***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **1** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** 6560

- 50

- P

**ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part**  **s 9 and 63**  **[ EPA**  **- HQ**  **- OAR**  **- 20**  **10 -**  **0239 ; FRL**  **- 9140**  **- 7**  ] **RIN 2060**  **- AP48**  **National Emission Standards for Hazardous Air Pollutants: Gold Mine**  **Ore Processing and Production**  **Area Source Category ; and**  **Addition to Sour ce Category List for Standards**  **. AGENCY:**  Environmental Protection Agency (EPA).
**ACTION:** Final rule
. **SUMMARY:** EPA is adding the gold mine ore processing and production area source category to the list of source categories to be regulated under Section 1 12(c)(6) of the Clean Air Act due to its mercury emissions . EPA is also p romulgating national emission standards for hazardous air pollutants to regulate mercury emissions from this source category . EPA proposed these actions on April 28, 2010 (75 FR 224 70).
**DATES:** This final rule is effective on [INSERT DATE 60 DAYS AFTER PUBLICATION IN THE FEDERAL REGISTER].
**ADDRESSES:** EPA has established a docket for this action under Docket ID No. EPA

- HQ

- OAR

- 20 10

- 0239
. All documents in the docket are listed on th e www.regulations.gov w ebsite. Although listed in the index, some information is not publicly available, e.g., Confidential Business Information (CBI) or other information***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **2** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** whose disclosure is restricted by statute. Certain other material, such as copyrig hted material, is not placed on the Internet and will be publicly available only in hard copy form. Publicly available docket materials are available either electronically through www.regulations.gov or in hard copy at the EPA Headquarters Library, Room Nu mber 3334, EPA West Building, 1301 Constitution Ave., NW, Washington, DC. The EPA/DC Public Reading Room hours of operation are 8:30 a.m. to 4:30 p.m. Eastern Standard Time (EST), Monday through Friday. The telephone number for the Public Reading Room is (202) 566

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

- 1742.
**FOR FURTHER INFORMATION CONTACT:** Mr. Chuck French , Sector Policies and Program Division, Office of Air Quality Planning and Standards (D 243

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

- 7912; fax number (919) 541

- 3207, e

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

The information presented in this preambl e is organized as follows:
I. General Information A. Does this action apply to me?***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **3** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** B. Where can I get a copy of this document? C. Judicial Review II. Addition to Section 112(c)(6) Source Category List III . Summary of Significant Changes Since Proposa l A. Applicability B. Final Emission Standards C. Compliance Dates D. Compliance Requirements E. Monitoring Requirements F. Definitions I V. Summary of Responses to Major Comments A. Statutory Requirements B. Applicability C. MACT Floors D. Compl iance Determinations E. Monitoring V. Summary of Environmental, Economic and Health Benefits? VI. Statutory and Executive Order Reviews A. E xecutive Order 12866: Regulatory Planning and Review B. Paperwork Reduction Act C. Regulatory Flexibility Ac t D. Unfunded Mandates Reform Act E. Executive Order 13132: Federalism F. Executive Order 13175: Consultation and Coordination with Indian Tribal Governments G. Executive Order 13045: Protection of Children from Environmental Health and Safety Risks H. Executive Order 13211: Actions Concerning Regulations that Significantly Affect Energy Supply, Distribution, or Use I. National Technology Transfer and Advancement Act J. Executive Order 12898: Federal Actions to Address Environmental Justice in M inority Populations and Low

- Income Populations K. Congressional Review Act **I. General Information 60** 
A. Does this action apply to me The regulated categories and entities potentially affected by th is final rule include: ?***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **4** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** Category NAICS code 1 Examples o f regulated E ntities Industry: Gold Ore Mining 212221 Establishments primarily engaged in developing the mine site, mining, and/or beneficiating (i.e., preparing) ores valued chiefly for their gold content. Establishments primarily engaged in transfo rmation of the gold into bullion or dore bar in combination with mining activities are included in this industry.

1 North American Industry Classification System. This table is not intended to be exhaustive, but rather provides a guide for readers reg arding entities likely to be affected by this action. To determine whether your facility would be regulated by this action, you should examine the applicability criteria in 40 CFR 63. 11640 of subpart EEEEEEE (National Emission Standards for Hazardous Air Pollutants: Gold Mine Ore Pro c essing and Production Area Source Category ). If you have any questions regarding the applicability of this action to a particular entity, consult either the air permit authority for the entity or your EPA Regional representa tive, as listed in 40 CFR 63.13 of subpart A (General Provisions).
B . Where can I get a copy of this document In addition to being available in the docket, an electronic copy of this final action will also be available on the Worldwide Web (WWW) through the EPA Technology Transfer Network ?***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **5** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** (TTN). Following signature, a copy of th is final action will be posted on the TTN’s policy and guidance page for newly proposed or promulgated rules at the following address: www.epa.gov/ttn/oarpg/ . The TTN provides information and technology exchange in various areas of air pollution control.
C. Under section 307(b)(1) of the Clean Air Act (CAA), judicial review of this final rule is available only by filing a petition for review in the U.S. Court of Appeals for the District of Columbia Circuit by [INSERT DATE 60 DAYS AFTER PUBLICATION IN FEDERAL REGISTER]. Under section 307(d)(7)(B) of the CAA, only an objection to this final rule that was raised with reasonable specificity during the period for public comment can be raised during judicial review. Moreover, under section Judicial Review

307(b)(2) of the CAA, the requirements established by this final rule may not be challenged separately in any civil or criminal
proc eedings brought by EPA to enforce these requirements. Section 307(d)(7)(B) also provides a mechanism for us to convene a proceeding for reconsideration, “[i]f the person raising an objection can demonstrate to EPA that it was impracticable to raise such o bjection within [the period for public comment] or if the grounds for such objection arose after***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **6** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** the period for public comment (but within the time specified for judicial review) and if such objection is of central relevance to the outcome of the rule.” A ny person seeking to make such a demonstration to us should submit a Petition for Reconsideration to the Office of the Administrator, U.S. EPA, Room 3000, Ariel Rios Building, 1200 Pennsylvania Ave., NW., Washington, DC 20460, with a copy to the person lis ted in the preceding
**FOR FURTHER INFORMATION CONTACT** section
. **II. Addition to**  **Section 112(c)(6) Source Category List**  For reasons stated in the preamble to the proposed rule ( 75
F R 22470, April 28, 2010 ) , we are adding the gold mine ore processing and pro duction area source category to the list of source categories under section 112(c)(6) on the basis of its mercury emissions.
**III .**  **Summary of Significant Changes Since Proposal** This section summarizes the significant changes to the rule since proposal. A dditional information on the basis for these changes and other changes can be found in the Summary of Responses to Major Comments in Section IV of this preamble.
A. We have clarified in §63.116 51 of the final rule that the term "gold mine ore processing and production facility" does not Applicability***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **7** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** include laboratories (see CAA section 112(c)(7) ) , individual prospectors, and very small pilot scale mining operations. The types of operations are very small and were not included in the section 112(c)(6) inventory that was the basis for the listing of gold mine ore processing and production source category . B. We have made changes to all of the proposed emission standards a s the result of the following developments: (1) inc lusion of additional emission s test data received since proposal; (2) additional analyses in response to public comments on the proposed rule ; and (3) further review of the data used to develop the standards for the proposed rule. The changes are summariz ed below and described in more detail in section IV of this preamble. Final emission standards

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

were 149 pounds per million tons of ore pr ocessed ( lb /million tons of ore). In the final rule, the emission standard for existing sources is 12 7 lb/million tons of ore; for new sources the emission standard is 84 lb/million tons o f ore. The final emission standards are based on several changes t o the data set Ore Pretreatment Processes***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **8** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** used in the MACT analysis. Since we issued the proposed rule,

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

- the

- floor analysis for roasters, which was not included in the proposed rule. The new information and analyses described above are discussed in m ore detail in Section IV.C of this preamble and in the MACT Floor document in the docket for this rulemaking
. The resulting data set included emissions data for four facilities that ranged from 45 to 165 lb/million tons of ore. Based on these data, and u sing the same upper prediction limit (UPL) approach used for proposal to account for variability, we determined the MACT floor to be 158 lb/million tons o f ore for existing sources of ore pretreatment processes and 84 lb/million tons of ore for new sources
. As explained in the proposed rule (75 FR at 22482), the technologies for achieving the MACT floor***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **9** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** for existing ore pretreatment processes include calomel mercury scrubbers on roasters and venturi scrubbers on autoclaves and ancillary roaster operations. After applying the beyond

- the

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

- the

- floor analysis for these sources. Table 1

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

Table 2

— B eyond

- the

- F loor Results for Ore Pretreatment Processes Facility Average performance (lb/million tons of ore ) C 3 7 D 49 E 5 8 A 8 0 Highest Average 8 0 99% UPL existing ( BTF Floor) 12 7***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **10** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** Under the proposed rule, all carbon process es were subject to the same proposed mercury emissions limits of 2.6 pounds per ton of concentrate (lb/ton of concentrate) for existing sources and , for new sources, either 0.14 lb/ton of concentrate or 97 percent reduction in uncontrolled mercury emissions . These limits would have applied to facilities that operate mercury retorts and facilities that do not operate mercury retorts. In the final rule, we distinguish between carbon processes with
mercury retorts and carbon processes without mercury retorts because we believe there are unique differences in these two types of processes
. Therefore, the final ru le specifies separate emission standards for these two types of processes. Moreover, the final emission standards for carbon processes reflect inclusion of new test data that were not available at proposal. We also removed from the data set emissions dat a based on previously uncontrolled sources that installed controls in 2009; for those sources, only the controlled emissions data were used. (see section IV for further details). For carbon processes with mercury retorts, the emission standard in the fina l rule is 2.2 lb/ton of concentrate for existing sources and 0.8 lb/ton of concentrate for new sources. For carbon processes Carbon Processes***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **11** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** without mercury retorts, the emission standard in the final rule is 0.1 7 lb/ton of concentrate for existing sources and 0. 14 lb/to n of concentrate for new sources
. W e considered beyond

the

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

- percent reduction for new carbon processes. After reviewing the comments received on this standard and giving further consideration to the pr acticality of how it would be measured, we concluded that this option would be difficult to implement , particularly when multiple processes that are operated at different times vent to a single control device and stack . In addition, we have limited data s upporting this compliance alternative. In proposing this alternative for comment, we had hoped to , but did not , receive additional data indicating that the 97 percent reduction option would be equivalent to the proposed new source limit of 0.14 pounds of mercury per ton of concentrate. For the reasons stated above, we eliminated the 97 percent control efficiency option for new carbon processes in the final rule.***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **12** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** Table 3 summarizes the results of the MACT floor analysis for carbon processes with mercur y retorts, and Table 4 summarizes the analysis for carbon processes without mercury
retorts. Table 3

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

Table 4

— MACT Floor Results for Carbon Processes without Mercury
Retort s Facility Average performance (lb/ton of concentrate ) M 0.0 58 F 0.0 9 8 Average of top 2 0.0 78 99% UPL existing (MACT Floor) 0. 1 7 99% UPL new (MACT Floor) 0. 14
For carbon processes, regardless of whether the facility operates a mercury retort, the MACT floor is based on control of***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **13** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** mercury emissions using mercury condensers and carbon adsorbers. For the beyond

- the

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

Under the proposed rule, the mercury emission standards for

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

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

- the

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

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

- carbon concentrate processes. Non

- Carbon Concentrate Processes

Table 5

— MACT Floor Results for Non

- Carbon Concentrate Processes Facility Average perform ance (lb/ton of concentrate ) K 0.047 L 0.078 Average of top 2 0.062 99% UPL existing (MACT Floor) 0. 2 99% UPL new (MACT Floor) 0.1

For non

- carbon concentrate processes, the MACT floor is based on***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **14** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** control of mercury emissions using mercury condenser s and carbon adsorbers. For the beyond

- the

- floor analysis, we considered adding a second carbon adsorber to the MACT floor level controls.
C. In the final rule, we provide in §63.11641 that the compliance date for existing sources is 3 years after promulgation of the final rule as opposed to 2 years as proposed
. We review ed the information provided in public comments on the challenges of installing new controls, especially for autoclaves , which , although the controls have not yet been d emonstrated , have been proposed by facilities with autoclaves in their Nevada Mercury Control Program ( NMCP ) permit applications ; and the consideration of installing new controls on the roaster preheaters , which also have not been demonstrated yet , but hav e been proposed by these facilities in their NMCP permit applications. W e concluded th at allowing 3 years for existing sources to comply is appropriate , given the complexity of the sources, the combinations of control devices that are needed in many cases , and the amount of time necessary for designing, install ing, testing, and commissioning addition al emission controls for mercury. Compliance Dates***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **15** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** D. Section 63.11646(a)(1)(v) of the final rule does not include Method 30A , as was proposed, as an appropriate method for determining mercury concentration because it is not yet in general use. T his paragraph further clarifies that the use of ASTM D6784

