ished operating parameter and maintain the inlet gas temperature below the established operating parameter limit
. ( c ) For facilities with roasters and a calomel

- based mercury control system that choose to monitor for mercury emissions using the procedure s in paragraph (a)(1) of this section or that qualify for and follow the requirements in paragraph (a)( 5 ) of this section , you must establish operating parameter range s for mercuric ion and chloride ion concentrations or for oxidation reduction potential a nd pH using the procedures in paragraph (c)(1) or (2) of this section respectively
. (1) Establish the mercuric ion concentration and chloride ion concentration range s for each calomel

- based mercury control system. The mercuric ion concentration and chlo ride ion concentration ranges for each calomel

- based mercury control system must be based on the manufacturer’s specifications. Alternatively, the mercuric ion concentration and chloride ion concentration range s for each calomel

- based mercury control

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## syst em may be based on approv al by your permitting authority. Measure the mercuric ion concentration and chloride ion concentrations at least once during each run of your initial compliance test. The measurements must be within the established concentration range for mercuric ion concentration and chloride ion concentration. Subsequently, you must sample at least once daily and maintain the mercuric ion concentration and chloride ion concentrations within their established range. (2) Establish the oxidation reduction potential and pH range for each calomel

- based mercury control system. The oxidation reduction potential and pH range for each calomel

based mercury control system must be based on the manufacturer’s specifications. Alternatively, the oxidation reduction potential and pH range for each calomel

- based mercury control system may be based on approv al by your permitting authority. Install monitoring equipment to continuously monitor the oxidation reduction potential and pH of the calomel

- based

mercu ry control system scrubber liquor. Measure the oxidation reduction potential and pH of the scrubber liquor during each run of your initial compliance test. The measurements must be within the established range for oxidation reduction potential and pH. S ubsequently, you must monitor the oxidation reduction potential and pH of the scrubber liquor continuously and

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## maintain it within the established operating range. (d) If you have an exceedance of a control device operating parameter range provided in para graphs (b) or (c) of this section, you must take corrective action and bring the parameters back into the established parametric range s . I f the corrective actions taken following an exceedance do not result in the operating parameter value being returned within the established range within 48 hours, a mercury concentration
measurement (with method 12B or 30B) must be made to determine if the operating limit for mercury concentration is being exceeded. The measurement must be performed and the mercury

conc entration determined within 48 hours (after the initial 48 hours , or a total of 96 hours from the time the parameter range was exceeded ). If the measured mercury concentration meets the operating limit for mercury concentration established under
§ 63.11647 (a)(4) , the corrective actions are deemed successful , and the owner or operator can request the permit authority to establish a new limit or range for the parameter . If the measured mercury concentration exceeds the operating limit for mercury concentrati on after these 96 hours , the exceedance must be reported as a deviation within 24 hours to the permitting authority . The owner or operator must conduct a compliance test pursuant to §63.1164 6 ( a ) within 40 days to determine if the

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## roaster operations are in compliance with the MACT emission standard
. If the source is determined to be in compliance with the MACT emission standard, the compliance test may also be used to establish a new operating limit for mercury concentration ( see paragraph ( e) of this sect ion )
. ( e ) You may submit a request to your permitting authority for approval to change the operating limit s established under paragraph (a)( 4 ) of this section for the monitoring required in paragraph (a)(1) , (2) , or (3) of this section. In the request, you must demonstrate that the proposed change to the operating limit detects changes in levels of mercury emission control. An approved change to the operating limit under this paragraph only applies until a new operating limit is established during the

n ext annual compliance test. ( f ) You must monitor each process unit at each new and existing affected source that uses a carbon adsorber to control mercury emissions using the procedures in paragraphs ( f )(1) or (2) of this section. A carbon adsorber may in clude a fixed carbon bed, carbon filter packs or modules, carbon columns, and other variations. (1) Continuously sample and analyze the exhaust stream from the carbon adsorber for mercury using Method 30B (40 CFR part 60, appendix A

- 8) for a duration of a t least the minimum

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## sampling time specified in Method 30B and up to one week that includes the period of the annual performance test. (i) Establish an upper operating limit for the process as determined using the mercury concentration measurements from th e sorbent trap as calculated from Equation (3) of this section.
OLC = C trap 

## * (EL/CT) (Eq 3) where
OLC = mercury concentration operating limit for the carbon adsorber control device on the process as measured using the sorbent trap, (micrograms per c ubic meter); C trap 

## = average mercury concentration measured using the sorbent trap during the week that includes the performance test, (micrograms per cubic meter); EL = emission standard for the affected sources (lb/ton of concentrate); CT = compliance t est results for the affected sources (lb/ton of concentrate).
(ii) Sample and analyze the exhaust stream from the carbon adsorber for mercury at least monthly using Method 30B (40 CFR part 60, appendix A

- 8). When the mercury concentration reaches
75 per cent of the operating limit, begin weekly sampling and analysis. When the mercury concentration reaches 9 0 percent of the operating limit, replace the carbon in the carbon adsorber within 30 days. If mercury concentration exceeds the operating limit, cha nge the carbon in the carbon adsorber within 30 days and report the deviation to your permitting authority. (2) Conduct an initial sampling of the carbon in the

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## carbon bed for mercury 90 days after the replacement of the carbon. A representative sample m ust be collected from the inlet of the bed and the exit of the bed and analyzed using EPA Method 7471A (incorporated by reference

- see §63.14). The depth to which the sampler is inserted must be recorded. The design capacity is established by c alculat in g the average carbon loading from the inlet and outlet measurements. Sampling and analysis of the carbon bed for mercury must be performed quarterly thereafter. When the carbon loading reaches 50 percent of the design capacity of the carbon, monthly samp ling must be performed until 90 percent of the carbon loading capacity is reached. The carbon must be removed and replaced with fresh carbon no later than 30 days after reaching 90 percent of capacity. For carbon designs where there may be multiple carbo n columns or beds, a representative sample may be collected from the first and last column or bed instead of the inlet or outlet. If the carbon loading exceeds the design capacity of the carbon, change the carbon within 30 days and report the deviation to your permitting authority. ( g ) You must monitor gas stream temperature at the inlet to the carbon adsorber for each autoclave, carbon kiln, melt furnace, and mercury retort equipped with a carbon adsorber
. E stablish a maximum value for the inlet temp erature either

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## during the annual performance test as required in §63.11646(a), according to the manufacturer’s specifications, or as approved by your permitting authority
. If you choose to establish the temperature operating limit during the performance t est,

e stablish the temperature operating limit based on either the highest reading during the test or a t 10°F higher than the average temperature measured during the performance test
. M onitor the inlet temperature once per shift . If a n inlet temperature exceeds the temperature operating limit, you must follow the requirements for outlet concentration measurement in paragraph ( f )(1) of this section. If the concentration is below 90 percent of the operating limit, you may set a new temperature operating li mit 10°F above the previous operating limit. If the concentration is above 90 percent of the operating limit, you
must take corrective action to reduce the temperature back below the temperature operating limit and again measure the outlet concentration a ccording to paragraph ( f )(1) of this section. If the concentration is still above 90 percent of the operating limit , then you must change the carbon in the bed within 30 days and report the deviation to your permitting authority
. ( h ) For each wet scrub ber at each new and existing affected source not followed by a mercury control system , you must monitor the water flow rate (or line pressure) and pressure

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## drop
. E stablish a minimum value as the operating limit either during the performance test required in §63.11646(a), according to the manufacturer’s specifications, or as approved by your permitting authority. If you choose to establish the operating limit based on the results of the performance test, the new operating limit must be establish ed based on either the lowest average value during any test run or no lower than 10 percent of the average value measured during the test. For wet scrubbers on an autoclave , establish the range according to manufacturer’s specifications. You must monitor the water flow rate and pressure drop once per shift and take corrective action within 24 hours if any daily average is less than the operating limit. If the parameters are not in range within 72 hours, the owner or operator must report the deviation to the permitt ing authority and perform a compliance test within 4 0 days to determine if the source is in compliance with the MACT limit
. ( i ) You may conduct additional compliance tests according to the procedures in § 63.11646 and re

- establish the operating limits req uired in paragraphs (a) through (c) and ( f ) through ( h ) of this section at any time. You must submit a request to your permitting authority for approval to re

- establish the operating limits. In the request, you must demonstrate that the proposed change t o the operating limit detects changes in levels

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## of mercury emission control. An approved change to the operating limit under this paragraph only applies until a new operating limit is established during the next annual compliance
test.

§ 63.11648

I n response to an action to enforce the standards set forth in paragraph § 63. 11645 you may assert an affirmative defense to a claim for civil penalties for exceedances of such standards
t hat are caused by malfunction, as defined at 40 CFR 63.2. Appropriate penalties may be assessed, however, if you fail to meet your burden of proving all of the requirements in the affirmative defense. The affirmative defense shall not be available for cl aims for injunctive relief. Affirm ative Defense for Exceedance of Emission Limit During Malfunction.

(a) To establish the affirmative defense in any action to enforce such a limit, you must timely meet the notification requirements in paragraph (b) of this section, and must prove by a preponderance of evidence that: (1) Th e excess emissions: (i) Were caused by a sudden, short, infrequent, and unavoidable failure of air pollution control and monitoring equipment, process equipment, or a process to operate in a

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## normal or usual manner, and (ii) Could not have been prevented through careful planning, proper design or better operation and maintenance practices; and (iii) Did not stem from any activity or event that could have been foreseen and avoided, or planned for; and (iv) Were not part of a recurring pattern indicative of inadequate design, operation, or maintenance; and (2) Repairs were made as expeditiously as possible when the applicable emission limitations were being exceeded. Off

- shift and overtime labor were used, to the extent practicable to make these repa irs; and (3) The frequency, amount and duration of the excess emissions (including any bypass) were minimized to the maximum extent practicable during periods of such emissions; and (4) If the excess emissions resulted from a bypass of control equ ipment or a process, then the bypass was unavoidable to prevent loss of life, severe personal injury, or severe property damage; and (5) All possible steps were taken to minimize the impact of the excess emissions on ambient air quality, the environmen t and human health; and (6) All emissions monitoring and control systems were kept

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## in operation if at all possible; and (7) All of the actions in response to the excess emissions were documented by properly signed, contemporaneous operating logs; a nd (8) At all times, the facility was operated in a manner consistent with good practices for minimizing emissions; and (9) A written root cause analysis has been prepared to determine, correct, and eliminate the primary causes of the malfunction and the excess emissions resulting from the malfunction event at issue. The analysis shall also specify, using best monitoring methods and engineering judgment, the amount of excess emissions that were the result of the malfunction. (b) Notification. The owner or operator of the facility experiencing an exceedance of its emission limit(s) during a malfunction shall notify the Administrator by telephone or facsimile (FAX) transmission as soon as possible, but no later than two business days after the initia l occurrence of the malfunction, if it wishes to avail itself of an affirmative defense to civil penalties for that malfunction. The owner or operator seeking to assert an affirmative defense shall also submit a written report to the Administrator within 30 days of the initial occurrence of the exceedance of the standard in

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## § 63. 11645 to demonstrate, with all necessary supporting documentation, that it has met the requirements set forth in paragraph (a) of this section.
§ 63.1164 9 What are my notification, reporting, and recordkeeping requirements (a) You must submit the Initial Notification required by §63.9(b)(2) no later than 120 calendar days after the date of publication of the final rule in the ?

Federal Register

(b) You must submit an initial Notification of Compliance Status as required by §63.9(h). or within 120 days after the source be comes subject to the standard. The Initial Notification must include the information specified in §63.9(b)(2)(i) through (b)(2)(iv).

(c) If a deviation occurs du ring a semiannual reporting period, you must submit a deviation report to your permitting authority according to the requirements in paragraphs (c)(1) and (2) of this section. (1) The first reporting period covers the period beginning on the compliance d ate specified in §63.11641 and ending on June 30 or December 31, whichever date comes first after your compliance date. Each subsequent reporting period covers the semiannual period from January 1 through June 30 or from July 1 through December 31. Your deviation report must be postmarked

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## or delivered no later than July 31 or January 31, whichever date comes first after the end of the semiannual reporting period. (2) A deviation report must include the information in paragraphs (c)(2)(i) through (iv) of this section. (i) Company name and address. (ii) Statement by a responsible official, with the official’s name, title, and signature, certifying the truth, accuracy and completeness of the content of the report. (iii) Date of the report and beginning a nd ending dates of the reporting period. (iv) Identification of the affected source, the pollutant being monitored, applicable requirement, description of deviation, and corrective action taken. (d) If you had a malfunction during the reporting period, th e compliance report must include the number, duration, and a brief description for each type of malfunction which occurred during the reporting period and which caused or may have caused any applicable emission limitation to be exceeded. The report must i nclude r ecords of the occurrence and duration of each malfunction of operation (i.e., process equipment) or the air pollution control and monitoring equipment. The report must also include a description of actions taken by an owner or operator during perio ds of malfunction of an

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## affected source to minimize emissions in accordance with §63.11646(c), including corrective actions taken to restore malfunctioning process and air pollution control and monitoring equipment to its normal or usual manner of operatio n. ( e ) You must keep the records specified in paragraphs ( e )(1) through (3) of this section. The form and maintenance of records must be consistent with the requirements in section 63.10(b)(1) of the General Provisions. (1) As required in §63.10(b )(2)(xiv), you must keep a copy of each notification that you submitted to comply with this subpart and all documentation supporting any Initial Notification, Notification of Compliance Status, and semiannual compliance certifications that you submitted. (2) You must keep the records of all performance tests, measurements, monitoring data, and corrective actions required by §§63.11646 and 63.11647, and the information identified in paragraphs (c)(2)(i) through (vi) of this section for each corrective acti on required by §63.11647. (i) The date, place, and time of the monitoring event requiring corrective action; (ii) Technique or method used for monitoring; (iv) Operating conditions during the activity; (v) Results, including the date, time, and dur ation of the

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## period from the time the monitoring indicated a problem to the time that monitoring indicated proper operation; and (vi) Maintenance or corrective action taken (if applicable). (3) You must keep records of operating hours for each
process a s required by §63.11646(a)( 5 ) and records of the monthly quantity of ore and concentrate processed as required by §63.11646(a)( 10 ). ( f ) Your records must be in a form suitable and readily available for expeditious review, according to §63.10(b)(1). As

s pecified in §63.10(b)(1), you must keep each record for 5 years following the date of each recorded action. You must keep each record onsite for at least 2 years after the date of each recorded action according to §63.10(b)(1). You may keep the records o ffsite for the remaining 3 years. ( g ) After December 31, 2011, within 60 days after the date of completing each performance evaluation conducted to demonstrate compliance with this subpart, the owner or operator of the affected facility must submit the te st data to EPA by entering the data electronically into EPA’s WebFIRE data base through EPA’s Central Data Exchange. The owner or operator of an affected facility shall enter the test data into EPA’s data base using the Electronic Reporting Tool or other compatible

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## electronic spreadsheet. Only performance evaluation data collected using methods compatible with ERT are subject to this requirement to be submitted electronically into EPA’s WebFIRE database. **Other Requirements and Information** §63.11650 What General Provisions apply to this subpart Table 1 to this subpart shows which parts of the General Provisions in §§63.1 through 63.16 apply to you. ?

§63.11651 What definitions apply to this subpart Terms used in this subpart are defined in the Clean Ai r Act, in §63.2, and in this section as follows: ?

Affirmative defense means, in the context of an enforcement proceeding, a response or defense put forward by a defendant, regarding which the defendant has the burden of proof, and the merits of which are in dependently and objectively evaluated in a judicial or administrative proceeding.
A utoclave means a pressure oxidation vessel that is used to treat gold ores (primarily sulfide refractory ore) and involves pumping a slurry of milled ore into the vessel whi ch is highly pressurized with oxygen and heated to temperatures of approximately 350 ° to 430°F. Calomel

- based mercury control system means a mercury emissions control system that uses scrubbers to remove mercury

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## from the gas stream of a roaster or combinat ion of roasters by complexing the mercury from the gas stream with mercuric chloride to form mercurous chloride (calomel). T hese scrubbers are also referred to as “mercury scrubbers.” Carbon adso r ber means a control device consisting of a single fixed car bon bed, multiple carbon beds or columns, carbon filter packs or modules, and other variations that uses activated carbon to remove pollutants from a gas stream
. Carbon kiln means a kiln or furnace where carbon is regenerated by heating, usually in the pre sence of steam, after the gold has been stripped from the carbon. Carbon processes with mercury retorts means the affected source that includes carbon kilns, preg tanks, electrowinning cells , mercury retorts, and melt furnaces at gold mine ore processing a nd production facilities that use activated carbon , or resins that can used as a subsititute for activated carbon, to recover (adsorb) gold from the pregnant cyanide solution. Carbon processes without mercury retorts means the affected source that includes carbon kilns, preg tanks, electrowinning cells, and melt furnaces, but has no retorts, at gold mine ore processing and production facilities that use activated carbon , or resins that can used as a subsititute for activated carbon, to recover (adsorb) gold from the pregnant cyanide solution.

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## Concentrate means the sludge

- like material that is loaded with gold along with various other metals (such as silver, copper, and mercury) and various other substances , that is produced by electrowinning, the Merrill

- Cro we process, flotation and gravity separation processes. Concentrate is measured as the input to mercury retorts, or for facilities without mercury retorts, as the input to melt furnaces before any drying takes place. For facilities without mercury retort s or melt furnaces,
concentrate is measured as the quantity shipped. Deviation

(1) Fails to meet any requirement or obligation established by this subpart, including but not limited to any emissions limitation or work practice standard; means any instance where an affected source subject to this subpart, or an owner or operator of such a

source:

(2) Fails to meet any term or condition that is adopted to implement an applicable requirement in this subpart and that is included in the operating permit fo r any affected source required to obtain such a permit ; or (3) Exceeds any operating limit established under this subpart. Electrowinning means a process that uses induced voltage on anode and cathode plates to remove metals from the continuous

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## flow of solution, where the gold in solution is plated onto the cathode. Steel wool is typically used as the plating surface. Electrowinning Cells means a tank in which the electrowinning takes place. Gold mine ore processing and production facility means any industrial facility engaged in the processing of gold mine ore that uses any of the following processes: roasting operations, autoclaves, carbon kilns, preg tanks, electrowinning, mercury retorts, or melt furnaces. An operation that processes or produces less than 50 pounds of concentrate per year is not a gold mine ore processing and production facility. A facility that produces primarily metals other than gold, such as copper , lead, zinc, or nickel (where these metals other than gold comprise 95 percen t or more of the total metal production) that may also recover some gold as a byproduct is not a gold mine ore processing and production facility. Those facilities whereby 95 percent or more of total mass of metals produced are metals other than gold, whe ther final metal production is onsite or offsite , are not part of the gold mine or processing and production source category
. Melt furnace means a furnace (typically a crucible furnace) that is used for smelting the gold

- bearing material recovered from m ercury retorting , or the gold

- bearing material from

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## electrowinning , the Merrill

- Crowe process , or other processes for facilities without mercury retorts. Mercury r etort means a vessel that is operated under a partial vacuum at approximately 1100 ° to 1300 oF to remove mercury and moisture from the gold bearing sludge material that is recovered from electrowinning, the Merrill

- Crowe process , or other processes. Mercury retorts are usually equipped with condensers that recover liquid mercury during the proce ssing. Merrill

- Crowe process means a precipitation technique using zinc oxide for removing gold from a cyanide solution . Z inc dust is added to the solution , and gold is precipitated to produce a
concentrate.
Non

- carbon concentrate processes means the affe cted source that includes mercury retorts and melt furnaces at gold mine ore processing and production facilities that use the Merrill

- Crowe
process or other processes and do not use carbon to recover (adsorb) gold from the pregnant cyanide solution. Ore d ry grinding means a process in which the gold ore is ground and heated (dried) prior to additional preheating or prior to entering the roaster. Ore preheating means a process in which ground gold ore is preheated prior to entering the roaster. Ore pretreat ment processes means the affected source that

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## includes roasting operations and autoclaves that are used to
pre - treat gold mine ore at gold mine ore processing and production facilities prior to the cyanide leaching process. Preg nant solution tank (or preg tank) means a storage tank for pregnant solution, which is the cyanide solution that contains gold

- cyanide complexes that is generated from leaching gold ore with cyanide solution. Pregnant cyanide solution means the cyanide solution that contains gold

- cya nide complexes that are generated from leaching gold ore with a dilute cyanide solution. Quenching means a process in which the hot calcined ore is cooled and quenched with water after it leaves the roaster. Roasting operation

§ means a process that uses an industrial furnace in which milled ore is combusted across a fluidized bed to oxidize and remove organic carbon and sulfide mineral grains in refractory gold ore. The emissions points of the roasting operation subject to this subpart include ore dry grin ding, ore preheating, the roaster stack, and quenching.

63.11652 Who implements and enforces this subpart (a) This subpart can be implemented and enforced by the U.S. EPA or a delegated authority, such as your state, local, or tribal agency. If the U.S. EPA Administrator has delegated authority to your state, local, or tribal agency, then that ?

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## agency has the authority to implement and enforce this subpart. You should contact your U.S. EPA Regional Office to find out if this subpart is delegated to y our state, local, or tribal
agency. (b) In delegating implementation and enforcement authority of this subpart to a state, local, or tribal agency under 40 CFR part 63, subpart E, the authorities contained in paragraph (c) of this section are retained by the Administrator of the U.S. EPA and are not transferred to the state, local, or tribal
agency. (c) The authorities that will not be delegated to state, local, or tribal agencies are listed in paragraphs (c)(1) through (4) of this section. (1) Approv al of alternatives to the applicability requirements in §63.11640, the compliance date requirements in §63.11641, and the applicable standards in §63.11645. (2) Approval of an alternative nonopacity emissions standard under §63.6(g). (3) Approval of a major change to a test method under §63.7(e)(2)(ii) and (f). A “major change to test method” is defined in §63.90(a). (4) Approval of a major change to monitoring under §63.8(f). A “major change to monitoring” is defined in

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## §63.90(a). (5) Approval of a waiver of recordkeeping or reporting requirements under §63.10(f), or another major change to recordkeeping/reporting. A “major change to recordkeeping/reporting” is defined in §63.90(a). §63.11653 **[Reserved] Tables to Subpart EEEEEEE of Part 63**  Tab le 1 to Subpart EEEEEEE of Part 63

— Applicability of General Provisions to S ubpart EEEEEE As stated in §63.11650, you must comply with the applicable General Provisions requirements according to the following table:

**Citation Subject**  **Applies to subpart**  **EEEE EEE**  **Explanation** §63.1(a)(1), (a)(2), (a)(3), (a)(4), (a)(6), (a)(10)

– (a)(12), (b)(1), (b)(3), (c)(1), (c)(2), (c)(5), (e) Applicability Yes

§63.1(a)(5), (a)(7)

– (a)(9), (b)(2), (c)(3), (c)(4), (d) Reserved No

§63.2 Definitions Yes §63.3 Units and Abb reviations Yes
§63.4 Prohibited Activities and Circumvention Yes

§63.5 Preconstruction Yes

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## Review and Notification Requirements §63.6(a), (b)(1)

– (b)(5), (b)(7), (c)(1), (c)(2), (c)(5), (e)(1)(iii),(f)(2 ), (f)(3), (g), (i), (j) Compliance with Standar ds and Maintenance Requirements Yes

63.6(e)(1)(i) General Duty to minimize emissions No. See 63. 11646(b) for general duty requirement See 63.11646(b)

63.6(e)(1)(ii) Requirement to correct malfunctions as soon as possible. No

63.6(e)(3) SSM Plan requi rements No
63.6(f)(1) SSM exemption No Malfunctions are no longer exempt. All excursions are violations and there is no need to specify corrections. §63.6(h)(1), (h)(2), (h)(4),(h)(5)(i), (ii), (iii) and (v), (h)(6)

– (h)(9) Compliance with Opacity and V isible Emission Limits No Subpart EEEEEEE does not contain opacity or visible emission limits. §63.6(b)(6), (c)(3), (c)(4), (d), (e)(2), (e)(3)(ii), Reserved No

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## (h)(3), (h)(5)(iv) §63.7, except (e)(1) Applicability and Performance Test Dates Yes

§63. 7(e)(1) Performance Testing See 63.11646 See 63.11646(a)(3) §63.8(a)(1), (b)(1), (f)(1)

- (5), (g) Monitoring Requirements Yes

§63.8(a)(2), (a)(4), (b)(2)

- (3), (c)(ii), (d)(i), (e), (f)(6), (g) Continuous Monitoring Systems (CMS) Yes Except cross refer ences to SSM requirements in §63.6(e)(1) and (3) do not apply 63.8(c)(1)(i) General duty to minimize emissions and CMS operation No See 63.11646(b)
63.8(c)(1)(iii) Requirement to develop SSM Plan for CMS No

63.8(d)(3) Written procedures for CMS Yes, ex cept for last sentence
. Last sentence refers to an SSM Plan which is no longer required. §63.8(a)(3) [Reserved] No §63.9(a), (b)(1), (b)(2)(i)

- (v), (b)(4), (b)(5), (c), (d)(1), (d)(2), (e), (g), (h)(1)

– (h)(3), (h)(5), (h)(6), (i), (j) Notification Requi rements Yes

§63.9(f) No §63.9(b)(3), Reserved No

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## (h)(4) §63.10(a), (b)(1), (b)(2)(vi)

– (xiv), (b)(3), (c)(1)

- (14), (d)(1)

- (4), (e), (f) Recordkeeping and Reporting Requirements Yes

63.10(b)(2)(i) Recordkeeping of occurrence and duration of startup s and shutdowns No

63.10(b)(2)(ii) Recordkeeping of malfunctions No. See 63. 1164 9 for recordkeeping of (1) occurrence and duration and (2) actions taken during malfunction See 63.11648

63.10(b)(2)(iii) Maintenance records Yes. 63.10(b)(2)(iv) Action s taken to minimize emissions during SSM No.

63.10(b)(2)(v) Actions taken to minimize emissions during SSM No.

63.10(b)(2)(vi) Recordkeeping for CMS malfunctions Yes. 63.10(b)(2)(vii)

- (ix) Other CMS requirements Yes.

§63.10(c)(2)

– (c)(4), (c)(9 ) Reserved No
63.10(c)(7) Additional Yes

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## recordkeeping requirements for CMS

– identifying exceedances and excess emissions 63.10(c)(8) Additional recordkeeping requirements for CMS

– identifying exceedances and excess emissions Yes

63.10(c)(10) Reco rding nature and cause of malfunctions No. See 63. 11649 for malfunctions recordkeeping requirements. 63.10(d)(5) SSM reports No. See 63. 11649 for malfunction reporting requirements. See 63.11649

§63.11 Control Device Requirements No
§63.12 State Authority and Delegations Yes
§§63.13

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**ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part**  **s 9 and 63**  **[ EPA**  **- HQ**  **- OAR**  **- 20**  **10 -**  **0239 ; FRL**  **- 9140**  **- 7**  ] **RIN 2060**  **- AP48**  **National Emission Standards for Hazardous Air Pollutants: Gold**

**Mine Ore Processing**  **and Production Area Source Category**  **; and Addition to Sour**  **ce Category List for Standards .**  **AGENCY:** Environmental Protection Agency (EPA).
**ACTION:** Final rule
. **SUMMARY:** EPA is adding the gold mine ore processing and production area source category to the list of source categories to be regulated under Section 1 12(c)(6) of the Clean Air Act due to its mercury emissions . EPA is also p romulgating national emission standards for hazardous air pollutants to regulate mercury emissions from this source category
. EPA proposed these actions on April 28, 2010 (75 FR 224 70).
**DATES:** This final rule is effective on [INSERT DATE OF 60 DAYS
AFTER PUBLICATION IN THE FEDERAL REGISTER].
**ADDRESSES:** EPA has established a docket for this action under Docket ID No. EPA

- HQ

- OAR

- 20 10

- 0239
. All documents in the docket are listed on the www.regulations.gov w ebsite. Although listed in the index, some information is not publicly available, e.g., Confidential Business Information (CBI) or other information***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **2** of **206** whose disclosure is restricted by statute. Certain other material, such as copyr ighted material, is not placed on the Internet and will be publicly available only in hard copy form. Publicly available docket materials are available either electronically through www.regulations.gov or in hard copy at the EPA Headquarters Library, Room Number 3334, EPA West Building, 1301 Constitution Ave., NW, Washington, DC. The EPA/DC Public Reading Room hours of operation are 8:30 a.m. to 4:30 p.m. Eastern Standard Time (EST), Monday through Friday. The telephone number for the Public Reading Room is (202) 566

- 1744, and the telephone number for the Air and Radiation Docket and Information Center is (202) 566

- 1742.
**FOR FURTHER INFORMATION CONTACT:** Mr. Chuck French , Sector Policies and Program Division, Office of Air Quality Planning and Standards (D243

- 02), Environmental Protection Agency, Research Triangle Park, North Carolina 27711, telephone number (919) 541

- 7912; fax number (919) 541

- 3207, e

- mail address: french.chuck@epa.gov
**SUPPLEMENTARY INFORMATION:** .

