From: Chuck French/RTP/USEPA/US 

 

To: "King, Heidi R." <Heidi_R._King@omb.eop.gov> 

 

Cc: Branning.Amy@epamail.epa.gov; "Raymond, Gabrielle" 

<graymond@rti.org>; VanLare.Paula@epamail.epa.gov; "Marinshaw, Richard" 

<rjmarinshaw@rti.org>; Fruh.Steve@epamail.epa.gov; Blake.Wendy@epamail.epa.gov

 

 

Date: 12/15/2010 10:53 AM 

 

Subject: RE: EO 12866 Interagency Review comments on Gold Mine Draft Final

Hi Heidi,

 Attached are the revised Impacts and MACT Documents. One

clean version, and one with track changes for each. Let me know if

you have questions.

Thanks.

Chuck

(See attached file: Estimate of Impacts-Final-OMB_review_changes_12-15-2010_clean.doc)

(See attached file: Estimate of Impacts-Final-OMB_review_changes_12-15-2010.doc)

(See attached file: Gold Mine MACT Floor Document-Final-OMB_review_changes_12-15-10_clean.doc)

(See attached file: Gold Mine MACT Floor Document-Final-OMB_review_changes_12-15-10.doc)
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. Environmental Protection Agency

Research Triangle Park, NC

December 15, 2010
2

Estimates of Impacts for the Final Mercury Emission Standards for Gold Mine Ore 

Processing and Production

1.0 Cost Estimates

This section provides a summary of the estimated 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 process 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. Estimated Cost of Mercury Emission Controls for MACT Floor

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)

Goldstrike Elko, NV 107 658,512 135,968 198,131 1,854

Denton-Rawhide Fallon, NV 27 135,100 103,900 116,653 4,250

Florida Canyon Pershing Co., NV 87 367,868 165,382 200,109 2,305

Gold Quarry Carlin, NV 126 199,400 44,222 63,045 502

Jerritt Canyon Elko, NV 165 450,882 122,737 165,300 1,001

Lone Tree Valmy, NV 181 453,500 157,858 200,669 1,110

Midas Midas, NV 14 430,000 150,421 191,013 13,707

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 includes all of the gold mine ore processing 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

Facility Name Facility Location 

Number of stacksa Higher estimates of MRR costs Lower estimates of MRR costs

Roaster Other

Not in 

NVb

Monitoring 

capital

Method 29 

testing

Monitoring 

O&M

Monitoring 

total annual

Monitoring 

capital

Method 29 

testing

Monitoring 

O&M

Monitoring 

total annual

Goldstrike Elko, NV 2 15

 

120,000 

 

- 

 

182,061 

 

199,149 

 

200,668 

 

- 

 

78,619 

 

107,194 

Coeur Rochester Lovelock, NV 3

 

40,000 

 

- 

 

31,794 

 

37,490 

 

- 

 

- 

 

11,299 

 

11,299 

Cortez

Crescent Valley, 

NV 6

 

40,000 

 

- 

 

62,565 

 

68,261 

 

- 

 

- 

 

21,576 

 

21,576 

Cripple Creek Victor, CO 3 3

 

40,000 

 

28,260 

 

31,794 

 

65,750 

 

- 

 

28,260 

 

11,299 

 

39,559 

Denton-Rawhide Fallon, NV 4

 

40,000 

 

- 

 

42,051 

 

47,747 

 

- 

 

- 

 

14,725 

 

14,725 

Echo Bay/Kettle River Republic, WA 3 3

 

40,000 

 

28,260 

 

31,794 

 

65,750 

 

- 

 

28,260 

 

11,299 

 

39,559 

Florida Canyon

Pershing County, 

NV 7

 

40,000 

 

- 

 

72,822 

 

78,518 

 

- 

 

- 

 

25,001 

 

25,001 

Fort Knox Fairbanks, AK 2 2

 

40,000 

 

18,840 

 

21,537 

 

46,073 

 

- 

 

18,840 

 

7,873 

 

26,713 

Gold Quarry Carlin, NV 1 10

 

80,000 

 

- 

 

117,184 

 

128,576 

 

100,334 

 

- 

 

48,385 

 

62,672 

Golden Sunlight Whitehall, MT 3 3

 

40,000 

 

28,260 

 

31,794 

 

65,750 

 

- 

 

28,260 

 

11,299 

 

39,559 

Greens Creek Mine Greens Creek , AK 1 1

 

40,000 

 

9,420 

 

11,279 

 

26,395 

 

- 

 

9,420 

 

4,448 

 

13,868 

Bald Mountain Elko, NV 5

 

40,000 

 

- 

 

52,308 

 

58,004 

 

- 

 

- 

 

18,150 

 

18,150 

Jerritt Canyon Elko, NV 2 3

 

120,000 

 

- 

 

58,976 

 

76,064 

 

200,668 

 

- 

 

37,512 

 

66,087 

Lone Tree Valmy, NV 5

 

40,000 

 

- 

 

52,308 

 

58,004 

 

- 

 

- 

 

18,150 

 

18,150 

Marigold Valmy, NV 4

 

40,000 

 

- 

 

42,051 

 

47,747 

 

- 

 

- 

 

14,725 

 

14,725 

Midas Midas, NV 3

 

40,000 

 

- 

 

31,794 

 

37,490 

 

- 

 

- 

 

11,299 

 

11,299 

Ruby Hill Eureka, NV 4

 

40,000 

 

- 

 

42,051 

 

47,747 

 

- 

 

- 

 

14,725 

 

14,725 

Round Mountain

Round Mountain, 

NV 4

 

40,000 

 

- 

 

42,051 

 

47,747 

 

- 

 

- 

 

14,725 

 

14,725 

Twin Creeks Golconda, NV 13

 

40,000 

 

- 

 

134,365 

 

140,061 

 

- 

 

- 

 

45,555 

 

45,555 

Western Mesquite Brawley, CA 3 3

 

40,000 

 

28,260 

 

31,794 

 

65,750 

 

- 

 

28,260 

 

11,299 

 

39,559 

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 required in Nevada).
4

1.1 Cost of Mercury Emission Controls

The primary basis for the cost 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 

additional 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 those types of controls on other process units. Most 

of the facilities provided estimates of capital costs for the proposed emission control systems. 

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 

based 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 sitespecific 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 carbon 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 annualized 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 Copies 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

Facility Unit Control

a

Mercury 

reduction 

(lb/yr)

Flow 

(cfm)

b

Total 

capital costc

Annual 

O&M

coste

Total 

annualized 

cost

Cost 

effectiveness 

($/lb)

Denton Rawhide Melt furnace CA 27.4 6,500 135,1008 103,9008 116,653 4,250

Florida Canyon Carbon kilns CA 80.9 1,000 183,9347 82,6917 100,054 1,237

Florida Canyon

Electrowinning, preg 

tanks, melt furnace CA 5.9 1,000 183,9342 82,6917 100,054 16,962

Gold Quarry AARL carbon kiln CA 108.7 900 99,7006 22,111 31,523 290

Gold Quarry Zadra carbon kiln CA 16.9 900 99,7006 22,111 31,523 1,864

Goldstrike Carbon kilns WC, CA 106.9 4,406 658,512d 135,968 198,131 1,854

Jerritt Canyon Melt furnace CA 131.3 1,622 141,933d 31,966 45,365 346

Jerritt Canyon Carbon kiln & retort CA 33.9 5,930 308,949d 90,771 119,935 3,536

Lone Tree Electrowinning CA 24.3 10,000 423,0009 146,326 186,257 7,662

Lone Tree Preg tanks CA 156.4 125 30,50010 11,532 14,411 92

Twin Creeks Juniper preg tanks CA 94.5 3,085 209,0004 51,936 71,666 758

Twin Creeks Electrowinning CA 52.4 7,311 434,0005 109,621 150,591 2,871

Twin Creeks Melt furnace new CA 16.4 3,000 60,77614 50,776 56,513 3,455

Twin Creeks Melt furnace old CA 42.5 3,000 60,77614 50,776 56,513 1,329

Midas Furnace CA 13.9 10,300 430,00015 150,421 191,013 13,707

Twin Creeks Autoclave WC, CA 430.6 11,300 29,300,00019 2,150,000 4,904,200 11,390

Subtotal Carbon Group with Hg retorts (No. 1 through 

No. 14) 899 3,029,813 993,176 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 * (cfm/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

The final rule includes three monitoring options for roasters: a mercury continuous 

emission monitoring system (CEMS), continuous sorbent 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 the 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, moisture conditioner,

metering console, and data logger. The paired traps cost $150 each with an analysis cost of 

$200 each. The estimated labor to install 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 process units other than roasters, the common mercury control device is a carbon 

adsorber. The final rule provides options for sampling carbon adsorbers: monthly sorbent trap 

sampling (except going to weekly when the adsorber reaches 75 percent of the operating 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 similar 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 stack that is sampled. The carbon bed sampling is much 

less expensive 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 per 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 stacks).
7

Table 5. Estimate of Reporting and Recordkeeping Costs

General Description 

Mean 

Hourly 

Ratea

Rate with 

overheadb hr/plant $/plant hr/stack $/stack

Environmental Engineer $35.24 $56.38 16 $902 4 $226

Managementc $57.27 $91.63 0.8 $73 0.20 $18

Office/Admin. Supportd $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 Statistics, May 2009, 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 rule also requires 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 Description 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 cost functions described in this section and the number of roaster stacks,

number of other (non-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

The affected sources with carbon processes with mercury retorts use 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 that 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 so 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. For 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 concentrations 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 first 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 pretreatment processes have installed, or would need to install

mercury scrubbers on their roasters and venturi scrubbers and/ maybe carbon adsorbers on 

their autoclaves, to achieve the MACT floor for ore pretreatment processes. To achieve 

further reduction in mercury, one beyond-the-floor 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 capacity of the carbon adsorber. 