- 02 and Method 30B are allowed only if approved by the permit authority
. The final rule also does no t include the requirement to follow the acetone rinse procedures and the absence of cyclonic flow determination requirement, which were in subparagraph s (v) and (vi) respectively of our proposed §63.11646(a)(1). Method 29 already includes requirements for the acetone rinse, so there is no need to specify those procedures in the rule; and Method 1, which is required by the rule, addresses the issue of cyclonic flow. Compliance Requirements

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

- de tect values. If the emission testing results for any of the emission points yield a

non - detect value, the final rule requires that the minimum***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **16** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** detection limit (MDL) be used to calculate the mass emissions rate used to calculate the emissions factor (lb/to n) for that emission point and to calculate the sum of the emissions factors for all emission points subject to the emission standard. If the resulting mercury emissions factor is greater than the allowable emission standard , the owner or operator may rep eat the mercury emissions testing one additional time for any emission point for which the measured result was below the MDL using procedures that produce lower MDL results. If this additional testing is performed, the results from that testing must be us ed to determine compliance. For sources with multiple emission units (e.g., two roasters) ducted to a common control device and stack, we have clarified in §63.11646(a)(3) that compliance testing must be performed with all affected emissions units in oper ation , if this is possible . This same requirement applies to the establishment of operating limits for all process units. However, this requirement does not affect the frequency and schedule for monitoring , which are specified in the rule. If facilities have batch type processes that cannot be operated simultaneously, then the facility can test some or all of the units individually.***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **17** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** In §63.11646(a)(6) and (7) , we clarify that the production data used in compliance determinations are based on full calend ar months. For the initial compliance test, data for all the full calendar months between publication of the final rule and the initial compliance test must be used. For subsequent annual compliance tests, data for the 12 full calendar months prior to th e annual compliance test must be used to demonstrate compliance. In addition, we clarify in paragraphs §63.11646(a)(5), (6) and (7) that compliance determinations are based on the number of 1

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

- hour p eriod terminology, the final rule language is consistent with the terminology used in the General Provisions to part 63.
Because the final rule does not include the 97 percent reduction option that was in §63.11645(e)(2) of the proposed rule , we have remo ved from the final rule the compliance requir e ment for that option that was in §63.11646(b) of the proposed rule , which addressed testing the inlets and outlets for sources choosing that proposed option
. E. Section 63.11647(a) of the final rule include s an additional option for monitoring mercury emissions from Monitoring Requirements***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **18** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** roasters. The proposed rule specified two options for monitoring mercury emissions: paragraph (a)(1) specified weekly sampling using PS 12B, and paragraph (a)(2) specified continuous monitoring using a mercury continuous emissions monitoring system ( CEMS ) . In the final rule, we added paragraph (a)(3) to provide a third option of continuous sampling using PS 12B. In addition, paragraph (a)(1) in the final rule was changed to require sampling at least twice per month using either PS 12B or Method 30B rather than weekly
. W e believe that Method 30B is an acceptable alternative method for monitoring purposes and allows owners and operators more flexibility in how they monitor roaster emissions. We also believe that sampling twice per month coupled with extensive parametric monitoring of control devices (as explained below) is sufficient for this monitoring option. Section 63.11647(a)(4)(iii) of the proposed rule would have

re quired additional compliance testing if the mercury concentration in the ore fed to the roaster was higher than any concentration measured in the previous 12 months. We have removed this requirement from the final rule because it is not clear that the mer cury content of the ore has a significant effect on the performance of mercury scrubbers applied to***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **19** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** roasters, which are designed to handle and operate efficiently for a range of mercury inlet concentrations. In addition, condense rs are used to recover ele mental mercury prior to the mercury scrubber, and any increase in mercury loading would likely result in an increase in the recovery of elemental
mercury. The final rule incorporates several changes to §63.11647(b), which addresses monitoring of calomel scrubbers that are used to control emissions from roasters. The final

r u le does not include the requirement to monitor pressure drop across calomel

- based scrubber s because we conclude that pressure drop is not related to mercury emission control performa nce by this type of control device . In addition, the final rule allow s hourly monitoring of the line pressure in the scrubber liquid supply line as an alternative to hourly monitoring of scrubber liquid flow rate. Line pressure monitoring is already in
p ractice at some facilities and provides the same type of information as does liquid flow rate. As was proposed, t he final rule allow s the operating limit for scrubber liquid flow
rate (or line pressure) to be based on the minimum flow rate ( or line pressu re ) established during the initial performance test
. It also includes two additional options for setting the***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **20** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** operating limit: (1) based on the manufacturer’s specifications if certain types of systems are designed to operate within a specified range of f low rates; and (2) based on limits established by the permitting authority. I f the facility chooses the first option (to establish the limits during initial compliance) , the final rule requires the operating limit to be based on either the lowest value fo r any run of the initial compliance test or 10 percent less than the average value measured during the compliance test. This requirement takes into account the fact that, although initially the system may exhibit little variability from test run to test r un, the short

term variability in performance may increase with time. Additional discussion of these changes can be found in Section IV.E of this preamble and in the Summary of Public Comments and Responses document in the docket for this rulemaking.
We have clarified the requirements for corrective action following control device monitoring parameter exceedances specified in §63.11647(d). Under the final rule, if the corrective actions taken following an exceedance do not result in the parameter value ( e.g. , water flow rate, pressure drop, etc.) being returned to within the parameter range or limit within 48 hours, a mercury concentration measurement must be***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **21** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** made to determine if the operating limit for mercury concentration is being exceeded. The measur ement must be performed and the concentration determined within 48 hours after the initial 48 hours , or a total of 96 hours from the time the parameter was exceeded . If the measured mercury concentration meets the operating limit for mercury concentration , the corrective actions are deemed successful. In addition, the owner or operator may request approval from the permitting authority to change the parameter range or limit based on measurements of the parameter at the time the mercury concentration measu rement was made. If , on the other hand, the measured mercury concentration indicates the operating limit for mercury concentration is exceeded, the exceedance must be reported as a deviation within 24 hours to the permit ting authority , and the facility mu st perform a compliance test (pursuant to §63.11647(d) ) within 40 days to determine whether the source is in compliance with the MACT standard
. We believe 40 days is reasonable because it may take 3 to 4 weeks to schedule and have the testing contractor o n site, and, following completion of the test, another week to receive the finals test results. In §63.11647(a)(1)(ii) of the final rule, we require t hese***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **22** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** same corrective action s described above (i.e., measuring mercury concentration within 48 hours , repor ting a deviation if the data show the operating limit was exceeded within 24 hours , and conducting a compliance test within 40 days ) for exceedances of mercury concentration operating limits indicated by the results of the twice month ly monitoring using PS 12B or Method 30B , CEMS, or continuous monitoring using PS 12B
. In such cases, the owner or operator must use the results of the compliance test to determine if the roaster operations are in compliance with the emission standard . If the source is determ ined to be in compliance , the owner or operator may use this compliance test to establish a new operating limit for mercury concentration. We also removed the requirement that roasters must shut down operations if a parameter is out of range. In the fina l rule, §63.11647(f)(1) require s monthly sampling of the exhaust stream of carbon adsorbers using Method 30B . The duration of sampling must be at least the minimum sampling time specified in Method 30B , up to one week. The proposed rule required a full w eek of such sampling, but, as pointed out by one of the commenters, breakthrough of the sampling trap from exhaust streams with high mercury concentrations could occur before a week had elapsed.***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **23** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** Section 63.11647(f)(2) of the final rule clarif ies that

sam pling of the carbon bed must be collected from the inlet and outlet of the bed. T his paragraph also specifies that, for carbon adsorbers with multiple carbon columns or beds, the sampling should be performed in the first and last column or bed rather than at the inlet or outlet. We have deleted §63.11647(f)(3) in the proposed rule , which allowed the carbon bed change

- out rate to be determined based on historical data and the estimated life of the carbon. We have concluded that this method would not be ad equate to ensure that breakthrough does not occur earlier than expected. We have clarified §63.11647(h) with respect to monitoring of scrubber s . Under the final rule, owners or operations are required to monitor and record water flow rate (or line
pres sure) and scrubber pressure drop once per shift ; they also must record any occurrences when the pressure drop was outside the manufacturer’s recommended operating range , take corrective actions to return the pressure drop back in range, and record the corr ective actions taken. At proposal , the water flow rate and pressure drop were to be monitored continuously . However , measuring pressure drop once per shift will provide two to three measurements per day, and we believe that is sufficient to***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **24** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** assure proper operating of the wet scrubber, and thus assure compliance with the emission standards
. We have also added the option of monitoring the line pressure in the scrubber liquid supply line as an alternative to monitoring scrubber liquid flow
rate because l ine pressure monitoring is already in practice at some facilities and provides the same type of information as does liquid flow rate
. We have also clarified that , for scrubbers on autoclaves, the pressure drop parameter range should be established from manuf acturer’s specifications only.
**F.** We have added a definition of carbon adsorber to §63.11651 to clarify that this term, as used in the final rule, includes control devices consisting of a single fixed carbon bed, multiple carbon beds or co lumns, carbon filter packs or modules, and other variations of carbon adsorber design
. **Definitions**

T he definition of "gold mine ore processing and production facility" in §63.116 51 of the rule has been clarif ied to state that operations, such as prospectors, laborat ories, and very small pilot scale mining operations, that process or produce less than 5 0 pounds of concentrate per year are excluded from the source category. These prospectors and very small pilot

scale operations (that process at or below th is cutoff) are***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **25** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** orders of magnitude smaller than all the facilities in our database. These very small operations process far less material than the typical facility in our inventory. For example, the 21 facilities that are in our current inventory and that we expect will be subject to the final rule process or produce between 4,000 to 500,000 pounds of concentrate per year (i.e., at least 100 times the 5 0 lb/yr cut o ff). These types of very small operations were not intended to be subject to the final rule , and we do not expect any significant emissions from them. We also clarified that the source category does not include facilities at which 95 percent or more of the metals produced are metals other than gold. For example, if other non

- ferrous metals (such as coppe r, lead, nickel, or zinc) comprise 95 percent or more of the product, the facility is not part of the gold ore processing and production source category. **IV. Summary of Responses to Major Comments** A. Statutory Requirements 1. Listing of the Gold Min e Ore Processing and Production Source Category Under Section 112(c)(6)
**Comment :**  One commenter stated that adding the gold mine ore processing and production category to the list of categories required by Clean Air Act (CAA) section 112(c)(6) was correct***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **26** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** and required because gold mines accounted for a significant portion of the aggregate emissions of mercury in the baseline year (1990) and because they still do so today
. Several other commenters claimed that EPA did not provide the legal basis for listing gold mining as a source category under section 112(c)(6). The se commenters stat ed that EPA does not have the authority to list gold mining as a source category under section 112(c)(6) and noted that section 112(c)(6) requires EPA to list, by 1995, catego ries of sources that make up 90 percent of the 1990 emissions for a subset of hazardous air pollutants (HAP), including mercury. The commenters said that EPA concluded its statutory listing obligation for mercury in 1998 with the publication of a list of source categories constituting 90 percent of aggregate mercury emissions, and that gold mining was not included on that list in 1998. In addition, the commenters said that the CAA requires EPA to list all categories under section 112(c)(6) by 1995 and com plete issuance of standards for all listed sources by 2000, a task that would be impossible if EPA had the authority to add source categories ad infinitum. **Response :**  Section 112(c)(6) does not prescribe any methodology that EPA must follow in listing sou rce categories, thus giving EPA discretion on how to carry out this obligation.***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **27** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** Therefore, unless sources from the gold mine ore processing and production area source category did not emit mercury in the 1990 baseline year, EPA has authority to list that category for regulation pursuant to section 112(c)(6). Some commenters questioned EPA’s estimated emission s of 4.4 tons from this source category in the 1990 baseline year; however, they did not estimate or explain what the baseline emission should have been. EPA continues to believe that its baseline emission s estimate is reasonable and, as mentioned above, we have not received other estimates. We disagree with the comment that , because EPA already completed this listing obligation when it published it s section 112(c)(6) category list on April 10, 1998 (63 FR 17838), EPA has no authority to list gold mine ore processing and production as a category under section 112(c)(6) . Section 112(c)(6) requires that EPA list sufficient categories to ensure that so urces accounting for not less than 90 percent of the aggregate emissions of each of the HAP specified in section 112(c)(6) are subject to standards. Although section 112(c)(6) requires that EPA list the categories by 1995, it contains no language prohibit ing EPA from revising the list . In fact, i n order for EPA to regulate sufficient source categories to meet the 90 percent statutory requirement,***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **28** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** EPA must have the authority to revise the category list, including adding categories , should it discover durin g the course of developing section 112(c)(6) standards that such revision is necessary to meet the statutory 90 percent obligation. Further, were the section 112(c)(6) list of source categor ies that EPA published in 1998 considered final and unchangeable under the CAA , the CAA would have made the list judicial ly reviewable upon publication to ensure that EPA can later regulate sufficient categories to meet the statutory 90 percent requirement. To the contrary, CAA section 112(e)(4)
states that listing of a source category under section 112(c) is not a final agency action subject to judicial review , but such action may be reviewed when EPA issue s the standards. In l ight of section 112(e)(4), and were EPA prohibited from revising the category list, as the c ommenter claimed, it could potentially be impossible for EPA to meet the 90 percent requirement under section 112(c)(6). We do not believe that Congress would have structured the CAA in a way that c ould potentially make it impossible for EPA to meet a sta tutory requirement. For the reasons stated above , w e believe that EPA has authority to revise the section 112(c)(6) category list as necessary to ensure that sufficient categories are subject to regulation***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **29** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** under section 112(c)(6)
. W e also reject the comm ent that the task of completing standards by 2000 would be impossible if EPA had the authority to add source categories.
**Comment :**  Several commenters stated that Phase 2 permits under the Nevada Mercury Control Program ( NMCP ) , which are schedul ed for issuance by the end of 2010, will result in MACT