The information presented in this pream ble is organized as follows:
I. General Information A. Does this action apply to me?***E.O. 12866 Review

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B. Where can I get a copy of this document? C. Judicial Review II. Addition to Section 112(c)(6) Source Category List III
. Summary of Significant Changes Since Propo sal A. Applicability B. Final Emission Standards C. Compliance Dates D. Compliance Requirements E. Monitoring Requirements F. Definitions I V. Summary of Responses to Major Comments A. Statutory Requirements B. Applicability C. MACT Floors D. Com pliance Determinations E. Monitoring V. Summary of Environmental, Economic and Health Benefits? VI. S **tartup ,**  **Shutdown and Malfunctions** 
V II
. Statutory and Executive Order Reviews A. E xecutive Order 12866: Regulatory Planning and Review B. Paperwork R eduction Act C. Regulatory Flexibility Act D. Unfunded Mandates Reform Act E. Executive Order 13132: Federalism F. Executive Order 13175: Consultation and Coordination with Indian Tribal Governments G. Executive Order 13045: Protection of Children from Environmental Health and Safety Risks H. Executive Order 13211: Actions Concerning Regulations that Significantly Affect Energy Supply, Distribution, or Use I. National Technology Transfer and Advancement Act J. Executive Order 12898: Federal Act ions to Address Environmental Justice in Minority Populations and Low

- Income Populations K. Congressional Review Act **I. General Information 60** 
A. Does this action apply to me The regulated categories and entities potentially affected by th is final rul e include: ?***E.O. 12866 Review

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Category NAICS code 1 Examples of regulated E ntities Industry: Gold Ore Mining 212221 Establishments primarily engaged in developing the mine site, mining, and/or beneficiating (i.e., preparing) ores valued chiefly for their gold content. E stablishments primarily engaged in transformation of the gold into bullion or dore bar in combination with mining activities are included in this industry.

1 North American Industry Classification System. This table is not intended to be exhaustive, b ut rather provides a guide for readers regarding entities likely to be affected by this action. To determine whether your facility would be regulated by this action, you should examine the applicability criteria in 40 CFR 63. 11640 of subpart EEEEEEE (Nati onal Emission Standards for Hazardous Air Pollutants: Gold Mine Ore Pro c essing and Production Area Source Category ). If you have any questions regarding the applicability of this action to a particular entity, consult either the air permit authority for the entity or your EPA Regional representative, as listed in 40 CFR 63.13 of subpart A (General Provisions).
B
. Where can I get a copy of this document In addition to being available in the docket, an electronic copy of this final action will also be av ailable on the Worldwide Web (WWW) through the EPA Technology Transfer Network ?***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **5** of **206** (TTN). Following signature, a copy of th is final action will be posted on the TTN’s policy and guidance page for newly proposed or promulgated rules at the following address: www.epa.gov/ttn/oarpg/ . The TTN provides information and technology exchange in various areas of air pollution control.
C. Under section 307(b)(1) of the Clean Air Act (CAA), judicial revie w of this final rule is available only by filing a petition for review in the U.S. Court of Appeals for the District of Columbia Circuit by [INSERT DATE 60 DAYS AFTER PUBLICATION IN FEDERAL REGISTER]. Under section 307(d)(7)(B) of the CAA, only an objecti on to this final rule that was raised with reasonable specificity during the period for public comment can be raised during judicial review. Moreover, under section Judicial Review

307(b)(2) of the CAA, the requirements established by this final rule may not be challenge d separately in any civil or criminal proceedings brought by EPA to enforce these requirements. Section 307(d)(7)(B) also provides a mechanism for us to convene a proceeding for reconsideration, “[i]f the person raising an objection can demonstrate to EPA that it was impracticable to raise such objection within [the period for public comment] or if the grounds for such objection arose after***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **6** of **206** the period for public comment (but within the time specified for judicial review) and if such objection is of central relevance to the outcome of the rule.” Any person seeking to make such a demonstration to us should submit a Petition for Reconsideration to the Office of the Administrator, U.S. EPA, Room 3000, Ariel Rios Building, 1200 Pennsylvania Ave., NW., Washingto n, DC 20460, with a copy to the person listed in the preceding
**FOR FURTHER INFORMATION CONTACT** section
. **II. Addition to**  **Section 112(c)(6) Source Category List**  For reasons stated in the preamble to the proposed rule ( 75
F R 22470, April 28, 2010 ) , we are a dding the gold mine ore processing and production area source category to the list of source categories under section 112(c)(6) on the basis of its mercury emissions.
**III .**  **Summary of Significant Changes Since Proposal** This section summarizes the signific ant changes to the rule since proposal. Additional information on the basis for these changes and other changes can be found in the Summary of Responses to Major Comments in Section IV of this preamble.
A. We have clarified in §63.116 51 o f the final rule that the term "gold mine ore processing and production facility" does not Applicability***E.O. 12866 Review

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include laboratories (see CAA section 112(c)(7) ) , individual prospectors, and very small pilot scale mining operations. The The se types of operations are very small and were not included in the section 112(c)(6) inventory that was the basis for the listing of the gold mine ore processing and production source category
. B. We have made changes to all of the proposed emission standards a s the result of the following developments: (1) inclusion of additional emission s test data received since proposal; (2) additional analyses in response to public comments on the proposed rule ; and (3) further review of the data used to develop the standar ds for the proposed rule. The changes are summarized below and described in more detail in section IV of this preamble. Final emission standards

In the proposed rule, the proposed mercury emission standards for both existing and new ore pretreatment p rocess es

were 149 pounds per million tons of ore processed ( lb /million tons of ore). In the final rule, the emission standard for existing sources is 12 7 lb/million tons of ore; for new sources the emission standard is 84 lb/million tons o f ore. The fina l Ore Pretreatment Processes***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **8** of **206** emission standards are based on several changes to the data set used in the MACT analysis. Since we issued the proposed rule,

w e collected emissions data from more recent tests that were not available at proposal
. Further , we learned that two emission s
test s that we used to develop the MACT floor in our proposed rule had been invalidated by the N evada D ivision of Environmental Protection (ND EP ) , and we removed those test results from the database. We also discovered that the test data for a unit within the ore pretreatment affected source at a facility should have been included as part of a different unit at the same facility. Moreover, we conducted a dditional beyond

the

- floor analys e i s for the ore pretreatment affected

source roasters , which was not in cluded in the proposed rule
. The new information and analyses described above are discussed in more detail in Section IV.C of this preamble and in the MACT Floor document in the docket for this rulemaking
. The resulting data set included emissions data f or four facilities that ranged from 45 to 165 lb/million tons of ore. Based on these data, and using the same upper prediction limit (UPL) approach used for proposal to account for variability, we determined the MACT floor to be 158 lb/million tons o f ore for existing sources of ore pretreatment processes and 84 lb/million***E.O. 12866 Review

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tons of ore for new sources
. As explained in the proposed rule (75 FR at 22482), the technologies for achieving the MACT floor for existing ore pretreatment processes include calomel

- ba sed mercury scrubbers on roasters and venturi scrubbers on autoclaves and ancillary roaster operations. After applying the beyond

- the

- floor analysis to the data, we determined the MACT limit for existing sources to be 12 7 lb/million tons of ore
. For new sources, t he MACT limit is 84 lb/million tons ( which is the same as the MACT floor for new sources)
. Table 1 summarizes the MACT floor analysis for existing and new ore pretreatment
processes . Table 2 summarizes the results of the beyond

- the

floor analys is for these sources. Table 1

— MACT Floor Results for Ore Pretreatment Processes Facility Average performance (lb/million tons of ore ) A 45 C 56 E 71 D 165 Average of top 4 84 99% UPL existing (MACT Floor) 15 8 99% UPL new 1 (MACT Floor) 84 1 The M ACT Floor for new sources i s based on the average performance of Facility A plus an amount to account for variability (i.e., 45 + 39 = 84)
.

Table 2

— B eyond

- the

- F loor Results for Ore Pretreatment Processes Facility Average performance (lb/million tons of or e ) C 3 7 D 49***E.O. 12866 Review

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E 5 8 A 8 0 Highest Average 8 0 99% UPL existing ( BTF Floor) 12 7

Under the proposed rule, all carbon process es were subject to the same proposed mercury emissions limits of 2.6 pounds per ton of concentrate (lb/ton of c oncentrate) for existing sources and , for new sources, either 0.14 lb/ton of concentrate or 97 percent reduction in uncontrolled mercury emissions . These limits would have applied to facilities that operate mercury retorts and facilities that do not opera te mercury retorts. In the final rule, we distinguish between carbon processes with
mercury retorts and carbon processes without mercury retorts because we believe there are unique differences in these two types of processes
. Therefore, the final rule sp ecifies separate emission standards for these two types of processes. Moreover, the final emission standards for carbon processes reflect inclusion of new test data that were not available at proposal. We also removed from the data set emissions data bas ed on previously uncontrolled sources that installed controls in 2009; for those sources, only the controlled emissions data were used. (see section IV for further details). For carbon Carbon Processes***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **11** of **206** processes with mercury retorts, the emission standard in the final rul e is 2.2 lb/ton of concentrate for existing sources and 0.8 lb/ton of concentrate for new sources. For carbon processes without mercury retorts, the emission standard in the final rule is 0.1 7 lb/ton of concentrate for existing sources and 0. 14 lb/ton of concentrate for new sources
. W e considered beyond

the

- floor options for these affected sources ; however , we rejected those options because they were not cost effective. Additional information on the analyses performed can be found in the MACT Floor docum ent in the docket for this rulemaking. We also eliminated in the final rule the compliance alternative of 97

- percent reduction for new carbon processes. After reviewing the comments received on this proposed alternative standard and giving further conside ration to the practicality of how it would be measured, we concluded that this option would be difficult to implement , particularly when multiple processes that are operated at different times vent to a single control device and stack . In addition, we hav e limited data supporting this compliance alternative. In proposing this alternative for comment, we had hoped to , but did not , receive additional data indicating that the 97 percent reduction option would be equivalent to the proposed new source limit of 0.14***E.O. 12866 Review

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pounds of mercury per ton of concentrate. For the reasons stated above, we eliminated the 97 percent control efficiency option for new carbon processes in the final rule. Table 3 summarizes the results of the MACT floor analysis for carbon proce sses with mercury retorts, and Table 4 summarizes the analysis for carbon processes without mercury
retorts. Table 3

— MACT Floor Results for Carbon Processes with Mercury
Retort s Facility Average performance (lb/ton of concentrate ) N 0.53 J 0.74 I 1.06 A 1.47 H 1.67 D 2.20 C 3.71 G 8.17 B 20.60 Average of top 5 1.1 99% UPL existing (MACT Floor) 2.2 99% UPL new (MACT Floor) 0.8

Table 4

— MACT Floor Results for Carbon Processes without Mercury
Retort s Facility Average performance (lb/ton of concen trate ) M 0.0 58 F 0.0 9 8 Average of top 2 0.0 78 99% UPL existing (MACT Floor) 0. 1 7***E.O. 12866 Review

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99% UPL new (MACT Floor) 0. 14
For carbon processes, regardless of whether the facility operates a mercury retort, the MACT floor is based on control of mercury emission s using mercury condensers and carbon adsorbers. For the beyond

- the

- floor analysis, we considered adding a second carbon adsorber to the MACT floor level controls.

Under the proposed rule, the mercury emission standards f or

non - carbon concentrate processes were 0.25 lb/ton of concentrate for existing sources and 0.2 lb/ton of concentrate for new

sources. In the final rule, t he emission standards for these sources are 0.2 lb/ton of concentrate for existing sources and 0.1 lb/ton of concentrate for new sources. The se standards are based on using new emissions data that were not available when we developed the proposal , along with most of the data that were used for the proposal
. We also considered beyond

- the

- floor controls for these sources, but concluded th ose controls would not be a cost

- effective option. Table 5 summarizes the results of the MACT floor analysis for non

- carbon concentrate processes. Non

- Carbon Concentrate Processes

Table 5

— MACT Floor Results for Non

- Carbon Concentrate Processes Facility Average performance (lb/ton of concentrate ) K 0.047***E.O. 12866 Review

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L 0.078 Average of top 2 0.062 99% UPL existing (MACT Floor) 0. 2 99% UPL new (MACT Floor) 0.1

For non

- carbon concentrate processes, the MACT floor is based on control of mercury emissions using m ercury condensers and carbon adsorbers. For the beyond

- the

- floor analysis, we considered adding a second carbon adsorber to the MACT floor level controls.
C. In the final rule, we provide in §63.11641 that the compliance date for existi ng sources is 3 years after promulgation of the final rule as opposed to 2 years as proposed
. We review ed the information provided in public comments on the challenges of installing new controls, especially for autoclaves , which , although the controls hav e not yet been demonstrated , have been proposed by facilities with autoclaves in their Nevada Mercury Control Program ( NMCP ) permit applications ; and the consideration of installing new controls on the roaster preheaters , which also have not been demonstra ted yet , but have been proposed by these facilities in their NMCP permit applications. W e concluded th at allowing 3 years for existing sources to comply is appropriate , given the complexity Compliance Dates***E.O. 12866 Review

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of the sources, the combinations of control devices that are need ed in many cases, and the amount of time necessary for designing, install ing, testing, and commissioning addition al emission controls for mercury.
D. Section 63.11646(a)(1)(v) of the final rule does not include Method 30A , as was proposed, as an appropriate method for determining mercury concentration because it is not yet in general use. T his paragraph further clarifies that the use of ASTM D6784

- 02 and Method 30B are allowed for compliance tests only if approved by the permit au thority
. The final rule also does not include the requirement to follow the acetone rinse procedures and the absence of cyclonic flow determination requirement, which were in subparagraph s (v) and (vi) respectively of our proposed §63.11646(a)(1). Method 29 already includes requirements for the acetone rinse, so there is no need to specify those procedures in the rule; and Method 1, which is required by the rule, addresses the issue of cyclonic flow. Compliance Requirements

In §63.11646(a)(2) , we changed the minimum sample volu me when Method 29 is used to determine compliance from the proposed 60 dry standard cubic feet ( dscf ) to 30 d s c f . We believe this volume is adequate for detecting mercury in the samples and***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **16** of **206** determining mercury emissions for this industry . We have also

ex panded this section to address non

- detect values. If the emission testing results for any of the emission points yield a

non - detect value, the final rule requires that the minimum detection limit (MDL) be used to calculate the mass emissions rate used to calculate the emissions factor (lb/ton) for that emission point and to calculate the sum of the emissions factors for all emission points subject to the emission standard. If the resulting mercury emissions factor is greater than the allowable emission st andard , the owner or operator may repeat the mercury emissions testing one additional time for any emission point for which the measured result was below the MDL using procedures that produce lower MDL results. If this additional testing is performed, the results from that testing must be used to determine compliance. For sources with multiple emission units (e.g., two roasters) ducted to a common control device and stack, we have clarified in §63.11646(a)(3) that compliance testing must be performed with all affected emissions units in operation , if this is possible . This same requirement applies to the establishment of operating limits for all process units. However, this requirement does not affect the frequency and***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **17** of **206** schedule for monitoring , which are specified in the rule. If facilities have batch type processes that cannot be operated simultaneously, then the facility can test some or all of the units individually.
In §63.11646(a)(6) and (7) , we clarify that the production data used in compliance de terminations are based on full calendar months. For the initial compliance test, data for all the full calendar months between publication of the final rule and the initial compliance test must be used. For subsequent annual compliance tests, data for th e 12 full calendar months prior to the annual compliance test must be used to demonstrate compliance. In addition, we clarify in paragraphs §63.11646(a)(5), (6) and (7) that compliance determinations are based on the number of 1

- hour periods each process unit operates. By using the 1

- hour period terminology, the final rule language is consistent with the terminology used in the General Provisions to part 63.
Because the final rule does not include the 97 percent reduction option that was in §63.11645(e)( 2) of the proposed rule , we have removed from the final rule the compliance requir e ment for that option that was in §63.11646(b) of the proposed rule , which addressed testing the inlets and outlets***E.O. 12866 Review

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for sources choosing that proposed option
. E. Section 63.11647(a) of the final rule include s an additional option for monitoring mercury emissions from roasters. The proposed rule specified two options for monitoring mercury emissions: paragraph (a)(1) specified weekly sampling using P S 12B, and paragraph (a)(2) specified continuous monitoring using a mercury continuous emissions monitoring system ( CEMS ) . In the final rule, we added paragraph (a)(3) to provide a third option of continuous sampling using PS 12B. In addition, paragraph (a)(1) in the final rule was changed to require sampling at least twice per month using either PS 12B or Method 30B rather than weekly
. W e believe that Method 30B is an acceptable alternative method for monitoring purposes and allows owners and operators more flexibility in how they monitor roaster emissions. We also believe that sampling twice per month coupled with extensive parametric monitoring of control devices (as explained below) is sufficient for this th e monitoring option in paragraph (a)(1)
. Monitoring Requirements

Se ction 63.11647(a)(4)(iii) of the proposed rule would have required additional compliance testing if the mercury concentration in the ore fed to the roaster was higher than any***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **19** of **206** concentration measured in the previous 12 months. We have removed this requirem ent from the final rule because it is not clear that the mercury content of the ore has a significant effect on the performance of mercury scrubbers applied to roasters, which are designed to handle and operate efficiently for a range of mercury inlet conc entrations. In addition, condense rs are used to recover elemental mercury prior to the mercury scrubber, and any increase in mercury loading would likely result in an increase in the recovery of elemental
mercury. The final rule incorporates several ch anges to §63.11647(b), which addresses monitoring of calomel

- based
mercury scrubbers (i.e., mercury scrubbers) that are used to control emissions from roasters. The final r u le does not include the requirement to monitor pressure drop across calomel

based scrubber s because we conclude that pressure drop is not related to mercury emission control performance by this type of control device . In addition, the final rule allow s hourly monitoring of the line pressure in the scrubber liquid supply line as an alte rnative to hourly monitoring of scrubber liquid flow rate. Line pressure monitoring is already in practice at some facilities and provides the same type of information as***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **20** of **206** does liquid flow rate. As was proposed, t he final rule allow s the operating limit f or scrubber liquid flow rate (or line pressure) to be based on the minimum flow rate ( or line
pressure ) established during the initial performance test . It also includes two additional options for setting the operating limit: (1) based on the manufacture r’s specifications if certain types of systems are designed to operate within a specified range of flow rates; and (2) based on limits established by the permitting authority. I f the facility chooses the first option (to establish the limits during initia l compliance) , the final rule requires the operating limit to be based on either the lowest value for any run of the initial compliance test or 10 percent less than the average value measured during the compliance test. This requirement takes into account the fact that, although initially the system may exhibit little variability from test run to test run, the short

term variability in performance may increase with time. Additional discussion of these changes can be found in Section IV.E of this preamble and in the Summary of Public Comments and Responses document in the docket for this rulemaking. We have clarified the requirements for corrective action following control device monitoring parameter exceedances***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **21** of **206** specified in §63.11647(d). Under the final rule, if the corrective actions taken following an exceedance do not result in the parameter value (e.g. , water liquid flow rate , or line
pressure drop, etc. ) being returned to within the parameter
range or limit within 48 hours, a mercury concentration

mea surement must be made to determine if the operating limit for mercury concentration is being exceeded. The measurement must be performed and the concentration determined within 48 hours after the initial 48 hours , or a total of 96 hours from the time the parameter was exceeded . If the measured mercury concentration meets the operating limit for mercury concentration, the corrective actions are deemed successful. In addition, the owner or operator may request approval from the permitting authority to chan ge the parameter range or limit based on measurements of the parameter at the time the mercury concentration measurement was made. If , on the other hand, the measured mercury concentration indicates the operating limit for mercury concentration is exceede d, the exceedance must be reported as a deviation within 24 hours to the permit ting authority , and the facility must perform a compliance test (pursuant to §63.11647(d) ) within 40 days to determine whether the source is in compliance with the MACT standard
. We believe***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **22** of **206** 40 days is reasonable because it may take 3 to 4 weeks to schedule and have the testing contractor on site, and, following completion of the test, another week to receive the finals final test results. In §63.11647(a)(1)(ii) of the final rule , we require t hese

same corrective action s described above (i.e., measuring mercury concentration within 48 hours , reporting a deviation if the data show the operating limit was exceeded within 24 hours , and conducting a compliance test within 40 days ) for exceedances of mercury concentration operating limits indicated by the results of the twice month ly monitoring using PS 12B or Method 30B , CEMS, or continuous monitoring using PS 12B
. In such cases, the owner or operator must use the results of the compl iance test to determine if the roaster operations are ore pretreatment process affected source is in compliance with the emission standard . If the source is determined to be in compliance , the owner or operator may use this compliance test to establish a new operating limit for mercury concentration for the roaster
. We also removed the requirement that roasters must be shut down operations if a parameter is out of range. In the final rule, §63.11647(f)(1) require s monthly sampling of the exhaust stream o f carbon adsorbers using Method***E.O. 12866 Review

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30B . The duration of sampling must be at least the minimum sampling time specified in Method 30B , up to one week. The proposed rule required a full week of such sampling, but, as pointed out by one of the commenters, break through of the sampling trap from exhaust streams with high mercury concentrations could occur before a week had elapsed. Section 63.11647(f)(2) of the final rule clarif ies that sampling of the carbon bed must be collected from the inlet and outlet of th e bed. T his paragraph also specifies that, for carbon adsorbers with multiple carbon columns or beds, the sampling should be performed in the first and last column or bed rather than at the inlet or outlet. We have deleted §63.11647(f)(3) in the proposed rule , which allowed the carbon bed change

- out rate to be determined based on historical data and the estimated life of the carbon. We have concluded that this method would not be adequate to ensure that breakthrough does not occur earlier than expected. We have clarified §63.11647(h) with respect to the monitoring of scrubber s (other than the calomel

- based mercury scrubbers described above) . Under the final rule, owners or operations operat ors are required to monitor and record water flow rate (or lin e pressure) and scrubber pressure drop once per***E.O. 12866 Review

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shift ; they also must record any occurrences when the pressure drop was outside the manufacturer’s recommended operating range , take corrective actions to return the pressure drop back in
range, and record th e corrective actions taken. At proposal , the water flow rate and pressure drop were to be monitored continuously . However , measuring pressure drop once per shift will provide two to three measurements per day, and we believe that is sufficient to assure proper operating operati ons of the wet scrubber, and thus assure compliance with the emission standards
. We have also added the option of monitoring the line pressure in the scrubber liquid supply line as an alternative to monitoring scrubber liquid flow rate because l ine pressure monitoring is already in practice at some facilities and provides the same type of information as does liquid flow rate
. We have also clarified that , for scrubbers on autoclaves, the pressure drop parameter range should be estab lished from manufacturer’s specifications only.
**F.** We have added a definition of carbon adsorber to §63.11651 to clarify that this term, as used in the final rule, includes control devices consisting of a single fixed carbon bed, multiple carbon beds or columns, carbon filter packs or modules, **Definitions*****E.O. 12866 Review

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and other variations of carbon adsorber design
. T he definition of "gold mine ore processing and production facility" in §63.116 51 of the rule has been clarif ied to state that operations, such as pro spectors, laboratories, and very small pilot scale mining operations, that process or produce less than 5 0 pounds of concentrate per year are excluded from the source category. These prospectors and very small pilot

scale operations (that process at or be low th is cutoff) are orders of magnitude smaller than all the facilities in our database. These very small operations process far less material than the typical facility in our inventory. For example, the 21 facilities that are in our current inventory a nd that we expect will be subject to the final rule process or produce between 4,000 to 500,000 pounds of concentrate per year (i.e., at least 100 times the 5 0 lb/yr cut o ff). These types of very small operations were not intended to be subject to the fina l rule , and we do not expect any significant emissions from them. We also clarified that the source category does not include facilities at which 95 percent or more of the metals produced are metals other than gold. For example, if other non

- ferrous
meta ls (such as copper, lead, nickel, or zinc) comprise 95 percent or more of the product, the facility is not part of the***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **26** of **206** gold ore processing and production source category. **IV. Summary of Responses to Major Comments** A. Statutory Requirements 1. Listin g of the Gold Mine Ore Processing and Production Source Category Under Section 112(c)(6)
**Comment :**  One commenter stated that adding the gold mine ore processing and production category to the list of categories required by Clean Air Act (CAA) section 112(c )(6) was correct and required because gold mines accounted for a significant portion of the aggregate emissions of mercury in the baseline year (1990) and because they still do so today
. Several other commenters claimed that EPA did not provide the legal basis for listing gold mining as a source category under section 112(c)(6). The se commenters stat ed that EPA does not have the authority to list gold mining as a source category under section 112(c)(6) and noted that section 112(c)(6) requires EPA to list , by 1995, categories of sources that make up 90 percent of the 1990 emissions for a subset of hazardous air pollutants (HAP), including mercury. The commenters said that EPA concluded its statutory listing obligation for mercury in 1998 with the publicat ion of a list of source categories constituting 90 percent of aggregate mercury emissions, and that gold mining was***E.O. 12866 Review

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not included on that list in 1998. In addition, the commenters said that the CAA requires EPA to list all categories under section 112(c)(6 ) by 1995 and complete issuance of standards for all listed sources by 2000, a task that would be impossible if EPA had the authority to add source categories ad infinitum. **Response**

Some commenters questioned EPA’s estimated emission s of 4.4 tons from this source category in the 1990 baseline year; however, they did not estimate or explain what the baseline emis sion should have been. EPA continues to believe that its baseline emission s estimate is reasonable and, as mentioned above, we have not received other estimates. We disagree with the comment that , because EPA already completed this listing obligation whe n it published its section 112(c)(6) category list on April 10, 1998 (63 FR 17838), EPA has no authority to list gold mine ore processing and production as a category under **:** Section 112(c)(6) does not prescribe any methodology that EPA must foll ow in listing source categories, thus giving EPA discretion on how to carry out this obligation. Therefore, unless sources from the gold mine ore processing and production area source category did not emit mercury in the 1990 baseline year, EPA has author ity to list that category for regulation pursuant to section 112(c)(6).***E.O. 12866 Review

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section 112(c)(6) . Section 112(c)(6) requires that EPA list sufficient categories to ensure that sources accounting for not less than 90 percent of the aggregate emissions of each of the HAP specified in section 112(c)(6) are subject to standards. Although section 112(c)(6) requires that EPA list the categories by 1995, it contains no language prohibiting EPA from revising the list . In fact, i n order for EPA to regulate sufficient source categories to meet the 90 percent statutory requirement,
EPA must have the authority to revise the category list, including adding categories , should it discover during the course of developing section 112(c)(6) standards that such revision is necessary to meet the statutory 90 percent obligation. Further, were the section 112(c)(6) list of source categor ies that EPA published in 1998 considered final and unchangeable under the CAA , the CAA would have made the list judicial ly reviewable upon publication to ensure that EPA can later regulate sufficient categories to meet the statutory 90 percent requirement. To the contrary, CAA section 112(e)(4)
states that listing of a source category under section 112(c) is not a final agency action subject to judicial review , but such action may be reviewed when EPA issue s the standards. In l ight of section 112(e)(4), and were EPA prohibited from revising the***E.O. 12866 Review

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catego ry list, as the commenter claimed, it could potentially be impossible for EPA to meet the 90 percent requirement under section 112(c)(6). We do not believe that Congress would have structured the CAA in a way that c ould potentially make it impossible for EPA to meet a statutory requirement. For the reasons stated above , w e believe that EPA has authority to revise the section 112(c)(6) category list as necessary to ensure that sufficient categories are subject to regulation under section 112(c)(6)
. W e als o reject the comment that the task of completing standards by 2000 would be impossible if EPA had the authority to add source categories.
**Comment :**  Several commenters stated that Phase 2 permits under the Nevada Mercury Control Program ( NMCP ) , which are scheduled for issuance by the end of 2010, will result in MACT

level controls on all thermal units at Nevada gold mines. According to the commenters, these permits are the culmination of a 7

- year collaborative effort between NDEP and the gold mi ning industry to substantially reduce mercury emissions from gold mine processes
. The commenters said that the proposal does not address how the NESHAP will result in reductions in mercury at gold mines in areas of the country other than Nevada, where the mercury content of the ore in gold mines is non

- existent or***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **30** of **206** only a fraction of the amount found in Nevada, and Nevada accounted for 99 percent of mercury emissions associated with gold mining operations in the United States. According to the commenters, this shows that if Nevada has an equivalent mercury control program for the gold mining industry, then there is nothing to be gained from imposing a federal program, and if EPA acknowledges that the mines in Nevada are already well controlled, then the lis ting of gold mining and the promulgation of an additional layer of regulation at substantial cost to industry , but with little environmental benefit, is both legally indefensible and practically unsupportable. **Response :**  We believe it is appropriate to p romulgate MACT standards for mercury emissions for this industry. Based on our 1990 baseline inventory for 112(c)(6) and other emission information for subsequent years, w e estimate that this industry was among the top ten highest

- emitting categories of m ercury emissions in the U.S. in 1990 and has remained in the top 10 since that time. Moreover, even though most emissions are from facilities located in Nevada, several commenters expressed serious concerns about the potential for mercury emissions from

n ew gold mines in other States (e.g., Alaska). We share these

concerns about potential emissions from new gold mine***E.O. 12866 Review

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facilities
. In summary, we believe it is necessary and appropriate to promulgate a federal NESHAP for existing and new gold mine ore proces sing and production facilities
. 2 . Emission Standards for HAP Other t han Mercury
**Comment**