The Twin Creeks facility will not be able to meet the final MACT standard without adding 

controls, thus the costs to add controls to the Twin Creek’s autoclaves has been included in 

the total cost of controls for facilities to meet the MACT standard (see Table 3). The 

estimated capital cost for the additional controls for the autoclaves at Twin Creeks would be 

$29.3 million, with a total annualized cost of $4.9 million/yr. Based on an estimated control 

efficiency of 70 percent, mercury emissions would be reduced by 431 lbs/yr, resulting in an 

estimated cost effectiveness of $11,390/lb. The Goldstrike facility can already meet the 

MACT standard so the costs to add controls to their autoclaves are considered beyond-thefloor. 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. Based on an estimated control 

efficiency of 70 percent, mercury emissions would be reduced 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, mercury emissions would be reduced by 118 lbs/yr, resulting in an estimated cost 

effectiveness of $13,784/lb. 

We also evaluated a beyond-the-floor option for the new source standard. The best 

performing similar source for the ore pretreatment affected source is the Goldstrike facility. We 

identified as a beyond-the-floor option the installation of a carbon adsorber on the autoclaves and 

on ore preheater units at this facility. We estimated the capital cost for the additional controls as 
9

$48,100,000, with a total annualized cost of $9,419,000/yr. Based on an estimated control 

efficiency of 70 percent for the controls on the autoclaves and the ore preheaters, mercury 

emissions would be reduced by 44.6 lbs/yr, resulting in an estimated cost effectiveness of 

$211,188/lb.

Table 7. Estimate of Costs for a Second Carbon Adsorber for Carbon Processes with 

Mercury Retorts

Facility Unit

Flow 

(cfm)

Total 

capital 

costa

Annual 

O&M 

costb

Total 

annualized 

cost

Mercury 

reduction 

(lb/yr)

Twin Creeks Juniper P/B tanks 3,085 209,000 51,936 71,666 0.90

Twin Creeks Electrowinning 7,311 434,000 109,621 150,591 0.50

Goldstrike Carbon kilns 4,406 658,512 135,968 198,131 1.00

Gold Quarry AARL carbon kiln 900 99,700 22,111 31,523 1.03

Florida Canyon Carbon kilns 1,000 183,934 82,691 100,054 0.77

Florida Canyon

Electrowinning, P/B 

tanks, melt furnace 1,000 183,934 82,691 100,054 0.06

Denton Rawhide Melt furnace 6,500 135,100 103,900 116,653 0.26

Lone Tree Electrowinning 10,000 423,000 146,326 186,257 0.23

Lone Tree P/B tanks 125 30,500 11,532 14,411 1.48

Gold Quarry Zadra Carbon kiln 900 99,700 22,111 31,523 0.16

Twin Creeks Melt furnace new 3,000 60,776 50,776 56,513 0.15

Twin Creeks Melt furnace old 3,000 60,776 50,776 56,513 0.40

Jerritt Canyon Melt furnace 1,622 141,933 31,966 45,365 1.24

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 * (cfm/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 into the electrowinning control device. For a beyondthe-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, the capital cost for a 

carbon adsorber was estimated to be $0.2 million with a total annualized cost of $72,000/yr. The 

mercury emissions 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-floor, 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 system 

flow rate, we 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 $191,013/year. 

Emissions would be reduced by 0.13 lb/year, which results in a cost effectiveness of 

$1.4 million/lb.
10

Table 8 summarizes the final mercury emission control costs including the beyond-thefloor costs for ore pretreatment and the MACT floor costs for all the affected sources.

Table 8. Final Mercury Emission Control Costsa

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)

Goldstrike Elko, NV 141 858,512 1,335,968 1,417,131 10,016

Denton-Rawhide Fallon, NV 27 135,100 103,900 116,653 4,250

Florida Canyon Pershing Co., NV 87 367,868 165,382 200,109 2,305

Gold Quarry Carlin, NV 189 2,451,400 74,672 305,045 1,617

Jerritt Canyon Elko, NV 185 960,882 235,737 326,300 1,761

Lone Tree Valmy, NV 181 453,500 157,858 200,669 1,110

Midas Midas, NV 14 430,000 150,421 191,013 13,707

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 Includes beyond-the-floor costs for ore pretreatment and MACT floor costs for all other affected sources.

Table 9 summarizes the overall costs 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
11

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 provides the 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 available. Emissions for the facility were determined by summing emissions for each of 

the process units at the facility. 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.

Emission reductions attributable to MACT for the carbon processes with mercury retorts, 

carbon processes 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 carbon 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 adsorbers 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 temperature 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 furnace 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.

 2 Copies of the emission test reports are available in the rulemaking docket: EPA-HQ-OAR 2010-0239.
12

Table 10. Baseline Mercury Emissions Estimates for the Four Groups of Affected 

Sources (based on data for 2007-2009)

Ore Pretreatment Processes

Facility Mercury Emissions (lb/yr)

Gold Quarry 186

Goldstrike 538

Jerritt Canyon Mine 112

Twin Creeks Mine 615

Subtotal 1,451

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 230

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

Subtotal 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, using a combination of data from 2007 to 2009, we 

estimate that current emissions are about 2,636 lb/yr. Overall, the proposed MACT limits are 

expected to reduce mercury emissions by about 1,461 to 1,174 lb/yr.
13

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

Group

Facility Unit

Maximum 

concentrate 

usage (tpy)

Unit average 

(lb/ton 

concentrate)

Unit 

emissions 

lb/yr

Reductions 

@95% 

(lb/yr)

Reductions 

@99% 

(lb/yr)

Twin Creeks Juniper PregTanks 104.57 0.95 99.50 94.52 98.50

Twin Creeks Electrowinning 104.57 0.53 55.21 52.45 54.66

Goldstrike Carbon Kiln #2-Drum 105.93 1.05 110.94 105.40 109.83

Goldstrike Preg and Barren Tank A 105.93 0.01 0.92 0.88 0.91

Goldstrike Preg and Barren Tank B 105.93 0.01 0.65 0.61 0.64

Gold Quarry AARL Carbon Kiln 62.10 1.84 114.43 108.71 113.28

Florida Canyon Carbon Kiln 11.35 7.50 85.16 80.90 84.31

Florida Canyon Electrowinning Cell A 11.35 0.55 6.21 5.90 6.15

Denton-Rawhide Refinery Furnace 18.50 1.56 28.89 27.45 28.60

Lone Tree Mine Electrowinning Scavenger 11.00 2.33 25.59 24.31 25.33

Lone Tree Mine Pregnant & Barren Tanks 11.00 14.97 164.63 156.40 162.98

Gold Quarry Zadra Carbon Kiln 62.10 0.29 17.80 16.91 17.63

Twin Creeks Furnace (New) 104.57 0.16 17.22 16.36 17.05

Twin Creeks Furnace (Old) 104.57 0.43 44.77 42.53 44.32

Jerritt Canyon Carbon Kiln & Retort 12.00 2.98 35.70 33.92 35.34

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. These increases are due in part to facilities that will have to add additional 

controls to their units to meet the MACT standards, specifically the addition of carbon adsorbers. 

The increase in electricity consumption was estimated from the following equation from the 

OAQPS Cost Manual18:

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/yr.

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 (about 0.1 lb mercury/lb 

carbon). For a mercury reduction of 1,461 lbs, approximately 14,600 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

Facility Unit

Operating 

hr/yr

Flow 

(cfm) kw hr/yr

Denton-Rawhide Melt Furnace 347 6,500 10,962

Florida Canyon 

Electrowinning, P/B tanks, melt 

furnace 8,760 1,000 42,574

Florida Canyon Carbon Kiln 8,760 1,000 42,574

Gold Quarry Zadra Carbon Kiln 8,760 900 38,316

Gold Quarry AARL Carbon Kiln 6,471 900 28,304

Goldstrike Carbon Kiln 6,884 4,406 147,408

Jerritt Canyon Carbon Kiln & Retort 1,541 5,930 44,411

Jerritt Canyon Melt Furnace 872 1,622 6,874

Lone Tree Electrowinning 2,424 10,000 117,806

Lone Tree P/B Tanks 8,760 125 5,322

Midas Furnace 832 10,300 41,648

Twin Creeks Melt Furnace 2 (new) 8,760 3,000 127,721

Twin Creeks Melt Furnace 1 (old) 8,760 3,000 127,721

Twin Creeks Electrowinning 8,760 7,311 311,256

Twin Creeks Juniper P/B tanks 8,760 3,085 131,340

Twin Creeks Autoclave 11,300 11,389,107a

Total 12,613,343 a Electricity consumption for the refrigeration unit taken from Phase 2 application (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 Protection. 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 