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

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

- existent or only a fraction of the amount found in Nevada, and Nevada accounted for 99 percent of mercury emissions associated with gold mining operations in the United States. According to the commenters, this shows that i f Nevada has an equivalent mercury control program for the gold mining industry, then there is nothing to be gained from imposing a federal program, and if EPA acknowledges that the mines in Nevada are already well controlled, then the listing of gold mini ng and the promulgation***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **30** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** of an additional layer of regulation at substantial cost to industry , but with little environmental benefit, is both legally indefensible and practically unsupportable. **Response :**  We believe it is appropriate to promulgate MACT
st andards for mercury emissions for this industry. Based on our 1990 baseline inventory for 112(c)(6) and other emission information for subsequent years, w e estimate that this industry was among the top ten highest

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

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

concerns about potential emissions from new gold mine facilities
. In summary, we believe it is necessary and appropriate to promulgate a federal NESHAP for existing and new gold mine ore processing and producti on facilities
. 2 . Emission Standards for HAP Other t han Mercury
**Comment :**  One commenter stated that CAA section 112(c)(6) provides that EPA must “list categories and subcategories of sources assuring that sources accounting for not less than 90 percent of each [enumerated] pollutant are subject to standards***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **31** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** under subsection (d)(2) or (d)(4) of this section.” The commenter also stated that the D.C. Circuit has held repeatedly that when EPA sets standards for a category or subcategory of sources under secti on 112(d)(2), EPA has a clear statutory duty to set emission standards for each HAP that the sources in that category or subcategory emit (e.g., National Lime Ass’n v. EPA , 233 F.3d 625, 633

- 634 (D.C. Cir. 2000)). The commenter concluded that when EPA set s standards for gold mines under section 112(d)(2), as section 112(c)(6) requires it to do, EPA must set section 112(d)(2) emission standards for all the HAP that gold mines emit. The commenter said that EPA appears to believe that because gold mines are needed only to reach section 112(c)(6) requirement of 90 percent for mercury and not for the other pollutants enumerated in section 112(c)(6), EPA’s only obligation under section 112(c)(6) is to set section 112(d)(2) standards for mercury. The commenter said that section 112(c)(6) expressly requires EPA to issue section 112(d)(2) standards for the “sources” in the categories listed under section 112(c)(6), not some subset of the pollutants that those sources emit, and that section 112(d)(2) standards must include emission standards for each HAP that a source category emits.***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **32** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** The commenter continued by stating that nothing in the CAA exempts EPA from this requirement. The commenter concluded that , had Congress wished to give EPA discretion to set standards for only some of the pollutants emitted by a category listed under section 112(c)(6), it would have done so expressly. **Response :**  EPA disagrees with the comment that , even though EPA lists a category under section 112(c)(6) due to the emissions of one or more HAP specified in that section, EPA must issue emission standards for all HAP (including HAP not listed in section 112(c)(6)) that sources in that category emit
. The commenter cited in support the opinion by the United States Court of Appeals for the D.C. Circuit in National Lime Ass’n v.
EPA , 233 F.3d 625, 633

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

no sources using control technologies for those HAP. In rejecting EPA’s argument , t he c ourt state d that EPA has “a statutory obligation to set emission standards for each listed
HAP.” Id
. at 634. T he Court noted the l ist of HAP in section 112(b) and stated that section 112(d)(1) require s that EPA

“ promulgate regulations establishing emission standards for each***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **33** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** category or subcategory of major sources ... of hazardous air pollutants listed for regulation ..” Id. (Emphas is added). For the reasons stated below, we do not believe that today’s final rule conflicts with the National Lime decision. There are several important distinctions between the National Lime case and this final rule for Gold Mine Ore Processing and Pro duction area source category. First, the National Lime case dealt with a major source category
. Second , the relevant issue in the portion of the opinion referenced by the commenter was how EPA set standards for a HAP where there are no control technologi es being used to control that HAP
. Accordingly, the court’s statements described above in National Lime were made to address th is specific issue and in the context of a major source category. Today’s final rule applies to EPA’s obligation to issue emissi on standards for a listed area source category under CAA section 112(c)(6)
. The National Lime case did not address area source categories or EPA’s obligation under section 112(c)(6). We further note that the applicable lists of HAP under the CAA differ for major and area source categories
. Under CAA section 112(c) , a major source category must be listed for regulation if it emit s any of the HAP listed in section 112(b)
.***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **34** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** Accordingly, in National Lime , t he c ourt referenced the 112(b) HAP list in requirin g that EPA “ promulgate regulations establishing emission standards for each category or subcategory of major sources ... of hazardous air pollutants listed for regulation.” Id. Unlike major source categories, the CAA does not require that EPA list an ar ea source category for regulation if it emits a pollutant listed in section 112(b). Rather, an area source category may be listed for regulation under section 112 if EPA ma kes an adverse effect finding pursuant to Section 112(c)(3) or if that area source category emits an urban HAP listed under section 112(k) or a HAP listed in section 112(c)(6). T he gold mine ore processing and production area source category is listed for regulation under section 112(c)(6 ) because it emits mercury, one of the HAP listed in section 112(c)(6). Because the lis ted HAP at issue is only mercury , we have established in this final rule mercury emission standards for this area source category
. For the reasons stated above, EPA disagrees with the comment that it must set emissio n standards for all HAP emitted by the gold mine ore processing and production area source category.***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **35** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** 3 . Emission Standards for Fugitive Emissions
**Comment :**  One commenter stated that gold mines have significant fugitive emissions of mercury, but that EPA did not propose standards for these emissions or mention them in its proposal. The commenter said that EPA has a statutory obligation to set standards for gold mine mercury emissions under section 112(d)(2) and (3), and must set emission standards for all the mercury emissions from the listed category
. The commenter described a recent preliminary study at two facilities in Nevada that found fugitive mercury air emissions from various

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

- based complexing agents for removing mercury during cyanidization of gold. According to the commenter, research indicates that these***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **36** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** products appear useful for substantially reducing mercury in process solution during heap leaching. **Response**

Furthermore, we have very little information on how these fugitive mercury emissions might be controlled. A few commenters suggested that certain compounds were available that may be useful for limiting these emissions. However, as far as we know, there has been no demonstration that these compounds would work effectively to limit the emissions, and we do not **:** W e have not included fugitive mercury emissions at gold mine facilities in our 1990 baseline emission s estimate , or in our more recent emissions estimates, largely due to the lack of information about these emissions. Accordingl y, these fugitive emissions are not part of the source category we are listing and regulating in this final rule. Other than the

r ecent preliminary research at two facilities , we have no data on fugitive mercury emissions from gold mine facilities. The

r ecent preliminary research suggests that some fugitive emissions may be occurring at these facilities from large non

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

reviewed
.***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **37** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** know the costs or potential adverse impacts of applying these chemicals. Therefore, we question the f easibility and practicality of applying these chemicals to limit fugitive mercury emissions from these non

- point sources. We also question the feasib ility and practical ity of enclos ing the leaching operations or the tailings ponds , as suggested by some

co mmenters . As explained in the proposed rule, the gold mine ore processing and production area source category covers the thermal processes that occur after ore crushing, including roasting operations (i.e., ore dry grinding, ore preheating, roasting, and quenching), autoclaves, carbon kilns, electrowinning, preg tanks, retorts, and furnaces. T he data and calculations used to derive the estimate d 4.4 tons of mercury emissions for this source category for the 1990 baseline inventory for section 112(c)(6) r eflect emissions from the thermal processes described above, and t he final MACT standards address all of these processes
. 4 . Major Source Determination
**Comment :**  One commenter noted that the proposal stated that the gold mining processing and production source category consists of only area sources; however, the proposal indicated***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **38** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** that actual emissions of hydrogen cyanide (HCN) at a few facilities were near the major source threshold. The commenter concluded that EPA violates both the CAA and its own re gulations by basing its evaluation of whether gold mines are major sources on their actual emissions instead of their potential emissions. The commenter also stated that EPA’s failure to apply the same variability analysis in calculating gold mines’ pote ntial to emit that was used in setting floors was internally inconsistent, unexplained, and arbitrary and capricious. The commenter noted that the proposal requested comment on a certification process that would allow gold mines to avoid major
source stat us whereby companies could certify that they are area sources by implementing certain “management practices” and then certifying to EPA that they had done so. The commenter stated that such a certification process would be unlawful in calculating a source s “potential to emit” because the management practices are not “control equipment,” “restrictions on hours of operation or on the type or amount of material combusted, stored, or processed,” and would not be “federally enforceable.” Other commenters suppor ted EPA’s conclusion and determination that the gold mines are area sources of HAP. According to the commenters, EPA’s methodology in making this***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **39** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** determination was extremely conservative and resulted in higher calculated HCN emissions than may actually be present. The commenters stated that fence line testing at selected gold mine operations demonstrated that there was no concern with offsite levels of HCN emissions. The commenters believe that , because the gold mines are area sources of HCN, they should not be subject to section 112 work practice standards or newly developed certification requirements. The commenters noted that it is not technically practical to set systematic work practice standards to reduce HCN emissions for every gold mining operatio n to follow because each mine is unique in its mineralogy and cyanide leaching
processes , and different process solution pH values are necessary to enhance gold recovery. The commenters explained that for economic, health, and safety reasons, they alread y implement work practice standards designed to minimize HCN. The commenter concluded that the combination of these work practice standards and the annual TRI reporting more than adequately ensure that gold mining operations will remain area sources of HC N. **Response :**  Based on available data we estimate that the largest emitting facility emits between 5 to 9 tons per year of***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **40** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** hydrogen cyanide , and that a ll other facilities emit less than this level. Based on test data, a ll facilities emit less than 25 tons per year for the sum of all HAP. Our analysis of the test data included calculations based on facilities operating at full capacity. We understand that these facilities implement various management practices to minimize the use and emissions of cyanide to protect workers , to comply with Mine Safety and Health Administration (MSHA) standards , to comply with their agreements to the International Cyanide Code , and for economic reasons (to reduce operational and supply costs) . Most companies are signatories to the international Cyanide Management Code , which includes a number of provisions to minimize the use and release of cyanide
. As a commenter correctly notes, in determining whether a source is a major source under CAA section 112, we must consider the source’s potential to emit as well as its actual emissions. See CAA section 112(a)(1) and 40 CFR 63.2. In determining a source’s potential to emit, we may consider physical and operation limitations that are “federal ly enforceable,” which is defined in our regulation as limitations and conditions that are enforceable by EPA and the citizens under the CAA or by EPA under other statutes. See 40 CFR 63.2 for definitions of***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **41** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** “potential to emit” and “federally enforceable.” It is our current understanding th at t he above

- mentioned standards and agreements for implementing hydrogen cyanide management practices are not federally enforceable, as that term is defined. Accordingly, we believe that the emission s reduction s achieved through these management practice s would not be considered in determining gold mine facilities’ potential to emit. We currently do not have sufficient information to quantify the emissions reductions achieved through these management practices. However, based on our current knowledge of these management practices and our hydrogen cyanide emission estimates, we believe that most of these facilities are area sources. Accordingly, we are taking final action today to list the gold mine ore processing and production area source category and regulate its mercury emissions pursuant to CAA section 112(c)(6). In addition, we plan to evaluate the area source status of the largest facilities by gathering additional information about these management practices, including information on their emiss ions reduction potential. We plan to use the additional information to further evaluate the potential to emit of these few large facilities and subsequently address their cyanide and***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **42** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** other emissions if necessary or appropriate.
5 . Title V Permit Exemptio n **Comment**