The commenter said that EPA appears to believe that becau se gold mines are needed only to reach the section 112(c)(6) requirement of 90 percent for mercury and not for the other **:** One commenter stated that CAA section 112(c)(6) provides that EPA must “list categories and subcategories of sources assuring that sources accounting for not less t han 90 percent of each [enumerated] pollutant are subject to standards under subsection (d)(2) or (d)(4) of this section.” The commenter also stated that the D.C. Circuit has held repeatedly that when EPA sets standards for a category or subcategory of

so urces under section 112(d)(2), EPA has a clear statutory duty to set emission standards for each HAP that the sources in that category or subcategory emit (e.g., National Lime Ass’n v. EPA , 233 F.3d 625, 633

- 634 (D.C. Cir. 2000)). The commenter concluded that when EPA sets standards for gold mines under section 112(d)(2), as section 112(c)(6) requires it to do, EPA must set section 112(d)(2) emission standards for all the HAP that gold mines emit.***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **32** of **206** pollutants enumerated in section 112(c)(6), EPA’s only obligation under section 112(c)(6) is to set section 112(d)(2) standards for mer cury. The commenter said that section 112(c)(6) expressly requires EPA to issue section 112(d)(2) standards for the “sources” in the categories listed under section 112(c)(6), not some subset of the pollutants that those sources emit, and that section 112 (d)(2) standards must include emission standards for each HAP that a source category emits. The commenter continued by stating that nothing in the CAA exempts EPA from this requirement. The commenter concluded that , had Congress wished to give EPA discre tion to set standards for only some of the pollutants emitted by a category listed under section 112(c)(6), it would have done so expressly. **Response :**  EPA disagrees with the comment that , even though EPA lists a category under section 112(c)(6) due to the emissions of one or more HAP specified in that section, EPA must issue emission standards for all HAP (including HAP not listed in section 112(c)(6)) that sources in that category emit
. The commenter cited in support the opinion by the United States
Cour t of Appeals for the D.C. Circuit in National Lime Ass’n v.
EPA , 233 F.3d 625, 633

- 634 (D.C. Cir. 2000)). The part of the National Lime opinion referenced in the comment dealt with EPA’s***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **33** of **206** failure to set emission standards for certain HAPs emitted by major sources of cement manufacturing because the Agency found

no sources using control technologies for those HAP. In rejecting EPA’s argument , t he c ourt state d that EPA has “a statutory obligation to set emission standards for each listed
HAP.” Id
. at 634. T he Court noted the list of HAP in section 112(b) and stated that section 112(d)(1) require s that EPA

“ promulgate regulations establishing emission standards for each category or subcategory of major sources ... of hazardous air pollutants listed for regul ation ..” Id. (Emphasis added). For the reasons stated below, we do not believe that today’s final rule conflicts with the National Lime decision. There are several important distinctions between the National Lime case and this final rule for Gold Mine O re Processing and Production area source category. First, the National Lime case dealt with a major source category
. Second , the T he relevant issue in the portion of the opinion referenced by the commenter was how EPA set standards for a HAP where there are no control technologies being used to control that HAP
. Accordingly, the court’s statements described above in National Lime were made to address th is specific issue and in the context of a major source category. Today’s final rule applies to EPA’s***E.O. 12866 Review

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o bligation to issue emission standards for a listed area source category under CAA section 112(c)(6)
. The On the other hand, t he National Lime case did addressed a major source category and not address area source categories or EPA’s obligation under section 112(c)(6). We further note that the applicable lists of HAP under the CAA differ for major and area source categories
. Under CAA section 112(c) , a major source category must be listed for regulation if it emit s any of the HAP listed in section 112(b)
. Accordingly, in National Lime , t he c ourt referenced the 112(b) HAP list in requiring that EPA “ promulgate regulations establishing emission standards for each category or subcategory of major sources ... of hazardous air pollutants listed for regulation.” Id. Unlike major source categories, the CAA does not require that EPA list an area source category for regulation if it emits a pollutant listed in section 112(b). Rather, an area source category may be listed for regulation under section 112 if EPA m a kes an adverse effect finding pursuant to Section 112(c)(3) or if that area source category emits an urban HAP listed under section 112(k) or a HAP listed in section 112(c)(6). T he gold mine ore processing and production area source category is listed fo r regulation under section 112(c)(6 )***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **35** of **206** because it emits mercury, one of the HAP listed in section 112(c)(6). Because the lis ted HAP at issue is only mercury , we have established in this final rule mercury emission standards for this area source category
. F or the reasons stated above, EPA disagrees with the comment that it must set emission standards for all HAP emitted by the gold mine ore processing and production area source category.
3 . Emission Standards for Fugitive Emissions
**Comment :**  One commenter stated that gold mines have significant fugitive emissions of mercury, but that EPA did not propose standards for these emissions or mention them in its proposal. The commenter said that EPA has a statutory obligation to set standards for gold mine mercur y emissions under section 112(d)(2) and (3), and must set emission standards for all the mercury emissions from the listed category
. The commenter described a recent preliminary study at two facilities in Nevada that found fugitive mercury air emissions f rom various

non - point sources at those two mining operations such as from leach pads and tailings ponds. One commenter stated that means to control fugitive emissions are available, such as enclosing their leaching operations. By enclosing the leaching p rocess, the commenter believes that mines could eliminate this source of***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **36** of **206** fugitive emissions. The commenter also stated that mines should not send tailings into open tailing ponds , but into closed treatment facilities that would remove mercury and other HA P from the tailings and prevent their release to the air. The commenter recommended that EPA evaluate the use of sulfur

- based complexing agents for removing mercury during cyanidization of gold. According to the commenter, research indicates that these
p roducts appear useful for substantially reducing mercury in process solution during heap leaching. **Response :**  W e have not included fugitive mercury emissions at gold mine facilities in our 1990 baseline emission s estimate , or in our more recent emissions estimates, largely due to the lack of information about these emissions. Accordingly, these fugitive emissions are not part of the source category we are listing and regulating in this final rule. Other than the

r ecent preliminary research at two facilit ies , we have no data on fugitive mercury emissions from gold mine facilities. The recent preliminary research suggests that some fugitive emissions may be occurring at these facilities from large non

point sources such as tailings ponds, leach fields, and waste rock piles
. However , it is our understanding that this preliminary research has not yet been published or peer

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reviewed
. Furthermore, we have very little information on how these fugitive mercury emissions might be controlled. A few
commenters su ggested that certain compounds were available that may be useful for limiting these emissions. However, as far as we know, there has been no demonstration that these compounds would work effectively to limit the emissions, and we do not know the costs or potential adverse impacts of applying these chemicals. Therefore, we question the feasibility and practicality of applying these chemicals to limit fugitive mercury emissions from these non

- point sources. We also question the feasib ility and practical ity of enclos ing the leaching operations or the tailings ponds , as suggested by some
commenters
. As explained in the proposed rule, the gold mine ore processing and production area source category covers the thermal processes that occur after ore crushing, including roasting operations (i.e., ore dry grinding, ore preheating, roasting, and quenching), autoclaves, carbon kilns, electrowinning, preg tanks, retorts, and furnaces. T he data and calculations used to derive the estimate d 4.4 tons of mercury emissi ons for this source category for the 1990 baseline***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **38** of **206** inventory for section 112(c)(6) reflect emissions from the thermal processes described above, and t he final MACT standards address all of these processes
. 4 . Major Source Determination
**Comment**

The commenter also stated that EPA’s failure to apply the same variability analysis in calculating gold mines’ potential to emit that was used in setting floors was internally inconsistent, unexplained, and arbitrary and capricious. The **:** One com menter noted that the proposal stated state s t he following: “ data indicate that the gold mining processing and production source category consists of only area sources ; however, ( i.e. facilities that emit less than 10 tons per year of any single HAP and les s than 25 tons per year of any combination of HAP).” 75 Fed. Reg. at 22479. The commenter also claimed that the proposal indicated indicates that actual emissions of hydrogen cyanide (HCN) at a few facilities were are near the major source threshold. The commenter concluded that EPA violates both the CAA and its own regulations continued by saying that “b y basing its evaluation of whether gold mines are major sources on their actual emissions instead of their potential emissions
. , EPA violates both the Clea n Air Act and its own regulations. ”***E.O. 12866 Review

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commenter noted that the proposal requested comment on a certification process that would allow gold mines to avoid major source status whereby companies could certify that they are area sources by implementing certain “management prac tices” and then certifying to EPA that they had done so. The commenter stated that such a certification process would be unlawful in calculating a sources “potential to emit” because the management practices are not “control equipment,” “restrictions on h ours of operation or on the type or amount of material combusted, stored, or processed,” and would not be “federally enforceable.” Other commenters supported EPA’s conclusion and determination t h at the gold mines are area sources of HAP. According to the commenters, EPA’s methodology in making this determination was extremely conservative and resulted in higher calculated HCN emissions than may actually be present. For instance, EPA did not apply what the commenters believe to be a key correction factor t o account for the fact that much of the mass transfer of HCN for large surface areas is expected to be gas phase limited. Application of this correction factor would have reduced the estimates for HCN emissions from the mines tested by about 40

- 50%. The c ommenters also stated that fence line testing at selected gold mine operations demonstrated that***E.O. 12866 Review

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there was no concern with offsite fenceline levels of HCN emissions , and that these levels of HCN were b elow all applicable public health standards
. The commen ters believe that , because the gold mines are

area sources o f HCN, they should not be subject to section 112 work practice standards or newly developed certification requirements. The commenters noted that it is not technically practical to set systematic work practice standards to reduce HCN emissions for every gold mining operation to follow because each mine is unique in its mineralogy and cyanide leaching
processes , and different process solution pH values are necessary to enhance gold recovery. The commenters explained that for economic, health, and safety reasons, they already implement work practice standards designed to minimize HCN. The commenter concluded that the combination of these work practice standards and the annual TRI reporting more th an adequately ensure that gold mining operations will remain area sources of HCN. **Response :**  Based on available data we estimate that the largest emitting facility emits between 5 to 9 tons per year of hydrogen cyanide , and that a ll other facilities emit l ess than this level. Based on test data, a ll facilities emit less than***E.O. 12866 Review

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25 tons per year for the sum of all HAP. Our analysis of the test data included calculations based on facilities operating at full capacity. We understand that these facilities imple ment various management practices to minimize the use and emissions of cyanide to protect workers , to comply with Mine Safety and Health Administration (MSHA) standards , to comply with their agreements to the International Cyanide Code , and for economic

re asons (to reduce operational and supply costs) . Most companies are signatories to the international Cyanide Management Code , which includes a number of provisions to minimize the use and release of cyanide
. As a commenter correctly notes, in determining whether a source is a major source under CAA section 112, we must consider the source’s potential to emit as well as its actual emissions. See CAA section 112(a)(1) and 40 CFR 63.2. In determining a source’s potential to emit, we may consider physical a nd operation limitations that are “federal ly enforceable,” which is defined in our regulation as limitations and conditions that are enforceable by EPA and the citizens under the CAA or by EPA under other statutes. See 40 CFR 63.2 for definitions of “pote ntial to emit” and “federally enforceable.” It is our current understanding that t he above

- mentioned standards and***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **42** of **206** agreements for implementing hydrogen cyanide management practices are not federally enforceable, as that term is defined. Accordingly, we b elieve that the emission s reduction s achieved through these management practices would not be considered in determining gold mine facilities’ potential to emit. We currently do not have sufficient information to quantify the emissions reductions achieved through these management practices. However, based on our current knowledge of these management practices and our hydrogen cyanide emission estimates, we believe that most of these facilities are area sources. Accordingly, we are taking final action toda y to list the gold mine ore processing and production area source category and regulate its mercury emissions pursuant to CAA section 112(c)(6). In addition, we plan to evaluate the area source status of the largest facilities by gathering additional inf ormation about these management practices, including information on their emissions reduction potential. We plan to use the additional information to further evaluate the potential to emit of these few large facilities and subsequently address their cyani de and other emissions if necessary or appropriate. **Response :**  As explained above, some commenters believe that***E.O. 12866 Review

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EPA’s estimates of hydrogen cyanide emissions are overly conservative (i.e., overestimated)
. O ther commenter s believe that EPA’s estimates do n ot reflect the “ potential to emit ” from these sources. However, t h ese commenter s also incorrectly suggested that EPA’s estimates included only actual emissions. Nevertheless, in determining whether a source is a major source under CAA section 112, we must consider the source’s potential to emit as well as its actual emissions. See CAA section 112(a)(1) and 40 CFR 63.2. For each gold mine facility in our inventory we developed a range of estimated emissions, including an upper

- end estimate for each fa cility. B ased on these estimates the largest facility emits between 5 and 9 tons per year of hydrogen cyanide . A ll other facilities emit less than this level. Based on test data, a ll facilities emit less than 25 tons per year for the sum of all HAP. Ou r analysis of the test data include calculations for estimated emissions based on facilities operating at full capacity. We understand that these facilities implement various management practices as part of their operations to minimize the use and emissi ons of cyanide to protect workers , to comply with Mine Safety and Health Administration (MSHA) standards , to comply with their agreements to the International Cyanide Code ,***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **44** of **206** and for economic reasons (to reduce operational and supply costs)
. We currently do not have sufficient information to explicitly quantify emissions reductions achieved through these management practices. Nevertheless, b ased on our current knowledge of these management practices and based on the results of the emission s testing, we beli eve that these facilities are

area sources. We have no information that would indicate these facilities are major sources. Accordingly, we are taking final action today to list the gold mine ore processing and production area source category and regulate its mercury emissions pursuant to CAA section 112(c)(6). In addition, we intend to send letters to various Gold Production companies pursuant to Section 114 of the Clean Air Act to obtain additional information which we will use to further evaluate the f acilities’ potential to emit and to address any remaining questions regarding the ir area
source status
. 5 . Title V Permit Exemption
**Comment :**  In the proposal preamble, EPA solicited comment on whether a title V exemption “is appropriate under section 502( a) for any particular sources in this category.” One commenter offered the following reasons for not exempting gold mines from title V permitting requirements:***E.O. 12866 Review

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**•** EPA did not properly determine whether some or all sources in the category are major sources by determining each source’s potential to emit.

**•** The CAA allows EPA to exempt area sources from title V permitting only if it establishes that compliance with the title V permitting requirements would be “impracticable, infeasible or unnecessarily burdensom e.” However, EPA does not claim that such requirements are “impracticable,” “infeasible,” or “unnecessarily burdensome” for gold mines.

**•** It is feasible and within the gold mining companies’ financial means to comply with title V permitting requirements. The commenter believes that the text and legislative history of the CAA make plain that Congress intended ordinary citizens to be able to get emissions and compliance information about air toxics sources and to be able to use that information in enforceme nt actions and in public policy decisions on a State and local level. According to the commenter, Congress did not think that enforcement by States or other government entities was enough; if it had, Congress would not have enacted the citizen suit provis ions. The commenter said that , if a source does not have a title V permit, it is difficult or impossible for a member of the public to obtain relevant information about its emissions and compliance status or to bring enforcement actions. The commenter st ated that to the extent the informational and enforcement benefits provided by title V***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **46** of **206** permits can be considered a burden, the se benefits far outweigh that burden. The commenter also noted that title V provides important monitoring benefits and that title V permits are necessary to provide adequate monitoring. The commenter concluded by stating that the legislative history of the CAA shows that Congress did not intend EPA to exempt source categories from compliance with title V unless doing so would not a dversely affect public health, welfare, or the environment; however, exempting gold mines from title V would adversely affect public health, welfare and the environment by depriving the public of important informational and enforcement benefits.
One State agency commented that additional title V permitting would subject both the source and the State agency to additional resource burdens. The commenter points out that major sources of criteria pollutant emissions are currently subject to title V permit req uirements in Nevada and that sources not subject to major source permitting requirements are subject to Nevada’s minor source permitting program. In addition, the NMCP requires all mining sources to obtain
mercury - specific operating permits to construct. The commenter believes that these permit programs would provide a strong basis***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **47** of **206** for implementing and enforcing any F ederal MACT requirements for the gold mining industry, and there would be nothing gained by subjecting these sources to title V permitting. Several commenters stated that EPA should exercise its discretion and exempt the gold mine ore processing and production industry from the title V requirements as impracticable, infeasible, and unnecessarily burdensome. The commenters said that, in light of EPA’s findings in other similar rulemakings for area sources, the four factors set forth in the Exemption Rule support a finding that title V permitting is “unnecessarily burdensome” for the gold mine ore processing and production area source category. In discussing the first factor of the Exemption Rule, whether title V would result in significant improvements to the compliance requirements, the commenters said that the proposed NESHAP for the gold mine ore processing and production area source categor y includes extensive monitoring, recordkeeping, and reporting requirements that are more comprehensive than title V requirements. The commenters believe that Nevada regulations and permits provide an additional layer of compliance assurance on the federal NESHAP that obviates the need for title V permitting. The commenters claimed that the***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **48** of **206** additional layering of title V does not “significantly improve” upon the proposed and existing compliance requirements. Regarding the second factor in the Exemption Rul e, whether title V permitting would impose significant burdens on the area source category and whether the burdens would be aggravated by any difficulty the sources may have in obtaining assistance from permitting agencies, the commenters said that there a re extensive administrative burdens and costs associated with the title V permitting process, including mandatory activities that have been previously identified by EPA. The commenters claimed that many of the area source gold mines are owned and operated by small entities that are already required to comply with comprehensive State permitting requirements for mercury emissions and that requiring title V permits for them would result in resources being redirected away from more useful and necessary efforts
. The commenters explained that the third factor in the Exemption Rule examines whether the costs of title V permitting for the area source category would be justified, taking into consideration any potential gains in compliance likely to occur for such so urces. The commenters claim that there do not appear to be any gains in compliance to justify the additional costs***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **49** of **206** that would be imposed on these area sources from title V permitting based on the lack of significant improvements in compliance requirements and the substantial additional costs and burdens associated with title V compliance. The commenters noted that the fourth factor in the Exemption Rule analysis is whether there are implementation and enforcement programs in place that are sufficient to as sure compliance with the NESHAP for the area source category, without relying on title V permits. The commenters claimed that the proposed rule includes all necessary monitoring to effectively implement its requirements, and the area sources for the gold mine ore processing and production are already permitted under State permit programs. According to the commenters, all non

title V sources in Nevada are required to hold “Class II” operating permits that must contain, among other things, all applicable em ission limitations and standards. The commenters said that other States where gold mine ore processing and production area source are located either would be covered by a comparable delegated State air program or by EPA. The commenters stated that EPA reg ularly provides title V exemptions for area sources similar to gold mine ore processing and production area sources and cited examples from the past***E.O. 12866 Review

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year. The commenters claim that the existing and proposed compliance and monitoring requirements for the gold mines are generally more stringent than those found in the other NESHAPs for which EPA has granted a title V permit exemption. The commenters stated that exempting the gold mine ore processing and production area source category from title V permittin g will not adversely affect public health, welfare, or the environment because title V permits do not generally impose substantive air quality control requirements
. According to the commenters, requiring title V permits also carries the potential of adver sely affecting public health, welfare, or the environment by shifting State agency resources away from ensuring compliance with a program that is reducing mercury emissions from gold mines. The commenters stated that EPA should exempt the gold mine
ore pro cessing and production area source category from title V permitting requirements, and at a minimum, should exempt area source gold mines that are subject to Nevada’s comprehensive mercury control program
. **Response :**  After reviewing the comments, w e continu e to believe that it is appropriate that all gold mine ore processing and production facilities be required to obtain title V permits.***E.O. 12866 Review

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Most of the other area source categories for which we have provided title V permit exemption s have hundreds or thousands of facilities that are mostly owned by small businesses
. In contrast, t here are an estimated 21 facilities that are subject to this final rule , and , based on our research and analyses , none of the facilities are owned by small business es ; most of these f acilities a re owned by large, and i n some cases, multi

national , corporations . Therefore, we do not believe that the argument of financial burden, which has supported title V exemption for other source categories, applies to the gold mining industry.
Cu rrently, it is our understanding that 7 of the 21 facilities that will be subject to the final rule already have title V permits ( 5 in Nevada and 2 in other states )
. Further, there are approximately 5 facilities in all other States ( i.e., except Nevada) t hat do not have title V permits that will be subject to this final r ule , so title V permitting w ill apply to no more than a few facilities in any one of the se other States. Therefore, we do not believe the requirement for title V permitting will be overly burdensome to the permitting authorities in those States
. Although there are many more facilities in Nevada that will be subject to the final rule, a s***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **52** of **206** the commenters point out, Nevada already has an effective permitting system in place. Five of the 14 g old mine facilities in Nevada already have title V permits . Because of Nevada’s existing permitting system and experience with title V permitting , w e do not think that it is an undue burden on the State of Nevada to require title V permits from the other gold mine facilities located within the State. We also think it is important for the public in those States , where these facilities are located , to have access to emissions and monitoring data and the opportunity for public involvement in the permitting o f these facilities that is provided by title V permitting
. 6 . Reconstruction
**Comment :**  Several commenters believe it is appropriate to group under each of the umbrella “affected sources” all the equipment associated with each particular process in order to ensure a reasonable application of the reconstruction provisions found in the General Provisions. The commenters asked that EPA reaffirm that the 50 percent fixed capital cost trigger for determining reconstruction would be measured against all equipme nt components needed for the defined processes, and that reconstruction at one affected source as defined in the standard will not affect or result in reconstruction at another affected***E.O. 12866 Review

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source. The commenters also noted that the definition of
“reconstruct ion” authorizes EPA to establish special provisions in a particular standard for the application of the reconstruction criteria to the affected source. The commenters said that the “carbon processes” affected source illustrates that the affected source ca n consist of several pieces of interconnected equipment that together constitute the process line, and it can be anticipated that production needs will give rise to the need to add more pieces of equipment to an existing carbon process line or even to inst all a whole new carbon process line. The commenters provided three examples: adding a new component to an existing carbon processes group , construction of a new carbon group due to expansion at a facility that has an existing carbon group ; and installatio n of new pollution control equipment . The commenter said that consideration of whether or where new MACT requirements should apply in these examples warrants the development of special reconstruction provisions in this standard, or EPA should clarify that the three examples would not be considered reconstruction under the proposed rule. The commenters asked that EPA either clarify that the three***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **54** of **206** examples would not be considered reconstruction, or alternatively, add the following provisions to the proposed rule: (1) an addition of a new piece of equipment to address production requirements is not considered a reconstruction, (2) the expansion of a facility by the construction of a completely new process line will not be considered a reconstruction of an

ex isting process line, and (3) the installation of air pollution control equipment to comply with this standard is not considered a reconstruction. **Response**

Reconstruction, unless otherwise defined in a relevant standard, means the replacement of components of an affected or a previously nonaffected source to such an extent t hat: **:** The determination of what constitutes a reconstruction is directly tied to the definition of the af fected source and the definition of reconstruction in the p art 63 General Provisions:

(1) The fixed capital cost of the new components exceeds 50 percent of the fixed capital cost that would be required to construct a comparable new [affected] source; and (2) It is technologically and economically feasible for the reconstructed source to meet the relevant standard(s) established by the Administrator (or a State) pursuant to section 112 of the Act. Upon reconstruction, an affected source, or a stationary source that becomes an affected source, is subject to relevant standards for new sou rces, including compliance dates, irrespective of any change in emissions of hazardous air pollutants from that source.***E.O. 12866 Review

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For each of the four affected sources in the final rule, we have defined the affected source as the collection of processes associated w ithin each affected source. Consequently, if one process within the affected source is upgraded or replaced with a new process, the 50 percent fixed capital cost criterion would be based on the fixed capital cost of replacing all processes in the affected source, not just the capital cost of the process being upgraded or replaced. For example, if a new carbon kiln is added to an existing group of carbon processes with mercury
retorts , the capital cost of the new carbon kiln would be divided by the fixed c apital cost of constructing a comparable new affected source containing all of the processes within the existing affected source of carbon processes with mercury
retorts to calculate the percent for comparison to the 50 percent criterion. With regard to the scenario where a new carbon process es with a mercury retort s group is installed, t he affected source is defined as the collection of all applicable processes within the affected source, and because of this, a facility could not have two carbon processe s with mercury retorts affected sources, such as the commenter suggested, where one group is new and the other is existing. For example, if a new group of carbon***E.O. 12866 Review

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processes with mercury retorts is installed at a facility in addition to existing group of ca rbon processes with mercury
retorts , the two groups (all carbon processes with mercury
retorts at the facility) collectively would be a single affected source. In this case, the fixed capital cost criterion would be based on the fixed capital cost of repl acing the existing affected source with a comparable new affected source, and if the new processes exceed 50 percent of that cost, all of the carbon processes with mercury retorts would be subject to the new source limit for carbon processes. There would not be separate and different emission standards for the two sets of carbon sources with mercury retorts (the older group and newer group) because the collection of all of these processes is the affected source. We do not see a necessity to provide criter ia for this final rule that are different from the requirements in the General Provisions for determining what constitutes a reconstruction. We also think it is appropriate to exclude the cost of emission control equipment from the cost calculation for

re construction determinations. B. Applicability
**Comment :**  Several commenters stated the rule should exempt***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **57** of **206** individuals (prospectors), laboratories, small mining operations, and non

- leaching operations. The commenters urged EPA to include in the final rule all of the following exemptions to avoid the problem of unintended regulation of sources that were not meant to be included in the source category: gold mining operations that produce less than 100 pounds of concentrate per year, which would exempt analyti cal labs that perform small bench scale processing tests on gold ores; gold mining operations that do not leach or dissolve gold, which would exempt placer and other non

- leaching operators, including both small commercial efforts as well as individual recr eation

type prospectors; and gold mining operations that process less than 1,000 tons per year of gold ore, which would exempt certain small scale pilot plants and related testing operations. The commenters said that the exemptions suggested above will no t reduce in any way the effectiveness of the proposed rule in controlling mercury emissions from the targeted larger mines, nor will they lead to increased mercury emissions, but they will exclude regulation of a large number of small operators who do
not emit any significant mercury. **Response:** As mentioned above, we have clarified in this final rule that this area source category does not include***E.O. 12866 Review

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laboratories (see CAA section 112(c)(7)) , individual prospectors and very small pilot scale mining operations. Prospectors and other very small pilot

- scale operations (e.g., operations that produce or process less than 50 pounds of concentrate per year) are very small and were not included in the section 112(c)(6) inventory that was the basis for the listing of g old mine ore production and processing source category. A ll the facilities in our current inventory, as well as the facilities considered in developing the 1990 baseline emissions inventory , process or produce more than 4,000 lb/yr of concentrate. We bel ieve that emissions from the very small scale operations described above to be very minimal, especially in comparison to the mercury emissions from operations that are regulated under this rule, which process or produce concentrate at amounts far above th i s threshold. However, we believe that the 100 pound s of concentrate cut

off suggested by the commenters is too high. We believe that 50 pounds of concentrate per year more appropriately reflect these very small operations. We are not making the suggest ed change of excluding operations that do not leach or dissolve gold because certain gold mine facilities in the source category use flotation or***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **59** of **206** gravity flotation processes and perform thermal process ing of concentrate in melt furnace s, which can have sig nificant emissions of mercury
. We are also not making the exemption of facilities that process less than 1 , 000 tons per year of ore because we believe this exemption is not necessary or appropriate. C. MACT Floors 1. Consideration of Variability in Det ermining Floors
**Comment :**  One commenter acknowledged that EPA may consider variability in calculating the best sources’ performance, but stated that EPA’s method of considering variability seeks to assure that none of the sources among those identified as best performers would ever exceed the floor level. The commenter claims such an approach ignores the reality that sources’ emission levels are largely within their control, and although a great deal of variability may be statistically conceivable, that do es not mean that a well