Environmental 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 of 

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 Division 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. Nevada 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 Midas. 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. Nevada Division of 

Environmental Protection. 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 comments (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

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

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

DentonRawhide 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

DentonRawhide 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

DentonRawhide 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

DentonRawhide Electrowinning 3.83E-06 1.44E-06 3.79E-05 6.46E-04 2.43E-04 6.39E-03 2007 3,120 18.5

DentonRawhide Electrowinning 2.27E-05 4.25E-06 5.27E-06 1.40E-02 2.62E-03 3.25E-03 2008 5,667 9.2

DentonRawhide 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

DentonRawhide Melt Furnace 1.94E-01 8.31E-02 6.32E-02 3.64E+00 1.56E+00 1.19E+00 2007 347 18.5

DentonRawhide Melt Furnace 9.95E-02 2.07E-01 1.66E-01 8.90E-01 1.85E+00 1.48E+00 2008 82 9.2

DentonRawhide 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

DentonRawhide Retort 4.30E-07 4.66E-07 5.28E-07 5.84E-05 6.33E-05 7.17E-05 2007 2,513 18.5

DentonRawhide Retort 8.95E-07 2.93E-07 2.74E-07 4.59E-05 1.50E-05 1.40E-05 2008 472 9.2

DentonRawhide Retort 2.92E-04 2.05E-04 3.57E-04 6.24E-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-04 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 1.11E-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

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

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 2009 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

Goldstrike 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 2.02E-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 2.09E+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 Tank 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-03 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+00 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 325 104.57 104.57 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

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

Concentr

ate (tpy)

Max 

Concentr

ate (tpy)

Unit 

average 

(lb/ton)

Per unit 

(lb/yr)

Facility 

total 

(lb/ton)

Facility 

total 

(lb/yr)

Twin 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-01 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 Retort 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 4.18E-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 64.9

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 Creeks 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 1.51E+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 316 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

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

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 

Canyon 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 Quarry 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+00 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

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

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

Gold 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 62.0

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 62.1

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 PROCESSES 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 

total 

(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 Mountain 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 2.64E-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 23.7 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 

average 

(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 3,336,226

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-05 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 preheater - Mill 1 1.30E-03 9.00E-04 7.80E-04 8.61E-07 5.96E-07 5.17E-07 2007 7,940 11,985,898

Goldstrike

North Dry grinding 

process and preheater - 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 preheater - Mill 1 3.30E-03 1.70E-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 preheater - 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 preheater - 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

Goldstrike

South Dry grinding 

process and preheater - 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 

average 

(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 7,899 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-05 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 7,876 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 3.24E-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 138.6 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 3,410,717

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 Autoclave 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 3,728,849

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 1.65E-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/ton)

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-04 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 356 217

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-02 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 – 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. Environmental Protection Agency

Research Triangle Park, NC

December 15November 22, 2010
2

Estimates of Impacts for the Final Mercury Emission Standards for Gold Mine Ore 

Processing and Production

1.0 Cost Estimates

This section provides a summary of the estimated 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 process 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. Estimated Cost of Mercury Emission Controls for MACT Floor

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)

Goldstrike Elko, NV 107 658,512 135,968 198,131 1,854

Denton-Rawhide Fallon, NV 27 135,100 103,900 116,653 4,250

Florida Canyon Pershing Co., NV 87 367,868 165,382 200,109 2,305

Gold Quarry Carlin, NV 126 199,400 44,222 63,045 502

Jerritt Canyon Elko, NV 165 450,882 122,737 165,300 1,001

Lone Tree Valmy, NV 181 453,500 157,858 200,669 1,110

Midas Midas, NV 14 430,000 150,421 191,013 13,707

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 includes all of the gold mine ore processing 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

Facility Name Facility Location 

Number of stacksa Higher estimates of MRR costs Lower estimates of MRR costs

Roaster Other

Not in 

NVb

Monitoring 

capital

Method 29 

testing

Monitoring 

O&M

Monitoring 

total annual

Monitoring 

capital

Method 29 

testing

Monitoring 

O&M

Monitoring 

total annual

Goldstrike Elko, NV 2 15

 

120,000 

 

- 

 

182,061 

 

199,149 

 

200,668 

 

- 

 

78,619 

 

107,194 

Coeur Rochester Lovelock, NV 3

 

40,000 

 

- 

 

31,794 

 

37,490 

 

- 

 

- 

 

11,299 

 

11,299 

Cortez

Crescent Valley, 

NV 6

 

40,000 

 

- 

 

62,565 

 

68,261 

 

- 

 

- 

 

21,576 

 

21,576 

Cripple Creek Victor, CO 3 3

 

40,000 

 

28,260 

 

31,794 

 

65,750

 

- 

 

28,260 

 

11,299 

 

39,559 

Denton-Rawhide Fallon, NV 4

 

40,000 

 

- 

 

42,051 

 

47,747 

 

- 

 

- 

 

14,725 

 

14,725 

Echo Bay/Kettle River Republic, WA 3 3

 

40,000 

 

28,260 

 

31,794 

 

65,750 

 

- 

 

28,260 

 

11,299 

 

39,559 

Florida Canyon

Pershing County, 

NV 7

 

40,000 

 

- 

 

72,822 

 

78,518 

 

- 

 

- 

 

25,001 

 

25,001 

Fort Knox Fairbanks, AK 2 2

 

40,000 

 

18,840 

 

21,537 

 

46,073 

 

- 

 

18,840 

 

7,873 

 

26,713 

Gold Quarry Carlin, NV 1 10

 

80,000 

 

- 

 

117,184 

 

128,576 

 

100,334 

 

- 

 

48,385 

 

62,672 

Golden Sunlight Whitehall, MT 3 3

 

40,000 

 

28,260 

 

31,794 

 

65,750 

 

- 

 

28,260 

 

11,299 

 

39,559 

Greens Creek Mine Greens Creek , AK 1 1

 

40,000 

 

9,420 

 

11,279 

 

26,395 

 

- 

 

9,420 

 

4,448 

 

13,868 

Bald Mountain Elko, NV 5

 

40,000 

 

- 

 

52,308 

 

58,004 

 

- 

 

- 

 

18,150 

 

18,150 

Jerritt Canyon Elko, NV 2 3

 

120,000 

 

- 

 

58,976 

 

76,064 

 

200,668 

 

- 

 

37,512 

 

66,087 

Lone Tree Valmy, NV 5

 

40,000 

 

- 

 

52,308 

 

58,004 

 

- 

 

- 

 

18,150 

 

18,150 

Marigold Valmy, NV 4

 

40,000 

 

- 

 

42,051 

 

47,747 

 

- 

 

- 

 

14,725 

 

14,725 

Midas Midas, NV 3

 

40,000 

 

- 

 

31,794 

 

37,490 

 

- 

 

- 

 

11,299 

 

11,299 

Ruby Hill Eureka, NV 4

 

40,000 

 

- 

 

42,051 

 

47,747 

 

- 

 

- 

 

14,725 

 

14,725 

Round Mountain

Round Mountain, 

NV 4

 

40,000 

 

- 

 

42,051 

 

47,747 

 

- 

 

- 

 

14,725 

 

14,725 

Twin Creeks Golconda, NV 13

 

40,000 

 

- 

 

134,365 

 

140,061 

 

- 

 

- 

 

45,555 

 

45,555 

Western Mesquite Brawley, CA 3 3

 

40,000 

 

28,260 

 

31,794 

 

65,750 

 

- 

 

28,260 

 

11,299 

 

39,559 

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 required in Nevada).
4

1.1 Cost of Mercury Emission Controls

The primary basis for the cost 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 

additional 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 those types of controls on other process units. Most 

of the facilities provided estimates of capital costs for the proposed emission control systems. 

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 

based 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 sitespecific 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 carbon 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 annualized 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 Copies 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

Facility Unit Controla

Mercury 

reduction 

(lb/yr)

Flow 

(cfm)

b

Total 

capital costc

Annual 

O&M

coste

Total 

annualized 

cost

Cost 

effectiveness 

($/lb)

Denton Rawhide Melt furnace CA 27.4 6,500 135,1008 103,9008 116,653 4,250

Florida Canyon Carbon kilns CA 80.9 1,000 183,9347 82,6917 100,054 1,237

Florida Canyon

Electrowinning, preg 

tanks, melt furnace CA 5.9 1,000 183,9342 82,6917 100,054 16,962

Gold Quarry AARL carbon kiln CA 108.7 900 99,7006 22,111 31,523 290

Gold Quarry Zadra carbon kiln CA 16.9 900 99,7006 22,111 31,523 1,864

Goldstrike Carbon kilns WC, CA 106.9 4,406 658,512d 135,968 198,131 1,854

Jerritt Canyon Melt furnace CA 131.3 1,622 141,933d 31,966 45,365 346

Jerritt Canyon Carbon kiln & retort CA 33.9 5,930 308,949d 90,771 119,935 3,536

Lone Tree Electrowinning CA 24.3 10,000 423,0009 146,326 186,257 7,662

Lone Tree Preg tanks CA 156.4 125 30,50010 11,532 14,411 92

Twin Creeks Juniper preg tanks CA 94.5 3,085 209,0004 51,936 71,666 758

Twin Creeks Electrowinning CA 52.4 7,311 434,0005 109,621 150,591 2,871

Twin Creeks Melt furnace new CA 16.4 3,000 60,77614 50,776 56,513 3,455

Twin Creeks Melt furnace old CA 42.5 3,000 60,77614 50,776 56,513 1,329

Midas Furnace CA 13.9 10,300 430,00015 150,421 191,013 13,707

Twin Creeks Autoclave WC, CA 430.6 11,300 29,300,00019 2,150,000 4,904,200 11,390