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

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

**•** It is feasible and within the gold mining companies’ financial means to comply with title V permitting requirements. The commenter believes that the text and legislative history of the CAA make plain that Congress intended ordinary citizens to be able to get emissions and compliance information about air toxics sources and to be able to use that information in enforcement actions and in public policy decisions on a State and local level. According to the commenter, Congress did not think that enfo rcement by States or other government entities was enough; if it had, Congress would not have enacted the***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **43** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** citizen suit provisions. The commenter said that , if a source does not have a title V permit, it is difficult or impossible for a member of the publi c to obtain relevant information about its emissions and compliance status or to bring enforcement actions. The commenter stated that to the extent the informational and enforcement benefits provided by title V permits can be considered a burden, the se be nefits far outweigh that burden. The commenter also noted that title V provides important monitoring benefits and that title V permits are necessary to provide adequate monitoring. The commenter concluded by stating that the legislative history of the CA A shows that Congress did not intend EPA to exempt source categories from compliance with title V unless doing so would not adversely affect public health, welfare, or the environment; however, exempting gold mines from title V would adversely affect publi c health, welfare and the environment by depriving the public of important informational and enforcement benefits. One State agency commented that additional title V permitting would subject both the source and the State agency to additional resource burd ens. The commenter points out that major sources of criteria pollutant emissions are currently***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **44** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** subject to title V permit requirements in Nevada and that sources not subject to major source permitting requirements are subject to Nevada’s minor source permi tting program. In addition, the NMCP requires all mining sources to obtain
mercury - specific operating permits to construct. The commenter believes that these permit programs would provide a strong basis for implementing and enforcing any F ederal MACT req uirements for the gold mining industry, and there would be nothing gained by subjecting these sources to title V permitting. Several commenters stated that EPA should exercise its discretion and exempt the gold mine ore processing and production industry f rom the title V requirements as impracticable, infeasible, and unnecessarily burdensome. The commenters said that, in light of EPA’s findings in other similar rulemakings for area sources, the four factors set forth in the Exemption Rule support a finding that title V permitting is “unnecessarily burdensome” for the gold mine ore processing and production area source category. In discussing the first factor of the Exemption Rule, whether title V would result in significant improvements to the compliance r equirements, the commenters said that the proposed NESHAP for the gold mine ore processing and production area***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **45** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** source category includes extensive monitoring, recordkeeping, and reporting requirements that are more comprehensive than title V requirements. The commenters believe that Nevada regulations and permits provide an additional layer of compliance assurance on the federal NESHAP that obviates the need for title V permitting. The commenters claimed that the additional layering of title V does not “si gnificantly improve” upon the proposed and existing compliance requirements. Regarding the second factor in the Exemption Rule, whether title V permitting would impose significant burdens on the area source category and whether the burdens would be aggrava ted by any difficulty the sources may have in obtaining assistance from permitting agencies, the commenters said that there are extensive administrative burdens and costs associated with the title V permitting process, including mandatory activities that h ave been previously identified by EPA. The commenters claimed that many of the area source gold mines are owned and operated by small entities that are already required to comply with comprehensive State permitting requirements for mercury emissions and t hat requiring title V permits for them would result in resources being redirected away from more useful and necessary efforts.***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **46** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** The commenters explained that the third factor in the Exemption Rule examines whether the costs of title V permitting for the are a source category would be justified, taking into consideration any potential gains in compliance likely to occur for such sources. The commenters claim that there do not appear to be any gains in compliance to justify the additional costs that would be i mposed on these area sources from title V permitting based on the lack of significant improvements in compliance requirements and the substantial additional costs and burdens associated with title V compliance. The commenters noted that the fourth factor i n the Exemption Rule analysis is whether there are implementation and enforcement programs in place that are sufficient to assure compliance with the NESHAP for the area source category, without relying on title V permits. The commenters claimed that the proposed rule includes all necessary monitoring to effectively implement its requirements, and the area sources for the gold mine ore processing and production are already permitted under State permit programs. According to the commenters, all non

title V sources in Nevada are required to hold “Class II” operating permits that must contain, among other things, all applicable emission limitations and standards. The commenters***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **47** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** said that other States where gold mine ore processing and production area source are located either would be covered by a comparable delegated State air program or by EPA. The commenters stated that EPA regularly provides title V exemptions for area sources similar to gold mine ore processing and production area sources and cited examp les from the past
year. The commenters claim that the existing and proposed compliance and monitoring requirements for the gold mines are generally more stringent than those found in the other NESHAPs for which EPA has granted a title V permit exemption. The commenters stated that exempting the gold mine ore processing and production area source category from title V permitting will not adversely affect public health, welfare, or the environment because title V permits do not generally impose substantive air quality control requirements
. According to the commenters, requiring title V permits also carries the potential of adversely affecting public health, welfare, or the environment by shifting State agency resources away from ensuring compliance with a p rogram that is reducing mercury emissions from gold mines. The commenters stated that EPA should exempt the gold mine ore processing and production area source category from title V***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **48** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** permitting requirements, and at a minimum, should exempt area source gold mines that are subject to Nevada’s comprehensive mercury control program
. **Response**

Currently, it is our understanding that 7 of the 21 facilities that will be subject to the final rule already have title V permits ( 5 i n Nevada and 2 in other states )
. Further, there are approximately 5 facilities in all other States ( i.e., except Nevada) that do not have title V permits that will be **:** After reviewing the comments, w e continue to believe that it is appropriate that all gold mine ore processing and production facilities be required to obtain title V permi ts. Most of the other area source categories for which we have provided title V permit exemption s have hundreds or thousands of facilities that are mostly owned by small businesses
. In contrast, t here are an estimated 21 facilities that are subject to th is final rule , and , based on our research and analyses , none of the facilities are owned by small business; most of these facilities a re owned by large, and i n some cases, multi

national , corporations . Therefore, we do not believe that the argument of fin ancial burden, which has supported title V exemption for other source categories, applies to the gold mining industry.***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **49** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** subject to this final r ule , so title V permitting w ill apply to no more than a few facil ities in any one of the se other States. Therefore, we do not believe the requirement for title V permitting will be overly burdensome to the permitting authorities in those States
. Although there are many more facilities in Nevada that will be subject to the final rule, a s the commenters point out, Nevada already has an effective permitting system in place. Five of the 14 gold mine facilities in Nevada already have title V permits . Because of Nevada’s existing permitting system and experience with title V permitting , w e do not think that it is an undue burden on the State of Nevada to require title V permits from the other gold mine facilities located within the State. We also think it is important for the public in those States, where these facilities are located, to have access to emissions and monitoring data and the opportunity for public involvement in the permitting of these facilities that is provided by title V permitting
. 6 . Reconstruction
**Comment :**  Several commenters believe it is appropriate to group under each of the umbrella “affected sources” all the equipment associated with each particular process in order to ensure a reasonable application of the reconstruction provisions***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **50** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** found in the General Provisions. The commenters asked that EPA

r eaffirm that the 50 percent fixed capital cost trigger for determining reconstruction would be measured against all equipment components needed for the defined processes, and that reconstruction at one affected source as defined in the standard will not af fect or result in reconstruction at another affected

source. The commenters also noted that the definition of “reconstruction” authorizes EPA to establish special provisions in a particular standard for the application of the reconstruction criteria to th e affected source. The commenters said that the “carbon processes” affected source illustrates that the affected source can consist of several pieces of interconnected equipment that together constitute the process line, and it can be anticipated that pro duction needs will give rise to the need to add more pieces of equipment to an existing carbon process line or even to install a whole new carbon process line. The commenters provided three examples: adding a new component to an existing carbon processes group , construction of a new carbon group due to expansion at a facility that has an existing carbon group ; and installation of new pollution control equipment . The commenter said that***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **51** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** consideration of whether or where new MACT requirements should apply i n these examples warrants the development of special reconstruction provisions in this standard, or EPA should clarify that the three examples would not be considered reconstruction under the proposed rule. The commenters asked that EPA either clarify tha t the three examples would not be considered reconstruction, or alternatively, add the following provisions to the proposed rule: (1) an addition of a new piece of equipment to address production requirements is not considered a reconstruction, (2) the ex pansion of a facility by the construction of a completely new process line will not be considered a reconstruction of an existing process line, and (3) the installation of air pollution control equipment to comply with this standard is not considered

a rec onstruction. **Response**

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

(1) The fixed capital cost of the new components exceeds 50 percent of the fixed capital cost that***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **52** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** would be required to construc t a comparable new [affected] source; and (2) It is technologically and economically feasible for the reconstructed source to meet the relevant standard(s) established by the Administrator (or a State) pursuant to section 112 of the Act. Upon reconstructio n, an affected source, or a stationary source that becomes an affected source, is subject to relevant standards for new sources, including compliance dates, irrespective of any change in emissions of hazardous air pollutants from that source. For each of t he four affected sources in the final rule, we have defined the affected source as the collection of processes associated within each affected source. Consequently, if one process within the affected source is upgraded or replaced with a new process, the 50 percent fixed capital cost criterion would be based on the fixed capital cost of replacing all processes in the affected source, not just the capital cost of the process being upgraded or replaced. For example, if a new carbon kiln is added to an exist ing group of carbon processes with mercury
retorts , the capital cost of the new carbon kiln would be divided by the fixed capital cost of constructing a comparable new affected source containing all of the processes within the existing affected source of c arbon processes with mercury
retorts to calculate the percent for comparison to the 50 percent criterion. With regard to the scenario where a new carbon processes***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **53** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** with mercury retorts group is installed, t he affected source is defined as the collection o f all applicable processes within the affected source, and because of this, a facility could not have two carbon processes with mercury retorts affected sources, such as the commenter suggested, where one group is new and the other is existing. For exampl e, if a new group of carbon processes with mercury retorts is installed at a facility in addition to existing group of carbon processes with mercury retorts , the two groups (all carbon processes with mercury retorts at the facility) collectively would be a single affected source. In this case, the fixed capital cost criterion would be based on the fixed capital cost of replacing the existing affected source with a comparable new affected source, and if the new processes exceed 50 percent of that cost, all of the carbon processes with
mercury retorts would be subject to the new source limit for carbon processes. There would not be separate and different emission standards for the two sets of carbon sources with
mercury retorts (the older group and newer gro up) because the collection of all of these processes is the affected source. We do not see a necessity to provide criteria for this final rule that are different from the requirements in the General Provisions for determining what constitutes a***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **54** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** reconstruc tion. We also think it is appropriate to exclude the cost of emission control equipment from the cost calculation for reconstruction determinations. B. Applicability
**Comment :**  Several commenters stated the rule should exempt individuals (prospectors), la boratories, small mining operations, and non

- leaching operations. The commenters urged EPA to include in the final rule all of the following exemptions to avoid the problem of unintended regulation of sources that were not meant to be included in the sour ce category: gold mining operations that produce less than 100 pounds of concentrate per year, which would exempt analytical labs that perform small bench scale processing tests on gold ores; gold mining operations that do not leach or dissolve gold, which would exempt placer and other non

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

type prospectors; and gold mining operations that process less than 1,000 tons per year of gold ore, which would exempt certain small scale pilot plants and related testing operations. The commenters said that the exemptions suggested above will not reduce in any way the effectiveness of the proposed rule in controlling mercury emissions from the targeted larger mines,***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **55** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** nor will th ey lead to increased mercury emissions, but they will exclude regulation of a large number of small operators who do not emit any significant mercury. **Response:** As mentioned above, we have clarified in this final rule that this area source category does n ot include laboratories (see CAA section 112(c)(7)) , individual prospectors and very small pilot scale mining operations. Prospectors and other very small pilot

- scale operations (e.g., operations that produce or process less than 50 pounds of concentrate per year) are very small and were not included in the section 112(c)(6) inventory that was the basis for the listing of gold mine ore production and processing source category. A ll the facilities in our current inventory, as well as the facilities conside red in developing the 1990 baseline emissions inventory , process or produce more than 4,000 lb/yr of concentrate. We believe that emissions from the very small scale operations described above to be very minimal, especially in comparison to the mercury

em issions from operations that are regulated under this rule, which process or produce concentrate at amounts far above th i s threshold. However, we believe that the 100 pound s of concentrate cut

off suggested by the commenters is too high. We believe that 50***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **56** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** pounds of concentrate per year more appropriately reflect these very small operations. We are not making the suggested change of excluding operations that do not leach or dissolve gold because certain gold mine facilities in the source category use fl otation or gravity flotation processes and perform thermal process ing of concentrate in melt furnace s, which can have significant emissions of mercury
. We are also not making the exemption of facilities that process less than 1000 tons per year of ore bec ause we believe this exemption is not necessary or appropriate. C. MACT Floors 1. Consideration of Variability in Determining Floors
**Comment :**  One commenter acknowledged that EPA may consider variability in calculating the best sources’ performance, but stated that EPA’s method of considering variability seeks to assure that none of the sources among those identified as best performers would ever exceed the floor level. The commenter claims such an approach ignores the reality that sources’ emission lev els are largely within their control, and although a great deal of variability may be statistically conceivable, that does not mean that a well