- operated source actually would experience such variability. The commenter said that one of the main points of having emission standards is to ensure that sources not only deploy the appropriate control measures, but also use those control measures consistently to minimize emissions.***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **60** of **206** The commenter said that using an upper prediction limit to set standards reflecting the statistical worst performance these sources could have does not yield an accurate picture of the best sources pe rformance, and it is especially arbitrary in the absence of any explanation of why EPA thinks that the relevant best sources’ performance would ever be so bad, other than the fact that it is statistically possible. **Response :**  It is EPA policy to allow for variance in test data, between units, and among facilities when developing the MACT standard. For this rule , we used the UPL analysis on the emissions data for the top five perform ing sources to account for the variance. We believe that this calculation method does yield an accurate picture of the best performers. It is an incorrect statement that no sources among the best performers (i.e., the top five performers for this final rule) would ever exceed the floor limit. The variability that is accounted for in the UPL analysis of historical data would apply to future data as well. Thus, although the average of several data sets may show a top performing source meeting the emission standard by a wide margin, the variability in emissions inherent in any

o ne compliance test could easily indicate much higher emissions, and, in some cases, an exceedance of the emission standard.***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **61** of **206** The operating conditions under which emissions measurements are made for a given process unit will directly affect those

measuremen ts. For example, emissions obtained from a process that is operating poorly will almost certainly be higher than when operating properly. Therefore, the process that is operating poorly will be less likely to be included in the pool of best performers th an if it were operating properly.
We believe the data we use d to calculate the MACT limits are based on representative and normal performance of the

source s for many reasons. First, the test results that we are using in our MACT database are tests conduct ed under Nevada’s mercury emission control program, and some of these tests are to determine whether a facility is in compliance with a State or operating permit emission standard requirements . Facilities typically try to perform as well as they can during performance such tests to avoid violations, fines, and other enforcement actions . State (and often EPA) permitting authority staff are notified before a performance test is conducted to provide an opportunity to attend and observe the test, and they often attend to ensure the source is operating properly and that the testing is performed according to the strict requirements in the codified test methods.***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **62** of **206** Test reports are carefully reviewed by the permitting authority, and any failure to follow the test meth od or abnormal operation of a source is flagged. These data are usually invalidated, and invalidated tests are not used in our MACT floor calculations . For example, several tests from these facilities were invalidated by the NDEP because the specified
te sting procedures were not followed or the emission control device was not operating properly, and we have not used those results in our analysis for those reasons. We have collected additional data from test reports not available at the time of proposal, and one of those tests was invalidated because NDEP representatives discovered that the emission control device was not operating properly during the test, therefore, we also did not use those test data
. The commenter believes that floors must be set at th e average emission level achieved by the best performers when they are operating properly. We agree that the performance data characterizing the emission level achieved by the top performers must be data obtained when they are operating properly, and we b elieve that is the case for our current database for this source category . The MACT floor is based on the average performance of the top performers, and we can and must develop a***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **63** of **206** MACT floor limit from this average that accounts for variability. We accomp lish this by calculating the MACT floor limit from this average performance and account for variability by using the 99 percent UPL, which is discussed in more detail in the Summary of Public Comments and Responses document in the docket for this rulemakin g . It is not appropriate to ignore the variability in the data because that would be contrary to established statistical theory and practice, and it is also at odds with recent judicial decisions. Finally, on a practical level and in terms of achievabili ty, ignoring variability and using only the average performance would virtually guarantee that some of even the best performers would exceed the floor limit.
**Comment :**  Another commenter stated that consideration should be given to defining the inherent ran ge of measurement error and requiring more test runs in order to reduce variability due to process variation. The commenter said that this would also better clarify when variability was due to operational controls, which could be addressed, rather than du e to factors that cannot be controlled, such as mercury content in the ore. The commenter asked for clarification on how inconsistent runs should be treated, what defines an acceptable***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **64** of **206** set of runs, and at what point more runs would be required to provide reliable data. The commenter also stated that the degree of variability allowed in the development of the new source limit for ore pretreatment appears to be out of line with the new source limits for carbon processes and non

- carbon processes. The
comment er believes that ore pretreatment variability for new sources is higher than existing sources because low thermal units were included in the same category, high emissions were allowed in the data set, and variable emissions were allowed in data set. The c ommenter recommended that , if EPA continues to use Goldstrike as the best performing source for new source MACT, then they should re

- evaluate and reduce the variability to be equal to or less than the variability for existing sources. **Response :**  We agree with the commenter that the testing process would be more accurate if the number of test runs was increased. However, we balance several factors in determining the minimum number of runs required, and because the compliance testing is supplemented by var ious types of continuous or periodic parametric monitoring, we have concluded that three test runs are appropriate for this final rule. Although we have not proposed a formal procedure to assess the consistency of***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **65** of **206** test runs, the permitting authority perfo rms routine reviews of compliance test data to identify potential outliers and results that suggest further investigation is needed. For example, a routine review tracks trends in performance, and in particular, flags any trends in deteriorating performan ce over time. An unusually high run among the three runs also attracts attention and would be examined to determine if it might have been caused by a problem with the process, control device, sampling, or analysis. We agree with the commenter that the v ariability used in the development of the proposed new source MACT for the ore pretreatment group appeared to be inconsistent with other data , and it was due in part to two tests of the ore preheater/dry grinding process at Goldstrike that the commenter id entified. As discussed in more detail below in this preamble, we have obtained new (additional) test data for the ore pretreatment group, including the ore preheater/dry grinding process at Goldstrike. We have determined that the tests the commenter is

r eferring to are not representative of normal operation, and those tests have been removed from our database because the NDEP invalidated the tests due to possible sample contamination. (See the MACT Floor D ocument in the docket for the final***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **66** of **206** rulemaking). In addition, we have performed additional analyses using the newer test data, which show lower emissions and lower variability than the previous data available at the time of proposal. Also, we have conducted additional beyond

- the

- floor analyses. The va riability associated with the new source MACT is now significantly lower than the estimate of variability at proposal, and the new source standard in the final rule is more stringent tha n the proposed standard . As discussed in more detail below, MACT for new sources for the ore pretreatment group has been reduced from 149 lb/million tons of ore at proposal to 84 lb/million tons in the final rule. 2. General Comments on MACT
**Comment :**  Some commenters stated that the MACT floor already represents installa tion and operation of MACT controls, and the use of emissions data from facilities that are already controlling their mercury emissions creates an artificially low MACT floor. The commenters said that the low MACT floor penalizes facilities that voluntari ly invested in pollution control technology and creates a substantial disincentive for industry and States to move ahead of EPA in reducing emissions of HAP. **Response :**  We acknowledged at proposal that many gold mine***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **67** of **206** facilities are already well controlled for many reasons, including participation in the NMCP . We also acknowledge that the top performing facilities that are the basis for the MACT floor calculation are the top performers because they have installed controls. CAA section 112(d)(3)(B) require s that, for a category with fewer than 30 sources, the MACT floor not be less stringent than “the average emission limitation achieved by the best performing 5 sources ( for which the Administrator has or could reasonably obtain emission information ).” (Em phasis added). EPA has information on these well

- controlled facilities and use d the information to conduct MACT floor analysis, as required by the CAA. Although the MACT floor may be considered more stringent in comparison to floors that would have been established if no facilities had mercury emission controls, we do not consider the floor to be “artificially low” because it has been demonstrated as achievable in practice by facilities that installed mercury emission controls. 3. MACT for the Ore Pretr eatment Group
**Comment :**  Several commenters supported EPA’s general approach to establish three groups of affected sources in the proposal. On the other hand, s everal commenters suggested that EPA develop separate emission standards for roasters and***E.O. 12866 Review

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autocl aves for existing and new sources. One commenter stated that roaster and autoclave processes are different from each other based on the mercury species released, controls utilized, and their rates of mercury emissions. The commenter said that
roasters co mmonly reach temperatures of 400 ° to 700°C, releasing gaseous elemental mercury, whereas autoclaves commonly reach temperatures of 175 ° to 230°C producing reactive gaseous mercury and sulfate and forming mercury sulfate. According to the commenter, autocl aves are expected to be able to improve efficiency over time. The commenter noted that roasters produce one to two orders of magnitude higher emissions than do autoclaves. The commenter believes that facilities that only use autoclaves should not be allo wed the leeway to emit at the rate that facilities employing roasters are allowed. The commenter recommends that the ore pretreatment group be divided into high temperature pretreatment processes (roasters) and low temperature pretreatment processes (auto claves and ancillary roaster processes, such as dry grinding, pre

- heating, and quenching). **Response :**  We discussed in Section V.A. of the preamble to the proposed rule our rationale for establishing the different affected sources , including the ore pretrea tment processes***E.O. 12866 Review

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affected source. We believe it is appropriate to maintain the ore pretreatment group affected source, as we had proposed. We do not agree with the comment that roasters necessarily have higher emissions that are one to two orders of magni tude higher than emission from autoclaves
. The available data show a wide range in emissions from autoclaves (from 0.4 to 115 lb/million tons of ore). This range overlaps the range for roasters and their ancillary equipment , which have combined emissions between 42 to 71 lb/million tons of ore. Moreover, autoclaves and roasters process that same input material (i.e., ore) and are intended for the same purpose (to oxidize the ore). Therefore, we believe that it is appropriate to maintain the ore pretreat ment affected source as we had proposed, keeping roasting operations and autoclaves together.
**Comment**

A commenter also stated that although EPA’s standard for new ore pretreatment facilities is as high as its standard for existing facilities, EPA does not propose or discuss setting beyon d

- the

- floor standards for new sources. The commenter **:** One commenter stated that EPA failed to consider beyond

- the

- floor standards for roasters and that if additional reductions are achievable at roasters, then EPA must set additional beyond

- the

- floor standards for roasters.***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **70** of **206** claims that EPA has a statutory obligation to ensure that its new source standards reflect the maximum achievable reduction in emissions. **Response**

Based on the addition and change described above with respect to our available data, we revised the MACT floor analysis for the ore pretreatment processes. The re vised MACT **:** Following proposal, we continued to investigate th e performance of facilities with ore pretreatment processes and opportunities for additional control. We collected data from more recent tests that were not available at proposal, and these new data show that emission control performance at these faciliti es has continued to improve. We identified two previous
test s in the proposal database that w ere suspect, and we confirmed with NDEP that th ese test s should be invalidated and not used in the analysis because of possible sample contamination. We have als o dropped the data for one f acility from the analysis because their autoclave was shutdown in 2007 and dismantled, and we only had one test of the autoclave when it was operating in 2006. For these reasons, it is not appropriate to include data for that f acility in the analysis, which is now based on the only four facilities currently operating.***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **71** of **206** floor for existing sources decreased from 175 lb/million tons at proposal to 158 lb/million tons, and the new source MACT floor dropped from 163 lb/million tons to 84 lb/million tons. The MACT floor limit for existing ore pretreatment
processe s is based on the use of wet scrubbers, calomel scrubbers, and carbon adsorbers, depending on the specific processing unit included in the affected source . We conducted a beyond

- the

- floor analysis d uring the development of the proposed rule
. The roasters were already equipped with very good mercury controls, and we did not identify any beyond

- the

- floor options for the roasters. However, we identified as a beyond

- the

- floor control for autoclaves the installation of both a refrigeration unit (or condenser) and a carbon adsorber. Since our proposal, we have identified a beyond

- the

- floor control option (carbon adsorption ) for the ore pre

- heaters /dryers that could achieve additional emissions reductions of approximately 70 percent (or more) for those units
. Two of the three facilities with roasters have already proposed in their NMCP Phase 2 permit applications to apply controls to their preheaters/ore dryers, and these two companies have submitted cost estimates for applying a carbon adsorption system. Usin g the cost estimates submitted by the affected facilities, we estimate the capital***E.O. 12866 Review

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costs for control of roaster preheaters/dryers for the three facilities with roasters as $3 million with a total annualized cost of $1.6 million per year . We also estimate a reduction of 160 118 lb/yr of mercury emissions would be achieved at an overall cost effectiveness of about $ 10,000 13,800 per pound of mercury. We believe that the costs and cost effectiveness are reasonable
. As required under CAA section 112(d)(2), we have also considered non

- air quality health and environmental impacts and energy requirements of this additional control
. W e conclude that this is an acceptable beyond

- the

- floor control technology for existing roaster preheaters/ore dryers. Therefore, we included the beyond

- the

- floor control for ore preheaters/dryers , as well as the beyond

- the

- floor control for autoclaves, in determining the MACT standard in this final rule for existing

sources of ore pre - treatment processes . A fter applying the appropria te variability analyses to the data, we determined that the MACT standard for existing sources is 12 7 lb/million tons of

ore . Beyond

- the

- floor analyses have been included in the determination of the MACT limit for existing ore pre

- treatment affected sou rces based on the emissions level achieved by the best controlled similar source
. We did not go beyond

- the

- floor***E.O. 12866 Review

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the floor for new sources because we did not identify a feasible and cost

- effective technology that would achieve reduction greater than the n ew source floor. Therefore, for new sources of ore pretreatment processes, the MACT “ floor ” is the MACT standard for the affected source. T he final new source MACT standard is 84 lb/million tons of ore , which is considerably more stringent c ompared to th e proposed standard of 149 lb/million tons o f ore . **Comment**

Another commenter estimated that for the installation of **:** One commenter stated that the proposed estimated capital costs of $890,000 and total annualized cost of $720,000 for beyond

- the

- floor autoclave controls are not representative of actual costs of installing a refrigeration unit (or condenser) and a carbon adsorber on autoclaves. The commenter estimates that capital costs for autoclave controls will range from $18 million to at least $30 million, and annual operating costs could range from $2 milli on to $60 million, depending on which controls, if any, are determined to be technically feasible. The commenter believes that based on these cost estimates, beyond

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- floor MACT controls would be cost prohibitive and are not justified for the ore pretre atment affected source group.***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **74** of **206** carbon adsorbers on their autoclaves to control mercury emissions, the capital costs w ould range from $30 million to $35 million, annual operating costs would be $2 mill ion per year, and the annual energy requirements would be 11,400 megawatt

hours per year with an annual energy cost of $900,000. **Response :**  After reviewing the new cost estimates provided by the commenters, we agree that capital and total annualized
cost estimates of the beyond

- the

- floor controls on autoclaves in the proposal w ere underestimated. We evaluated the detailed cost estimate based on an engineering study for a carbon adsorption system provided by one of the commenter s (see details in the commen t above on capital , operating, and energy costs ), and our review of these details indicates it to be a reasonable cost estimate. Therefore , we have used this estimate as the basis for our estimate of the costs of the beyond

- the

- floor mercury emission cont rols for autoclaves. Our revised estimate s are that the capital cost for install ing carbon adsorbers on autoclaves would be $29.3 million , with a total annualized cost of $4.9 million per year , which would result in an estimated reduction of 480 431 lb/yr of mercury emissions per year and an overall cost effectiveness of about $1 1 ,000 per pound of
mercury . Based on these new costs and estimated reductions we***E.O. 12866 Review

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conclude that the beyond the floor controls are justified for the ore pretreatment affected source
. **Comment** : Several commenters noted that , at the proposed new source MACT limit of 149 pounds/million tons of ore, the proposed new source Donlin Creek Mine, located in Alaska, would be allowed to emit 3,200 lb /yr of mercury based on a projected producti on rate of 22 million tons /yr of ore. **Response**

With the new source MACT standard in the final rule that is about two times more stringent than the proposed MACT standard , along with corrections described above, we estimate that far less than 3,200 lb/yr would be emitted from this new source if : With respect to the proposed new gold mine in Alaska, the commenters’ estimate of 3,200 lb /yr of mercury emissions is inaccurate and a significant overestimate for several reasons. The two primary reasons are that , based on available information , if the facility is built, only an estimated 15 percent of the ore mined will be processed in autoclaves (not 100 percent as assumed by the commenters), and that the commenters’ estimate is based on assuming that th e average emissions level for the facility throughout the year would be at the maximum allowed at the proposed new source limit (149 lb/million tons of ore )
.***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **76** of **206** it is ever built. Assuming continuous operation for 365 days per year, an estimated 21.5 million tons / yr of ore mined, about 3.2 million tons /yr processed in autoclaves (15 percent), and assuming the source would emit at the average emission level used to calculate the revised new source MACT (45 lb/million tons of ore), we calculate that mercury emissions would be about 144 lb/yr , which is about 5 percent of the estimate provided by the commenters. Considering that the facility has yet to go through the permitting process and that if they could not meet the new source MACT limit, installation of carbon ad sorbers would likely reduce the emissions below 45 lb/million tons, we believe that, if the facility is built, emissions w ould quite likely be lower than 144 lb/yr
. 4. MACT for Carbon Processes
**Comment :**  Several commenters objected to including Facility M in the MACT floor determination for new and existing sources in the carbon processes affected source because it is not representative of , or similar to , other sources, because it has unusually low mercury concentrations in its ore, and no need for
a reto rt to remove and recover mercury. They noted that , because the mercury content of the gold ore is fixed, the only way for other facilities to reduce emissions of mercury is to***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **77** of **206** apply mercury emission controls, but , for many facilities, emission controls wi ll not be enough to meet the proposed MACT standard. The commenters stated they were aware that the D.C. Circuit Court had constrained EPA’s discretion to set floors that fail to consider material inputs, but they said gold mines were different from the r emanded source categories (brick kilns and cement kilns) because gold mining operations process very large quantities of ore, and the ore is the only material input that results in mercury emissions. The commenters stated that , in adopting section 112, Co ngress expressly cautioned EPA against setting standards that would require mining operations to change the ore used as essential feedstock. The commenters said that , by ignoring the mercury content in the ore being mined and processed at the facilities i n the MACT floor determination, EPA is requiring facilities to consider the substitution of, or changes in, the ore that is processed because there is no other way to achieve the standard. The commenters recommended that EPA address, as a threshold matter , the differences in processing and emissions across facilities that result from the variable concentration of mercury in ore. The commenters recommended that Facility M not be considered the “best controlled similar source” for purposes of setting the ne w***E.O. 12866 Review

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source MACT floor because the facility is not similar to other sources. The commenters stated that , if EPA does not exclude from the source category facilities that do not use retorts to process concentrate, then they should subcategorize them
. **Response :**  After consideration of comments and a re

examination of the emission controls and factors affecting emissions from the carbon processes at Facility M, we agree that this facility is quite different and unique compared to most other gold mine ore process ing and production facilities , including other facilities in Nevada, in its carbon process. The mercury emissions from carbon processes at this facility are a factor of 10 less than the next “best” performer ( F acility N) and a factor of 23 less than the a verage of the top 5 performing facilities in the proposed rule . This level of emissions is due primarily to the very low levels of mercury in the ore rather than having better emission controls than those found at the other top performing facilities. Fac ility M has good controls for mercury emissions from its carbon processes , but they are
not as effective as the controls at F acility N. Facility N has
state

- of

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- art controls. The difference is further manifested by the differences in the processing tr ain for the carbon group in that mercury retorts are not needed or used at Facility M to***E.O. 12866 Review

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recover mercury because the mercury levels are so low. As the commenter notes, t he CAA allows EPA to “distinguish among classes, types and sizes of sources within a c ategory” in developing MACT emission standards , and gold mine facilities without mercury retorts are different in both class and type from those with mercury retorts
. Accordingly , in the final rule, we identify and set separate MACT standards for two type s of carbon processes: those that use mercury retorts ; and those , such as the carbon process at F acility M , that do not use
mercury retorts. As part of our re

- analysis of the MACT floor and MACT for sources that are in the carbon processes with mercury r etorts and those without mercury retorts, we considered new data that

w ere not available at the time of proposal. Over the past one to two years since our data collection effort for the proposal, facilities in Nevada have continued to add controls and imp rove emission control as part of the N MCP . The new data indicate that there were two facilities with carbon processes without
mercury retorts operating in 2009 . Using the data from these two facilities , we determined that the MACT floor limits for carbon processes without mercury retorts are 0.1 7 lb/ton of concentrate for existing sources and 0. 14 lb/ton of concentrate***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **80** of **206** for new sources (based on the best performing facility).
In our beyond

- the

- floor analysis , we considered the addition of a carbon adsorb er on an uncontrolled emission unit within an existing affected source. We estimate the capital cost as $210,000 with a total annualized cost of $72,000 per year, an emission reduction of 1.63 lb/yr o f mercury, and a cost effectiveness of $44,000 /lb of me rcury. In l ight of the small emission reduction and the high cost effectiveness of this beyond

- the

- floor option, we decided not to go beyond

- the

- floor. Therefore, for existing sources of carbon processes without mercury retorts, the MACT floor limit is t he MACT standard for this affected source
. As part of our re

- analysis for the carbon group processes with mercury retorts, we collected and evaluated additional data. As discussed above, several of the facilities have improved emission control over the levels observed in the database we used at proposal. Two facilities with newly

installed controls replaced two higher

- emitting facilities that were in the top 5 at proposal, and all three of the other facilities that remained in the top 5 had lower level s of emissions after considering the new data. The results are that the MACT floor limits for carbon processes with mercury retorts***E.O. 12866 Review

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are 2.2 lb/ton of concentrate for exi s ting sources and 0.8 lb/ton of concentrate for new sources (based on the best perform ing facility). In the beyond

- the

- floor analysis, we evaluated the impacts of adding a second carbon adsorber in series with the controls applied to achieve the MACT floor level of control. We estimate the capital cost would be $3 million with a total ann ualized cost of $1 .3 million per year, an emission reduction of 9 lb/yr or mercury, and a cost effectiveness of $150,000/lb of mercury. B ecause of the small emission reduction and high cost effectiveness associated with this additional control, we decided not to go beyond the floor. Therefore, for existing sources of carbon processes with mercury retorts, the MACT floor limit is the MACT standard for this affected source
. 5. Compliance Alternative for New Carbon Process Sources
**Comment :**  One commenter n oted that the compliance “alternative” of 97 percent would be unlawful unless EPA specified that carbon sources had to meet the more stringent of either the floor standard or a 97 percent reduction standard. The commenter stated that because floors must r eflect the emission level achieved by the best performing sources, allowing sources to meet a 97 percent reduction standard that was less***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **82** of **206** stringent than the emission level actually achieved by the relevant best sources would contravene section 112(d)(3) an d well

- established D.C. Circuit court precedent. One commenter supported EPA’s use of the percent control alternative to the new source MACT for the carbon group. The commenter believes that the percent control alternative for new source carbon group MACT should also be available as an alternative to the existing source MACT for the carbon group. Another commenter stated that another facility, which has an average mercury reduction efficiency level of 99.995 percent, represents the “best controlled” simi lar source for the carbon process group and should be the basis for the alternative limits for new carbon processes. Several commenters requested clarification of the way in which compliance with the alternative for percent reduction would be demonstrated for new sources when there are multiple control devices on an emission unit. **Response :**  We eliminated in the final rule the compliance alternative of 97

- percent reduction for new carbon processes. After reviewing the comments received on this standard and giving further consideration to the practicality of how it would be measured, we concluded that this option would be difficult to***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **83** of **206** implement , particularly when multiple processes that are operated at different times vent to a single control device and

s tack . In addition, we have limited data supporting this compliance alternative. In proposing this alternative for comment, we had hoped to but did not receive additional data indicating that the 97 percent reduction option would be equivalent to the prop osed new source limit of 0.14 pounds of mercury per ton of concentrate. Largely due to the reasons stated above, we have eliminated the 97 percent control efficiency option for new carbon processes in the final rule. D. Compliance Determinations 1. Timi ng for Compliance Determinations
**Comment :**  Several commenters requ ested that the compliance deadline for existing sources be 3 years after the effective date of the rule, rather than the 2 years proposed. The commenters noted that several facilities will have to install control devices to achieve the MACT floor limits that have been proposed. The commenters explained that the controls must be custom designed for the unique characteristics of each process and associated process streams at each facility and stated that it can be time consuming and difficult to design, procure, construct, and implement emission controls to ensure effective***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **84** of **206** operation for the particular source. **Response :**  After reviewing the information provided in public comments on the chal lenges of retrofitting new controls , and the fact that these controls have not yet been demonstrated

on autoclaves and ore preheaters, w e believe th at allowing 3 years for existing sources to comply is appropriate . G iven the complexity of the sources, the combinations of control devices that are needed in many cases, and the amount of time necessary for designing, install ing, testing, and commissioning addition al emission controls for mercury , we conclude that 2 years may not provide adequate time for exis ting sources to comply with the final emission standards
. **Comment :**  Several commenters recommended that the rule specify that source testing results be used to determine compliance for the calendar year in which the test was conducted rather than to determ ine compliance for the prior 12 months. The commenters suggested that the source test results be applied to the hours of operation at the end of the calendar year to determine the source’s compliance with the MACT standard on an annual basis, as required in the NMCP. The commenters suggested that , if more than one source test is conducted in a year, the facility should average the mercury emission test results to***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **85** of **206** determine compliance for the calendar year in which the tests were conducted. Another comme nter commented that the annual compliance testing should not be constrained to the same calendar quarter each year. The commenter stated that this can lead to testing during periods of operation that may not represent normal production capacities. The co mmenter believes that mercury emissions testing should be scheduled for the most appropriate time interval throughout the calendar year. **Response :**  The permitting authority needs to be able to determine compliance with the NESHAP as soon as possible afte r the tests are completed and test results are available. Consequently, the final rule requires that initial compliance be determined based on production data and operating hours for all full calendar months between the date the rule is published in the Federal Register and the date of the compliance test, and subsequently, annual compliance must be based on the 12 full calendar months preceding the compliance test. This allows the permitting authority to determine if the affected source is in compliance in a timely manner. (This is consistent with the way compliance determinations are made in another MACT rule that uses a similar format

- National Emission Standards for***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **86** of **206** Hazardous Air Pollutants for Primary Lead Smelting, 40 CFR part 63, subpart TTT.) I f compliance was based on a calendar year, as suggested by the commenter, then we would not know if a source is in compliance until after December each year. For example, if a source conducted its compliance test in March, we would have to wait about 9 mo re months before we could determine if that source was actually in compliance. After those 9 months, if the source was not in compliance, it would mean that the source could have been out of compliance for the previous 9 months. Moreover, we do not beli eve that compliance with the NESHAP based on the production data from the 12 months prior to the compliance test would cause problems with reporting under the State program. It is our understanding that the emissions limits in the Nevada State phase 2 per mits are (or will be) based on concentration in the stacks (e.g., micrograms per cubic meter (μg/m 3 )). The limits in this final rule are based either on pounds of mercury per million tons of ore or pounds of mercury per tons of concentrate. Therefore, th e companies can continue to report the annual emissions as required under the TRI program and the State program without conflict with this rule.***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **87** of **206** If multiple compliance tests are conducted during the year, then a compliance determination must be made for each separate compliance test based on the production data for the 12 months preceding each test (i.e., the results of multiple compliance tests conducted throughout the year are not averaged to provide a single compliance determination for the year).
We understand that the rule , as proposed , may have required all existing sources to conduct their subsequent annual compliance tests in the same calendar quarter, and this may pose a scheduling problem because of the large number of facilities located in the same State (Nevada). Our concern was that subsequent annual compliance tests, if not separated in time, could be conducted for two different years with little time between the two tests (e.g., only a few days apart for the extreme case where the first tes t is conducted in late December and the second one in early January of the following year). We are providing scheduling flexibility by requiring that annual compliance tests be at least 3 months apart and no more than 15 months apart, and we are providing a similar separation for the period between the initial compliance test and the first annual compliance test. We do not believe that tracking multiple compliance dates is a particular problem for the permitting***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **88** of **2 06**  authority because that is the case for many other source categories of sources subject to annual compliance testing. 2. Test Methods
**Comment :**  Several commenters supported EPA’s proposal of alternate Methods 30A and 30B for demonstrating compliance. One commenter supported EPA’s requirement to us e Method 29 as an emission test method, but recommended two revisions: requiring a determination of the absence of cyclonic flow before sampling, and a minimum sampling time of 90 minutes for each test run. The commenter also stated that they do not supp ort the use of the Ontario Hydro Method (ASTM D6784

- 02), Method 30A, or Method 30B as mercury test methods. The commenter believes that the methods of demonstrating compliance with the emissions standards should be consistent with the methods utilized to establish the emission standards , which were based on Method 29 data. The commenter said that the typical gas streams associated with the mining industry have high particulate loadings, high mercury concentrations, sulfur dioxide (SO 2 ) , and contain partic ulate

bound mercury. The commenter also stated that the alternative methods were not developed specifically for the gold mining industry and their typical gas streams and concluded that the results from the various alternative methods will yield varying***E.O. 12866 Review

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r esults, will not be comparable, and will provide inconsistent reporting of overall mercury emissions. **Response**

When specifying the minimum requirements for compliance tests, it is more important to specify a minimum sampling volume than a minimum sampling time because the detection of a regulated pollutant is a function of the volume of the samp le rather than the length of time taken to collect the sample
. Thus , the final rule does not specify a minimum sampling time
. We are also changing the required minimum sampling volume to be 30 dscf rather than the 60 dscf as proposed because we believe
t hat 30 dscf generally will be adequate for detecting mercury emissions for this industry . Affected facilities should be aware, however, that the minimum sample volume may sometimes result in a failure to detect any mercury (a non

- detect) emitted from a pr ocess unit subject to the emission standard (for the **:** Method 29 references Method 1, which requires cyclonic flow checks under certain circumstances. Consequently, in the final rule, we have remov ed the specific requirements for cyclonic flow checks prior to every stack test that were in the proposed rule. Owners or operators should follow the requirements in the applicable EPA reference method and any additional requirements specified by the perm itting authority.***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **90** of **206** group of process units within the affected source) because of a mercury concentration at the outlet lower than expected. If the emission testing results for any of the emission points yield a

non - detect value, then the minimum detection limit (MDL) must be used in calculating the emissions for that emission point and, in turn, for calculating the sum of the mass emissions for all emission points subject to the emission standard for determining compliance . If the resulting mercury mass emissions rate is greater than the allowable emission limit, the owner or operator
may use procedures that produce lower MDL results and repeat the mercury emissions testing one additional time for any emission point for wh ich the measured result was below the MDL. If this additional testing is performed, the results from that testing must be used to determine compliance (i.e., there are no additional opportunities allowed to lower the MDL). We agree with the commenter tha t M ethod 29 is the most appropriate method for compliance determinations for this source category because of the unique characteristics of these sources , however alternative methods (such as 30B and OHM) may prove to be more appropriate under certain circu mstances . Therefore, w e are promulgating M ethod 29 as the main method for compliance in this rule . Alternative methods , such as 30B and the Ontario***E.O. 12866 Review

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Hydro method (OHM), could be used to demonstrate compliance for this source category if approv ed by the pe rmit ting authority. We have omitted Method 30A as an option in the final rule, as it is not yet in general use. Both Method 30B and the O H M (ASTM D6784