Subtotal Carbon Group with Hg retorts (No. 1 through 

No. 14) 899 3,029,813 993,176 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 * (cfm/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

The final rule includes three monitoring options for roasters: a mercury continuous 

emission monitoring system (CEMS), continuous sorbent 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 the 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, moisture conditioner,

metering console, and data logger. The paired traps cost $150 each with an analysis cost of 

$200 each. The estimated labor to install 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 process units other than roasters, the common mercury control device is a carbon 

adsorber. The final rule provides options for sampling carbon adsorbers: monthly sorbent trap 

sampling (except going to weekly when the adsorber reaches 75 percent of the operating 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 similar 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 stack that is sampled. The carbon bed sampling is much 

less expensive 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 per 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 stacks).
7

Table 5. Estimate of Reporting and Recordkeeping Costs

General Description 

Mean 

Hourly 

Ratea

Rate with 

overheadb hr/plant $/plant hr/stack $/stack

Environmental Engineer $35.24 $56.38 16 $902 4 $226

Managementc $57.27 $91.63 0.8 $73 0.20 $18

Office/Admin. Supportd $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 Statistics, May 2009, 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 rule also requires 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 Description 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 cost functions described in this section and the number of roaster stacks,

number of other (non-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

The affected sources with carbon processes with mercury retorts use 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 that 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 so 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. For 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 concentrations 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 first 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 pretreatment processes have installed, or would be need 

required to install mercury scrubbers and carbon adsorbers on their roasters and venturie

scrubbers and/ maybe carbon adsorbers on their autoclaves, to achieve the MACT floor for 

ore pretreatment processes. To achieve further reduction in mercury, one beyond-the-floor 

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 capacity of the carbon adsorber. The Twin Creeks facility will not be able to meet 

the final MACT standard without adding controls, thus the costs to add controls to the Twin 

Creek’s autoclaves has been included in the total cost of controls for facilities to meet the 

MACT standard (see Table 3). The estimated capital cost for the additional controls for the 

autoclaves at Twin Creeks would be $29.3 million, with a total annualized cost of $4.9

million/yr. Based on an estimated control efficiency of 70 percent, mercury emissions would 

be reduced by 431 lbs/yr, resulting in an estimated cost effectiveness of $11,390/lb. The 

Goldstrike facility can already meet the MACT standard so the costs to add controls to their 

autoclaves are considered beyond-the-floor. 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. Based on an estimated control efficiency of 70 percent, mercury emissions 

would be reduced 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, mercury emissions would be reduced by 118 lbs/yr, resulting in an estimated cost 

effectiveness of $13,784/lb. 

We also evaluated a beyond-the-floor option for the new source standard. The best 

performing similar source for the ore pretreatment affected source is the Goldstrike facility. We 

identified as a beyond-the-floor option the installation of a carbon adsorber on the autoclaves and 
9

on ore preheater units at this facility. We estimated the capital cost for the additional controls as 

$48,100,000, with a total annualized cost of $9,419,000/yr. Based on an estimated control 

efficiency of 70 percent for the controls on the autoclaves and the ore preheaters, mercury 

emissions would be reduced by 44.6 lbs/yr, resulting in an estimated cost effectiveness of 

$211,188/lb.

Table 7. Estimate of Costs for a Second Carbon Adsorber for Carbon Processes with 

Mercury Retorts

Facility Unit

Flow 

(cfm)

Total 

capital 

costa

Annual 

O&M 

costb

Total 

annualized 

cost

Mercury 

reduction 

(lb/yr)

Twin Creeks Juniper P/B tanks 3,085 209,000 51,936 71,666 0.90

Twin Creeks Electrowinning 7,311 434,000 109,621 150,591 0.50

Goldstrike Carbon kilns 4,406 658,512 135,968 198,131 1.00

Gold Quarry AARL carbon kiln 900 99,700 22,111 31,523 1.03

Florida Canyon Carbon kilns 1,000 183,934 82,691 100,054 0.77

Florida Canyon

Electrowinning, P/B 

tanks, melt furnace 1,000 183,934 82,691 100,054 0.06

Denton Rawhide Melt furnace 6,500 135,100 103,900 116,653 0.26

Lone Tree Electrowinning 10,000 423,000 146,326 186,257 0.23

Lone Tree P/B tanks 125 30,500 11,532 14,411 1.48

Gold Quarry Zadra Carbon kiln 900 99,700 22,111 31,523 0.16

Twin Creeks Melt furnace new 3,000 60,776 50,776 56,513 0.15

Twin Creeks Melt furnace old 3,000 60,776 50,776 56,513 0.40

Jerritt Canyon Melt furnace 1,622 141,933 31,966 45,365 1.24

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 * (cfm/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 into the electrowinning control device. For a beyondthe-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, the capital cost for a 

carbon adsorber was estimated to be $0.2 million with a total annualized cost of $72,000/yr. The 

mercury emissions 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-floor, 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 system 

flow rate, we 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 $191,013/year. 
10

Emissions would be reduced by 0.13 lb/year, which results in a cost effectiveness of 

$1.4 million/lb.

Table 8 summarizes the final mercury emission control costs including the beyond-thefloor costs for ore pretreatment and the MACT floor costs for all the affected sources.

Table 8. Final Mercury Emission Control Costsa

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)

Goldstrike Elko, NV 141 858,512 1,335,968 1,417,131 10,016

Denton-Rawhide Fallon, NV 27 135,100 103,900 116,653 4,250

Florida Canyon Pershing Co., NV 87 367,868 165,382 200,109 2,305

Gold Quarry Carlin, NV 189 2,451,400 74,672 305,045 1,617

Jerritt Canyon Elko, NV 185 960,882 235,737 326,300 1,761

Lone Tree Valmy, NV 181 453,500 157,858 200,669 1,110

Midas Midas, NV 14 430,000 150,421 191,013 13,707

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 Includes beyond-the-floor costs for ore pretreatment and MACT floor costs for all other affected sources.

Table 9 summarizes the overall costs 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
11

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 provides the 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 available. Emissions for the facility were determined by summing emissions for each of 

the process units at the facility. 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.

Emission reductions attributable to MACT for the carbon processes with mercury retorts, 

carbon processes 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 carbon 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 adsorbers 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 temperature 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 furnace 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.

 2 Copies of the emission test reports are available in the rulemaking docket: EPA-HQ-OAR 2010-0239.
12

Table 10. Baseline Mercury Emissions Estimates for the Four Groups of Affected 

Sources (based on data for 2007-2009)

Ore Pretreatment Processes

Facility Mercury Emissions (lb/yr)

Gold Quarry 186

Goldstrike 538

Jerritt Canyon Mine 112

Twin Creeks Mine 615

Subtotal 1,451

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 230

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

Subtotal 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, using a combination of data from 2007 to 2009, we 

estimate that current emissions are about 2,636 lb/yr. Overall, the proposed MACT limits are 

expected to reduce mercury emissions by about 1,461 to 1,174 lb/yr.
13

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

Group

Facility Unit

Maximum 

concentrate 

usage (tpy)

Unit average 

(lb/ton 

concentrate)

Unit 

emissions 

lb/yr

Reductions 

@95% 

(lb/yr)

Reductions 

@99% 

(lb/yr)

Twin Creeks Juniper PregTanks 104.57 0.95 99.50 94.52 98.50

Twin Creeks Electrowinning 104.57 0.53 55.21 52.45 54.66

Goldstrike Carbon Kiln #2-Drum 105.93 1.05 110.94 105.40 109.83

Goldstrike Preg and Barren Tank A 105.93 0.01 0.92 0.88 0.91

Goldstrike Preg and Barren Tank B 105.93 0.01 0.65 0.61 0.64

Gold Quarry AARL Carbon Kiln 62.10 1.84 114.43 108.71 113.28

Florida Canyon Carbon Kiln 11.35 7.50 85.16 80.90 84.31

Florida Canyon Electrowinning Cell A 11.35 0.55 6.21 5.90 6.15

Denton-Rawhide Refinery Furnace 18.50 1.56 28.89 27.45 28.60

Lone Tree Mine Electrowinning Scavenger 11.00 2.33 25.59 24.31 25.33

Lone Tree Mine Pregnant & Barren Tanks 11.00 14.97 164.63 156.40 162.98

Gold Quarry Zadra Carbon Kiln 62.10 0.29 17.80 16.91 17.63

Twin Creeks Furnace (New) 104.57 0.16 17.22 16.36 17.05

Twin Creeks Furnace (Old) 104.57 0.43 44.77 42.53 44.32

Jerritt Canyon Carbon Kiln & Retort 12.00 2.98 35.70 33.92 35.34

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. These increases are due in part to facilities that will have to add additional 

controls to their units to meet the MACT standards, specifically the addition of a carbon 

adsorbers. The increase in electricity consumption was estimated from the following equation 

from the OAQPS Cost Manual18:

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/yr.