- operated source actually would***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **57** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** experience such variability. The commenter said that one of the main points of h aving emission standards is to ensure that sources not only deploy the appropriate control measures, but also use those control measures consistently to minimize emissions. The commenter said that using an upper prediction limit to set standards reflect ing the statistical worst performance these sources could have does not yield an accurate picture of the best sources performance, and it is especially arbitrary in the absence of any explanation of why EPA thinks that the relevant best sources’ performanc e would ever be so bad, other than the fact that it is statistically possible. **Response :**  It is EPA policy to allow for variance in test data, between units, and among facilities when developing the MACT standard. For this rule , we used the UPL analysis on the emissions data for the top five perform ing sources to account for the variance. We believe that this calculation method does yield an accurate picture of the best performers. It is an incorrect statement that no sources among the best performers ( i.e., the top five performers for this final rule) would ever exceed the floor limit. The variability that is accounted for in the UPL analysis of historical data would apply to future***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **58** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** data as well. Thus, although the average of several data sets may sho w a top performing source meeting the emission standard by a wide margin, the variability in emissions inherent in any one compliance test could easily indicate much higher emissions, and, in some cases, an exceedance of the emission standard. The operati ng conditions under which emissions measurements are made for a given process unit will directly affect those measurements. For example, emissions obtained from a process that is operating poorly will almost certainly be higher than when operating properl y. Therefore, the process that is operating poorly will be less likely to be included in the pool of best performers than if it were operating properly.
We believe the data we use d to calculate the MACT limits are based on representative and normal perfor mance of the

source s for many reasons. First, the test results that we are using in our MACT database are tests conducted under Nevada’s mercury emission control program, and some of these tests are to determine whether a facility is in compliance with a State or operating permit emission standard . Facilities try to perform as well as they can during performance tests to avoid violations, fines, and other enforcement actions. State (and often EPA) permitting authority staff are notified before a***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **59** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** performa nce test is conducted to provide an opportunity to attend and observe the test, and they often attend to ensure the source is operating properly and that the testing is performed according to the strict requirements in the codified test methods. Test repor ts are carefully reviewed by the permitting authority, and any failure to follow the test method or abnormal operation of a source is flagged. These data are usually invalidated, and invalidated tests are not used in our MACT floor calculations . For exam ple, several tests from these facilities were invalidated by the NDEP because the specified testing procedures were not followed or the emission control device was not operating properly, and we have not used those results in our analysis for those reasons . We have collected additional data from test reports not available at the time of proposal, and one of those tests was invalidated because NDEP representatives discovered that the emission control device was not operating properly during the test, theref ore, we also did not use those test data
. The commenter believes that floors must be set at the average emission level achieved by the best performers when they are operating properly. We agree that the performance data***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **60** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** characterizing the emission level a chieved by the top performers must be data obtained when they are operating properly, and we believe that is the case for our current database for this source category . The MACT floor is based on the average performance of the top performers, and we can a nd must develop a MACT floor limit from this average that accounts for variability. We accomplish this by calculating the MACT floor limit from this average performance and account for variability by using the 99 percent UPL, which is discussed in more de tail in the Summary of Public Comments and Responses document in the docket for this rulemaking . It is not appropriate to ignore the variability in the data because that would be contrary to established statistical theory and practice, and it is also at

o dds with recent judicial decisions. Finally, on a practical level and in terms of achievability, ignoring variability and using only the average performance would virtually guarantee that some of even the best performers would exceed the floor limit.
**Comm ent**  **:** Another commenter stated that consideration should be given to defining the inherent range of measurement error and requiring more test runs in order to reduce variability due to process variation. The commenter said that***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **61** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** this would also better clar ify when variability was due to operational controls, which could be addressed, rather than due to factors that cannot be controlled, such as mercury content in the ore. The commenter asked for clarification on how inconsistent runs should be treated, wha t defines an acceptable set of runs, and at what point more runs would be required to provide reliable data. The commenter also stated that the degree of variability allowed in the development of the new source limit for ore pretreatment appears to be out of line with the new source limits for carbon processes and non

- carbon processes. The commenter believes that ore pretreatment variability for new sources is higher than existing sources because low thermal units were included in the same category, high e missions were allowed in the data set, and variable emissions were allowed in data set. The commenter recommended that , if EPA continues to use Goldstrike as the best performing source for new source MACT, then they should re

- evaluate and reduce the varia bility to be equal to or less than the variability for existing sources. **Response :**  We agree with the commenter that the testing process would be more accurate if the number of test runs was increased. However, we balance several factors in determining***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **62** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** the minimum number of runs required, and because the compliance testing is supplemented by various types of continuous or periodic parametric monitoring, we have concluded that three test runs are appropriate for this final rule. Although we have not prop osed a formal procedure to assess the consistency of test runs, the permitting authority performs routine reviews of compliance test data to identify potential outliers and results that suggest further investigation is needed. For example, a routine revie w tracks trends in performance, and in particular, flags any trends in deteriorating performance over time. An unusually high run among the three runs also attracts attention and would be examined to determine if it might have been caused by a problem wit h the process, control device, sampling, or analysis. We agree with the commenter that the variability used in the development of the proposed new source MACT for the ore pretreatment group appeared to be inconsistent with other data , and it was due in p art to two tests of the ore preheater/dry grinding process at Goldstrike that the commenter identified. As discussed in more detail below in this preamble, we have obtained new (additional) test data for the ore pretreatment group, including the ore prehe ater/dry grinding process at***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **63** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** Goldstrike. We have determined that the tests the commenter is referring to are not representative of normal operation, and those tests have been removed from our database because the NDEP invalidated the tests due to possible sample contamination. (See the MACT Floor D ocument in the docket for the final rulemaking). In addition, we have performed additional analyses using the newer test data, which show lower emissions and lower variability than the previous data available a t the time of proposal. Also, we have conducted additional beyond

- the

- floor analyses. The variability associated with the new source MACT is now significantly lower than the estimate of variability at proposal, and the new source standard in the final ru le is more stringent tha n the proposed standard . As discussed in more detail below, MACT for new sources for the ore pretreatment group has been reduced from 149 lb/million tons of ore at proposal to 84 lb/million tons in the final rule. 2. General Comm ents on MACT
**Comment :**  Some commenters stated that the MACT floor already represents installation and operation of MACT controls, and the use of emissions data from facilities that are already controlling their mercury emissions creates an artificially lo w MACT floor. The commenters said that the low MACT floor***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **64** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** penalizes facilities that voluntarily invested in pollution control technology and creates a substantial disincentive for industry and States to move ahead of EPA in reducing emissions of HAP.
**Res ponse**  **:** We acknowledged at proposal that many gold mine facilities are already well controlled for many reasons, including participation in the NMCP . We also acknowledge that the top performing facilities that are the basis for the MACT floor calculation are the top performers because they have installed controls. CAA section 112(d)(3)(B) requires that, for a category with fewer than 30 sources, the MACT floor not be less stringent than “the average emission limitation achieved by the best performing 5 so urces ( for which the Administrator has or could reasonably obtain emission information ).” (Emphasis added). EPA has information on these well

- controlled facilities and use d the information to conduct MACT floor analysis, as required by the CAA. Although the MACT floor may be considered more stringent in comparison to floors that would have been established if no facilities had mercury emission controls, we do not consider the floor to be “artificially low” because it has been demonstrated as achievable i n practice by facilities that installed mercury emission controls.***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **65** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** 3. MACT for the Ore Pretreatment Group
**Comment :**  Several commenters supported EPA’s general approach to establish three groups of affected sources in the proposal. On the other hand, s ev eral commenters suggested that EPA develop separate emission standards for roasters and autoclaves for existing and new sources. One commenter stated that roaster and autoclave processes are different from each other based on the mercury species released, controls utilized, and their rates of mercury emissions. The commenter said that roasters commonly reach temperatures of 400 ° to 700°C, releasing gaseous elemental mercury, whereas autoclaves commonly reach temperatures of 175 ° to 230°C producing reactiv e gaseous mercury and sulfate and forming mercury sulfate. According to the commenter, autoclaves are expected to be able to improve efficiency over time. The commenter noted that roasters produce one to two orders of magnitude higher emissions than do

a utoclaves. The commenter believes that facilities that only use autoclaves should not be allowed the leeway to emit at the rate that facilities employing roasters are allowed. The commenter recommends that the ore pretreatment group be divided into high temperature pretreatment processes (roasters) and low temperature pretreatment processes (autoclaves and ancillary***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **66** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** roaster processes, such as dry grinding, pre

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

- t he

- floor standards for roasters and that if additional reductions are achievable at roasters, then EPA must set***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **67** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** additional beyond

- the

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

- the

- floor standards for new sources. The commenter claims that EPA has a statutory obligation to ensure that its new source standards reflect the maximum achie vable reduction in emissions. **Response :**  Following proposal, we continued to investigate the performance of facilities with ore pretreatment processes and opportunities for additional control. We collected data from more recent tests that were not avai lable at proposal, and these new data show that emission control performance at these facilities has continued to improve. We identified two previous
test s in the proposal database that w ere suspect, and we confirmed with NDEP that th ese test s should be i nvalidated and not used in the analysis because of possible sample contamination. We have also dropped the data for one f acility from the analysis because their autoclave was shutdown in 2007 and dismantled, and we only had one test of the autoclave when it was operating in 2006. For these reasons, it is not appropriate to include data for that f acility in the analysis,***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **68** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** which is now based on the only four facilities currently operating. Based on the addition and change described above with respect to our available data, we revised the MACT floor analysis for the ore pretreatment processes. The revised MACT floor for existing sources decreased from 175 lb/million tons at proposal to 158 lb/million tons, and the new source MACT floor dropped from 163 lb/mil lion tons to 84 lb/million tons. The MACT floor limit for existing ore pretreatment processes is based on the use of wet scrubbers, calomel scrubbers, and carbon adsorbers, depending on the specific processing unit included in the affected source . We co nducted a beyond

- the

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

- the

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

- the

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

- the

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

- heaters /dryers that could ac hieve additional emissions reductions of approximately 70 percent (or more) for those units
. Two of the three facilities with***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **69** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** roasters have already proposed in their NMCP Phase 2 permit applications to apply controls to their preheaters/ore dryers, and th ese two companies have submitted cost estimates for applying a carbon adsorption system. Using the cost estimates submitted by the affected facilities, we estimate the capital costs for control of roaster preheaters/dryers for the three facilities with ro asters as $3 million with a total annualized cost of $1.6 million per year . We also estimate a reduction of 160 lb/yr of mercury emissions would be achieved at a n overall cost effectiveness of about $10,000 per pound of mercury. We believe that the costs and cost effectiveness are reasonable
. As required under CAA section 112(d)(2), we have also considered

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

- th e - floor control technology for existing roaster preheaters/ore dryers. Therefore, we included the beyond

- the

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

- the

- floor control for autoclaves, in determining the MACT standard in this final ru le for existing sources of ore
pre - treatment processes . A fter applying the appropriate variability analyses to the data, we determined that the MACT standard for existing sources is 12 7 lb/million tons of ore
.***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **70** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** Beyond

- the

- floor analyses have been includ ed in the determination of the MACT limit for existing ore pre

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

- the

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

- effective technology that would achieve reduction greater than the new source floor. Therefore, for new sources of ore pretreatment processes, the MACT “ floor ” is the MACT standard for the affected source. T he final new source MACT stand ard is 84 lb/million tons of ore , which is considerably more stringent c ompared to the proposed standard of 149 lb/million tons o f ore . **Comment :**  One commenter stated that the proposed estimated capital costs of $890,000 and total annualized cost of $720,0 00 for beyond

- the

- floor autoclave controls are not representative of actual costs of installing a refrigeration unit (or condenser) and a carbon adsorber on autoclaves. The commenter estimates that capital costs for autoclave controls will range from $18 million to at least $30 million, and annual operating costs could range from $2 million to $60 million, depending on which controls, if any, are determined to be technically feasible. The commenter believes that based on these cost***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **71** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** estimates, beyond