- 02) have been considered acceptable for some source categories. However, as described by the commente r, gold facilities have unique proce s ses and exhaust gas characteristics
. Method 29 can be used for any emission point for any of the affected sources
. T he alternative methods may eventually prove to be more appropriate under certain circumstances. Neve rtheless, b ecause it is not an isokinetic method, Method 30B is applicable to sampling only well

controlled PM emissions outlets. The OHM is similar to Method 29 , except that it is more expensive and more complicated, and is typically used to measure the individual species of mercury rather than just total mercury. E. Monitoring 1. Compliance Assurance
**Comment :**  One commenter noted that EPA’s proposed mercury standards are expressed in a format of pounds of mercury per million tons of ore processed and observed that the proposed rule requires stack testing only once a year. The commenter***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **92** of **206** claims that EPA’s proposed monitoring requirements would not demonstrate whether sources are in compliance with their emission standards, which renders the rule unenfo rceable. According to the commenter, the once

- a - year stack test would provide no indication as to what a mine’s emissions were the rest of the year. The commenter said that a source that failed its stack test would have only one violation of emission
sta ndards, even if that test showed that the source likely violated its emission standard throughout the year. The commenter believes that EPA’s proposed monitoring requirements would not assure compliance with the proposed emission standards. The commenter also noted that EPA proposes to require sources to monitor their mercury emissions either with CEMs, sampling, or various types of parametric monitoring; however, these methods do not provide direct information about the pounds of mercury emitted. Conseq uently, none of these monitoring methods could be used to demonstrate whether a source is in or out of compliance with the proposed emission standards. According to another commenter, all three affected source categories should be required to use CEMS at all times and at all emission points. The commenter stated that the ore pretreatment group especially needs CEMS because of variable***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **93** of **206** levels of mercury in the ore and different operational measures within the control of the facility. Other commenters su pported EPA’s decision to require continuous monitoring and said that the CEMS should be incorporated into the compliance regime as well. The commenters believe that, if the monitoring results indicate that the mine is consistently out of compliance for a period of one week without correction, the process unit should be subject to compliance

- based penalties and/or shut down until corrections are made and the process unit is back in compliance. According to the commenters, quarterly stack testing should st ill be required to demonstrate that the CEMS is working. **Response** : We recognize the importance of requiring adequate monitoring to assure compliance with the emission standards . Because of the higher mercury emitting potential of the roaster, we propose d the option of mercury monitoring using CEMS or weekly monitoring with PS 12B with associated parametric monitoring as well
. We are including in the final rule the option to perform continuous PS 12B monitoring, and, as with the CEMS, associated parametr ic monitoring would not be required. We are changing the frequency of the proposed weekly concentration monitoring approach for roasters to twice per***E.O. 12866 Review

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month (at least 1 1 days apart ) and would allow a facility to conduct a Method 30B test (as an alternative to a PS 12B test), supplemented with continuous parametric monitoring. We changed the frequency because we believe that sampling twice per month , coupled with continuous parametric monitoring , is sufficient for determining that the roaster control device s are operating properly. We added this alternative because Method 30B directly measures mercury concentration and is a valid means of determining whether the concentration is below the operating limit established during t he initial performance test
. T he
t wice per month Method 30B measurements will provide a concentration value that can be compare d to that operating limit to determine if an exceedance of the operating limit has occurred
. Also, if the twice monthly sampling shows repeated deviations over time, EPA could decide at a later date that CEMs are appropriate and necessary for roasters. We believe that the mercury concentrations monitoring for roasters along with the parametric monitoring of all control devices on all units is an acceptable ap proach to assure compliance with the emission standards
. Parametric monitoring of control devices assure s that the control devices are operating properly (and reducing emissions ) on an ongoing basis.***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **95** of **206** We disagree with the commenter that the proposed monit oring requirements render the rule unenforceable. The mercury operating limits in both the proposed and final rules are enforceable, and any exceedance of these operating limits triggers corrective action. If corrective action does not return the mercury concentration within the established limits, the plant must conduct a full compliance test and determine if the source is meeting the mass

- based (lb/million tons of ore) emission standard. We disagree with commenters that CEMS should be required for the non - roaster sources. These sources have less potential mercury emissions, and requiring CEMS on all these other units would be quite costly and burdensome. Moreover, m ost of these other units are , or will be, controlled with carbon adsorbers, and the car bon adsorber monitoring required by the final rule is an effective means of ensuring the controls are working effectively on a contin uing basis . We consider that either frequent testing of carbon beds to monitor for breakthrough using Method 30B , or frequ ent adsorbent sampling for mercury
content , is an effective way to ensure these mercury control systems are operating properly on a continuing basis. With regard to some of the units without carbon adsorbers, we believe***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **96** of **206** that annual tests coupled with appr opriate parametric monitoring of the control devices are sufficient to ensure emissions are properly controlled on a continuing basis. With regard to the comment that quarterly stack testing should be required for facilities using a CEMS, we believe tha t following the Quality Assurance (QA) procedures detailed in 40
CFR 60 , Appendix F , are sufficient to ensure the CEMS continues to operate as designed, and in this case, additional stack sampling is not necessary. 2. Operating Limits
**Comment :**  One commen ter stated that the operating limits for roasters and for carbon adsorbers are inappropriate and set up a second set of MACT standards. The commenter claimed that the operating limits do not take into account the effects of: hours of operation of a proc ess unit on mercury emissions; reduction in performance of a process unit offset by an improvement in performance of another process unit; variability in the exhaust gas flow rates with no appreciable effect on the corresponding mercury emission rate; and variability in the inlet mercury concentrations to a carbon adsorber . These factors all result in variability in the outlet mercury concentration. The commenter also noted that the proposed***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **97** of **206** operating limit for carbon adsorbers could result in premature

c arbon change out, resulting in the generation of more waste. The commenter recommended that EPA defer to the Nevada state monitoring requirements and only provide for monitoring of throughput and annual mercury emission testing to demonstrate compliance w ith the MACT emission standard. The commenter believes that any operating limit parameters must be established based on manufacturer specifications and recommendations in coordination with the permitting authority and not based on values measured during s ource compliance testing. **Response :**  We proposed the mercury operating limits as a monitoring tool to ensure that the processes within individual affected sources and their associated control devices are functioning properly on a continuing basis and not a s a second set of MACT standards
. We developed emission standards for four affected sources, and the emission standard for an affected source applies to the sum of emissions from all process units within the affected source. One unit could have an upward fluctuation in mercury concentration, but the group of process units could still meet the limit. We see the value of the operating limit approach as sufficient to detect significant increases in emissions and as a valuable tool to ensure the***E.O. 12866 Review

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control devi ces are operating effectively and provide quick notification of a potential problem with controls or emissions
. The monitoring parameters are used as compliance indicators , and the relevant mercury operating limits are the main “triggers” of a possible em issions increase and are set to alert facility operators when emissions are greater than the corresponding
mercury operating limit
. W e believe it is important to have such monitoring in the rule to ensure the control devices are working properly. Regard ing specific comments about monitoring the carbon adsorber, the State of Nevada has had good results with conducting sampling of the carbon adsorber to maintain its performance. The final rule offers an additional option of measuring the mercury concentra tion exiting the carbon adsorber that also achieves the same objective of avoiding breakthrough of the bed. We do not expect sudden dramatic failures of this technology. Instead, we expect to obtain close control of performance by ensuring that the carbo n is changed in a way that prevents breakthrough. This monitoring methodology should also prevent premature replacement of the bed. We disagree with the comments that only monitoring for throughput and annual emissions testing are sufficient to***E.O. 12866 Review

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demonstrat e compliance for sources controlled with carbon adsorbers. Such an approach does not provide for continuous monitoring . The parametric monitoring and operating limits specified in this final rule provide ongoing assurance that control devices are properl y operated and maintained between emissions tests , and exceedances of the operating limit require corrective action. W e also reject the comment that all operating limits should be based solely on manufacturer specifications and/or in consultation with the permitting authority. Control device operating parameter values often are site

- specific and are associated with a level of emissions from the source. In order to ensure continuous compliance, certain parameter limits generally should be associated with an emissions test that demonstrates compliance with the emissions standards. However, we agree that certain parameters for mercury scrubbers applied to roasters, such as the ranges associated with ensuring the proper chemistry of the scrubber, are best pr ovided by the system’s manufacturer. Guarantees of performance are usually conditioned by requiring that the system be operated as designed and specified by the manufacturer, and there is no assurance that a potentially narrow range that would be establis hed during a short performance test reflects the full***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **100** of **206** applicable range of proper operation. A facility may request us to consider alternative procedures for setting operating limits

on a case - by

- case basis under 40 CFR 63.8, if desired.
**Comment :**  Some co mmenters stated that their established parametric monitoring programs are sufficient to confirm that mercury emission controls are functioning properly for roasters. The commenters also stated that the NMCP permits have required parametric limits and tha t additional CEMS for mercury would neither improve the operation of these current controls, nor reduce mercury emissions. The commenters concluded that the operating parameters monitored on a regular basis are key parameters for measuring the efficiency and operation of the mercury controls and that operating each of these units within the optimum ranges ensures that mercury emissions are being effectively controlled. **Response :**  As discussed above, we do not believe parametric monitoring alone is suffic ient for roasters because of the very high mercury emission potential , unless the facility has adequately demonstrated that the mercury emissions from the roasters are consistently very low (e.g., less than 10 pounds per million tons)
. Nevertheless, w e have concluded that the combined approach of annual stack compliance testing along with***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **101** of **206** the monitoring requirements and options outlined in this rule

are necessary to detect excess emissions and to ensu r e controls are working effectively on a continuous b asis. 3. Mercury Concentration Monitoring for Roasters
**Comment :**  One commente r stated that the proposed provisions for monitoring mercury concentration s in roaster emissions are not based on roaster process and pollution control device operational param eters and would not yield reliable information that can be used for detecting and correcting problems. The commenter also stated that the formula for establishing the
mercury operation limit for roasters is not appropriate because it uses an emission limi t that is based on emission test data from several process units in addition to the roaster. The commenter recommended using the methods proposed for parametric monitoring of roaster emission control devices for all roasters. The commenter also has conce rns about utilizing PS 12A (mercury CEMS) and PS 12B for emissions monitoring purposes because there are terms and conditions listed in the proposed rule that are not fully defined. The commenter also recommended deleting the emissions monitoring requirem ents for mercury concentration for carbon adsorbers for the same reasons described above for
roasters.***E.O. 12866 Review

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**Response :**  We disagree with the comment that monitoring the mercury concentration in roaster emissions would not yield reliable information that can be u sed for detecting and correcting problems. An elevated mercury concentration in the roaster stack gas indicates that there could be a problem with either the process or the control device , which could result in excess mercury emissions from that unit . M o nitoring the mercury concentration in roaster emissions provides a direct measure of the regulated pollutant (mercury). The commenter is correct that the formula for establishing the mercury operating limit for roasters is based on emission tests performe d on several processes units in addition to the roaster. However, f or the facilities with roasters that will be subject to the requirements to monitor mercury concentration, the roaster is the biggest source of potential mercury emissions within the affec ted source. Therefore, we conclude that changes in the mercury concentration in the roaster exhaust gases provide a good indication of overall emissions from the affected source. In addition, the operating limit is not used directly to determine complian ce with the MACT emission standard . As mentioned above, it is designed to detect elevated mercury concentrations in the roaster stack gas, which could indicate a***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **103** of **206** problem with either the process or the control device. We continue to believe that it is nece ssary and appropriate to monitor mercury concentration for the largest source of potential mercury emissions in the source category (i.e., the roaster) to detect excursions in emissions that must be addressed when the operating limit is exceeded. By devel oping the mercury operating limit from the emission standard and compliance test results, an exceedance of the mercury operating limit will indicat e a potential increase in emissions and that corrective actions are need ed
. As described above, we believe that either continuous mercury sampling or mercury sampling twice per month, coupled with continuous parametric monitoring of the control device , should be required for the roaster emissions. If a CEMS is used, the daily average mercury concentration is calculated by averaging the hourly emissions concentrations during that day. If PS 12B is used for continuous integrated sampling (i.e., without parametric monitoring), the daily average concentration is determined by assigning the mercury concentration m easured by the sorbent trap monitoring system (total mass of mercury collected during the sampling period divided by the sample volume) as the daily average value to each of the days covered***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **104** of **206** by the integrated sample. As discussed above, the final rule incl ude s continuous sampling with PS 12B as a second option for monitoring roasters. A third option is based on short

- term sampling twice per month (at least 1 1 days apart) for mercury concentration using either PS 12B or Method 30B, and if this option is cho sen, parametric monitoring of the mercury scrubber must also be performed. For the third option (twice per month sampling) each measured mercury concentration must be compared to the operating limit to determine if an exceedance has occurred. For the con tents of the monitoring plan, see 40 FR 63.8(d)(3) and 40 CFR 60, Appendix F.
W e also disagree that parametric monitoring alone is sufficient for carbon adsorbers. For carbon adsorbers, measuring the mercury concentration exiting the carbon bed is also a direct measure of the pollutant of interest. (The other option as established for years in NDEP operating permits involves sampling the carbon for mercury content.) An elevated mercury concentration indicates that there could be a problem with either th e process or the control device , which could result in excess mercury emissions from that unit
. We have established exit concentration monitoring requirements in many***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **105** of **206** rules for emissions of organic compounds exiting carbon adsorbers . T hat monitoring has proven to be effective to prevent or detect breakthrough, and the same principles apply here for mercury . **Comment :**  Commenters stated that CEMS for gold mining operations are not capable of accurately measuring mercury emissions and that there are three major challenges with the feasibility of mercury CEMS for the gold mining industry: mercury CEMS calibration, sample transport, and system operability and reliability. The commenters are concerned with the unavailability of a means to calibrate the CEMS for roasters because existing calibrator designs are simply not capable of generating mercury concentrations high enough to provide meaningful upscale calibration points that correspond to gold mining source characteristics. The commenters noted the

unava ilability of National Institute of Standards and Technology (NIST) traceable calibration gas es and stated that the current calibration standards traceable to NIST do not apply to the full range of mercury concentrations that can be present in the exhaust g ases of roasters. The commenters concluded that the lack of a NIST

- traceable standard is a fatal flaw that precludes using mercury CEMS to monitor roaster emissions. Regarding***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **106** of **206** sample transport, the commenters said that current designs of mercury CEMS for coal

- fired electric generating units require high temperature umbilical lines to transport the sample from the stack to the analyzer and that CEMS on coal

- fired electric generating units have seen umbilical failures occur, representing another challenge t o having CEMS function consistently for the continuous monitoring of mercury from industrial sources. The commenters were also concerned with the CEMS operability and reliability because mercury CEMS must contain some type of converter to reduce oxidized mercury to elemental mercury and premature catalytic failures periodically occur in these units resulting in several days of missing data. The commenters continued by stating that users reported mercury CEMS to be unavailable as much as 30 to 40 percent o f the electric generating unit operating time. The commenters believe the amount of downtime to be expected from these systems on roasters would likely be even higher. The commenter concluded that the breakdown events, combined with the other types of fa ilures, result in data availability that is substantially inferior to parametric monitoring and cannot justify the significant cost and resource investment necessary to install, operate, and maintain these devices.***E.O. 12866 Review

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The commenters are concerned that continu ous data reports of mercury emissions that are not accurate, reliable, or credible could be offered as “credible evidence” to assert a violation. The commenter concluded by stating that this concern was particularly troubling in Nevada, where there are se parate mercury limits established pursuant to State law. **Response**

In addition, the NIST has recently completed certification of a ‘NIST Prime’ elemental mercury gas generator at concentrations of 41, 68, 85, 105, 140, 185, 230, 287, and 353 μg/m 3 . Mercury gas generator vendors may now submit elemental mercury gas generators for certification to serve as ‘Vendor Primes’ in a wide range of concentrations. Therefore NIST traceable mercury gas standards can now be made available in **:** Regarding the feasibility of using CEMS to monitor mercury emissions from roasters, CEMS have been demonstrated for process units similar to roasters (e.g., coal

fired power plants ), and w e believe there is no technical reason why they will not work for the roasters . Many of the issues with mercury CEMS have been resolved as facilities have gained experience with their use. As we discussed in the proposal preamble, CEMS manufacturers supp ly calibration standards for the ranges of concentrations seen at roasters.***E.O. 12866 Review

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concentrations th at exceed the concentrations typically seen from roasters. After consideration of public comments, we continue to believe CEMS are a valuable tool and a reasonable option for monitor ing mercury concentration and comparing those concentrations to the operat ing limit that is established by CEMS measurements made during the compliance test. In addition, we are promulgating a second option for continuous monitoring using PS 12B, and a third option of twice per month sampling using PS 12B or Method 30B coupled with parametric monitoring. We also point out that the final rule does not require the use of CEMS ; instead, the final rule includes CEMS as a one of the three monitoring option , the results of which will s to ensure that emissions from the roasters are no t exceed operating limits, or if they do exceed the operating limits, that corrective actions are taken in a timely manner to bring the emissions down to within the operating limits. The CEMs can also be used to help identify problems with control systems and ensure that corrective actions are taken immediately to fix such problems be used for compliance testing required in this rule
. . We understand the commenter ’s concerns regarding the transport of samples and converter failures. We have revised***E.O. 12866 Review

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the fin al rule to give facilities 3 years to successfully operate controls and monitoring equipment to be able to comply with the MACT standards.
**Comment :**  One commenter stated that the regulated industry has no experience with direct measurements of mercury

c oncentrations at the roaster exhaust gas stream. As a result, the commenter believes that there will be problems in collecting data, establishing appropriate timeframes for sampling under PS 12B, maintaining instrument reliability for CEMS, and in establi shing confidence in the accuracy of the results reported by these methods. The commenter claimed that the calculated operating limit based on source testing and simultaneous direct measurements may not be reflective of the future daily operations of all t he stack emissions. The commenter noted that flow rate measurements are critical in verifying compliance with actual emission limits because sometimes lower flow rates of the stack exhaust gas flow can artificially elevate the mercury concentration in the gas stream with no real effect on emissions. The commenter concluded that any exceedence exceed a nce in mercury concentration should be verified first with a compliance test before halting the roaster production.***E.O. 12866 Review

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**Response**

We agree that mercury concentration measurements are not direct measure ments of the emissions rate from the affected source and that flow rate, production, and other factors need to be considered. These are some of the reasons that the operating limit is not being used as a direct measure of compliance with the MACT limit. However, concentration measure ments above the operating limit should indicate that either controls are not working effectively or other problems are occurring . In either case, exceedances of the operating limit require investigation and may require corrective actions. **:** W e have learned from the comment s received that there may be a learning curve for facilities to implement the concentration monitoring procedures. As described in section
IV. D. of this preamble , w e have established in the final rule a compliance date that is 3 years after the effective date of the final rule for existing sources, part ly to allow sources time to ensure they can successfully comply with the monitoring requirements, but mainly to allow time to install new mercury emission controls that we believe will be necessary to meet t he emission standards in the final rule.

**Comment :**  One commenter requested that EPA reduce the weekly Method 12B monitoring frequency to quarterly or at most***E.O. 12866 Review

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monthly. The commenter also requested that EPA include a provision that allows for a source to demonstrate a correlation or consistency of performance such that the Method 12B sampling frequency can be further reduced based on the permitting authority’s acceptance of t he demonstration. The commenter suggested that if multiple Method 12B samples are collected in a single day or over multiple days in the calendar week, then the samples should be averaged, and this average concentration sh ould be compared to the operating limit. The commenter said that , for stacks with high mercury concentration, the sample collection time may be only an hour or two, and in this case, it may be important to collect more than one sample in a single day or over multiple days to obtain a rep resentative mercury concentration measurement. **Response :**  After taking into consideration the commenter’s rationale , the final rule requires monitoring mercury concentration twice per month (at least 1 1 days apart ) . If multiple samples are taken during th e twice per month period , each result must be compared to the operating limit separately (i.e., not averaged). Otherwise, a high result from a sample taken near the end of the sampling period might not trigger corrective actions to correct a problem that developed at that***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **112** of **206** time if the results are averaged with previous samples during periods of good performance. We do not agree with the suggestion to allow the monitoring frequency to be reduced if the monitoring results demonstrate consistency over the lon g term. We believe that monitoring the mercury concentration at least twice per month is necessary to ensure that potential problems with control systems are identified quickly and corrective actions are taken in a timely manner. 4. Parametric Monitoring of Control Device for Roasters
**Comment :**  Some commenters recommended that EPA remove the provisions requiring monitoring of the mercury scrubber liquor flow rate and scrubber pressure drop because each facility that has a roaster has a unique sequence of air pollution control devices, and monitoring parameters that may be appropriate for one roaster may not be applicable to another. One of the commenters said that the scrubber liquor flow rate is not currently monitored, nor is it considered a critical pa rameter in the daily operation of the scrubber mercury removal tower associated with roasters at their facility . The commenter further explained that the scrubber is not a spray tower, but instead the liquor is recirculated in the tower, so the pump is

mo nitored to insure it is operational. The commenter stated***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **113** of **206** that the pressure drop across the mercury removal tower at its roasters is monitored, but is not considered a critical parameter and that the mercuric ion and chloride ion concentrations that they monitor are the critical parameters that define the effectiveness of the mercury scrubber. Another commenter added that , for the calomel

- based mercury scrubbers, the key parameter is the reagent concentration in the solution exiting the scrubber and that maintaining the exit reagent concentration ensures there is sufficient reagent to react with the mercury vapor. The commenter noted that low exit concentrations indicate that either the liquor flow rate is too low, or the fresh reagent addition rate is t oo low. Thus, liquor flow rate does not need to be monitored in addition to reagent exit concentration. The commenter stated that if EPA continues to require them, the ranges should be based on the manufacturer’s specification or an alternative value app roved by the permitting authority, as opposed to three test runs. One commenter recommended that the corresponding range or limit for parametric deviations be applied to a daily average value rather than continuous instantaneous values or single samples. Another commenter also stated that the requirement to establish the minimum water flow rate and pressure drop of the***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **114** of **206** wet scrubber on readings taken during the performance test should not apply to scrubbers on roasters. The commenter noted that these par ameters were intended to monitor for physical processes, and the scrubbers on roasters often include chemical reaction s , which are not monitored. One commenter believes that establishing a maximum operating temperature for inlet gas concentrations by
art ificially increasing this temperature during compliance testing may destroy the control equipment, conflict with recommended operating temperatures, and artificially increase the reported mercury emissions. The commenter concluded that these parameters ar e not deemed critical in the effective operation of a mercury calomel scrubber. Another commenter added that their Compliance Assurance Monitoring (CAM) plan provides for an inlet gas temperature range of 32 ° to 134°F to prevent water freezing problems or extremely hot gas temperatures that could damage the mercury scrubber. The commenter stated that mercury scrubbers remove mercury from the gas stream through a chemical reaction and not a condensation mechanism and that lower temperatures will not remove (via condensation) additional mercury. The commenter explained that , although mercury scrubber inlet gas temperature is not a***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **115** of **206** relevant control performance parameter, their facility maintains the inlet gas temperature below 134°F and monitors the temperat ure daily to prevent damage to the controls system from excessively low or high gas temperatures
. **Response :**  After additional review of operating permits and consideration of public comments, we have found that the inlet temperature is monitored and mainta ined within a range to provide operational flexibility with the lower end bounded to prevent freezing and the upper end bounded to prevent damage to equipment, which in turn could lead to excess emissions. In addition, we have learned that this temperatur e is dependent on the cooling tower water temperature used in the process, and this water temperature can vary quite widely from winter to

summer. Facilities may not be able to address the issues described above if they can only use initial compliance tes ting to establish the inlet temperature operating range, as we proposed. Consequently, the final rule provides the following three ways for a facility with a roaster to establish an operating range for inlet temperature : (1) based on the maximum inlet te mperature during the initial compliance test ; (2) from the manufacturer’s specifications ; or (3) based on the limits established by the permitting authority . The facility must***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **116** of **206** monitor the temperature hourly, and any exceedance of the upper limit for tempe rature would trigger corrective action. We agree that pressure drop is not relevant to mercury scrubbers because, unlike venturi scrubbers applied to control
PM emissions, it is not related to its mercury emission control performance. We have removed pr essure drop monitoring from the final rule for mercury scrubbers. However, we continue to believe that it is important to monitor the scrubber flow rate to ensure the scrubber solution is being delivered to the system and that the flow is adequate, which is related to the system’s performance. We understand that some facilities monitor mercury scrubber solution line pressure (solution header pressure) as an indicator of flow rate, and we agree this is adequate to ensure proper flow. Consequently, the fin al rule requires hourly monitoring of scrubber flow rate (or line pressure) for mercury scrubbers on roasters. As with the inlet temperature operating range, t he minimum flow rate or line pressure must be established by one of the following three ways: (1 ) during the initial compliance test, (2) from the manufacturer’s specifications, or (3) based on the limits established by the permitting authority . The final rule requires hourly monitoring and that corrective action is triggered if the flow rate or lin e***E.O. 12866 Review

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pressure falls below the established parameters
. Regarding the acceptability of parameter values that were approved by permitting a uthorities prior to this final r ule , such values must be established as specified in the final rule and are not presumed in advance to be acceptable. 5. Exceeding the Operating Limits for Roasters
**Comment**

One commenter recommended that the corrective action response time be extended minimally to 48 hours after daily **:** One commenter was concerned about the consequences of exceeding a parametric monitoring limit . The commenter remarked that shutting down the roaster for exceeding a monit oring parameter without evidence of an ongoing emission limit exceedance is arbitrary and capricious, unnecessarily punitive, and threatens the economic viability of the regulated sources. The commenter pointed out that the ranges of parameters measured d uring source testing are not necessarily the only ranges within which the unit can operate effectively
. The parameters proposed by EPA are not the best parameters for monitoring roaster emissions and do not directly correlate to mercury emissions or prope r control system operation. The commenter also objected to the period of only 45 minutes to investigate and take corrective action.***E.O. 12866 Review

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average values are processed, plus an additional 24 hours to verify the daily average parametric value was within limits. For facilities that conduct PS 12B sampling and a daily average parametric deviation persists for 96 hours, the commenter recommended requiri ng sampling of the roaster’s exhaust using PS 12B within the next 24 hours, then evaluating the mercury concentration results. If the mercury concentration is below the operating limit, then , within 10 days of receiving the analytical results , the facilit y sho uld be required to either petition the permitting authority for a change in the parametric limits, or provide the permitting authority with a compliance plan that details corrective actions taken to date and the plan and schedule for bringing the para meter back within range. The commenter said that , if the mercury concentration is above the operating limit, the facility will be required to schedule an independent source testing firm to perform a compliance test within 45 days using one of the approved methods described in the rule. The commenter noted that the Nevada State agency requires 30 days to review the testing protocol, and source testing companies typically require 30 days or more advanced notice. For roasters where direct concentration meas urements are***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **119** of **206** not required and a daily average parametric deviation persists for 96 hours, the commenter recommended that within 48 hours, the facility sh ould : (1) provide the permitting authority with a compliance plan that details corrective actions take n to date and the plan and schedule for bringing the parameter back within the limits ; or (2) schedule an independent source testing firm to perform a compliance test within 45 days using one of the approved methods described in the rule. The commenter co ncluded that , if the test results show that the source has exceeded the threshold of 10 lb/million tons of ore, the facility would be required to implement direct mercury concentration measurements. One commenter requested that EPA provide an exception fro m the shutdown requirement when it can be demonstrated that, notwithstanding an exceedance of the parametric operating range, the roaster mercury emissions are less than the operating limit for mercury concentration. The commenter stated that the
mercury concentration measurement is a more direct indication of the ultimate mercury emissions that the parametric monitors are designed to address. **Response :**  We have investigated in greater detail the issues associated with monitoring roasters, and we have

co nsulted with NDEP and the owners and operators of roasters to***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **120** of **206** learn more about appropriate roaster monitoring. We believe the requirements of th is final rule provide assurance that timely corrective actions are taken when a monitoring parameter is exceede d, and we have included requirements for testing for mercury concentration s to determine if the corrective actions were successful or if a deviation has occurred. The final rule includes parametric monitoring of the mercury scrubbers applied
to roasters t o control mercury. If a parameter is outside of the established range or limit, corrective actions are triggered. If corrective actions do not result in the parameter reading being corrected and verified within 48 hours, a mercury concentration measureme nt (using method 30B, 12B, 29, or OHM) must be made to determine if the operating limit for mercury concentration is being exceeded. The measurement must be performed and the concentration determined within 48 hours (after the initial 48 hours , or a total of 96 hours ). If the measured mercury concentration meets the operating limit for mercury concentration, the corrective actions are deemed successful. In addition, the owner or operator may request approval from the permitting authority to change the pa rameter range or limit based on measurements of the parameter at the time the mercury concentration measurement was made. If the***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **121** of **206** operating limit is exceeded, the exceedance must be reported as a deviation and the facility must conduct a full compliance te st within 4 0 days to determine if the source is in compliance with the MACT limit
. **Comment**