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 (about 0.1 lb mercury/lb 

carbon). For a mercury reduction of 1,461 lbs, approximately 14,600 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

Facility Unit

Operating 

hr/yr

Flow 

(cfm) kw hr/yr

Denton-Rawhide Melt Furnace 347 6,500 10,962

Florida Canyon 

Electrowinning, P/B tanks, melt 

furnace 8,760 1,000 42,574

Florida Canyon Carbon Kiln 8,760 1,000 42,574

Gold Quarry Zadra Carbon Kiln 8,760 900 38,316

Gold Quarry AARL Carbon Kiln 6,471 900 28,304

Goldstrike Carbon Kiln 6,884 4,406 147,408

Jerritt Canyon Carbon Kiln & Retort 1,541 5,930 44,411

Jerritt Canyon Melt Furnace 872 1,622 6,874

Lone Tree Electrowinning 2,424 10,000 117,806

Lone Tree P/B Tanks 8,760 125 5,322

Midas Furnace 832 10,300 41,648

Twin Creeks Melt Furnace 2 (new) 8,760 3,000 127,721

Twin Creeks Melt Furnace 1 (old) 8,760 3,000 127,721

Twin Creeks Electrowinning 8,760 7,311 311,256

Twin Creeks Juniper P/B tanks 8,760 3,085 131,340

Twin Creeks Autoclave 11,300 11,389,107a

Total 12,613,343 a Electricity consumption for the refrigeration unit taken from Phase 2 application (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 Protection. 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 

Environmental 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 of 

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 Division 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. Nevada 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 Midas. 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. Nevada Division of 

Environmental Protection. 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 comments (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

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

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

DentonRawhide 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

DentonRawhide 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

DentonRawhide 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

DentonRawhide Electrowinning 3.83E-06 1.44E-06 3.79E-05 6.46E-04 2.43E-04 6.39E-03 2007 3,120 18.5

DentonRawhide Electrowinning 2.27E-05 4.25E-06 5.27E-06 1.40E-02 2.62E-03 3.25E-03 2008 5,667 9.2

DentonRawhide 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

DentonRawhide Melt Furnace 1.94E-01 8.31E-02 6.32E-02 3.64E+00 1.56E+00 1.19E+00 2007 347 18.5

DentonRawhide Melt Furnace 9.95E-02 2.07E-01 1.66E-01 8.90E-01 1.85E+00 1.48E+00 2008 82 9.2

DentonRawhide 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

DentonRawhide Retort 4.30E-07 4.66E-07 5.28E-07 5.84E-05 6.33E-05 7.17E-05 2007 2,513 18.5

DentonRawhide Retort 8.95E-07 2.93E-07 2.74E-07 4.59E-05 1.50E-05 1.40E-05 2008 472 9.2

DentonRawhide Retort 2.92E-04 2.05E-04 3.57E-04 6.24E-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-04 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 1.11E-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

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

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 2009 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

Goldstrike 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 2.02E-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 2.09E+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 Tank 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-03 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+00 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 325 104.57 104.57 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

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

Concentr

ate (tpy)

Max 

Concentr

ate (tpy)

Unit 

average 

(lb/ton)

Per unit 

(lb/yr)

Facility 

total 

(lb/ton)

Facility 

total 

(lb/yr)

Twin 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-01 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 Retort 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 4.18E-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 64.9

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 Creeks 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 1.51E+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 316 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

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

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 

Canyon 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 Quarry 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+00 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

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

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

Gold 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 62.0

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 62.1

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 PROCESSES 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 

total 

(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 Mountain 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 2.64E-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 23.7 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 

average 

(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 3,336,226

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-05 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 preheater - Mill 1 1.30E-03 9.00E-04 7.80E-04 8.61E-07 5.96E-07 5.17E-07 2007 7,940 11,985,898

Goldstrike

North Dry grinding 

process and preheater - 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 preheater - Mill 1 3.30E-03 1.70E-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 preheater - 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 preheater - 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

Goldstrike

South Dry grinding 

process and preheater - 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 

average 

(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 7,899 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-05 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 7,876 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 3.24E-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 138.6 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 3,410,717

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 Autoclave 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 3,728,849

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 1.65E-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/ton)

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-04 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 356 217

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-02 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
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

December 15, 2010
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 Production 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 21 gold 

mine ore processing facilities operating these processes in the United States in 2008.

The final rule applies 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 Gold Mine Ore Processing 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 process 

operations, the sources of mercury entering the processes, and the nature of the emissions.

The ore pretreatment affected source includes roasting operations and autoclaves that 

pretreat refractory ore, which contains organic carbon and 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 with 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 all four of these facilities. The potential for mercury emissions 

from 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 processes 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, and melt furnaces). Mercury emissions are subsequently generated by these 

Carbon Processes with Mercury Retorts
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 the 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 concentrate 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 facilities. In the 2007-2009 timeframe, the 

carbon processes with mercury retorts sources accounted for approximately 44 percent of the 

mercury emissions from the source category.

The third affected source is carbon processes 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 concentrations of mercury in 

their ore that they 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 

differentiates 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 emission 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 processes without mercury retorts sources accounted for approximately 

0.19 percent of the mercury emissions from the source category.
3

This affected source includes facilities with gold 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 amount 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 approximately 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 average 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 source 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 representing current 

performance based on their emissions and identified the lowest emitting of the existing 

affected sources, which resulted in 4 facilities with ore pretreatment 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 sources, MACT was based on the best performing source for each of the four

affected sources.

The run-by-run data and the details of the statistical calculations for the MACT floor 

analyses are provided in Appendices A through E.
4

2.1 Statistical Approach for Existing Sources 

To calculate the MACT floor limit for each of the affected sources, we established and 

ranked 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. 

The emissions data for those best performing affected sources were used to determine the 

final 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 under 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 UPL = x + t v

where:

UPL = upper prediction limit,

T x = the average total emission rate over the best performing affected sources,

df t = the 99th percentile of the t distribution, and

T v = the total variance for the top performing affected sources.

The degrees of freedom associated with df t is given by:

∑ ∑ ( ) = = = − N

i

M

j ij

i

df n

1 1

1
5

where:

N = number of best performing affected sources (2 to 4 for the four affected sources),

Mi = number of mercury emitting processes at each affected source, and

nij = number of mercury emission test runs for each process unit.

The average total emission rate ( T x ) is calculated from: 

∑=

=

N

i

T Ti x

N

x

1

1

where:

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

Ti x = the total emission rate of an entire ith affected source.

To calculate Ti x :

∑=

=

Mi

j

Ti ij x x

1

where: 

Mi = the number of distinct units within the ith affected source (i.e., we count all the distinct 

units in an affected source, so if a process type has two or more units, then each of those 

units must be counted), 

ij x = the unit average for the jth unit within the ith affected source. 

To calculate ij x :

∑=

=

ij n

k

ijk

ij

ij x

n

x

1

1

where:

nij = the number of runs within the jth unit of the ith affected source,

xijk = the observation associated with the kth run within the jth unit and ith affected source. 

The total variance ( T v ) consists of the following two variance components:

T B W v = v + v
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 individual run in the jth 

unit and ith affected source, then the variance of the unit average, ij x in the jth unit and ith 

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 ith affected 

source is 

∑=

=

Mi

j ij

ij

Ti

n

s

x

1

2

var( ) ,

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

∑∑= =

= =

N

i

M

j ij

ij

B T

i

n

s

N

v x

1 1

2

2

1 var( ) .

The second variance component ( Wv ) is the variance of T new x , , the total emission rate 

from new test runs at an affected source in the future to determine compliance. The theoretical

formulation of Wv based on these 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 kth run of the jth unit in the new affected source, and M is the number 

of units in the new affected source. Also note that the 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

formulation of Wv based on the data available from the runs already completed from the top N

affected sources:
7

2

2

1 11 1 1

1 1 1 var( )

N m M M i i 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 N Mi

T df ij

i j ij

UPL x t s

N Nn m = =

  = + +  

  ∑∑

The first term of the equation 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 

consists 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 sources 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 df T1 UPL = x + t v

where:

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

df t = the 99th percentile of the t distribution with (n – 1) degrees of freedom, and

T1 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

 

= +  

  ∑ ,
8

where 2

1 j s and 1 j n are the variance and number of runs, respectively, from the jth mercuryemitting unit of the best performing source, M1 is the number of distinct mercury-emitting units 

in this source, and m is the number of future runs to determine compliance (typically 3).

3. MACT Floor for Mercury

Most of the mercury emissions data used in the MACT floor analyses were obtained 

from annual testing that was required by the Nevada Division of Environmental Protection 

(NDEP) for 2007 through 2009.

1

The NDEP invalidated several mercury emission tests conducted in 2007 and 2008 

because of failures to comply with the federal reference test method, failure to comply with

the established testing protocol, possible sample contamination, etc. See docket item EPAHQ-OAR-2010-0239-0061 for a complete list and rationale for invalidated tests. 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 were

used in the analyses. The 2007 and 2008 tests for the mercury retorts at Goldstrike were also 

invalidated; however, test data for 2009 were available for the mercury retorts and were 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 tests at Marigold, two of 

the August 2007 ore preheater tests at Goldstrike, 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 melt furnaces for the Cortez Pipeline facility. The NDEP reported that, for that test, the 

 However, 2010 test data were used for one facility that 

installed new mercury emission controls on its roasters and resumed operation in late 2009. 