- the

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

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

- the

- floor controls on autoclaves in the proposal w ere underestimated. We evaluated the detailed cost estimate based on an engineering study for a carbon adsorption system provided by one of the commenter s (see details in the comment above on capital , operating, and energy costs ), and our review of these details indicates it to be a reasonable cost estimate. Therefore , we have used this estimate as the basis for our estimate of the costs of the beyond

- the

- floor mercury emission controls for autoclaves. Our revised estimate s are that the capital cost for install ing carbon adsorbers on autoclaves would be $29.3 million , with a total annualized cost***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **72** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** of $4.9 million per year , which would result in an estimated reduction of 480 lb/yr of mercury emissions per year and a n overall cost effectiveness of about $1 1 ,000 per pound of
mercury . Based on these new costs and estimated reductions we conclude that the beyond the floor controls are justified for the ore pretreatment affected source
. **Comment** : Several commenters noted that , at the proposed new source MACT limit of 149 pounds/million tons of ore, the proposed new source Donlin Creek Mine, located in Ala ska, would be allowed to emit 3,200 lb /yr of mercury based on a projected production rate of 22 million tons /yr of ore. **Response** : With respect to the proposed new gold mine in Alaska, the commenters’ estimate of 3,200 lb /yr of mercury emissions is inaccu rate and a significant overestimate for several reasons. The two primary reasons are that , based on available information , if the facility is built, only an estimated 15 percent of the ore mined will be processed in autoclaves (not 100 percent as assumed by the commenters), and that the commenters’ estimate is based on assuming that the average emissions level for the facility throughout the year would be at the maximum allowed at the proposed new source limit (149 lb/million tons of ore )
.***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **73** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** With the new source MACT standard in the final rule that is about two times more stringent than the proposed MACT standard , along with corrections described above, we estimate that far less than 3,200 lb/yr would be emitted from this new source if it is ever built. As suming continuous operation for 365 days per year, an estimated 21.5 million tons /yr of ore mined, about 3.2 million tons /yr processed in autoclaves (15 percent), and assuming the source would emit at the average emission level used to calculate the revise d new source MACT (45 lb/million tons of ore), we calculate that mercury emissions would be about
144 lb/yr , which is about 5 percent of the estimate provided by the commenters. Considering that the facility has yet to go through the permitting process an d that if they could not meet the new source MACT limit, installation of carbon adsorbers would likely reduce the emissions below 45 lb/million tons, we believe that, if the facility is built, emissions w ould quite likely be lower than 144 lb/yr
. 4. MACT for Carbon Processes
**Comment :**  Several commenters objected to including Facility M in the MACT floor determination for new and existing sources in the carbon processes affected source because it is not representative of , or similar to , other sources, beca use it has***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **74** of **18 7** 

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** unusually low mercury concentrations in its ore, and no need for a retort to remove and recover mercury. They noted that , because the mercury content of the gold ore is fixed, the only way for other facilities to reduce emissions of mercury is to apply mercury emission controls, but , for many facilities, emission controls will not be enough to meet the proposed MACT standard. The commenters stated they were aware that the D.C. Circuit Court had constrained EPA’s discretion to set floors that fa il to consider material inputs, but they said gold mines were different from the remanded source categories (brick kilns and cement kilns) because gold mining operations process very large quantities of ore, and the ore is the only material input that resu lts in mercury emissions. The commenters stated that , in adopting section 112, Congress expressly cautioned EPA against setting standards that would require mining operations to change the ore used as essential feedstock. The commenters said that , by ign oring the mercury content in the ore being mined and processed at the facilities in the MACT floor determination, EPA is requiring facilities to consider the substitution of, or changes in, the ore that is processed because there is no other way to achieve the standard. The commenters recommended that EPA address, as a threshold matter,***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **75** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** the differences in processing and emissions across facilities that result from the variable concentration of mercury in ore. The commenters recommended that Facility M not be considered the “best controlled similar source” for purposes of setting the new source MACT floor because the facility is not similar to other sources. The commenters stated that , if EPA does not exclude from the source category facilities that do not use retorts to process concentrate, then they should subcategorize them
. **Response :**  After consideration of comments and a re

examination of the emission controls and factors affecting emissions from the carbon processes at Facility M, we agree that this f acility is quite different and unique compared to most other gold mine ore processing and production facilities , including other facilities in Nevada, in its carbon process. The mercury emissions from carbon processes at this facility are a factor of 10 l ess than the next “best” performer ( F acility N) and a factor of 23 less than the average of the top 5 performing facilities in the proposed rule . This level of emissions is due primarily to the very low levels of mercury in the ore rather than having bett er emission controls than those found at the other top performing facilities. Facility M has good controls for mercury emissions from its carbon processes , but they are***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **76** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** not as effective as the controls at F acility N. Facility N has
state

- of

- the

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

- analysis of t he MACT floor and MACT for sources that are in the carbon processes with mercury retorts and those without mercury retorts, we considered new data that

w ere not available at the time of proposal. Over the past one to two years since our data collection ef fort for the proposal, facilities in Nevada have continued to add controls and improve emission control as part of the N MCP . The new data indicate that there were two facilities with carbon processes without***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **77** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** mercury retorts operating in 2009 . Using the d ata from these two facilities , we determined that the MACT floor limits for carbon processes without mercury retorts are 0.1 7 lb/ton of concentrate for existing sources and 0. 14 lb/ton of concentrate for new sources (based on the best performing facility).
In our beyond

- the

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

- the

- floor option, we decided not to go beyond

- the

- floor. Therefore, for exist ing sources of carbon processes without mercury retorts, the MACT floor limit is the MACT standard for this affected source
. As part of our re

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

installed controls replaced two higher

- emitting facilities that***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **78** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** were in the top 5 at proposal , and all three of the other facilities that remained in the top 5 had lower levels of emissions after considering the new data. The results are that the MACT floor limits for carbon processes with mercury retorts

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

- the

- floor analysis, we evaluated the impacts of adding a second carbon adsorber in series with the controls applied to achieve the MACT floor le vel of control. We estimate the capital cost would be $3 million with a total annualized cost of $1 million per year, an emission reduction of 9 lb/yr or mercury, and a cost effectiveness of $150,000/lb of mercury. B ecause of the small emission reduction and high cost effectiveness associated with this additional control, we decided not to go beyond the floor. Therefore, for existing sources of carbon processes with mercury retorts, the MACT floor limit is the MACT standard for this affected source
. 5. Compliance Alternative for New Carbon Process Sources
**Comment :**  One commenter noted that the compliance “alternative” of 97 percent would be unlawful unless EPA specified that carbon sources had to meet the more stringent of either the floor standard or a 97 percent reduction standard.***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **79** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** The commenter stated that because floors must reflect the emission level achieved by the best performing sources, allowing sources to meet a 97 percent reduction standard that was less stringent than the emission level actu ally achieved by the relevant best sources would contravene section 112(d)(3) and well

- established D.C. Circuit court precedent. One commenter supported EPA’s use of the percent control alternative to the new source MACT for the carbon group. The
commente r believes that the percent control alternative for new source carbon group MACT should also be available as an alternative to the existing source MACT for the carbon group. Another commenter stated that another facility, which has an average mercury red uction efficiency level of 99.995 percent, represents the “best controlled” similar source for the carbon process group and should be the basis for the alternative limits for new carbon processes. Several commenters requested clarification of the way in wh ich compliance with the alternative for percent reduction would be demonstrated for new sources when there are multiple control devices on an emission unit. **Response :**  We eliminated in the final rule the compliance alternative of 97

- percent reduction fo r new carbon processes.***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **80** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** After reviewing the comments received on this standard and giving further consideration to the practicality of how it would be measured, we concluded that this option would be difficult to implement , particularly when multiple proc esses that are operated at different times vent to a single control device and stack . In addition, we have limited data supporting this compliance alternative. In proposing this alternative for comment, we had hoped to but did not receive additional data indicating that the 97 percent reduction option would be equivalent to the proposed new source limit of 0.14 pounds of mercury per ton of concentrate. Largely due to the reasons stated above, we have eliminated the 97 percent control efficiency option fo r new carbon processes in the final rule. D. Compliance Determinations 1. Timing for Compliance Determinations
**Comment :**  Several commenters requ ested that the compliance deadline for existing sources be 3 years after the effective date of the rule, rathe r than the 2 years proposed. The commenters noted that several facilities will have to install control devices to achieve the MACT floor limits that have been proposed. The commenters explained that the controls must be custom designed for the unique cha racteristics of each process***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **81** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** and associated process streams at each facility and stated that it can be time consuming and difficult to design, procure, construct, and implement emission controls to ensure effective operation for the particular source.
**Re sponse**  **:** After reviewing the information provided in public comments on the challenges of retrofitting new controls , and the fact that these controls have not yet been demonstrated

on autoclaves and ore preheaters, w e believe th at allowing 3 years for exis ting sources to comply is appropriate . G iven the complexity of the sources, the combinations of control devices that are needed in many cases, and the amount of time necessary for designing, install ing, testing, and commissioning addition al emission contr ols for mercury , we conclude that 2 years may not provide adequate time for existing sources to comply with the final emission standards
. **Comment :**  Several commenters recommended that the rule specify that source testing results be used to determine compli ance for the calendar year in which the test was conducted rather than to determine compliance for the prior 12 months. The commenters suggested that the source test results be applied to the hours of operation at the end of the calendar year to determine the source’s compliance with the MACT standard on an***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **82** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** annual basis, as required in the NMCP. The commenters suggested that , if more than one source test is conducted in a year, the facility should average the mercury emission test results to determine com pliance for the calendar year in which the tests were conducted. Another commenter commented that the annual compliance testing should not be constrained to the same calendar quarter each year. The commenter stated that this can lead to testing during p eriods of operation that may not represent normal production capacities. The commenter believes that mercury emissions testing should be scheduled for the most appropriate time interval throughout the calendar year. **Response :**  The permitting authority n eeds to be able to determine compliance with the NESHAP as soon as possible after the tests are completed and test results are available. Consequently, the final rule requires that initial compliance be determined based on production data and operating ho urs for all full calendar months between the date the rule is published in the Federal Register and the date of the compliance test, and subsequently, annual compliance must be based on the 12 full calendar months preceding the compliance test. This allo ws the permitting authority to determine if the affected source is in***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **83** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** compliance in a timely manner. (This is consistent with the way compliance determinations are made in another MACT rule that uses a similar format

- National Emission Standards for
Haza rdous Air Pollutants for Primary Lead Smelting, 40 CFR part 63, subpart TTT.) If compliance was based on a calendar year, as suggested by the commenter, then we would not know if a source is in compliance until after December each year. For example, if a source conducted its compliance test in March, we would have to wait about 9 more months before we could determine if that source was actually in compliance. After those 9 months, if the source was not in compliance, it would mean that the source could h ave been out of compliance for the previous 9 months. Moreover, we do not believe that compliance with the NESHAP based on the production data from the 12 months prior to the compliance test would cause problems with reporting under the State program. I t is our understanding that the emissions limits in the Nevada State phase 2 permits are (or will be) based on concentration in the stacks (e.g., micrograms per cubic meter (μg/m 3 )). The limits in this final rule are based either on pounds of mercury per million tons of ore or pounds of mercury per tons of concentrate. Therefore, the companies can***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **84** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** continue to report the annual emissions as required under the TRI program and the State program without conflict with this rule. If multiple compliance tests are conducted during the year, then a compliance determination must be made for each separate compliance test based on the production data for the 12 months preceding each test (i.e., the results of multiple compliance tests conducted throughout the year are not averaged to provide a single compliance determination for the year). We understand that the rule , as proposed , may have required all existing sources to conduct their subsequent annual compliance tests in the same calendar quarter, and this may pos e a scheduling problem because of the large number of facilities located in the same State (Nevada). Our concern was that subsequent annual compliance tests, if not separated in time, could be conducted for two different years with little time between the two tests (e.g., only a few days apart for the extreme case where the first test is conducted in late December and the second one in early January of the following year). We are providing scheduling flexibility by requiring that annual compliance tests b e at least 3 months apart and no more than 15 months apart, and we are providing a similar separation for the***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **85** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** period between the initial compliance test and the first annual compliance test. We do not believe that tracking multiple compliance dates is a p articular problem for the permitting authority because that is the case for many other source categories of sources subject to annual compliance testing. 2. Test Methods
**Comment :**  Several commenters supported EPA’s proposal of alternate Methods 30A and 30 B for demonstrating compliance. One commenter supported EPA’s requirement to use Method 29 as an emission test method, but recommended two revisions: requiring a determination of the absence of cyclonic flow before sampling, and a minimum sampling time o f 90 minutes for each test run. The commenter also stated that they do not support the use of the Ontario Hydro Method (ASTM D6784