For facilities that choose PS 12B monitoring, the commenter recommended that a deviation be considered an exceedance of the operating limit if the average of three consecutive sampling results (three weeks) were above the established limit. The commenter proposed that the facility sh ould then have one week to take corrective actions, an additional week to take the verification sample using PS 12B, w ith receipt of results the following week (three weeks total). The commenter stated that if the exceedance persists, the facility sh ould be required to **:** For facilities that monitor roasters with a CEMS, one commenter proposed that corrective action be required within 48 hours of receiving and processing the resul ts from the CEMS data, plus an additional 24 hours sh ould be allowed to collect verification data to see if the daily average concentration was restored below the operating limit. The commenter recommended that , if the exceedance persists, the facility sh ould be required to schedule an independent source testing firm to perform a compliance test within 45 days.***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **122** of **206** schedule an independent source testing firm to perform a compliance test within 45 days using one of th e approved methods described in the proposed rule. **Response :**  After consider ing these comments on the mercury concentration operating limit and the above discussion on parametric monitoring of roasters , we have made several clarifications in the final rule
. If a mercury concentration operating limit is exceeded from either daily average measurements from a CEMS , continuous sampling using PS 12B, or from sampling twice per month (at least 1 1 days apart) using PS 12B or Method 30B, the exceedance must be rep orted to the permit authority as a deviation and corrective actions must be implemented within 48 hours upon receipt of the sampling results that show the deviation. Moreover, w ithin 96 hours of the exceedance, the owner or operator must measure the conce ntration again (with the CEMS or Method 12B or 30B) and demonstrate to the permit authority that the operating limit for mercury concentration has been met, or inform the permit authority that the limit continues to be exceeded
. If the operating limit is still exceeded after these 96 hours, t he owner or operator m ust conduct a full compliance test for the ore pretreatment affected source within 40 days to determine if the affected source is in***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **123** of **206** compliance with the MACT emission standard . If the source is d etermined to be in compliance, the compliance test may also be used to establish a new operating limit for mercury concentration.
**Comment :**  One commenter requested that EPA provide an exception to the shutdown requirement for facilities that have well

- cont rolled roasters and elect to monitor under the proposed Option 3. The commenter believes a facility should have time (45 days) to demonstrate that the roaster’s mercury emissions remain less than 10 lbs of mercury per million tons of ore. The
commenter st ated that this would be achieved by scheduling an independent source testing firm to perform a compliance test using methods described in the rule, and calculations that demonstrate compliance with the limit of 10 lbs per million tons of ore. **Response :**  A s we have discussed above, the final rule relies in part on parametric monitoring of mercury scrubbers used on roasters to assure compliance with the applicable emission standards , and when the measured parametric values are out of the established operatin g range, corrective actions must be taken. This is no different f or facilities that qualify for the exemption described in §63.11647(a)(5) (i.e., facilities***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **124** of **206** exempt from mercury concentration monitoring by having demonstrated that their roaster emissions a re less than 10 lb/million tons of ore ). For these facilities , the final rule similarly requires that corrective actions be taken to restore the scrubber operating parameters to the established operating range. If the parameters are not restored to the e stablished range within 48 hours of triggering the corrective actions, the owner or operator must perform mercury concentration sampling of the roaster emissions using PS 12B or Method 30B or Method 29 and determine the mercury concentration within 48 hour s following the initial 48 hours (or a total of 96 hours from the time the parameter range was exceeded) . The measured concentration must be compared to a mercury concentration operating limit that is based on Equation 3 in the final rule, where the value for “C trap ” in Equation 3 is based on the mercury concentration for the roaster measured during the most recent compliance test. If the measured mercury concentration meets the operating limit for mercury concentration, the corrective actions are deemed successful. In addition, the owner or operator may request approval from the permitting authority to change the parameter range or limit based on measurements of the parameter at the time the mercury concentration measurement was***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **125** of **206** made. If the operating l imit is exceeded, the facility must take corrective actions and report it to the permit authority as a deviation. The owner or operator m ust also conduct a compliance test within 40 days to determine if the roaster operations are in compliance with the em ission standard
. **Comment**

One commenter noted that continuous readings on wet scrubbers are unreliable and proposed monitoring the wate r flow rate and pressure drop once per shift. The commenter noted that if any water flow rate or pressure drop reading exceeds the operating limit, the facility should follow the procedures for operating limit exceedances. The commenter stated that many **:** One commenter proposed that only the scrubber water flow rate monitoring be required for wet scrubbers on the quenching circuits associated with the roaster. The commenter wanted to confirm that wet scrubber monitoring does not apply to wet scrubbers or condensers on roasters. Another commenter asked that EPA confirm that the term “wet scrubbers” does not include condensers, which are used throughout the mining processes for gas cooling to condense water or (in the case of
reto rts) mercury. Another commenter asked EPA to confirm that wet scrubber monitoring does not apply to wet scrubbers associated with ore preheaters.***E.O. 12866 Review

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facilities do not have d ata a cquisition s ystems capable of recording continuous data and that wet scrubbers are primarily used to control particulates. The commenter concluded by stating that wet scrubbers are not key mercury controls and monitoring once per shift is sufficient to maintain control performance on a continuing basis. One commenter wanted to confirm that the limits established during testing would not be more stringent than the requirements set forth in the Standards of Performance for New Stationary Sources for Metallic Mineral Processing Plants, which allows for plus or minus 30 percent. Another commenter recommended that the operating limit for wet scrubber monitoring be based on either the lowest average value during any test run or no lower than 10 percent below the average value measured during the
test. **Response :**  As discussed above, the scrubber monitoring for roasters applies to the mercury scrubber (located at or near the end of the exhaust gas treatment train) and does not apply t o the additional scrubbers that are used to remove PM and SO 2 prior to the mercury scrubber. We are also clarifying in the final rule that when the primary mercury emission control device is a carbon adsorber, which is the last stage of the exhaust gas***E.O. 12866 Review

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cl eaning treatment train, it is necessary to monitor the carbon adsorber to ensure it is operating properly and controlling mercury emissions, and the rule does not require that scrubbers in the gas treatment train (typically used for control of PM and/or SO 2 ) prior to the carbon adsorber be monitored under this rule for mercury emissions. However, if there is no carbon adsorber or mercury scrubber , and the scrubber in question is the only control device for mercury emissions, the final rule requires that it be monitored once per shift per operating day (e.g., minimum of two times) for pressure drop and flow rate with operating limits that either are established during the initial compliance test, from the manufacturer’s specifications,

or based on approval f rom the permitting authority (except for pressure drop for autoclaves as discussed above). This applies to scrubbers on ore preheaters and quenching if there is no carbon adsorber or mercury scrubber in the exhaust gas treatment train. We are clarifying in the final rule that condensers, such as those found at roasters and retorts, are not wet scrubbers. We agree that monitoring and recording the pressure drop once per shift is adequate for monitoring these wet scrubbers to ensure they are operating prop erly. We disagree that a buffer***E.O. 12866 Review

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of +/

- 30 percent based on a certain NSPS subpart is appropriate for this NESHAP for mercury. The comment suggesting an option of a +/

- 10 percent buffer around the average value during the performance test has merit as an option to only using the lowest value during any individual run as the operating limit. If the system is so stable that it shows very minimal variability during the performance test, we agree that it is appropriate to add +/

- 10 percent to account for pote ntial future variability
. Consequently, we are incorporating the option in the final rule , as suggested by the commenter.
6 . Carbon Adsorber Temperature Monitoring
**Comment :**  Several commenters stated their concern with the proposed requirement of monitor ing gas st r eam temperature at the inlet to the carbon adsorber and maintaining the inlet temperature below the maximum temperature established during the compliance test. They noted that the primary purpose for monitoring the inlet gas stream temperature of carbon adsorbers is to prevent spontaneous combustion of the sulfidized carbon in the adsorber, not to detect excursions in mercury emissions. The commenters also stated that some carbon adsorption systems heat the gas stream prior to the carbon adsorb er to prevent moisture buildup and/or subsequent condensation in the carbon.***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **129** of **206** The commenters explained that the NMCP already requires that the exit gas temperature of condensers prior to the carbon adsorbers be established to minimize mercury emissions fro m the condenser. The commenters believe that an increase in inlet gas temperature to a carbon adsorption unit is not indicative of an increase in inlet gas stream mercury emissions because the high operating temperatures of the processes volatilize approx imately 100 percent of mercury. The commenters stated that establishing a maximum operating temperature for inlet gas concentrations by artificially increasing this temperature during compliance testing may destroy mercury control equipment; conflict with NMCP requirements and/or manufacturer’s recommended operating temperatures; artificially increase the reported mercury emissions; or artificially decrease the allowable operating limit for mercury concentration. The commenters continued by stating that, i f EPA persisted in requiring the monitoring of the gas stream inlet temperature, the maximum inlet temperature limit should be established by either the manufacturer’s recommendation and/or concurrence with the permitting authority. The commenters propose d monitoring the inlet temperature once per shift as an option to continuously monitoring the inlet temperature and comparing the***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **130** of **206** daily averages rather than the hourly averages to the operating limit. The commenters noted that many facilities do not have d igital a cquisition s ystems capable of recording continuous data, and monitoring once per shift is sufficient to maintain control performance. The commenters suggested that , if corrective action is needed, the facility should be allowed to sample the carb on loading to demonstrate that the effectiveness of the carbon adsorber has not been adversely impacted. **Response :**  The purpose of monitoring the inlet temperature to carbon adsorbers is not to provide an indication of higher mercury concentrations in the inlet stream as suggested by the commenters. The purpose is related to the fact that temperature is a fundamental parameter that affects the efficiency and capacity of carbon adsorbers. Generally, higher temperature s result in lower capacity and earlier breakthrough and , in fact, high temperatures are used to desorb adsorbed pollutants to regenerate carbon. In the extreme of temperature, the carbon adsorber might actually be desorbing rather than acting as a control device. This is particularly importa nt for those carbon adsorbers applied to high temperature thermal processes, such as carbon kilns and melt furnaces, where it is possible for the exhaust temperature to rise above the normal operating***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **131** of **206** temperature or above the temperature at which the carbo n adsorber was designed to operate. For high temperature
processes ( such as furnaces) , and not those such as electrowinning where the temperature may be near ambient conditions), we continue to require monitoring the inlet temperature . Owners or operator s must establish an operating limit for temperature based on one of the following : (1) the maximum temperature during the initial compliance test ; (2) from the manufacturer’s specifications ; or (3) based on limits established by the permitting authority
. If this established operating limit is exceeded corrective action must be taken and the exceedance reported as a deviation to the permit authority
. Further , the final rule requires facilities to monitor inlet temperature once per shift rather than continu ously, as was proposed. Because inlet temperatures should not vary greatly over the course of an 8 to 12

- hour period, we believe monitoring once per shift is adequate. We also conclude that if a temperature exceedance has occurred, the carbon bed should be sampled or the outlet concentration determined, depending on the monitoring option chosen, within 48 hours to ensure no permanent damage to the carbon adsorber occurred as a result of the deviation. We believe the temperature exceedance should be***E.O. 12866 Review

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repor ted as a deviation even if the subsequent monitoring shows that the carbon bed is operating properly because the subsequent monitoring would not necessarily detect if mercury had been desorbed and excess emissions occurred.
7 . Monitoring of Multiple Units Ducted to One Stack
**Comment**

Commenters also requested clarification that , for facilities with multiple process units ducted together through a shared carbon adsorber, the mercury concentration monitoring would be conducted on the combined exhaust stream. The commenters also requested clarification that the mercury concentration operating limit for a carbon adsorber for multiple units that share the carbon adsorber would be established during the simultaneous operations of all process units in order to **:** Commenters requested clarification that , for facilities that have two roasters ducted together through a shared mercury control system, the mercury concentration monitoring would be conducted on the combined exhaust stream. The commenters also requested clarification that the mercury concentration operating limit for two roasters that share a control system would be established during the simultaneous operation of the roasters in order to account for the combined mercury emis sions from both roasters.***E.O. 12866 Review

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acco unt for the combined mercury emissions. **Response :**  We agree with the commenters in general and have made the following clarifications in the final rule. If two roasters share a common control device and stack, the mercury concentration operating limit , as well as stack testing for compliance w ill be based on both roasters operating. However, monitoring for mercury concentration must be performed at the frequency specified in the final rule whether only one or both roasters are operating. We also have c larified that , for multiple process units vented to a common carbon adsorber, the mercury concentration operating limit and the stack testing for compliance must be based on all units operating if possible
. However, the ongoing mercury concentration monit oring must be performed at the frequency specified in the final rule for whatever units are operating at the time.
8 . Monitoring Mercury Concentration in Roaster Ore
**Comment :**  One commenter objected to the proposed requirement to conduct additional compli ance testing if the mercury concentration in the ore fed to the roaster is higher than any concentration measured in the previous 12 months. The commenter stated that there would not be an increase in the mercury emissions from their roasters because of t he extensive***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **134** of **206** series of mercury controls, some of which operate more efficiently at higher mercury loadings with unchanged stack emissions. In addition, the commenter noted that the rule does not provide details on how to measure the mercury ore
concentrat ion or what threshold of significance would be used to show an increase in ore mercury content occurred. The commenter concluded that the requirement would only provide extra cost and burden without any environmental benefit. **Response :**  We agree with the commenter and have removed this requirement from the final rule. We have no data showing that the mercury content of the ore has a significant effect on the performance of mercury scrubbers applied to roasters, which are designed to handle and operate eff iciently for a range of mercury inlet concentrations. In addition, roasters condense and recover elemental mercury prior to the mercury scrubber, and any increase in mercury loading would likely result in an increase in the recovery of elemental mercury. We have identified and require the monitoring of parameters associated with the scrubber chemistry, and maintaining these parameters within the established range for which the mercury scrubber was designed . This monitoring approach helps ensure th at the mercury scrubbers are controlling mercury emission independent***E.O. 12866 Review

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of variations in ore mercury content
. **V. Summary of Environmental, Economic and Health Benefits?** For proposal, we estimated baseline mercury emissions to be 3,119 lb/yr based on the available emissions data and average process data for the period 2007 to 2009. To estimate the impacts of the final rule, we have revised our baseline mercury emissions estimate to account for the recent installation of new mercury emission controls at two facilit ies and additional test data received since proposal. As a result of these changes, we now estimate baseline mercury emissions to be 2, 635 636 lb/yr. We estimate the final MACT standard will reduce mercury emissions from gold mine ore processing and produ ction by 1, 496 461 lb/yr from the baseline emissions levels of 2, 635 636 lb/yr down to a level of 1, 139 176 lb/yr post

- MACT. The annual emissions expected after MACT ( 1, 139 176 lb /yr ) represent a n estimated 77 percent reduction from 2007 emissions (5,000 lb /y r ), a 95 percent reduction from the emissions level in 2001 (about 23,000 lb /yr ), and more than 97 percent reduction from uncontrolled emissions levels (more than 37,000 lb /yr ). The capital cost of emission controls is estimated as $36 million with a tota l annualized cost of $8 .1 million per year. The capital costs for monitoring, reporting, and recordkeeping are***E.O. 12866 Review

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estimated as $ 1. 0 .5 to $1. 3 0 million with a total annualized cost of $ 0. 8 7 to $1.5 million per year, depending on the monitoring option that is chosen. The overall cost effectiveness is estimated to be about $6, 400 300 per pound of mercury reduced. The cost of compliance is estimated to be less than 0. 8 percent of sales for all affected firms . We therefore believe that the economic impact on an affected company would be insignificant. Electricity consumption is expected to increase by about 12, 700 600 megawatt

- hours per year due to increased fan capacity for carbon adsorbers and the installation of refrigeration units or condensers on a few proc ess units. Non

hazardous solid waste (spent carbon containing mercury that must be regenerated or disposed of) would increase by about 7 tons
per ye ar.
VI. Startup , Shutdown , and Malfunctions The United States Court of Appeals for the District of Columb ia Circuit vacated portions of two provisions in EPA’s CAA Section 112 regulations governing the emissions of HAP during periods of startup, shutdown, and malfunction (SSM). S ierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 2008), cert. denied, 130 S. Ct. 1735 (U.S. 2010) . Specifically, the Court vacated the SSM exemption contained in 40 CFR 63.6(f)(1) and 40 CFR***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **137** of **206** 63.6(h)(1), that are part of a regulation, commonly referred to as the “General Provisions Rule,” that EPA promulgated under section 112 of the CAA. When incorporated into CAA Section 112(d) regulations for specific source categories, these two provisions exempt sources from the requirement to comply with the otherwise applicable CAA section 112(d) emission standard during periods of SSM. Consistent w ith Sierra Club v. EPA, EPA has established standards in this rule that apply at all times. In establishing the standards in this rule, EPA has taken into account startup and shutdown periods and, for the reasons explained below, has not established diffe rent standards for those periods. We have no reason to believe that emissions are different during startup or shutdown. The mercury emissions from significant emissions points are, or will be, controlled by condensers, carbon bed filters , or mercury scru bbers. The carbon beds, which are applied to most types of process units to control mercury emissions, will capture mercury as well, or better, during periods of startup and shutdown as compared to normal operations. Condensers also capture mercury as we ll, or better, during periods of startup and shutdown as compared to normal operations. Mercury scrubbers are applied only to roasters, and***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **138** of **206** roasters operate continuously for most of the year. Roasters are normally shutdown purposely only about once per y ear ( typically for a few weeks) for maint e n an ce and repair. The facilities that have roasters ensure that the control devices (including the mercury scrubbers) are fully operational before the roasters are start ed
. Also, the controls stay operational thr oughout the shutdown period. Th erefore , no increase s in emissions are expected during the startup and shutdown periods
. Moreover, the MACT limit is based on pounds of mercury emissions
per rate of input or production over a 12

- month rolling average ( e.g. , pounds of mercury per million tons of input ore ).
T herefore, no change in the emissions standard s are needed for periods of startup and shutdown
. Periods of startup, normal operations, and shutdown are all predictable and routine aspects of a source’s operations. However, by contrast, malfunction is defined as a “sudden, infrequent, and not reasonably preventable failure of air pollution control and monitoring equipment, process equipment or a process to operate in a normal or usual manner ” (40 CFR 63 .2). EPA has determined that malfunctions should not be viewed as a distinct operating mode and, therefore, any emissions that occur at such times do not need to be factored into development of CAA***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **139** of **206** section 112(d) standards, which, once promulgated, apply at all times. In Mossville Environmental Action Now v. EPA , 370 F.3d 1232, 1242 (D.C. Cir. 2004), the court upheld as reasonable standards that had factored in variability of emissions under all operating conditions. However, nothing in section 112(d) or in caselaw requires that EPA anticipate and account for the innumerable types of potential malfunction events in setting emission standards. See , Weyerhaeuser v Costle

Further, i t is reasonable to interpret section 112(d) as not requiring EPA t o account for malfunctions in setting emissions standards. For example, we note that Section 112 uses the concept of “best performing” sources in defining MACT. Applying the concept of “best performing” to a source that is , 590 F.2d 1011, 1058 (D.C. Cir. 1978) (“ In the nature of things, no general limit, in dividual permit, or even any upset provision can anticipate all upset situations. After a certain point, the transgression of regulatory limits caused by ‘uncontrollable acts of third parties,’ such as strikes, sabotage, operator intoxication or insanity, and a variety of other eventualities, must be a matter for the administrative exercise of case

- by

- case enforcement discretion, not for specification in advance by regulation.”)***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **140** of **206** malfunctioning presents signifi cant difficulties. The goal of best performing sources is to operate in such a way as to avoid malfunctions of their units. Moreover, even if malfunctions were considered a distinct operating mode, we believe it would be impracticable to take malfunctio ns into account in setting CAA section 112(d) standards for the gold mine ore processing and production source category. As noted above, by definition, malfunctions are sudden and u nexpected events and it would be difficult to set a standard that takes in to account the myriad different types of malfunctions that can occur across all sources in the category. Moreover, malfunctions can vary in frequency, degree, and duration, further complicating standard setting. We believe it un likely that malfunction s w ould result in violation s of the standard s in this rule
. The primary pollution control devices used in this industry to control mercury emissions ( condensers, carbon bed filters and mercury scrubbers) are not expected to be significantly affected by SSM e vents. Moreover, the standards in this rule are expressed in terms of long

- term averages (e.g., pounds of mercury emitted per rate of production over a 12

- month period ) . We believe that malfunctions ( which are expected to occur quite infrequently***E.O. 12866 Review

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over th at period ) are not likely to result in an exceedance of the standard s . In the unlikely event that a source fails to comply with the applicable CAA section 112(d) standards as a result of a malfunction event, EPA would determine an appropriate response base d on, among other things, the good faith efforts of the source to minimize emissions during malfunction periods, including preventative and corrective actions, as well as root cause analyses to ascertain and rectify excess emissions. EPA would also consid er whether the source's failure to comply with the CAA section 112(d) standard was, in fact, “sudden, infrequent, not reasonably preventable” and was not instead “caused in part by poor maintenance or careless operation.” 40 C.F.R. § 63.2 (definition of m alfunction). Finally, EPA recognizes that even equipment that is properly designed and maintained can sometimes fail and that such failure can sometimes cause an exceedance of the relevant emission standard. ( See, e.g., State Implementation Plans: Policy Regarding Excessive Emissions During Malfunctions, Startup, and Shutdown (Sept. 20, 1999); Policy on Excess Emissions During Startup, Shutdown, Maintenance, and Malfunctions (Feb. 15, 1983)). EPA is therefore adding to the***E.O. 12866 Review

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final rule an affirmative defen se to civil penalties for exceedances of emission limits that are caused by malfunctions. See 40 CFR 63. 11651 (defining “affirmative defense” to mean, in the context of an enforcement proceeding, a response or defense put forward by a defendant, regarding which the defendant has the burden of proof, and the merits of which are independently and objectively evaluated in a judicial or administrative proceeding.). We also have added other regulatory provisions to specify the elements that are necessary to es tablish this affirmative defense; the source must prove by a preponderance of the evidence that it has met all of the elements set forth in 63. 11648 . (See 40 C.F.R. 22.24). The criteria ensure that the affirmative defense is available only where the eve nt that causes an exceedance of the emission limit meets the narrow definition of malfunction in 40 C.F.R. 63.2 (sudden, infrequent, not reasonable preventable and not caused by poor maintenance and / or careless operation). For example, to successfully ass ert the affirmative defense, the source must prove by a preponderance of the evidence that excess emissions “[w]ere caused by a sudden, short, infrequent, and unavoidable failure of air pollution control and monitoring equipment, process equipment, or a pr ocess to operate in a normal or usual***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **143** of **206** manner....” The criteria also are designed to ensure that steps are taken to correct the malfunction, to minimize emissions in accordance with section 63. 1164 6(b) and to prevent future malfunctions. For example, the so urce must prove by a preponderance of the evidence that “[r]epairs were made as expeditiously as possible when the applicable emission limitations were being exceeded...” and that “[a]ll possible steps were taken to minimize the impact of the excess emission s on ambient air quality, the environment and human health....” In any judicial or administrative proceeding, the Administrator may challenge the assertion of the affirmative defense and, if the respondent has not met its burden of proving all of the requir ements in the affirmative defense, appropriate penalties may be assessed in accordance with Section 113 of the Clean Air Act (see also 40 C.F.R. Part 22.77).
**VI I**  **. Statutory and Executive Order Reviews** 
A. This action is a “significant regulatory action” under the terms of Executive Order 12866 (58 FR 51735, October 4, 1993) because it may raise novel legal or policy issues. Accordingly, EPA submitted this action to the Office of Management and Budget (OMB) for review under Executive Order 12866, and any changes Executive Order 12866: Regulatory Planning and Re view***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **144** of **206** made in response to OMB recommendations have been documented in the docket for this action.
B. The information collection requirements in this final rule have been su bmitted for approval to OMB under the Paperwork Reduction Act, 44 U.S.C. 3501 Paperwork Reduction Act

et s eq

The recordkeeping and reporting requirements in this final rule are based , in large part, on the information collection requirements in EPA’s NESHAP General Provisions (40 CFR part 63, subpart A). The recordkeeping and reporting requirements in the General Provisions are specifically authorized by section 114 of the CAA (42 U.S.C. 7414). All information other than emissions data submitted to EPA pursuant to the information collection requirements for which a claim of confidentiality is made is safeguarded according to CAA section 114(c) and EPA’s implementing regulat ions at 40 CFR part 2, subpart B. . The Information Collection Request (ICR) document prepared by EPA has been assigned EPA ICR No. 2383.01
.

This final NESHAP will require applicable one

- time notifications according to the NESHAP General Provisions. In addition, owners or operators must submit annual notifications of compliance status and report any deviation s in each***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **145** of **206** semiannual reporting period. Records of all performance tests, measurements of feed input rates, monitoring data, and corrective actions w ill be required. The average annual burden for this information collection averaged over the first 3 years of this ICR is estimated to total 483 labor hours per year at a cost of approximately $ 26,847 per year for the 2 1 facilities that w ill be subject to th is final rule, or approximately 23 hours per year per facility. Capital costs are estimated as $ 1. 3 4 0 m illion , operation and maintenance costs are estimated as $ 6 7 52 ,000 per year, and total annualized cost (including capital recovery) is estimated as $ 417,930 360,210 per year for th is final rule ’s information collection requirements. No costs or burden hour s are estimated for new sources because none is projected for the next 3 years. Burden is defined at 5 CFR 1320.3(b). An agency may not conduct or sponsor, and a person is not required to respond to, a collection of information unless the collection disp lays a currently valid OMB control number. The OMB control numbers for EPA’s regulations in 40 CFR part 63 are listed in 40 CFR part 9. In addition, EPA is amending the table in 40 CFR part 9 of currently approved OMB control numbers for various regulati ons to list the regulatory citations for the***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **146** of **206** information requirements contained in this final rule.
C. The Regulatory Flexibility Act generally requires an agency to prepare a regulatory flexibility analysis of any rule subjec t to notice and comment rulemaking requirements under the Administrative Procedure Act or any other statute unless the agency certifies that th is rule would not have a significant economic impact on a substantial number of small entities. Small entities i nclude small businesses, small not

- for

- profit enterprises, and small governmental jurisdictions. Regulatory Flexibility Act

For the purposes of assessing the impacts of th is final NESHAP on small entities, a small entity is defined as: (1) a small business whose parent company meets the Small Business Administration size standards for small businesses found at 13 CFR 121.201 (less than 500 employees for gold mine ore processing and production facil i ties

– NAICS 212221 ); (2) a small governmental jurisdiction that is a government of a city, county, town, school district, or special district with a population of less than 50,000; and (3) a small organization that is any not

- for

- profit enterprise that is independently owned and operated and is not dominant in its field. After consid ering the economic impacts of this final rule***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **147** of **206** on small entities, I certify that this action will not have a significant economic impact on a substantial number of small entities. This final rule is estimated to impact about 2 1 gold mine ore processing and production facilities, none of which are owned by small entities. T hus, there are no impacts to small entities from this final rule. Although this final rule will contain requirements for new sources, EPA expect s few, if any , new sources to be construct ed in the next several years.
T herefore, EPA did not estimate the impacts for new affected

sources for this final rule
. Although this final rule will not have a significant economic impact on a substantial number of small entities, EPA nonetheless has t ried to reduce the impact of this final rule on small and large entities. The se standards establish emission limits that reflect practices and controls that are used throughout the industry and in many cases are already required by State operating permits . The se standards also require only the essential monitoring, recordkeeping, and reporting needed to verify compliance. The se final standards were developed based on information obtained from industry representatives in our surveys, consultation with bus iness representatives and their trade association and other stakeholders
.***E.O. 12866 Review

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D. This final rule does not contain a federal mandate that may result in expenditures of $100 million or more for state, local, and tribal government s, in the aggregate, or to the private sector in any one year. This final rule is not expected to impact state, local, or tribal governments. The total nationwide annualized cost of this final rule for affected industrial sources is $9. 2 1 million/yr. Th us, this final rule is not subject to the requirements of sections 202 and 205 of the Unfunded Mandates Reform Act (UMRA). Unfunded Mandates Reform Act

This final rule is also not subject to the requirements of section 203 of UMRA because it contains no regulatory requirements that m ight significantly or uniquely affect small governments. This final rule will not apply to such governments and will not impose any obligations upon them.
E. This action does not have federalism implications. It will not have substantial direct effects on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government, as specified in Executive Order 13132
. This final rule does not impose any requirements on Executive Order 13132: Federalism***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **149** of **206**
state and local governments. Thus, Executive Order 13132 does not apply to this action
. In the spirit of Executive Order 13132, and consistent with EPA policy to promote communications between EPA and Stat e and local governments, EPA specifically solicit ed comment on this proposed action from State and local officials.
F.

This action does not have tribal implications, as specified in Executive Order 13175 (65 FR 67249, November 9, 2000). This final rule imposes no requirements on tribal governments; thus, Executive Order 13175 does not apply to this action. Although Executive Order 13175 does not apply to this action, EP A requested comment from tribal officials in developing this action
. However , no comments on the proposal were received from tribal governments
. However, the reductions in mercury emissions to the environment, which will be achieved by this final rule, w ill certainly benefit tribal populations within the vicinity of affected gold mine ore processing and production facilities. Executive Order 13175: Consultation and Coordination with Indian Tribal Governments

G. Executive Order 13045: Protection of Children from Environmental Health and Safety Risks***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **150** of **206** EPA interprets Executive Order 1304 5 (62 F.R. 19885, April 22, 1997) as applying only to those regulatory actions that are based on health or safety risks, such that the analysis required under section 5

- 501 of the Executive Order has the potential to influence the regulation. This action is not subject to Executive Order 13045 because it is based solely on technology performance. However, we note that the final rule will result in significant reductions in emissions of mercury, and thus will provide benefits to children's health.
H.