The tests generally consist of three runs per test per process at each affected 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 were 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 multiplied by the number of hours the process operated in 

2007, 2008, or 2009 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 Appendix A through F of this document.
9

mercury content of the concentrate was only 8 ppm, whereas the content 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 

unusually 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. 

Valid emissions data were available for all four of the facilities with ore pretreatment 

processes. As shown in Table 1, the average emissions level achieved by these four facilities 

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 this affected source would reduce emissions 

of mercury by about 431 pounds per year (lbs/yr), a reduction of 30 percent from current 

levels. In addition, energy consumption would increase by about 11,400 megawatt-hours per 

year (or 11.4 gigawatt-hours per year). Solid waste 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 (Facility A) 45 (14 tests, 42 runs)

Gold Quarry (Facility C) 56 (17 tests, 51 runs)

Jerritt Canyon Mine (Facility E) 71 (7 tests, 21 runs)

Twin Creeks Mine (Facility D) 165 (12 tests, 36 runs)

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
10

Valid emissions data were available for 10 facilities that operate carbon processes with 

mercury retorts. Based on the MACT floor analysis, the 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, the 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 this affected source would 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 (Facility N) 0.53 (7 tests, 21 runs)

Bald Mountain (Facility J) 0.74 (4 tests, 12 runs)

Ruby Hill (Facility I) 1.06 (4 tests, 11 runs)

Goldstrike (Facility A) 1.47 (18 tests, 54 runs)

Denton-Rawhide (Facility H) 1.67 (12 tests, 36 runs)

Twin Creeks (Facility D) 2.20 (31 tests, 93 runs)

Gold Quarry (Facility C) 3.71 (21 tests, 57 runs)

Florida Canyon (Facility G) 8.17 (18 tests, 54 runs)

Jerritt Canyon (Facility E) 14.49 (2 tests, 6 runs)

Lone Tree (Facility B) 20.60 (7 tests, 21 runs)

Summary of Statistical Analysis

Statistic Existing (top 5) New

Average (lb/tons) 1.1 0.53

Df 110 17

t 2.36 2.57

Vb 0.015 0.0032

Vw 0.20 0.0037

Vt 0.22 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 shown 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
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 (Facility M) 0.058 (5 tests, 15 runs)

Cortez (Facility F) 0.098 (13 tests, 39 runs)

Summary of Statistical Analysis

Statistic Existing (top 2) New

Average (lb/ton) 0.078 0.058

df 43 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 0.17 0.14

For this affected source, valid emissions data were available for two facilities. The 

results of the analysis are summarized in Table 4. Based on the MACT floor analysis, the 

average emissions level achieved by these 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 (Facility K) 0.047 (5 tests, 17 runs)

Midas Operations (Facility L) 0.078 (13 tests, 27 runs)

Summary of Statistical Analysis

Statistic Existing (top 2) New

Average (lb/ton) 0.062 0.047

df 39 15

t 2.43 2.60

Vb 0.00024 0.00026

Vw 0.0026 0.00052

Vt 0.0028 0.00077

99% UPL (lb/ton), MACT Floor 0.2 0.1
12

4. Beyond the Floor2

To evaluate opportunities for emission reductions beyond those that would result from 

requiring facilities 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 this "beyond-the-floor" analysis for 

the four affected sources for the Gold Mine Ore Processing and Production source category.

 

Facilities with ore pretreatment processes have installed, or would need to install, 

calomel mercury scrubbers on their roasters and venturi scrubbers and/ maybe carbon 

adsorbers on their autoclaves, to achieve the MACT floor for ore pretreatment processes. To 

achieve further reduction in mercury, one beyond-the-floor option the installation of both a 

refrigeration unit and a carbon adsorber on the remaining facilities 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 capacity of the carbon adsorber. 

We assumed that the additional control from the carbon adsorber would result in a 70 percent 

reduction of mercury emissions. This value was proposed by Newmont Twin Creeks facility 

in their Phase 2 application to the Nevada Mercury Control Program. We believe that it is an 

appropriate estimate of emissions reductions seeing as this control has never been 

demonstrated on an autoclave. 

Ore Pretreatment

We estimate that the Twin Creeks facility will not be able to meet the final MACT 

standard without adding controls, thus the costs to add controls to the Twin Creek’s 

autoclaves has been included in the total cost of controls for facilities to meet the MACT 

standard. The estimated capital cost for the additional controls for the autoclaves at Twin 

Creeks would be $29.3 million, with a total annualized cost of $4.9 million/yr. Based on an 

estimated control efficiency of 70 percent, mercury emissions would be reduced by 431 

lbs/yr, resulting in an estimated cost effectiveness of $11,390/lb. We are incorporating this 

beyond-the-floor analysis in the final rule.

 

2 Additional details and documentation for the estimates of emissions, emission reductions, and costs are provided 

in the rulemaking docket (EPA-HQ-OAR-2010-0239).
13

We estimate that the Goldstrike facility will be able meet the MACT standard without 

adding controls to their autoclaves so the costs to add controls to their autoclaves are 

considered beyond-the-floor. We estimate the capital cost for the additional controls on the 

autoclaves at Goldstrike 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. Because of the high cost effectiveness for addition controls to 

the autoclaves at Goldstrike, we are not incorporating this beyond-the-floor analysis in the 

final rule.

We also identified as a beyond-the-floor option the installation of a carbon adsorber on 

ore preheater/dryer units. Again, we assumed that the additional control from the carbon 

adsorber would result in a 70 percent reduction of mercury emissions on the ore 

preheater/dryer units. We believe that this is an appropriate estimate of emissions reductions 

because this control has never been demonstrated on these 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, mercury 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 that one facility, 

which has both roasters and autoclaves, would operate only their roasters. With these

additional controls, 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. 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. 

We also evaluated a beyond-the-floor option for the new source standard. The best 

performing similar source for the ore pretreatment affected source is the Goldstrike facility. 

We identified as a beyond-the-floor option the installation of a carbon adsorber on the 

autoclaves and on ore preheater units at this facility. We estimated the capital cost for the 

additional controls as $48,100,000, with a total annualized cost of $9,419,000/yr. Based on 

an estimated control efficiency of 70 percent for the controls on the autoclaves and the ore 
14

preheaters, mercury emissions would be reduced by 44.6 lbs/yr, resulting in an estimated cost 

effectiveness of $211,188/lb. Because of the high cost effectiveness values, the beyond-thefloor anyslsysis for new sources in the ore pretreatment affected source were not adopted in 

the final rule.

Table 5. Beyond the Floor Results for Ore Pretreatment

Affected Source

Average performance 

(lb Hg/million tons ore)

Gold Quarry (Facility C) (70% reduction) 37

Twin Creeks (Facility D) (70% reduction) 49

Jerritt Canyon (Facility E) (70% reduction) 58

Goldstrike (Facility A) (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 noncarbon concentrate processes), 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 the first or existing 

adsorber and would get an additional reduction of 90 percent. (We acknowledge that there is 

significant uncertainty in the additional reductions the redundant control system might 

achieve.) For carbon processes with mercury retorts, the capital cost for the additional control 

was estimated to be $3 million, with a total annualized cost of $1.3 million/yr. The emissions

reductions for this control option would be 9 lbs/yr, resulting in an estimated cost 

effectiveness of $150,275/lb. For non-carbon concentrate processes, we estimated the capital 

cost for the additional adsorber to be $0.4 million, with a total annualized cost of 

Other Affected Sources
15

$191,000/year. The mercury emissions reductions that would be achieved by this option 

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 were 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. The capital cost for a carbon adsorber was estimated 

to be $0.2 million with a total annualized cost of $72,000/yr. The mercury emissions

reduction associated with this option would be 1.6 lbs/yr, resulting in an estimated cost 

effectiveness of $44,000/lb. For the same 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 Limits

Existing Units

Sources

New 

Sources

Ore pretreatment processes 127 84 lb/million tons 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 concentrate
16

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 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 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 1.61E-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 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-07 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 

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
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 per 

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 2.07E-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 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 2.36E-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

t(.99): 2.36
18

Appendix B. Mercury Emissions Data for the Carbon Processes with Mercury Retorts Affected 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 1.09E-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 1.10E-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

Goldstrike Retort
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 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 1.89E-01 6.29E-02 1.47E+00 1.84E-05 3 2 6.13E-06 8.38E-02 6.13E-06 4.95E-01

DentonRawhide Carbon Kiln 3.16E-03 3.47E-03 1.66E-02

DentonRawhide Carbon Kiln 1.15E-02 6.48E-03 2.07E-03

DentonRawhide 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

DentonRawhide Electrowinning 6.46E-04 2.43E-04 6.39E-03

DentonRawhide Electrowinning 1.40E-02 2.62E-03 3.25E-03

DentonRawhide Electrowinning 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

DentonRawhide Melt Furnace 3.64E+00 1.56E+00 1.19E+00

DentonRawhide Melt Furnace 8.90E-01 1.85E+00 1.48E+00

DentonRawhide 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

DentonRawhide Retort 5.84E-05 6.33E-05 7.17E-05

DentonRawhide Retort 4.59E-05 1.50E-05 1.40E-05

DentonRawhide Retort 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

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
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