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

bound mercury. The commenter also stated that the alternative***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **86** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** methods were not developed specifically for the gold mining industry and their typical gas streams and conc luded that the results from the various alternative methods will yield varying results, will not be comparable, and will provide inconsistent reporting of overall mercury emissions. **Response**

When specifying the minimum requirements for compliance tests, it is more important to specify a minimum sampling volume than a minimum sampling time becaus e the detection of a regulated pollutant is a function of the volume of the sample rather than the length of time taken to collect the sample
. Thus , the final rule does not specify a minimum sampling time
. We are also changing the required minimum sampli ng volume to be 30 dscf rather than the 60 dscf as proposed because we believe that 30 dscf generally will be adequate for detecting mercury emissions for this industry . Affected facilities should be **:** Method 29 references Method 1, which requires cyclonic flow che cks under certain circumstances. Consequently, in the final rule, we have removed the specific requirements for cyclonic flow checks prior to every stack test that were in the proposed rule. Owners or operators should follow the requirements in the appli cable EPA reference method and any additional requirements specified by the permitting authority.***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **87** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** aware, however, that the minimum sample volume may some times result in a failure to detect any mercury (a non

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

non - detect value, then the minimum detection limit (MDL) must be used in calculating the emissions for that emission point and, in turn, for calculating the sum of the mass emissions for all emission points subject to the emission standard for determining compliance. If the resulting mercury mass emissions rate is greater than the allowable emission limit, the owner or operator
may use procedures that produce lower MDL results and repeat the mercury emissions testing one additional time for any emission point for which the measured result was below the MDL. If this additional testing is performed, the results from that testing must be used to determine compliance (i.e., there are no addi tional opportunities allowed to lower the MDL). We agree with the commenter that M ethod 29 is the most appropriate method for compliance determinations for this source category because of the unique characteristics of these sources
. Therefore, w e are pro mulgating M ethod 29 as the main method for***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **88** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** compliance in this rule . Alternative methods , such as 30B and the Ontario Hydro method (OHM), could be used to demonstrate compliance for this source category if approv ed by the permit ting authority. We have omi tted Method 30A as an option in the final rule, as it is not yet in general use. Both Method 30B and the O H M (ASTM D6784

- 02) have been considered acceptable for some source categories. However, as described by the commenter, gold facilities have unique p roce s ses and exhaust gas characteristics
. Method 29 can be used for any emission point for any of the affected sources
. T he alternative methods may eventually prove to be more appropriate under certain circumstances. Nevertheless, b ecause it is not an i sokinetic method, Method 30B is applicable to sampling only well

controlled PM emissions outlets. The OHM is similar to Method 29 , except that it is more expensive and more complicated, and is typically used to measure the individual species of mercury

ra ther than just total mercury. E. Monitoring 1. Compliance Assurance
**Comment :**  One commenter noted that EPA’s proposed mercury standards are expressed in a format of pounds of mercury per million tons of ore processed and observed that the proposed***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **89** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** rule requires stack testing only once a year. The commenter claims that EPA’s proposed monitoring requirements would not demonstrate whether sources are in compliance with their emission standards, which renders the rule unenforceable. According to the comme nter, the once

- a - year stack test would provide no indication as to what a mine’s emissions were the rest of the year. The commenter said that a source that failed its stack test would have only one violation of emission standards, even if that test showed that the source likely violated its emission standard throughout the year. The commenter believes that EPA’s proposed monitoring requirements would not assure compliance with the proposed emission standards. The commenter also noted that EPA proposes to require sources to monitor their mercury emissions either with CEMs, sampling, or various types of parametric monitoring; however, these methods do not provide direct information about the pounds of mercury emitted. Consequently, none of these monitoring methods could be used to demonstrate whether a source is in or out of compliance with the proposed emission standards. According to another commenter, all three affected source categories should be required to use CEMS at all times and at all emission points. The commenter stated that the ore***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **90** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** pretreatment group especially needs CEMS because of variable levels of mercury in the ore and different operational measures within the control of the facility. Other commenters supported EPA’s decision to requir e continuous monitoring and said that the CEMS should be incorporated into the compliance regime as well. The commenters believe that, if the monitoring results indicate that the mine is consistently out of compliance for a period of one week without corr ection, the process unit should be subject to compliance

- based penalties and/or shut down until corrections are made and the process unit is back in compliance. According to the commenters, quarterly stack testing should still be required to demonstrate t hat the CEMS is working. **Response** : We recognize the importance of requiring adequate monitoring to assure compliance with the emission standards . Because of the higher mercury emitting potential of the roaster, we proposed the option of mercury monitori ng using CEMS or weekly monitoring with PS 12B with associated parametric monitoring as well
. We are including in the final rule the option to perform continuous PS 12B monitoring, and, as with the CEMS, associated parametric monitoring would not be requi red. We are changing the frequency of the proposed weekly***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **91** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** concentration monitoring approach for roasters to twice per month (at least 1 1 days apart ) and would allow a facility to conduct a Method 30B test (as an alternative to a PS 12B test), supplemented with continuous parametric monitoring. We changed the frequency because we believe that sampling twice per month , coupled with continuous parametric monitoring , is sufficient for determining that the roaster control devices are operating properly. We ad ded this alternative because Method 30B directly measures mercury concentration and is a valid means of determining whether the concentration is below the operating limit established during t he initial performance test
. T he
t wice per month Method 30B meas urements will provide a concentration value that can be compare d to that operating limit to determine if an exceedance of the operating limit has occurred
. Also, if the twice monthly sampling shows repeated deviations over time, EPA could decide at a late r date that CEMs are appropriate and necessary for roasters. We believe that the mercury concentrations monitoring for roasters along with the parametric monitoring of all control devices on all units is an acceptable approach to assure compliance with the emission standards
. Parametric monitoring of control devices assure s that the control devices are***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **92** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** operating properly (and reducing emissions ) on an ongoing basis. We disagree with the commenter that the proposed monitoring requirements render the ru le unenforceable. The mercury operating limits in both the proposed and final rules are enforceable, and any exceedance of these operating limits triggers corrective action. If corrective action does not return the mercury concentration within the establ ished limits, the plant must conduct a full compliance test and determine if the source is meeting the mass

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

- roaster sources. These sour ces have less potential mercury emissions, and requiring CEMS on all these other units would be quite costly and burdensome. Moreover, m ost of these other units are , or will be, controlled with carbon adsorbers, and the carbon adsorber monitoring required by the final rule is an effective means of ensuring the controls are working effectively on a contin uing basis . We consider that either frequent testing of carbon beds to monitor for breakthrough using Method 30B , or frequent adsorbent sampling for mercu ry
content , is an effective way to ensure these mercury control systems are operating properly on a continuing basis. With***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **93** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** regard to some of the units without carbon adsorbers, we believe that annual tests coupled with appropriate parametric monitoring of the control devices are sufficient to ensure emissions are properly controlled on a continuing basis. With regard to the comment that quarterly stack testing should be required for facilities using a CEMS, we believe that following the Quality Assuranc e (QA) procedures detailed in 40
CFR 60 , Appendix F , are sufficient to ensure the CEMS continues to operate as designed, and in this case, additional stack sampling is not necessary. 2. Operating Limits
**Comment :**  One commenter stated that the operating li mits for roasters and for carbon adsorbers are inappropriate and set up a second set of MACT standards. The commenter claimed that the operating limits do not take into account the effects of: hours of operation of a process unit on mercury emissions;

r eduction in performance of a process unit offset by an improvement in performance of another process unit; variability in the exhaust gas flow rates with no appreciable effect on the corresponding mercury emission rate; and variability in the inlet mercury concentrations to a carbon adsorber . These factors all result in variability in the outlet mercury***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **94** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** concentration. The commenter also noted that the proposed operating limit for carbon adsorbers could result in premature carbon change out, resulting in t he generation of more waste. The commenter recommended that EPA defer to the Nevada state monitoring requirements and only provide for monitoring of throughput and annual mercury emission testing to demonstrate compliance with the MACT emission standard. The commenter believes that any operating limit parameters must be established based on manufacturer specifications and recommendations in coordination with the permitting authority and not based on values measured during source compliance testing. **Respon se**  **:** We proposed the mercury operating limits as a monitoring tool to ensure that the processes within individual affected sources and their associated control devices are functioning properly on a continuing basis and not as a second set of MACT standards
. We developed emission standards for four affected sources, and the emission standard for an affected source applies to the sum of emissions from all process units within the affected source. One unit could have an upward fluctuation in mercury concentr ation, but the group of process units could still meet the limit. We see the value of the operating limit approach as sufficient to detect significant***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **95** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** increases in emissions and as a valuable tool to ensure the control devices are operating effectively an d provide quick notification of a potential problem with controls or emissions
. The monitoring parameters are used as compliance indicators , and the relevant mercury operating limits are the main “triggers” of a possible emissions increase and are set to alert facility operators when emissions are greater than the corresponding
mercury operating limit
. W e believe it is important to have such monitoring in the rule to ensure the control devices are working properly. Regarding specific comments about moni toring the carbon adsorber, the State of Nevada has had good results with conducting sampling of the carbon adsorber to maintain its performance. The final rule offers an additional option of measuring the mercury concentration exiting the carbon adsorber that also achieves the same objective of avoiding breakthrough of the bed. We do not expect sudden dramatic failures of this technology. Instead, we expect to obtain close control of performance by ensuring that the carbon is changed in a way that
preve nts breakthrough. This monitoring methodology should also prevent premature replacement of the bed. We disagree with the comments that only monitoring for***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **96** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** throughput and annual emissions testing are sufficient to demonstrate compliance for sources control led with carbon adsorbers. Such an approach does not provide for continuous monitoring . The parametric monitoring and operating limits specified in this final rule provide ongoing assurance that control devices are properly operated and maintained betwee n emissions tests , and exceedances of the operating limit require corrective action. W e also reject the comment that all operating limits should be based solely on manufacturer specifications and/or in consultation with the permitting authority. Control device operating parameter values often are site

- specific and are associated with a level of emissions from the source. In order to ensure continuous compliance, certain parameter limits generally should be associated with an emissions test that demonstra tes compliance with the emissions standards. However, we agree that certain parameters for mercury scrubbers applied to roasters, such as the ranges associated with ensuring the proper chemistry of the scrubber, are best provided by the system’s manufactu rer. Guarantees of performance are usually conditioned by requiring that the system be operated as designed and specified by the manufacturer, and there is no assurance that a potentially narrow range that would***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **97** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** be established during a short performance t est reflects the full applicable range of proper operation. A facility may request us to consider alternative procedures for setting operating limits

on a case - by

- case basis under 40 CFR 63.8, if desired.
**Comment :**  Some commenters stated that their estab lished parametric monitoring programs are sufficient to confirm that mercury emission controls are functioning properly for roasters. The commenters also stated that the NMCP permits have required parametric limits and that additional CEMS for mercury wo uld neither improve the operation of these current controls, nor reduce mercury emissions. The commenters concluded that the operating parameters monitored on a regular basis are key parameters for measuring the efficiency and operation of the
mercury con trols and that operating each of these units within the optimum ranges ensures that mercury emissions are being effectively controlled. **Response :**  As discussed above, we do not believe parametric monitoring alone is sufficient for roasters because of the very high mercury emission potential , unless the facility has adequately demonstrated that the mercury emissions from the roasters are consistently very low (e.g., less than 10 pounds per million tons)
. Nevertheless, w e have concluded that the***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **98** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** combined approach of annual stack compliance testing along with the monitoring requirements and options outlined in this rule

are necessary to detect excess emissions and to ensu r e controls are working effectively on a continuous basis. 3. Mercury Concentratio n Monitoring for Roasters
**Comment :**  One commente r stated that the proposed provisions for monitoring mercury concentration s in roaster emissions are not based on roaster process and pollution control device operational parameters and would not yield reliab le information that can be used for detecting and correcting problems. The commenter also stated that the formula for establishing the
mercury operation limit for roasters is not appropriate because it uses an emission limit that is based on emission test data from several process units in addition to the roaster. The commenter recommended using the methods proposed for parametric monitoring of roaster emission control devices for all roasters. The commenter also has concerns about utilizing PS 12A (merc ury CEMS) and PS 12B for emissions monitoring purposes because there are terms and conditions listed in the proposed rule that are not fully defined. The commenter also recommended deleting the emissions monitoring requirements for mercury concentration f or carbon adsorbers for the same reasons described above for***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **99** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** roasters. **Response :**  We disagree with the comment that monitoring the mercury concentration in roaster emissions would not yield reliable information that can be used for detecting and correcting problems. An elevated mercury concentration in the roaster stack gas indicates that there could be a problem with either the process or the control device , which could result in excess mercury emissions from that unit . M onitoring the mercury concentrati on in roaster emissions provides a direct measure of the regulated pollutant (mercury). The commenter is correct that the formula for establishing the mercury operating limit for roasters is based on emission tests performed on several processes units in addition to the roaster. However, f or the facilities with roasters that will be subject to the requirements to monitor mercury concentration, the roaster is the biggest source of potential mercury emissions within the affected source. Therefore, we concl ude that changes in the mercury concentration in the roaster exhaust gases provide a good indication of overall emissions from the affected source. In addition, the operating limit is not used directly to determine compliance with the MACT emission standa rd . As mentioned above, it is designed to detect elevated mercury***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **100** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** concentrations in the roaster stack gas, which could indicate a problem with either the process or the control device. We continue to believe that it is necessary and appropriate to monitor mercury concentration for the largest source of potential mercury emissions in the source category (i.e., the roaster) to detect excursions in emissions that must be addressed when the operating limit is exceeded. By developing the mercury operating limi t from the emission standard and compliance test results, an exceedance of the mercury operating limit will indicat e a potential increase in emissions and that corrective actions are need ed
. As described above, we believe that either continuous
mercury sampling or mercury sampling twice per month, coupled with continuous parametric monitoring of the control device , should be required for the roaster emissions. If a CEMS is used, the daily average mercury concentration is calculated by averaging the hour ly emissions concentrations during that day. If PS 12B is used for continuous integrated sampling (i.e., without parametric monitoring), the daily average concentration is determined by assigning the mercury concentration measured by the sorbent trap moni toring system (total mass of mercury collected during the sampling period divided by the sample***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **101** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** volume) as the daily average value to each of the days covered by the integrated sample. As discussed above, the final rule include s continuous sampling with PS 12B as a second option for monitoring roasters. A third option is based on short