This action is not a “significant energy action” as defined in Executive Order 13211 (66 FR 28355, May 22, 2001) because it is not likely to h ave a significant adverse effect on the supply, distribution, or use of energy. We have concluded that this final rule will not likely have any significant adverse energy effects because energy consumption would increase by only 12, 7 00 600 megawatt

- hours p er year. Exec utive Order 13211: Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use

I. Section 12(d) of the National Technology Transfer and Advancement Act of 1995 (“NTTAA”), Public Law No. 104

- 113 (15 U.S.C. 272 note), directs EPA to use voluntary consensus National Technology Transfer and Advancement Act***E.O. 12866 Review

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standards (VCS) in its regulatory activities unless to do so would be inconsistent with applicable law or otherwise impractical. VCS are technical standards (e.g., materials specifications, test methods, sampling procedures, business practices) that are developed or adopted by voluntary consensus standards bodies. NTTAA directs EPA to provide Congress, through OMB, explanations when the Agency decides not to use available and applicable VCS. This final rulemaking involves technical standards. EPA decided to use ASME PTC 19.10

- 1981, “Flue and Exhaust Gas Analyses,” for its manual methods of measuring the oxygen or carbon dioxide content of the exhaust gas. These parts of ASME PTC 19.10

- 1981 are acceptable alternatives to EPA Method 3B. This standard is available from the American Society of Mechanical Engineers (ASME), Three Park Avenue, New York, NY 10016

– 5990. Another VCS, ASTM D6784

- 02, “Standard Test Method for Elemental, Oxidized, Particle

- Bound and Total Mercury in Flue Gas Generated from Coal

- Fired Stationary Sourc es (Ontario Hydro Method)” is an acceptable alternative to EPA Method 29. This performance test method is available from ASTM International. See http://www.astm.org/.***E.O. 12866 Review

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EPA has also decided to use EPA Methods 1, 1A, 2, 2A, 2C, 2D, 2F, 2G, 3, 3A, 3B, 4, 29 , 30B, Method 7471A, “Mercury in Solid or Semisolid Waste (Manual Cold

- Vapor Technique),” and ASTM D6784

– 02, “Standard Test Method for Elemental, Oxidized, Particle

- Bound and Total Mercury in Flue Gas Generated from Coal

- Fired Stationary Sources,” (incorpo rated by reference

– see 63.14). Although the Agency has identified 14 VCS as being potentially applicable to these methods cited in this rule, we have decided not to use these standards in this final rulemaking. The use of these VCS would have been impr actical because they do not meet the objectives of the standards cited in this rule. The search and review results are in the docket for this final rule. Under section 63.7(f) and section 63.8(f) of Subpart A of the General Provisions, a source may apply to EPA for permission to use alternative test methods or alternative monitoring requirements in place of any required testing methods, performance specifications, or procedures in the final rule.
J.

Executive Order 12898 (59 FR 7629, February 16, 1994) Executive Order 12898: Federal Actions to Address Envi ronmental Justice in Minority Populations and Low

- Income Populations***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **153** of **206** establishes federal executive policy on environmental justice. Its main provision directs federal agencies, to the greatest
extent practicable and permitted by law, to make environmental justice part of their mission by identifying and addressing, as appropriate, disproportionately high and adverse human health or environmental effects of their programs, policies, and activities on mi nority populations and low

- income populations in the United States. EPA has determined that this final rule will not have disproportionately high and adverse human health or environmental effects on minority or low

- income populations because it will incre ase the level of environmental protection for all affected populations without having any disproportionately high and adverse human health or environmental effects on any population, including any minority or low

- income population. This final rule is expe cted to reduce mercury emissions from gold mine ore processing and production facilities and thus decrease the amount of such emissions to which all affected populations are exposed
. K. The Congressional Review Act, 5 U.S.C. 801 e t seq., as added by the Small Business Regulatory Enforcement Fairness Act Congressional Review Act***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page **15 4**  of **206** of 1996, generally provides that before a rule may take effect, the agency promulgating the rule must submit a rule report, which includes a copy of the rule, to each House of the C ongress and to the Comptroller General of the United States. EPA will submit a report containing this final rule and other required information to the U.S. Senate, the U.S. House of Representatives, and the Comptroller General of the United States prior t o publication of this final rule in the Federal Register . A major rule cannot take effect until 60 days after it is published in the Federal Register . This action is not a “major rule” as defined by 5 U.S.C. 804(2). This final rule will be effective on [INSERT DATE OF PUBLICATION IN THE FEDERAL REGISTER].**National Emission Standards for Hazardous Air Pollutants: Gold**  **Mine Ore Pro cessing and Production**  **Area Source Category; and Addition to Source Category List for Standards**  **Page 155**  **of 206** 

**List of Subjects in 40 CFR Part s 9 and**  **63** Environmental protection, Air pollution control, Hazardous substances, Incorporations by reference, Reporting and recordkeeping requirements.

___________ Dat ed:

____________________________ Lisa P. Jackson, Administrator.***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 156 of 206 For the reasons stated in the preamble, title 40, chapter I, of the Code of Federal Regulations is amended as follows: **PART 9 —**  **[AMENDED]** 1. The authority citation for part 9 continues to read as follows: **Authority:** 7 U.S.C. 135, et seq ., 136

– 136y; 15 U.S.C. 2001, 2003, 2005, 2006, 2601

– 2671; 21 U.S.C. 331j, 346a, 348; 31 U.S.C. 9701; 33 U.S.C. 1251, et seq ., 1311, 1313d, 1314, 1318, 1321, 1326, 1330, 1342, 1344, 1345(d) and (e), 1361; E. O. 11735, 38 FR 21243, 3 CFR, 1971

– 1975 Comp. p. 973; 42 U.S.C. 241, 242b, 243, 246, 300f, 300g, 300g

– 1, 300g

– 2, 300g

– 3, 300g

– 4, 300g

– 5, 300g

– 6, 300j

– 1, 300j

– 2, 300j

– 3, 300j

– 4, 300j

– 9, 1857, et seq

**S ubpart A**  **— [Amended]**  ., 6901

– 6992k, 7401

– 7671q, 7542, 9601

– 9657, 11023, 11048.

* * * * * 2. The table in § 9.1 is amended by adding an entry in numerical order for “ 63.11647

– 63.11648 ” under the heading “National Emission Standards for Hazardous Air Pollutants for Source Categories” to read as follows: **§9.1 OMB App rovals under the Paperwork Reduction Act.** 
* * * * *
40 CFR citation OMB control No. * * * * ****E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 157 of 206 National Emission Standards for Hazardous Air Pollutants for Source Categories 3 * * * * * 63.11647

– 63.11648 2060

– NEW * * * * * * * * * *

3 The ICRs referenc ed in this section of the table encompass the applicable general provisions contained in 40 CFR part 63, subpart A, which are not independent information collection requirements.
* * * * * **PART 63 —**  **[AMENDED]** 3 . The authority citation for part 63 continue s to read as follows: **Authority** : 42 U.S.C. 7401 et seq **Subpart A —**  **[Amended]** .

4 . Section 63.14 is amended by revising paragraph s (b)(35) and (i)(1) and by adding paragraph (k)(1)(v) to read as follows: **§63.14 Incorporation by reference.**
* * * * * (b) * * * (35) ASTM D6784

– 02, Standard Test Method for Elemental, Oxidized, Particle

- Bound and Total Mercury in Flue Gas Generated from Coal

- Fired Stationary Sources (Ontario Hydro Method), IBR approved for §63.11646(a)(1)(v) and table 5 to subpart DDDDD of this part.***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 158 of 206 * * * * * (i) * * * (1) ANSI/ASME PTC 19.10

– 1981, “Flue and Exhaust Gas Analyses [Part 10, Instruments and Apparatus],” IBR approved for §§63.309(k)(1)(iii), 63.865(b), 63.3166(a)(3), 63.3360(e)(1)(iii), 63.3545(a)(3), 63.3555(a)(3), 63.4166(a)(3) , 63.4362(a)(3), 63.4766(a)(3), 63.4965(a)(3), 63.5160(d)(1)(iii), 63.9307(c)(2), 63.9323(a)(3), 63.11148(e)(3)(iii), 63.11155(e)(3), 63.11162(f)(3)(iii) and (f)(4), 63.11163(g)(1)(iii) and (g)(2), 63.11410(j)(1)(iii), 63.11551(a)(2)(i)(C), 63.11646(a)(1)( iii), table 5 to subpart DDDDD of this part, and table 1 to subpart ZZZZZ of this part.
* * * * * (k) * * * (1) * * * (v) Method 7471A, “Mercury in Solid or Semisolid Waste (Manual Cold

- Vapor Technique),” IBR approved for §63.11647( f )(2).
* * * * * 5
. Part 63 is amended by adding subpart EEEEEEE to read as follows: **Subpart EEEEEEE —**  **National Emission Standards for Hazardous Air Pollutants: Gold Mine Ore Processing and Production**  **Area Source*****E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 159 of 206 **Category**

**Applicability and Compliance Dates** Sec. 63.11640 Am I subject to this subpart? 63.11641 What are my compliance dates? **Standards and Compliance Requirements** 63.11645 What are my mercury emission standards? 63.11646 What are my compliance requirements? 63.11647 What are my monitoring requirements? 63.11648 A ffirmative Defense for Exceedance of Emission Limit s During Malfunction. 63.1164 9 What are my notification, reporting, and recordkeeping requirements? **Other Requirements and Information** 63.11650 What General Provisions apply to this subpart? 63.11651 Wh at definitions apply to this subpart? 63.11652 Who implements and enforces this subpart? 63.11653 [Reserved] **Tables to Subpart EEEEEEE of Part 63** Table 1 to Subpart EEEEEEE of Part 63

— Applicability of General Provisions to Subpart EEEEEEE **Subpart EEEEEE E**  **— National Emission Standards for Hazardous Air**  **Pollutants: Gold Mine Ore Processing and Production Area Source**  **Category Applicability and Compliance Dates**  §63.11640 Am I subject to this subpart (a) You are subject to this subpart if you own or operat e a gold mine ore processing and production facility as defined in §63.11651 , that is an area source
. ?***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 160 of 206 (b) This subpart applies to each new or existing affected

source. The affected sources are each collection of “ore pretreatment processes” at a gold mi ne ore processing and production facility, each collection of “carbon processes with
mercury retorts ” at a gold mine ore processing and production facility, each collection of “carbon processes without mercury retorts” at a gold mine ore processing and pro duction facility, and each collection of “non

- carbon concentrate processes" at a gold mine ore processing and production facility, as defined in §63.11651. (1) An affected source is existing if you commenced construction or reconstruction of the affected source on or before April 28, 2010
. (2) An affected source is new if you commenced construction or reconstruction of the affected source after April 28, 2010
. (c) This subpart does not apply to research and development facilities, as defined in sectio n 112(c)(7) of the Clean Air Act (CAA). (d) If you own or operate a source subject to this subpart, you must have or you must obtain a permit under 40 CFR part 70 or 40 CFR part 71. §63.11641 What are my compliance dates ?***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 161 of 206 (a) If you own or operate an existing affected source, you
must comply with the applicable provisions of this subpart no later than [INSERT DATE 3 YEARS AFTER PUBLICATION OF THIS FINAL RULE IN THE FEDERAL REGISTER]
. (b) If you own or operate a new affected source , and the initial st artup of your affected source is on or before [INSERT DATE OF PUBLICATION OF THIS FINAL RULE IN THE FEDERAL REGISTER] , you must comply with the provisions of this subpart no later than [INSERT DATE OF PUBLICATION OF THIS FINAL RULE IN THE FEDERAL REGISTER]
. (c) If you own or operate a new affected source , and the initial startup of your affected source is after [INSERT DATE OF PUBLICATION OF THIS FINAL RULE IN THE FEDERAL REGISTER] , you
must comply with the provisions of this subpart upon startup of
your affected source. **Standards and Compliance Requirements**
§ 63.11645 What are my mercury emission standards (a) For existing ore pretreatment processes, you must emit no more than 12 7 pounds of mercury per million tons of ore processed
. ?

(b) For existing carbon processes with mercury retorts , you must emit no more than 2.2 pounds of mercury per ton of
concentrate processed
.***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 162 of 206 (c) For existing carbon processes without mercury retorts, you must emit no more than 0.1 7 pounds of mercury per ton of
concentrate processed. ( d ) For existing non

- carbon concentrate processes, you must emit no more than 0. 2 pounds of mercury per ton of
concentrate processed
. ( e ) For new ore pretreatment processes, you must emit no more than 84 pounds of mercury per million tons of ore processed
. ( f ) For new carbon processes with mercury retorts , you
must emit no more than 0.8 pounds of mercury per ton of concentrate processed. (g) For new carbon processes without mercury retorts, you must emit no more than 0. 14 pounds of mercur y per ton of concentrate processed. ( h ) For new non

- carbon concentrate processes, you must emit no more than 0.1 pounds of mercury per ton of concentrate processed
. ( i ) The standards set forth in this section apply at all times.
§ 63.11646 What are my compliance requirements (a) Except as provided in paragraph (b) of this section, you must conduct a mercury compliance emission test within 180 ?***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 163 of 206 days of the compliance date for all process units at new and existing affected sources according to the r equirements in paragraphs (a)(1) through (1 3 ) of this section. This compliance testing must be repeated annually thereafter , with no two consecutive annual compliance tests occurring less than 3 months apart or more than 15 months apart
. (1) You must det ermine the concentration of mercury and the volumetric flow rate of the stack gas according to the following test methods and procedures: (i) Method 1 or 1A (40 CFR part 60, appendix A

- 1) to select sampling port locations and the number of traverse points in each stack or duct. Sampling sites must be located at the outlet of the control device (or at the outlet of the emissions source if no control device is present) and prior to any releases to the atmosphere. (ii) Method 2, 2A, 2C, 2D, 2F (40 CFR par t 60, appendix A

1), or Method 2G (40 CFR part 60, appendix A

- 2) to determine the volumetric flow rate of the stack gas. (iii) Method 3, 3A, or 3B (40 CFR part 60, appendix A

- 2) to determine the dry molecular weight of the stack gas. You may use ANSI/AS ME PTC 19.10

- 1981, “Flue and Exhaust Gas Analyses” (incorporated by reference

- see §63.14) as an alternative to EPA Method 3B.***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 164 of 206 (iv) Method 4 (40 CFR part 60, appendix A

- 3) to determine the moisture content of the stack gas. (v) Method 29 (40 CFR part 60, appendix A

- 8) to determine the concentration of mercury, except as provided in paragraphs (a)(1)(vi) and (vii) of this section. (vi) Upon approval by the permitting authority , ASTM D6784

– 02 ; “Standard Test Method for Elemental, Oxidized, Particle

- Bound an d Total Mercury in Flue Gas Generated from Coal

- Fired Stationary Sources (Ontario Hydro Method)” (incorporated by reference

– see §63.14) may be used as an alternative to Method 29 to determine the concentration of
mercury. (vii) Upon approval by the perm itting authority, Method 30B (40 CFR part 60, appendix A

- 8 ) may be used as an alternative to Method 29 to determine the concentration of mercury for those process units with relatively low particulate

- bound mercury as specified in Section 1.2 of Method 30B
. (2) A minimum of three test runs must be conducted for each performance test of each process unit . Each test run conducted with Method 29 must collect a minimum sample volume of 0.85 dry standard cubic meters ( 30 dry standard cubic feet)
. If conduct ed with Method 30B or Ontario Hydro Method, determine sample time and volume according to the testing criteria set***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 165 of 206 forth in the relevant method. If the emission testing results for any of the emission points yields a non

- detect value, then the minimum det ection limit (MDL) must be used in calculating the emissions for that emission point and, in turn, for calculating the sum of the mass emissions for all emission points subject to the emission standard for determining compliance. If the resulting mercury mass emissions rate is greater than the allowable emission standard , the owner or operator may use procedures that produce lower MDL results and repeat the mercury emissions testing one additional time for any emission p o int for which the measured result w as below the MDL. If this additional testing is performed, the results from that testing must be used to determine compliance (i.e., ther e are no additional opportunities allowed to lower the MDL). (3) Tests Performance tests shall be conducted under such conditions as the Administrator specifies to the owner or operator based on representative performance of the affected source for the period being tested. Upon request, the owner or operator shall make available to the Administrator such records

as may be necessary to determine the conditions of performance tests. Performance t ests must be conducted under operating conditions (including process or production throughputs) that are based on representative performance. Record and report to***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 166 of 206 the permit authority the process throughput for each test run. For sources with multiple emission units (e.g., two roasters) ducted to a common control device and stack, c ompliance testing must be performed with all affected emissions units in operation if possible
. If it is not possible to test all sources ducted to a common control device simultaneously, the sources can be tested separately. In such cases, any source that is not tested initially must be tested as soon as is practicable. (4) Calculate the mercury emission rate , based on the average of 3 test run values, for each process unit using Equation (1) of this section: E = Cs * Qs * K (Eq. 1) Where:
E = mercury emissions in lb/hr; Cs = concentration of mercury in the stack gas, in grains per dry stan dard cubic foot (gr/dscf) ; Qs = volumetric flow rate of the stack gas, in dry standard cubic feet per hour; and K = conversion factor f or grains (gr) to pounds (lb), 1.43 x 10 - 4

. (5) Monitor and report to the permit authority the number of one - hour peri ods each process unit operates during each month. (6) For the initial compliance determination for both new and existing sources, determine the total mercury emissions for all the full calendar month s between the compliance date and the date of the initia l compliance test by multiplying the emission***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 167 of 206 rate in lb/hr for each process unit by the number of hours each process unit operated during t h ose full calendar month s prior to the initial compliance test
. After the initial compliance test , for subsequent c ompliance tests, determine the mercury mass emissions for the 12 month period prior to the compliance test in accordance with the procedures in paragraph (a)(7) of this section. Existing sources may use a previous emission test for their initial complianc e determination in lieu of conducting a new test if the test was conducted within one year of the compliance date using the methods specified in paragraphs (a)(1) through (4) of this section, and the tests were representative of current operating processes and conditions. ( 7 ) For compliance determinations following the initial compliance test for new and existing sources, d etermine the total mercury mass emissions for each process unit for the 12

- month period preceding the performance test by multiplying the emission rate in lb/hr for each process unit by the number of hours each process unit operated during the 12 full calendar months preceding the completion of the performance tests. ( 8 ) You must install, calibrate, maintain and operate an appropriate weight measurement device , mass flow meter, or densitometer and volumetric flow meter to measure ore throughput for each roast ing operation and autoclave and calculate hourly,***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 168 of 206 daily and monthly totals in tons of ore according to paragraphs (a)(8)(i) and ( ii) of this section
. (i) Measure the weight or the density and volumetric flow rate of the oxidized ore slurry as it exits the roaster oxidation circuit and before the carbon

- in

- leach tanks. (ii) Measure the weight or the density and volumetric flow
rate of the ore slurry as it is fed to or as it exits the autoclave(s). ( 9 ) Measure the weight of concentrate ( produced by electrowinning, Mer r ill Crowe process, gravity feed, or other methods) using weigh scales for each batch prior to processing in mercury retort s or melt furnaces . The concentrate must be weighed in the same state and condition as it is when fed to the
mercury retort. F or facilities without mercury retorts, the concentrate must be weighed prior to being fed to the melt furnace before dryin g in any ovens. For facilities that ship concentrate offsite , measure the weight of concentrate as shipped offsite. You must keep accurate records of the weights of each batch of concentrate processed and calculate , record , and report to the permit autho rity the total weight of concentrate processed each month. ( 10 ) You must maintain the systems for measuring density, volumetric flow rate, and weight within ±5 percent accuracy.***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 169 of 206 You must describe the specific equipment used to make measurements at your facility and how that equipment is periodically calibrated. You must also explain, document, and maintain written procedures for determining the accuracy of the measurements and make these written procedures available to your permitting authority upon req uest. You must determine, record, and maintain a record of the accuracy of the measuring systems before the beginning of your initial compliance test and during each subsequent quarter of affected source operation. (1 1 ) R ecord the weight in tons of ore f or ore pretreatment processes and concentrate for carbon processes with mercury retorts, carbon processes without mercury retorts, and for non

carbon concentrate processes on a daily and monthly basis and report the monthly values to the permit authority
. (1 2 ) Calculate the emissions from each new and existing affected source for the sum of all full month s between the compliance date and the date of the initial compliance test in pounds of mercury per ton of process input using the procedures in paragraphs (a)(1 2 )(i) through (i v ) of this section to determine initial compliance with the emission standards in §63.11645. After th is initial compliance test period, d etermine annual compliance using the procedures in paragraph (a)(13) of this section for existin g sources.***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 170 of 206 (i) For o re pretreatment processes, divide the sum of
mercury mass emissions from all roasting operations and autoclaves during the number of full months between the compliance date and the initial compliance test by the sum of the total amoun t of gold mine ore processed in these process units during th ose same full month s following the compliance date
. (ii) For carbon processes with mercury retorts , divide the sum of mercury mass emissions from all carbon kilns, preg tanks, electrowinning, mercury retorts, and melt furnaces during the initial number of full months between the compliance date and the initial compliance tests by the total amount of concentrate processed in these process units during those same full months following the complia nce date. (iii) For carbon processes without mercury retorts, divide the sum of mercury mass emissions from all carbon kilns, preg tanks, electrowinning, and melt furnaces during the initial number of full months between the compliance date and the initia l compliance tests by the total amount of concentrate processed in these process units during those same full months following the compliance date
. (i v ) For non

- carbon concentrate processes, divide the sum of mercury mass emissions from mercury retorts an d melt furnaces***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 171 of 206 during the initial number of full months between the compliance date and the initial compliance tests by the total amount of concentrate processed in these process units during those same full months fol lowing the compliance date
. (13) Aft er the initial compliance test, c alculate the emissions from each new and existing affected source for each
12

- month period preceding each subsequent compliance test in pounds of mercury per ton of process input using the procedures in paragraphs (a)(13)(i ) through (i v ) of this section to determine c ompliance with the emission standards in §63.11645. (i) For ore pretreatment processes, divide the sum of
mercury mass emissions from all roasting operations and autoclaves in the 12

- month period preceding a compliance test by the sum of the total amount of gold mine ore processed in th at 12

- month period
. (ii) For carbon processes with mercury retorts , divide the sum of mercury mass emissions from all carbon kilns, preg tanks, electrowinning, mercury retorts, and melt furnaces in the 12

- month period preceding a compliance test by the total amount of concentrate processed in these process units in that 12

- month period
. (iii) For carbon processes without mercury retorts, divide the sum of mercury mass emissions from all carbon kilns, preg***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 172 of 206 tanks, electrowinning, and melt furnaces in the 12

- month period preceding a compliance test by the total amount of concentrate processed in these process units in that 12

- month period. (i v ) For non

- carbon concentrate processes , divide the sum of mercury mass emissions from mercury retorts and melt furnaces in the 12

- month period preceding a compliance test by the total amount of concentrate processed in these process units in that 12

- month period
. ( b ) At all times, you you must operate and maintain any affected source, including associated air pollution control equipment and monitoring equipment, in a manner consistent with safety and good air pollution control practices for minimizing emissions. Determination of whether such o peration and maintenance procedures are being used will be based on information available to the Administrator which may include, but is not limited to, monitoring results, review of operation and maintenance procedures, review of operation and maintenance records, and inspection of the source.

(a) Except as provided in paragraph (a)( 5 ) of this section, you must monitor each roaster for mercury emissions using one of the procedures in paragraphs (a)(1) , (2) , or (3) of this section and establish operating limits for mercury §63.11647 What are my monitoring requirements?***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 173 of 206 concentration as described in paragraph (a)( 4 ) of this section. ( 1 ) Perform sampling and analysis of the roaster’s exhaust for mercury concentration using EPA Performance Specification
12B or EPA Method 30B at least twice per month . A minimum of two measurements must be taken per month that are at least 11 days apart from other consecutive tests. T he mercury concentration must be maintained below the operating limit established in paragrap h (a)( 4 ) of this section. The results of the sampling must be obtained within 72 hours of the time the sample is taken. (i) To determine the appropriate sampling duration, you must review the available data from previous stack tests to determine the uppe r 99th percentile of the range of mercury concentrations in the exit stack gas. Based on this upper end of expected concentrations, select an appropriate sampling duration that is likely to provide a valid sample and not result in breakthrough of the samp ling tubes. If breakthrough of the sampling tubes occurs, you must re - sample within 30 days using a shorter sampling duration. (ii) If the any mercury concentration measurement from the twice per month sampling with method 12B or 30B is higher than the operating limit, the exceedance must be reported to the permit authority as a deviation and corrective actions must be***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 174 of 206 implemented within 48 hours upon receipt of the sampling results. Moreover, within 96 hours of the exceedance, the owner or operator mus t measure the concentration again (with method 12B or 30B) and demonstrate to the permit authority that the mercury concentration is no higher than the operating limit, or inform the permit authority that the limit continues to be exceeded. If the operati ng limit is still exceeded after these 96 hours, the owner or operator must conduct a full compliance test for the ore

- pretreatment affected source within 40 days to determine if the affected source is in compliance with the MACT emission standard . If the source is determined to be in compliance, the compliance test may also be used to establish a new operating limit for mercury concentration ( in accordance with paragraph (e) of this section )
. (2) Install, operate, calibrate, and maintain a continuous emi ssions monitoring system (CEMS) to continuously measure the mercury concentration in the final exhaust stream from each roaster according to the requirements of Performance Specification 12A (40 CFR part 60, appendix B) except that calibration standards tr aceable to the National Institute of Standards and Technology are not required. You must perform a data accuracy assessment of the CEMS according to section 5 of Appendix F in part 60 and follow the monitoring requirements in***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 175 of 206 §63.8 , . e xcept that 63.8 (c ) (1 ) (i) and (iii) no longer apply
. Moreover, 63.8(d) (3) applies except the last sentence, which refers to an SSM plan. SSM plan s are no longer required. (i) You must continuously monitor the daily average mercury concentration from the roaster and maint ain the daily average concentration below the operating limit established in paragraph (a)( 4 ) of this section. (ii) If the daily average mercury concentration from the CEMs is higher than the operating limit, the exceedance must be reported to the permi t authority as a deviation and corrective actions must be implemented within 48 hours upon receipt of the sampling results. Moreover, within 96 hours of the exceedance, the owner or operator must measure the concentration again (with the CEMs) and demonst rate to the permit authority that the mercury concentration is no higher than the operating limit, or inform the permit authority that the limit continues to be exceeded. If the operating limit is still exceeded after these 96 hours, the owner or operator must conduct a full compliance test for the ore

- pretreatment affected source within 40 days to determine if the affected source is in compliance with the MACT emission standard . If the source is determined to be in compliance, the compliance test results may also be used to establish a new operating limit for mercury concentration ( in***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 176 of 206 accordance with paragraph (e) of this section )
. (ii i ) You must submit a monitoring plan that includes quality assurance and quality control (QA/QC) procedures sufficient t o demonstrate the accuracy of the CEMS to your permitting authority for approval 180 days prior to your initial compliance test. At a minimum, the QA/QC procedures must include daily calibrations and an annual accuracy test for the
CEMS. (3) Continuously measure the mercury concentration in the final exhaust stream from each roaster using EPA Performance Specification 12B. (i) You must continuously measure the mercury concentration in the roaster exhaust and maintain the average daily mercury concentrati on below the operating limit established in paragraph (a)(4) of this section. To determine the appropriate sampling duration, you must review the available data from previous stack tests to determine the upper 99th percentile of the range of mercury conce ntrations in the exit stack gas. Based on this upper end of expected concentrations, select an appropriate sampling duration that is likely to provide a valid sample and not result in breakthrough of the sampling tubes. If breakthrough of the sampling tu bes occurs, you must re

- sample within 30 days using a shorter sampling***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 177 of 206 duration. (ii) If the daily average mercury concentration is higher than the operating limit, the exceedance must be reported to the permit authority as a deviation and corrective acti ons must be implemented within 48 hours upon receipt of the sampling results. Moreover, within 96 hours of the exceedance, the owner or operator must measure the concentration again with method 12B or 30B and demonstrate to the permit authority that the m ercury concentration is no higher than the operating limit, or inform the permit authority that the limit continues to be exceeded. If the operating limit is still exceeded after these 96 hours, the owner or operator must conduct a full compliance test fo r the ore

- pretreatment affected source within 40 days to determine if the affected source is in compliance with the MACT emission standard . If the source is determined to be in compliance, the compliance test results may also be used to establish a new
op erating limit for mercury concentration ( in accordance with paragraph (e) of this section )
. ( 4 ) Use Equation (2) of this section to establish an upper operating limit for mercury concentration as determined by using the procedures in paragraphs (a)(1) , (2) , or (3) of this section concurrently while you are conducting your annual compliance performance stack test according to the procedures in***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 178 of 206 §63.11646(a)
. OLR = C test * ( EL /CT) (Eq 2) where
OLR = mercury concentration operating limit for the roast er ( in micrograms per cubic meter); C test = average mercury concentration measured by the monitoring procedures (PS 12A or PS 12B or 30B ) during the annual performance stack test ( in micrograms per cubic meter); EL = emission standard for ore pretreatment processes ( in lb/ million tons of ore); CT = compliance test results for ore pretreatment processes ( in lb/ million tons of ore). ( 5 ) For r oaster s that utilize calomel