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 1.16E-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 5.83E-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 Creeks 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-04 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

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
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 Electrowinning 7.32E-02 6.70E-02 5.94E-02

Gold Quarry Electrowinning 4.48E-01 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 1.81E-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 Quarry 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 9.23E-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 1.45E-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 Electrowinning 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

Florida 

Canyon Electrowinning 7.60E-02 3.41E-02 4.57E-02
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

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

Florida 

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
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 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

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 Electrowinning 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: 43Vb: 3.08E-04

Vw 

(unpooled): 1.02E-03

t(.99): 2.42
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 

Rochester 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 2.01E-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
25

Appendix E. New 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

Facility 

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 1.39E-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 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-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

Average = 4.49E-05

DF = 42

t = 2.42

Vb = 6.50E-11

Vw = 1.98E-10

Vt = 2.63E-10

Facility 

99% UPL 

= 8.41E-05
26

Carbon Processes with 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

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

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 (n1) 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 1.56E-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
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

Coeur 

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
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

Goldstrike

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 1.48E-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
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 1.05E-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

Twin 

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 

Creeks 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
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:

3.00E11

Vw 

(unpooled

): 3.69E-10

56 t(.99): 2.36
***E.O. 12866 Review – Draft – Do Not Cite, Quote, or Release During Review***

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

December 15November 10, 2010
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 Production 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 21 gold 

mine ore processing facilities operating these processes in the United States in 2008.

The final rule applies 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 Gold Mine Ore Processing 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 process 

operations, the sources of mercury entering the processes, and the nature of the emissions.

The ore pretreatment affected source includes roasting operations and autoclaves that 

pretreat refractory ore, which contains organic carbon and 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 with 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 all four of these facilities. The potential for mercury emissions 

from 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 processes 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, and melt furnaces). Mercury emissions are subsequently generated by these 

Carbon Processes with Mercury Retorts
***E.O. 12866 Review – Draft – Do Not Cite, Quote, or Release During Review***

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 the 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 concentrate 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 facilities. In the 2007-2009 timeframe, the 

carbon processes with mercury retorts sources accounted for approximately 44 percent of the 

mercury emissions from the source category.

The third affected source is carbon processes 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 concentrations of mercury in 

their ore that they 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 

differentiates 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 emission 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 processes without mercury retorts sources accounted for approximately 

0.19 percent of the mercury emissions from the source category.
***E.O. 12866 Review – Draft – Do Not Cite, Quote, or Release During Review***

3

This affected source includes facilities with gold 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 amount 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 approximately 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 average 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 source 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 representing current 

performance based on their emissions and identified the lowest emitting of the existing 

affected sources, which resulted in 4 facilities with ore pretreatment 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 sources, MACT was based on the best performing source for each of the four

affected sources.

The run-by-run data and the details of the statistical calculations for the MACT floor 

analyses are provided in Appendices A through E.
***E.O. 12866 Review – Draft – Do Not Cite, Quote, or Release During Review***

4

2.1 Statistical Approach for Existing Sources 

To calculate the MACT floor limit for each of the affected sources, we established and 

ranked 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. 

The emissions data for those best performing affected sources were used to determine the

final 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 under 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 UPL = x + t v

where:

UPL = upper prediction limit,

T x = the average total emission rate over the best performing affected sources,

df t = the 99th percentile of the t distribution, and

T v = the total variance for the top performing affected sources.

The degrees of freedom associated with df t is given by:

∑ ∑ ( ) = = = − N

i

M

j ij

i

df n

1 1

1
***E.O. 12866 Review – Draft – Do Not Cite, Quote, or Release During Review***

5

where:

N = number of best performing affected sources (2 to 4 for the four affected sources),

Mi = number of mercury emitting processes at each affected source, and

nij = number of mercury emission test runs for each process unit.

The average total emission rate ( T x ) is calculated from: 

∑=

=

N

i

T Ti x

N

x

1

1

where:

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

Ti x = the total emission rate of an entire ith affected source.

To calculate Ti x :

∑=

=

Mi

j

Ti ij x x

1

where: 

Mi = the number of distinct units within the ith affected source (i.e., we count all the distinct 

units in an affected source, so if a process type has two or more units, then each of those 

units must be counted), 

ij x = the unit average for the jth unit within the ith affected source. 

To calculate ij x :

∑=

=

ij n

k

ijk

ij

ij x

n

x

1

1

where:

nij = the number of runs within the jth unit of the ith affected source,

xijk = the observation associated with the kth run within the jth unit and ith affected source. 

The total variance ( T v ) consists of the following two variance components:

T B W v = v + v
***E.O. 12866 Review – Draft – Do Not Cite, Quote, or Release During Review***

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 individual run in the jth 

unit and ith affected source, then the variance of the unit average, ij x in the jth unit and ith 

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 ith affected 

source is 

∑=

=

Mi

j ij

ij

Ti

n

s

x

1

2

var( ) ,

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

∑∑= =

= =

N

i

M

j ij

ij

B T

i

n

s

N

v x

1 1

2

2

1 var( ) .

The second variance component ( Wv ) is the variance of T new x , , the total emission rate 

from new test runs at an affected source in the future to determine compliance. The theoretical

formulation of Wv based on these 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 kth run of the jth unit in the new affected source, and M is the number 

of units in the new affected source. Also note that the 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

formulation of Wv based on the data available from the runs already completed from the top N

affected sources:
***E.O. 12866 Review – Draft – Do Not Cite, Quote, or Release During Review***

7

2

2

1 11 1 1

1 1 1 var( )

N m M M i i 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 N Mi

T df ij

i j ij

UPL x t s

N Nn m = =

  = + +  

  ∑∑

The first term of the equation 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 

consists 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 sources 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 df T1 UPL = x + t v

where:

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

df t = the 99th percentile of the t distribution with (n – 1) degrees of freedom, and

T1 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

 

= +  

  ∑ ,
***E.O. 12866 Review – Draft – Do Not Cite, Quote, or Release During Review***

8

where 2

1 j s and 1 j n are the variance and number of runs, respectively, from the jth mercuryemitting unit of the best performing source, M1 is the number of distinct mercury-emitting units 

in this source, and m is the number of future runs to determine compliance (typically 3).

3. MACT Floor for Mercury

Most of the mercury emissions data used in the MACT floor analyses were obtained 

from annual testing that was required by the Nevada Division of Environmental Protection 

(NDEP) for 2007 through 2009.

1

The NDEP invalidated several mercury emission tests conducted in 2007 and 2008 

because of failures to comply with the federalfollow the reference test method, orfailure to 

comply with the established testing protocol, possible sample contamination, etc. See docket 

item EPA-HQ-OAR-2010-0239-0061 for a complete list and rationale for invalidated tests. 

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 were used in the analyses. The 2007 and 2008 tests for the mercury retorts at 

Goldstrike were also invalidated; however, test data for 2009 were available for the mercury 

retorts and were 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 tests at Marigold, two of the August 2007 ore preheater tests at Goldstrike, and one of 

the February 2010 roaster tests at Jerritt Canyon. In addition, we excluded data from the 

 However, 2010 test data were used for one facility that 

installed new mercury emission controls on its roasters and resumed operation in late 2009. 

The tests generally consist of three runs per test per process at each affected 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 were 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 multiplied by the number of hours the process operated in 

2007, 2008, or 2009 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 Appendix A through F of this documenta spreadsheet in 

docket item “Mercury Emissions Test Data” in the rulemaking docket.
***E.O. 12866 Review – Draft – Do Not Cite, Quote, or Release During Review***

9

October 2009 emission test on one of the melt furnaces for the Cortez Pipeline facility. The 

NDEP reported that, for that test, the mercury content of the concentrate was only 8 ppm, 

whereas the content 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 unusually 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. 

Valid emissions data were available for all four of the facilities with ore pretreatment 

processes. As shown in Table 1, the average emissions level achieved by these four facilities 

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 this affected source would reduce emissions 

of mercury by about 431 pounds per year (lbs/yr), a reduction of 30 percent from current 

levels. In addition, energy consumption would increase by about 11,400 megawatt-hours per 

year (or 11.4 gigawatt-hours per year). Solid waste 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 (Facility A) 45 (14 tests, 42 runs)

Gold Quarry (Facility C) 56 (17 tests, 51 runs)

Jerritt Canyon Mine (Facility E) 71 (7 tests, 21 runs)

Twin Creeks Mine (Facility D) 165 (12 tests, 36 runs)

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
***E.O. 12866 Review – Draft – Do Not Cite, Quote, or Release During Review***

10

Valid emissions data were available for 10 facilities that operate carbon processes with 

mercury retorts. Based on the MACT floor analysis, the 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, the 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 this affected source would 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 (Facility N) 0.53 (7 tests, 21 runs)

Bald Mountain (Facility J) 0.74 (4 tests, 12 runs)

Ruby Hill (Facility I) 1.06 (4 tests, 11 runs)

Goldstrike (Facility A) 1.47 (18 tests, 54 runs)

Denton-Rawhide (Facility H) 1.67 (12 tests, 36 runs)

Twin Creeks (Facility D) 2.20 (31 tests, 93 runs)

Gold Quarry (Facility C) 3.71 (21 tests, 57 runs)

Florida Canyon (Facility G) 8.17 (18 tests, 54 runs)

Jerritt Canyon (Facility E) 14.49 (2 tests, 6 runs)

Lone Tree (Facility B) 20.60 (7 tests, 21 runs)

Summary of Statistical Analysis

Statistic Existing (top 5) New

Average (lb/tons) 1.1 0.53

Df 110 17

t 2.36 2.57

Vb 0.015 0.0032

Vw 0.20 0.0037

Vt 0.22 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 shown 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
***E.O. 12866 Review – Draft – Do Not Cite, Quote, or Release During Review***

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 (Facility M) 0.058 (5 tests, 15 runs)

Cortez (Facility F) 0.098 (13 tests, 39 runs)

Summary of Statistical Analysis

Statistic Existing (top 2) New

Average (lb/ton) 0.078 0.058

df 43 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 0.17 0.14

For this affected source, valid emissions data were available for two facilities. The 

results of the analysis are summarized in Table 4. Based on the MACT floor analysis, the 

average emissions level achieved by these 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 (Facility K) 0.047 (5 tests, 17 runs)

Midas Operations (Facility L) 0.078 (13 tests, 27 runs)

Summary of Statistical Analysis

Statistic Existing (top 2) New

Average (lb/ton) 0.062 0.047

df 39 15

t 2.43 2.60

Vb 0.00024 0.00026

Vw 0.0026 0.00052

Vt 0.0028 0.00077

99% UPL (lb/ton), MACT Floor 0.2 0.1
***E.O. 12866 Review – Draft – Do Not Cite, Quote, or Release During Review***

12

4. Beyond the Floor2

To evaluate opportunities for emission reductions beyond those that would result from 

requiring facilities 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 this "beyond-the-floor" analysis for 

the four affected sources for the Gold Mine Ore Processing and Production source category.

 

Facilities with ore pretreatment processes either have installed, or would needbe 

required to install, calomel mercury scrubbers and carbon adsorbers on their roasters and 

venturi scrubbers and/ maybe carbon adsorbers on their autoclaves, to achieve the MACT 

floor for ore pretreatment processes. To achieve further reduction in mercury, one We 

identified as a beyond-the-floor option the installation of both a refrigeration unit and a 

carbon adsorber on the remaining facilitiesy 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 capacity of the carbon adsorber. We assumed that 

the additional control from the carbon adsorber would result in a 70 percent reduction of 

mercury emissions. This value was proposed by Newmont Twin Creeks facility in their Phase 

2 application to the Nevada Mercury Control Program. We believe that it is an appropriate 

estimate of emissions reductions seeing as this control has never been demonstrated on an 

autoclave. 

Ore Pretreatment

We estimate that the Twin Creeks facility will not be able to meet the final MACT 

standard without adding controls, thus the costs to add controls to the Twin Creek’s 

autoclaves has been included in the total cost of controls for facilities to meet the MACT 

standard. The estimated capital cost for the additional controls for the autoclaves at Twin 

Creeks would be $29.3 million, with a total annualized cost of $4.9 million/yr. Based on an 

estimated control efficiency of 70 percent, mercury emissions would be reduced by 431 

lbs/yr, resulting in an estimated cost effectiveness of $11,390/lb. We are incorporating this 

 

2 Additional details and documentation for the estimates of emissions, emission reductions, and costs are provided 

in the rulemaking docket (EPA-HQ-OAR-2010-0239).
***E.O. 12866 Review – Draft – Do Not Cite, Quote, or Release During Review***

13

beyond-the-floor analysis in the final rule.

We estimate that the Goldstrike facility will be able meet the MACT standard without 

adding controls to their autoclaves so the costs to add controls to their autoclaves are 

considered beyond-the-floor. We estimate the capital cost for the additional controls on the 

autoclaves at Goldstrike 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. Because of the high cost effectiveness for addition controls to 

the autoclaves at Goldstrike, we are not incorporating this beyond-the-floor analysis in the 

final rule.

We also identified as a beyond-the-floor option the installation of a carbon adsorber on 

ore preheater/dryer units. Again, we assumed that the additional control from the carbon 

adsorber would result in a 70 percent reduction of mercury emissions on the ore 

preheater/dryer units. We believe that this is an appropriate estimate of emissions reductions 

because this control has never been demonstrated on these 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, mercury 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 that one facility, 

which has both roasters and autoclaves, would operate only their roasters. With these

additional controls, 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. 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. 

We also evaluated a beyond-the-floor option for the new source standard. The best 

performing similar source for the ore pretreatment affected source is the Goldstrike facility. 

We identified as a beyond-the-floor option the installation of a carbon adsorber on the 

autoclaves and on ore preheater units at this facility. We estimated the capital cost for the 

additional controls as $48,100,000, with a total annualized cost of $9,419,000/yr. Based on 
***E.O. 12866 Review – Draft – Do Not Cite, Quote, or Release During Review***

14

an estimated control efficiency of 70 percent for the controls on the autoclaves and the ore 

preheaters, mercury emissions would be reduced by 44.6 lbs/yr, resulting in an estimated cost 

effectiveness of $211,188/lb. Because of the high cost effectiveness values, the beyond-thefloor anyslsysis for new sources in the ore pretreatment affected source were not adopted in 

the final rule.

Table 5. Beyond the Floor Results for Ore Pretreatment

Affected Source

Average performance 

(lb Hg/million tons ore)

Gold Quarry (Facility C) (70% reduction) 37

Twin Creeks (Facility D) (70% reduction) 49

Jerritt Canyon (Facility E) (70% reduction) 58

Goldstrike (Facility A) (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 noncarbon concentrate processes), 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 the first or existing 

adsorber and would get an additional reduction of 90 percent. (We acknowledge that there is 

significant uncertainty in the additional reductions the redundant control system might 

achieve.) For carbon processes with mercury retorts, the capital cost for the additional control

was estimated to be $3 million, with a total annualized cost of $1.3 million/yr. The emissions

reductions for this control option would be 9 lbs/yr, resulting in an estimated cost 

effectiveness of $150,275/lb. For non-carbon concentrate processes, we estimated the capital 

Other Affected Sources
***E.O. 12866 Review – Draft – Do Not Cite, Quote, or Release During Review***

15

cost for the additional adsorber to be $0.4 million, with a total annualized cost of 

$191,000/year. The mercury emissions reductions that would be achieved by this option 

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 were 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. The capital cost for a carbon adsorber was estimated 

to be $0.2 million with a total annualized cost of $72,000/yr. The mercury emissions

reduction associated with this option would be 1.6 lbs/yr, resulting in an estimated cost 

effectiveness of $44,000/lb. For the same 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 Limits

Existing Units

Sources

New 

Sources

Ore pretreatment processes 127 84 lb/million tons 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 concentrate
***E.O. 12866 Review – Draft – Do Not Cite, Quote, or Release During Review***

16

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 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 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 1.61E-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 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-07 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 

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
***E.O. 12866 Review – Draft – 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 per 

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 2.07E-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 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 2.36E-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 – Draft – Do Not Cite, Quote, or Release During Review***

18

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

t(.99): 2.36
***E.O. 12866 Review – Draft – Do Not Cite, Quote, or Release During Review***

19

Appendix B. Mercury Emissions Data for the Carbon Processes with Mercury Retorts Affected 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 1.09E-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 1.10E-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 – Draft – 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

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 1.89E-01 6.29E-02 1.47E+00 1.84E-05 3 2 6.13E-06 8.38E-02 6.13E-06 4.95E-01

DentonRawhide Carbon Kiln 3.16E-03 3.47E-03 1.66E-02

DentonRawhide Carbon Kiln 1.15E-02 6.48E-03 2.07E-03

DentonRawhide 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

DentonRawhide Electrowinning 6.46E-04 2.43E-04 6.39E-03

DentonRawhide Electrowinning 1.40E-02 2.62E-03 3.25E-03

DentonRawhide Electrowinning 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

DentonRawhide Melt Furnace 3.64E+00 1.56E+00 1.19E+00

DentonRawhide Melt Furnace 8.90E-01 1.85E+00 1.48E+00

DentonRawhide 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

DentonRawhide Retort 5.84E-05 6.33E-05 7.17E-05

DentonRawhide Retort 4.59E-05 1.50E-05 1.40E-05

DentonRawhide Retort 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 – 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

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 1.16E-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 5.83E-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 Creeks 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-04 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***

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

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-01 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 1.81E-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 Quarry 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 9.23E-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 1.45E-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 Electrowinning 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***

23

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

Florida 

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

Florida 

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***

24

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 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

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 Electrowinning 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: 43Vb: 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***

25

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 

Rochester 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 2.01E-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***

26

Appendix E. New 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

Facility 

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 1.39E-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 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-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

Average = 4.49E-05

DF = 42

t = 2.42

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***

27

Carbon Processes with 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

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

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 (n1) 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 1.56E-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***

28

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

Coeur 

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***

29

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

Goldstrike

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 1.48E-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***

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

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 1.05E-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

Twin 

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 

Creeks 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
***E.O. 12866 Review – Draft – Do Not Cite, Quote, or Release During Review***

31

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:

3.00E11

Vw 

(unpooled

): 3.69E-10

56 t(.99): 2.36