- based mercury control systems for emissions controls , y ou are not required to perform the monitoring for mercury emissions in paragraphs (a)(1) , (2) , or (3) of this section if you demonstrate to the satisfaction of your permitting authority that mercury emissions from the roaster are less than 10 pounds of mercury per million tons of ore t hroughput. If you make this demonstration , you must conduct the parametric monitoring as described below in paragraphs (b) and (c) of this section. (i) The initial demonstration must include three or more consecutive independent stack tests for mercury at least one month apart on the roaster exhaust stacks . Subsequent demonstrations may be based upon the single stack test required in paragraph (a) of section §63.11646 . The results of each of the tests must be less than 10 pounds of mercury per million***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 179 of 206 tons of ore. The testing must be performed according to the procedures in §63.11646(a)(1) through (4) to determine mercury emissions in pounds per hour. (ii) Divide the mercury emission rate in pounds per hour by the ore throughput rate during the test expressed in millions of tons per hour to determine the emissions in pounds per million tons of ore. (b) For facilities with roasters and a calomel

- based mercury control system that choose to monitor for mercury emissions using the procedures in paragr aph (a)( 1 ) of this section or that qualify for and choose to follow the requirements in paragraph (a)( 5 ) of this section , you must establish operating parameter limit s for scrubber liquor flow (or line pressure) and scrubber inlet gas temperature and monit or these parameters. You may establish your operating parameter limit s from the initial compliance test, according to the manufacturer’s specifications, or based on limits established by the permitting authority. If you choose to establish your operating parameter limit s from the initial compliance test, m onitor the scrubber liquor flow (or line pressure) and scrubber inlet gas temperature during each run of your initial compliance test. The minimum operating limit for scrubber liquor flow rate (or line pressure) is the lowest value***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 180 of 206 during any run of the initial compliance test, and your maximum scrubber inlet temperature limit is the highest measured during any run of the initial compliance test. Y ou must monitor the scrubber liquor flow rate (or line p ressure) and scrubber inlet gas temperature hourly and maintain the scrubber liquor flow (or line pressure) at or above the established operating parameter and maintain the inlet gas temperature below the established operating parameter limit
. ( c ) For fa cilities with roasters and a calomel

- based mercury control system that choose to monitor for mercury emissions using the procedures in paragraph (a)(1) of this section or that qualify for and follow the requirements in paragraph (a)( 5 ) of this section , you must establish operating parameter range s for mercuric ion and chloride ion concentrations or for oxidation reduction potential and pH using the procedures in paragraph (c)(1) or (2) of this section respectively
. (1) Establish the mercuric ion concentra tion and chloride ion concentration range s for each calomel

- based mercury control system. The mercuric ion concentration and chloride ion concentration ranges for each calomel

- based mercury control system must be based on the manufacturer’s specifications
. Alternatively, the mercuric ion concentration and chloride ion***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 181 of 206 concentration range s for each calomel

- based mercury control system may be based on approv al by your permitting authority. Measure the mercuric ion concentration and chloride ion concentrati ons at least once during each run of your initial compliance test. The measurements must be within the established concentration range for mercuric ion concentration and chloride ion concentration. Subsequently, you must sample at least once daily and ma intain the mercuric ion concentration and chloride ion concentrations within their established range. (2) Establish the oxidation reduction potential and pH range for each calomel

- based mercury control system. The oxidation reduction potential and pH ran ge for each calomel

based mercury control system must be based on the manufacturer’s specifications. Alternatively, the oxidation reduction potential and pH range for each calomel

- based mercury control system may be based on approv al by your permitting au thority. Install monitoring equipment to continuously monitor the oxidation reduction potential and pH of the calomel

- based mercury control system scrubber liquor. Measure the oxidation reduction potential and pH of the scrubber liquor during each run of your initial compliance test. The measurements must be within the established range for oxidation reduction potential and pH. Subsequently, you must monitor the oxidation reduction***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 182 of 206 potential and pH of the scrubber liquor continuously and maintain it wit hin the established operating range. (d) If you have an exceedance of a control device operating parameter range provided in paragraphs (b) or (c) of this section, you must take corrective action and bring the parameters back into the established parametr ic range s . I f the corrective actions taken following an exceedance do not result in the operating parameter value being returned within the established range within 48 hours, a mercury concentration
measurement (with method 12B or 30B) must be made to det ermine if the operating limit for mercury concentration is being exceeded. The measurement must be performed and the mercury concentration determined within 48 hours (after the initial 48 hours , or a total of 96 hours from the time the parameter range

was exceeded ). If the measured mercury concentration meets the operating limit for mercury concentration established under
§ 63.11647(a)(4) , the corrective actions are deemed successful , and the owner or operator can request the permit authority to establish a new limit or range for the parameter . If the measured mercury concentration exceeds the operating limit for mercury concentration after these 96 hours , the exceedance must be reported as a deviation within 24 hours to the permitting authority . The owne r or operator must conduct a compliance test***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 183 of 206 pursuant to §63.1164 6 ( a ) within 40 days to determine if the roaster operations are in compliance with the MACT emission standard
. If the source is determined to be in compliance with the MACT emission standard, the compliance test may also be used to establish a new operating limit for mercury concentration ( see paragraph ( e) of this section )
. ( e ) You may submit a request to your permitting authority for approval to change the operating limit s established und er paragraph (a)( 4 ) of this section for the monitoring required in paragraph (a)(1) , (2) , or (3) of this section. In the request, you must demonstrate that the proposed change to the operating limit detects changes in levels of mercury emission control. A n approved change to the operating limit under this paragraph only applies until a new operating limit is established during the next annual compliance test. ( f ) You must monitor each process unit at each new and existing affected source that uses a carbo n adsorber to control mercury emissions using the procedures in paragraphs ( f )(1) or (2) of this section. A carbon adsorber may include a fixed carbon bed, carbon filter packs or modules, carbon columns, and other variations. (1) Continuously sample and a nalyze the exhaust stream from the carbon adsorber for mercury using Method 30B (40 CFR***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 184 of 206 part 60, appendix A

- 8) for a duration of at least the minimum sampling time specified in Method 30B and up to one week that includes the period of the annual performanc e test. (i) Establish an upper operating limit for the process as determined using the mercury concentration measurements from the sorbent trap as calculated from Equation (3) of this section.
OLC = C trap * (EL/CT) (Eq 3) where
OLC = mercury concent ration operating limit for the carbon adsorber control device on the process as measured using the sorbent trap, (micrograms per cubic meter); C trap = average mercury concentration measured using the sorbent trap during the week that includes the performan ce test, (micrograms per cubic meter); EL = emission standard for the affected sources (lb/ton of concentrate); CT = compliance test results for the affected sources (lb/ton of concentrate).
(ii) Sample and analyze the exhaust stream from the carbon ads orber for mercury at least monthly using Method 30B (40 CFR part 60, appendix A

- 8). When the mercury concentration reaches
75 percent of the operating limit, begin weekly sampling and analysis. When the mercury concentration reaches 9 0 percent of the ope rating limit, replace the carbon in the carbon adsorber within 30 days. If mercury concentration exceeds the operating limit, change the carbon in the carbon adsorber within 30 days and report the deviation to your permitting authority.***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 185 of 206 (2) Conduct an in itial sampling of the carbon in the carbon bed for mercury 90 days after the replacement of the carbon. A representative sample must be collected from the inlet of the bed and the exit of the bed and analyzed using EPA Method 7471A (incorporated by refere nce - see §63.14). The depth to which the sampler is inserted must be recorded. The design capacity is established by c alculat ing the average carbon loading from the inlet and outlet measurements. Sampling and analysis of the carbon bed for mercury must be performed quarterly thereafter. When the carbon loading reaches 50 percent of the design capacity of the carbon, monthly sampling must be performed until 90 percent of the carbon loading capacity is reached. The carbon must be removed and replaced wi th fresh carbon no later than 30 days after reaching 90 percent of capacity. For carbon designs where there may be multiple carbon columns or beds, a representative sample may be collected from the first and last column or bed instead of the inlet or outl et. If the carbon loading exceeds the design capacity of the carbon, change the carbon within 30 days and report the deviation to your permitting authority. ( g ) You must monitor gas stream temperature at the inlet to the carbon adsorber for each autocl ave, carbon kiln, melt furnace, and mercury retort equipped with a carbon adsorber
.***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 186 of 206 E stablish a maximum value for the inlet temperature either during the annual performance test as required in §63.11646(a), according to the manufacturer’s specifications, or as approved by your permitting authority
. If you choose to establish the temperature operating limit during the performance test,

e stablish the temperature operating limit based on either the highest reading during the test or a t 10°F higher than the average temperature measured during the performance test
. M onitor the inlet temperature once per shift . If a n inlet temperature exceeds the temperature operating limit, you must follow the requirements for outlet concentration measurement in paragraph ( f )(1) of this section. If the concentration is below 90 percent of the operating limit, you may set a new temperature operating limit 10°F above the previous operating limit. If the concentration is above 90 percent of the operating limit, you
must take c orrective action to reduce the temperature back below the temperature operating limit and again measure the outlet concentration according to paragraph ( f )(1) of this section. If the concentration is still above 90 percent of the operating limit , then you must change the carbon in the bed within 30 days and report the deviation to your permitting authority
. ( h ) For each wet scrubber at each new and existing affected source not followed by a mercury control system , you***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 187 of 206 must monitor the water flow rate (o r line pressure) and pressure drop
. E stablish a minimum value as the operating limit either during the performance test required in §63.11646(a), according to the manufacturer’s specifications, or as approved by your permitting authority. If you choose t o establish the operating limit based on the results of the performance test, the new operating limit must be establish ed based on either the lowest average value during any test run or no lower than 10 percent of the average value measured during the test
. For wet scrubbers on an autoclave , establish the range according to manufacturer’s specifications. You must monitor the water flow rate and pressure drop once per shift and take corrective action within 24 hours if any daily average is less than the op erating limit. If the parameters are not in range within 72 hours, the owner or operator must report the deviation to the permitting authority and perform a compliance test within 4 0 days to determine if the source is in compliance with the MACT limit
. ( i ) You may conduct additional compliance tests according to the procedures in § 63.11646 and re

- establish the operating limits required in paragraphs (a) through (c) and ( f ) through ( h ) of this section at any time. You must submit a request to your permit ting authority for approval to re

- establish the operating limits. In the request, you must demonstrate that the***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 188 of 206 proposed change to the operating limit detects changes in levels of mercury emission control. An approved change to the operating limit under this paragraph only applies until a new operating limit is established during the next annual compliance
test.

§ 63.11648

I n response to an action to enforce the standards set for th in paragraph § 63. 11645 you may assert an affirmative defense to a claim for civil penalties for exceedances of such standards that are caused by malfunction, as defined at 40 CFR 63.2. Appropriate penalties may be assessed, however, if you fail to
meet your burden of proving all of the requirements in the affirmative defense. The affirmative defense shall not be available for claims for injunctive relief. Affirmative Defense for Exceedance of Emission Limit During Malfunction.

(a) To establish the affirmative defense in any action to enforce such a limit, you must timely me et the notification requirements in paragraph (b) of this section, and must prove by a preponderance of evidence that: (1) The excess emissions: (i) Were caused by a sudden, short, infrequent, and unavoidable failure of air pollution control and moni toring***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 189 of 206 equipment, process equipment, or a process to operate in a normal or usual manner, and (ii) Could not have been prevented through careful planning, proper design or better operation and maintenance practices; and (iii) Did not stem from any act ivity or event that could have been foreseen and avoided, or planned for; and (iv) Were not part of a recurring pattern indicative of inadequate design, operation, or maintenance; and (2) Repairs were made as expeditiously as possible when the applica ble emission limitations were being exceeded. Off

- shift and overtime labor were used, to the extent practicable to make these repairs; and (3) The frequency, amount and duration of the excess emissions (including any bypass) were minimized to the maxi mum extent practicable during periods of such emissions; and (4) If the excess emissions resulted from a bypass of control equipment or a process, then the bypass was unavoidable to prevent loss of life, severe personal injury, or severe property damag e; and (5) All possible steps were taken to minimize the impact of the excess emissions on ambient air quality, the environment and human health; and***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 190 of 206 (6) All emissions monitoring and control systems were kept in operation if at all possible; and (7) All of the actions in response to the excess emissions were documented by properly signed, contemporaneous operating logs; and (8) At all times, the facility was operated in a manner consistent with good practices for minimizing emissions; and ( 9) A written root cause analysis has been prepared to determine, correct, and eliminate the primary causes of the malfunction and the excess emissions resulting from the malfunction event at issue. The analysis shall also specify, using best monitoring me thods and engineering judgment, the amount of excess emissions that were the result of the malfunction. (b) Notification. The owner or operator of the facility experiencing an exceedance of its emission limit(s) during a malfunction shall notify the Ad ministrator by telephone or facsimile (FAX) transmission as soon as possible, but no later than two business days after the initial occurrence of the malfunction, if it wishes to avail itself of an affirmative defense to civil penalties for that malfunctio n. The owner or operator seeking to assert an affirmative defense shall also submit a written report to the Administrator within 30 days of***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 191 of 206 the initial occurrence of the exceedance of the standard in
§ 63. 11645 to demonstrate, with all necessary supporting documentation, that it has met the requirements set forth in paragraph (a) of this section.
§ 63.1164 9 What are my notification, reporting, and recordkeeping requirements (a) You must submit the Initial Notification required by §63.9(b)(2) no later tha n 120 calendar days after the date of publication of the final rule in the ?

Federal Register

(b) You must submit an initial Notification of Compliance Status as required by §63.9(h). or within 120 days after the source becomes subject to the standard. The Initial Notification must include the information specified in §63.9(b)(2)(i) through (b)( 2)(iv).

(c) If a deviation occurs during a semiannual reporting period, you must submit a deviation report to your permitting authority according to the requireme nts in paragraphs (c)(1) and (2) of this section. (1) The first reporting period covers the period beginning on the compliance date specified in §63.11641 and ending on June 30 or December 31, whichever date comes first after your compliance date. Each subsequent reporting period covers the semiannual period from January 1 through June 30 or from July 1***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 192 of 206 through December 31. Your deviation report must be postmarked or delivered no later than July 31 or January 31, whichever date comes first after the end of the semiannual reporting period. (2) A deviation report must include the information in paragraphs (c)(2)(i) through (iv) of this section. (i) Company name and address. (ii) Statement by a responsible official, with the official’s name, title, and signature, certifying the truth, accuracy and completeness of the content of the report. (iii) Date of the report and beginning and ending dates of the reporting period. (iv) Identification of the affected source, the pollutant being monitored, applicabl e requirement, description of deviation, and corrective action taken. (d) If you had a malfunction during the reporting period, the compliance report must include the number, duration, and a brief description for each type of malfunction which occurred dur ing the reporting period and which caused or may have caused any applicable emission limitation to be exceeded. The report must include r ecords of the occurrence and duration of each malfunction of operation (i.e., process equipment) or the air pollution control and monitoring equipment. The report must also include a description of actions taken by***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 193 of 206 an owner or operator during a periods of malfunction of an affected source to minimize emissions in accordance with §63.11646(c), including corrective actions t aken to correct a malfunction. restore malfunctioning process and air pollution control and monitoring equipment to its normal or usual manner of operation. ( e ) You must keep the records specified in paragraphs ( e )(1) through (3) of this section. Th e form and maintenance of records must be consistent with the requirements in section 63.10(b)(1) of the General Provisions. (1) As required in §63.10(b)(2)(xiv), you must keep a copy of each notification that you submitted to comply with this subpart an d all documentation supporting any Initial Notification, Notification of Compliance Status, and semiannual compliance certifications that you submitted. (2) You must keep the records of all performance tests, measurements, monitoring data, and corrective actions required by §§63.11646 and 63.11647, and the information identified in paragraphs (c)(2)(i) through (vi) of this section for each corrective action required by §63.11647. (i) The date, place, and time of the monitoring event requiring corrective action;***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 194 of 206 (ii) Technique or method used for monitoring; (iv) Operating conditions during the activity; (v) Results, including the date, time, and duration of the period from the time the monitoring indicated a problem to the time that monitoring indic ated proper operation; and (vi) Maintenance or corrective action taken (if applicable). (3) You must keep records of operating hours for each process as required by §63.11646(a)( 5 ) and records of the monthly quantity of ore and concentrate processed as required by §63.11646(a)( 10 ). ( f ) Your records must be in a form suitable and readily available for expeditious review, according to §63.10(b)(1). As specified in §63.10(b)(1), you must keep each record for 5 years following the date of each recorded ac tion. You must keep each record onsite for at least 2 years after the date of each recorded action according to §63.10(b)(1). You may keep the records offsite for the remaining 3 years. ( g ) After December 31, 2011, within 60 days after the date of compl eting each performance evaluation conducted to demonstrate compliance with this subpart, the owner or operator of the affected facility must submit the test data to EPA by entering the data electronically into EPA’s WebFIRE data base***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 195 of 206 through EPA’s Central Data Exchange. The owner or operator of an affected facility shall enter the test data into EPA’s data base using the Electronic Reporting Tool or other compatible electronic spreadsheet. Only performance evaluation data collected using methods compatibl e with ERT are subject to this requirement to be submitted electronically into EPA’s WebFIRE database. **Other Requirements and Information** §63.11650 What General Provisions apply to this subpart Table 1 to this subpart shows which parts of the General
P rovisions in §§63.1 through 63.16 apply to you. ?

§63.11651 What definitions apply to this subpart Terms used in this subpart are defined in the Clean Air Act, in §63.2, and in this section as follows: ?

Affirmative defense means, in the context of an enfor cement proceeding, a response or defense put forward by a defendant, regarding which the defendant has the burden of proof, and the merits of which are independently and objectively evaluated in a judicial or administrative proceeding.
A utoclave means a pr essure oxidation vessel that is used to treat gold ores (primarily sulfide refractory ore) and involves pumping a slurry of milled ore into the vessel which is highly pressurized with oxygen and heated to temperatures of***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 196 of 206 approximately 350 ° to 430°F. Calome l

- based mercury control system means a mercury emissions control system that uses scrubbers to remove mercury from the gas stream of a roaster or combination of roasters by complexing the mercury from the gas stream with mercuric chloride to form mercurous chloride (calomel). T hese scrubbers are also referred to as “mercury scrubbers.” Carbon adso r ber means a control device consisting of a single fixed carbon bed, multiple carbon beds or columns, carbon filter packs or modules, and other variations that us es activated carbon to remove pollutants from a gas stream
. Carbon kiln means a kiln or furnace where carbon is regenerated by heating, usually in the presence of steam, after the gold has been stripped from the carbon. Carbon processes with mercury retort s means the affected source that includes carbon kilns, preg tanks, electrowinning cells , mercury retorts, and melt furnaces at gold mine ore processing and production facilities that use activated carbon , or resins that can used as a subsititute for activ ated carbon, to recover (adsorb) gold from the pregnant cyanide solution. Carbon processes without mercury retorts means the affected source that includes carbon kilns, preg tanks, electrowinning cells, and melt furnaces, but has no retorts, at gold mine o re***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 19 7 of 206 processing and production facilities that use activated carbon , or resins that can used as a subsititute for activated carbon, to recover (adsorb) gold from the pregnant cyanide solution.
Concentrate means the sludge

- like material that is loaded with go ld along with various other metals (such as silver, copper, and mercury) and various other substances , that is produced by electrowinning, the Merrill

- Crowe process, flotation and gravity separation processes. Concentrate is measured as the input to mercu ry retorts, or for facilities without mercury retorts, as the input to melt furnaces before any drying takes place. For facilities without mercury retorts or melt furnaces,
concentrate is measured as the quantity shipped. Deviation

(1) Fails to meet any requirement or obligation established by this subpart, including but not limited to any emissions limitation or work practice standard; means any instance wh ere an affected source subject to this subpart, or an owner or operator of such a

source:

(2) Fails to meet any term or condition that is adopted to implement an applicable requirement in this subpart and that is included in the operating permit for any affected source required to obtain such a permit ; or (3) Exceeds any operating limit establish ed under this***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 198 of 206 subpart. Electrowinning means a process that uses induced voltage on anode and cathode plates to remove metals from the continuous flow of solution, where the gold in solution is plated onto the cathode. Steel wool is typically used as the plating surface. Electrowinning Cells means a tank in which the electrowinning takes place. Gold mine ore processing and production facility means any industrial facility engaged in the processing of gold mine ore that uses any of the following processe s: roasting operations, autoclaves, carbon kilns, preg tanks, electrowinning, mercury retorts, or melt furnaces. An operation that processes or produces less than 50 pounds of concentrate per year is not a gold mine ore processing and production facility
. A facility that produces primarily metals other than gold, such as copper , lead, zinc, or nickel (where these metals other than gold comprise 95 percent or more of the total metal production) that may also recover some gold as a byproduct is not a gold mine ore processing and production facility. Those facilities whereby 95 percent or more of total mass of metals produced are metals other than gold, whether final metal production is onsite or offsite , are not part of the gold mine or processing and prod uction source category
.***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 199 of 206 Melt furnace means a furnace (typically a crucible furnace) that is used for smelting the gold

- bearing material recovered from mercury retorting , or the gold

- bearing material from electrowinning , the Merrill

- Crowe process , or othe r processes for facilities without mercury retorts. Mercury r etort means a vessel that is operated under a partial vacuum at approximately 1100 ° to 1300oF to remove mercury and moisture from the gold bearing sludge material that is recovered from electro winning, the Merrill

- Crowe process , or other processes. Mercury retorts are usually equipped with condensers that recover liquid mercury during the processing. Merrill

- Crowe process means a precipitation technique using zinc oxide for removing gold from a cyanide solution . Z inc dust is added to the solution , and gold is precipitated to produce a
concentrate.
Non

- carbon concentrate processes means the affected source that includes mercury retorts and melt furnaces at gold mine ore processing and production facilities that use the Merrill

- Crowe
process or other processes and do not use carbon to recover (adsorb) gold from the pregnant cyanide solution. Ore dry grinding means a process in which the gold ore is ground and heated (dried) prior to additional pre heating or prior to entering the roaster.***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 200 of 206 Ore preheating means a process in which ground gold ore is preheated prior to entering the roaster. Ore pretreatment processes means the affected source that includes roasting operations and autoclaves that are use d to
pre - treat gold mine ore at gold mine ore processing and production facilities prior to the cyanide leaching process. Preg nant solution tank (or preg tank) means a storage tank for pregnant solution, which is the cyanide solution that contains gold

- cya nide complexes that is generated from leaching gold ore with cyanide solution. Pregnant cyanide solution means the cyanide solution that contains gold

- cyanide complexes that are generated from leaching gold ore with a dilute cyanide solution. Quenching mea ns a process in which the hot calcined ore is cooled and quenched with water after it leaves the roaster. Roasting operation

§ means a process that uses an industrial furnace in which milled ore is combusted across a fluidized bed to oxidize and remove orga nic carbon and sulfide mineral grains in refractory gold ore. The emissions points of the roasting operation subject to this subpart include ore dry grinding, ore preheating, the roaster stack, and quenching.

63.11652 Who implements and enforces this s ubpart (a) This subpart can be implemented and enforced by the ?***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 201 of 206 U.S. EPA or a delegated authority, such as your state, local, or tribal agency. If the U.S. EPA Administrator has delegated authority to your state, local, or tribal agency, then that
agenc y has the authority to implement and enforce this subpart. You should contact your U.S. EPA Regional Office to find out if this subpart is delegated to your state, local, or tribal
agency. (b) In delegating implementation and enforcement authority of th is subpart to a state, local, or tribal agency under 40 CFR part 63, subpart E, the authorities contained in paragraph (c) of this section are retained by the Administrator of the U.S. EPA and are not transferred to the state, local, or tribal
agency. (c) The authorities that will not be delegated to state, local, or tribal agencies are listed in paragraphs (c)(1) through (4) of this section. (1) Approval of alternatives to the applicability requirements in §63.11640, the compliance date requirements in §63.11641, and the applicable standards in §63.11645. (2) Approval of an alternative nonopacity emissions standard under §63.6(g). (3) Approval of a major change to a test method under §63.7(e)(2)(ii) and (f). A “major change to test method” is***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 202 of 206 defi ned in §63.90(a). (4) Approval of a major change to monitoring under §63.8(f). A “major change to monitoring” is defined in §63.90(a). (5) Approval of a waiver of recordkeeping or reporting requirements under §63.10(f), or another major change to

recor dkeeping/reporting. A “major change to recordkeeping/reporting” is defined in §63.90(a). §63.11653 **[Reserved] Tables to Subpart EEEEEEE of Part 63**  Table 1 to Subpart EEEEEEE of Part 63

— Applicability of General Provisions to S ubpart EEEEEE As stated in §63.11650, you must comply with the applicable General Provisions requirements according to the following table:

**Citation Subject**  **Applies to subpart**  **EEEEEEE Explanation**  §63.1(a)(1), (a)(2), (a)(3), (a)(4), (a)(6), (a)(10)

– (a)(12), (b)(1), (b)(3), (c)(1), (c)(2), (c)(5), (e) Applicability Yes

§63.1(a)(5), (a)(7)

– (a)(9), (b)(2), (c)(3), (c)(4), (d) Reserved No

§63.2 Definitions Yes §63.3 Units and Yes***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 203 of 206

Formatted: Portuguese (Brazil) Formatted: HTML Preformatted Abbreviations §63.4 Prohibited Activities and Circumvention Yes

§63.5 Preconstruction Review and Notification Requirements Yes

§63.6(a), (b)(1)

– (b)(5), (b)(7), (c)(1), (c)(2), (c)(5), (e)(1)(iii),(f)(2 ), (f)(3), (g), (i), (j) Compliance with Standards and Maintenance Requirements Yes

§ 63.6(e)(1)(i) and (ii), (e)(3), and (f)(1) Startup, Shutdown and Malfunction Requirements (SSM) General Duty to minimize emissions No
. See 63. 11646(b) for general duty requirement Subpart EEEEEEE standards apply at all times
. See 63.11646(b) 63.6(e)(1)(ii) Requirement to correct malfunctions as soon as possible. No

6 3.6(e)(3) SSM Plan requirements No
63.6(f)(1) SSM exemption No Malfunctions are no longer exempt. All excursions are violations and there is no need to specify corrections. §63.6(h)(1), (h)(2), (h)(4),(h)(5)(i), (ii), (iii) and (v), (h)(6)

– Compl iance with Opacity and Visible Emission Limits No Subpart EEEEEEE does not contain opacity or visible***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 204 of 206

Formatted: Spanish (Spain-Traditional Sort) (h)(9) emission limits. §63.6(b)(6), (c)(3), (c)(4), (d), (e)(2), (e)(3)(ii), (h)(3), (h)(5)(iv) Reserved No

§63.7, except (e)(1) Applicability and Performan ce Test Dates Yes

§ 63.7(e)(1) Performance Testing Requirements Related to SSM No See 63.11646 See 63.11646(a)(3)

§63.8(a)(1), (b)(1), (f)(1)

- (5), (g) Monitoring Requirements Yes

§63.8(a)(2), (a)(4), (b)(2)

- (3), (c )(ii ), (d )(i ), (e), (f)(6), (g) Cont inuous Monitoring Systems (CMS) Yes Except cross references to SSM requirements in §63.6(e)(1) and (3) do not apply 63.8(c)(1)(i) General duty to minimize emissions and CMS operation No See 63.11646(b)
63.8(c)(1)(iii) Requirement to develop SSM Plan for CMS No

63.8(d)(3) Written procedures for CMS Yes, except for last sentence
. Last sentence refers to an SSM Plan which is no longer required. §63.8(a)(3) [Reserved] No §63.9(a), (b)(1), (b)(2)(i)

- (v), (b)(4), (b)(5), Notification Requirements Yes***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 205 of 206 (c), (d )(1), (d)(2 ), (e), (g), (h) (1)

– (h)(3), (h)(5), (h)(6), (i), (j) §63.9(f) No §63.9(b)(3), (h)(4) Reserved No
§63.10(a), (b)(1), (b)(2)(vi)

– (xiv), (b)(3), (c )(1)

- (14 ), (d)(1)

- (4), (e), (f) Recordkeeping and Reporting Requirements Yes

63.10(b)(2) (i) Recordkeeping of occurrence and duration of startups and shutdowns No

63.10(b)(2)(ii) Recordkeeping of malfunctions No. See 63. 1164 9 for recordkeeping of (1) occurrence and duration and (2) actions taken during malfunction See 63.11648

63.10(b)(2) (iii) Maintenance records Yes. 63.10(b)(2)(iv) Actions taken to minimize emissions during SSM No.

63.10(b)(2)(v) Actions taken to minimize emissions during SSM No.

63.10(b)(2)(vi) Recordkeeping for CMS malfunctions Yes.***E.O. 12866 Review

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– Do Not Cite, Quote, or Release During Review*** Page 206 of 206 63.10(b)(2)(vii)

- (ix) Other CMS requirements Yes. § 63.10(b)(2)(i)

- (v), (d)(5) Recordkeeping/Repo rting Associated with SSM No

§63.10(c)(2)

– (c)(4), (c)(9) Reserved No
63.10(c)(7) Additional recordkeeping requirements for CMS

– identifying exceedances and excess emissions Yes

6 3.10(c)(8) Additional recordkeeping requirements for CMS

– identifying exceedances and excess emissions Yes

63.10(c)(10) Recording nature and cause of malfunctions No. See 63. 11649 for malfunctions recordkeeping requirements. 63.10(d)(5) SSM report s No. See 63. 11649 for malfunction reporting requirements. See 63.11649

§63.11 Control Device Requirements No
§63.12 State Authority and Delegations Yes
§§63.13

– 63.16 Addresses, Incorporations by Reference, Availability of Information, Performance Track Provisions Yes