- term sampling twice per month (at least 1 1 days apart) for mercury concentration using either PS 12B or Method 30B, and if this option is chosen, parametric monitoring of th e mercury scrubber must also be performed. For the third option (twice per month sampling) each measured mercury concentration must be compared to the operating limit to determine if an exceedance has occurred. For the contents of the monitoring plan, se e 40 FR 63.8(d)(3) and 40 CFR 60, Appendix F.
W e also disagree that parametric monitoring alone is sufficient for carbon adsorbers. For carbon adsorbers, measuring the mercury concentration exiting the carbon bed is also a direct measure of the pollutant of interest. (The other option as established for years in NDEP operating permits involves sampling the carbon for mercury content.) An elevated mercury concentration indicates that there could be a problem with either the process or the control device , which could result in excess mercury emissions from that unit
. We have***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **102** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** established exit concentration monitoring requirements in many rules for emissions of organic compounds exiting carbon adsorbers . T hat monitoring has proven to be effective to
preven t or detect breakthrough, and the same principles apply here for mercury . **Comment :**  Commenters stated that CEMS for gold mining operations are not capable of accurately measuring mercury emissions and that there are three major challenges with the feasib ility of mercury CEMS for the gold mining industry: mercury CEMS calibration, sample transport, and system operability and reliability. The commenters are concerned with the unavailability of a means to calibrate the CEMS for roasters because existing ca librator designs are simply not capable of generating mercury concentrations high enough to provide meaningful upscale calibration points that correspond to gold mining source characteristics. The commenters noted the unavailability of National Institute of Standards and Technology (NIST) traceable calibration gas es and stated that the current calibration standards traceable to NIST do not apply to the full range of mercury concentrations that can be present in the exhaust gases of roasters. The commenter s concluded that the lack of a NIST

- traceable standard is a fatal flaw that precludes***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **103** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** using mercury CEMS to monitor roaster emissions. Regarding sample transport, the commenters said that current designs of mercury CEMS for coal

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

- fired electric generating units have seen umbilical failures occur, representing another challenge to having CEMS function consisten tly for the continuous monitoring of mercury from industrial sources. The commenters were also concerned with the CEMS operability and reliability because mercury CEMS must contain some type of converter to reduce oxidized mercury to elemental mercury and premature catalytic failures periodically occur in these units resulting in several days of missing data. The commenters continued by stating that users reported mercury CEMS to be unavailable as much as 30 to 40 percent of the electric generating unit o perating time. The commenters believe the amount of downtime to be expected from these systems on roasters would likely be even higher. The commenter concluded that the breakdown events, combined with the other types of failures, result in data availabil ity that is substantially inferior to parametric monitoring and cannot justify the significant cost and resource investment necessary to install,***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **104** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** operate, and maintain these devices. The commenters are concerned that continuous data reports of mercury emis sions that are not accurate, reliable, or credible could be offered as “credible evidence” to assert a violation. The commenter concluded by stating that this concern was particularly troubling in Nevada, where there are separate mercury limits establishe d pursuant to State law. **Response**

In addition, the NIST has recently completed certification of a ‘NIST Prime’ elemental mercury gas generator at concentrations of 41, 68, 85, 105, 140, 185, 230, 287, and 353 μg/m 3 . Mercury gas generator vendors may now submit elemental mercury gas generators for certification to serve as ‘Vendor Primes’ in a wide range of concentrations. Therefore NIST **:** Regarding the feasibility of using CEMS to monitor mercury emissions from roasters, CEMS have been demonstrated for process units similar to roasters (e.g., coal

fired power plants ), and we believe there is no technical reason why they will not work for the roasters . Many of the issues with mercury CEMS have been resolved as facilities have gained experience with their use. As we discussed in the proposal preamble, CEMS manufacturers supply calibration standards for the ranges of concentrations seen at roasters.***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **105** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** traceable mercury gas standards can now be made available in concentrations that exceed the concentrations typ ically seen from roasters. After consideration of public comments, we continue to believe CEMS are a valuable tool and a reasonable option for monitor ing mercury concentration and comparing those concentrations to the operating limit that is established by CEMS measurements made during the compliance test. In addition, we are promulgating a second option for continuous monitoring using PS 12B, and a third option of twice per month sampling using PS 12B or Method 30B coupled with parametric monitoring.
We also point out that the final rule does not require the use of CEMS ; instead, the final rule includes CEMS as a monitoring option, the results of which will not be used for compliance testing required in this rule
. We understand the commenter ’s concerns r egarding the transport of samples and converter failures. We have revised the final rule to give facilities 3 years to successfully operate controls and monitoring equipment to be able to comply with the MACT standards.
**Comment :**  One commenter stated t hat the regulated industry has no experience with direct measurements of mercury***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **106** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** concentrations at the roaster exhaust gas stream. As a result, the commenter believes that there will be problems in collecting data, establishing appropriate timeframes for sampling under PS 12B, maintaining instrument reliability for CEMS, and in establishing confidence in the accuracy of the results reported by these methods. The commenter claimed that the calculated operating limit based on source testing and simultaneous direct measurements may not be reflective of the future daily operations of all the stack emissions. The commenter noted that flow rate measurements are critical in verifying compliance with actual emission limits because sometimes lower flow rates of th e stack exhaust gas flow can artificially elevate the mercury concentration in the gas stream with no real effect on emissions. The commenter concluded that any exceedence in mercury concentration should be verified first with a compliance test before hal ting the roaster production. **Response :**  W e have learned from the comments received that there may be a learning curve for facilities to implement the concentration monitoring procedures. As described in section
IV. D. of this preamble , w e have established in the final rule a compliance date that is 3 years after the effective date of the final rule for existing sources, part ly to allow sources time to***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **107** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** ensure they can successfully comply with the monitoring requirements, but mainly to allow time to install n ew mercury emission controls that we believe will be necessary to meet the emission standards in the final rule. We agree that mercury concentration measurements are not direct measure ments of the emissions rate from the affected source and that flow rate, production, and other factors need to be considered. These are some of the reasons that the operating limit is not being used as a direct measure of compliance with the MACT limit. However, concentration measure ments above the operating limit should ind icate that either controls are not working effectively or other problems are occurring . In either case, exceedances of the operating limit require investigation and may require corrective actions.
**Comment :**  One commenter requested that EPA reduce the week ly Method 12B monitoring frequency to quarterly or at most monthly. The commenter also requested that EPA include a provision that allows for a source to demonstrate a correlation or consistency of performance such that the Method 12B sampling frequency ca n be further reduced based on the permitting authority’s acceptance of the demonstration. The commenter suggested that if multiple Method 12B samples are collected in a***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **108** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** single day or over multiple days in the calendar week, then the samples should be aver aged, and this average concentration sh ould be compared to the operating limit. The commenter said that , for stacks with high mercury concentration, the sample collection time may be only an hour or two, and in this case, it may be important to collect mo re than one sample in a single day or over multiple days to obtain a representative mercury concentration measurement. **Response :**  After taking into consideration the commenter’s rationale , the final rule requires monitoring mercury concentration twice per month (at least 1 1 days apart ) . If multiple samples are taken during the twice per month period , each result must be compared to the operating limit separately (i.e., not averaged). Otherwise, a high result from a sample taken near the end of the samplin g period might not trigger corrective actions to correct a problem that developed at that time if the results are averaged with previous samples during periods of good performance. 4. Parametric Monitoring of Control Device for Roasters
**Comment :**  Some com menters recommended that EPA remove the provisions requiring monitoring of the mercury scrubber liquor flow rate and scrubber pressure drop because each facility that***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **109** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** has a roaster has a unique sequence of air pollution control devices, and monitoring para meters that may be appropriate for one roaster may not be applicable to another. One of the commenters said that the scrubber liquor flow rate is not currently monitored, nor is it considered a critical parameter in the daily operation of the scrubber mer cury removal tower associated with roasters at their facility . The commenter further explained that the scrubber is not a spray tower, but instead the liquor is recirculated in the tower, so the pump is monitored to insure it is operational. The commente r stated that the pressure drop across the mercury removal tower at its roasters is monitored, but is not considered a critical parameter and that the mercuric ion and chloride ion concentrations that they monitor are the critical parameters that define th e effectiveness of the mercury scrubber. Another commenter added that , for the calomel

- based mercury scrubbers, the key parameter is the reagent concentration in the solution exiting the scrubber and that maintaining the exit reagent concentration ensure s there is sufficient reagent to react with the mercury vapor. The commenter noted that low exit concentrations indicate that either the liquor flow rate is too low, or the fresh reagent addition rate is too low. Thus,***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **110** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** liquor flow rate does not need to b e monitored in addition to reagent exit concentration. The commenter stated that if EPA continues to require them, the ranges should be based on the manufacturer’s specification or an alternative value approved by the permitting authority, as opposed to t hree test runs. One commenter recommended that the corresponding range or limit for parametric deviations be applied to a daily average value rather than continuous instantaneous values or single samples. Another commenter also stated that the requireme nt to establish the minimum water flow rate and pressure drop of the wet scrubber on readings taken during the performance test should not apply to scrubbers on roasters. The commenter noted that these parameters were intended to monitor for physical
proc esses, and the scrubbers on roasters often include chemical reaction s , which are not monitored. One commenter believes that establishing a maximum operating temperature for inlet gas concentrations by artificially increasing this temperature during compl iance testing may destroy the control equipment, conflict with recommended operating temperatures, and artificially increase the reported mercury emissions. The commenter concluded that these parameters are not deemed critical in the effective***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **111** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** operation o f a mercury calomel scrubber. Another commenter added that their Compliance Assurance Monitoring (CAM) plan provides for an inlet gas temperature range of 32 ° to 134°F to prevent water freezing problems or extremely hot gas temperatures that could damage the mercury scrubber. The commenter stated that mercury scrubbers remove mercury from the gas stream through a chemical reaction and not a condensation mechanism and that lower temperatures will not remove (via condensation) additional mercury. The comme nter explained that , although mercury scrubber inlet gas temperature is not a relevant control performance parameter, their facility maintains the inlet gas temperature below 134°F and monitors the temperature daily to prevent damage to the controls system from excessively low or high gas temperatures
. **Response :**  After additional review of operating permits and consideration of public comments, we have found that the inlet temperature is monitored and maintained within a range to provide operational flexibi lity with the lower end bounded to prevent freezing and the upper end bounded to prevent damage to equipment, which in turn could lead to excess emissions. In addition, we have learned that this temperature is dependent on the cooling tower water temperat ure used in the process, and***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **112** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** this water temperature can vary quite widely from winter to

summer. Facilities may not be able to address the issues described above if they can only use initial compliance testing to establish the inlet temperature operating range, as we proposed. Consequently, the final rule provides the following three ways for a facility with a roaster to establish an operating range for inlet temperature : (1) based on the maximum inlet temperature during the initial compliance test ; (2) from the manufacturer’s specifications ; or (3) based on the limits established by the permitting authority . The facility must monitor the temperature hourly, and any exceedance of the upper limit for temperature would trigger corrective action. We agree that pressure drop is not relevant to mercury scrubbers because, unlike venturi scrubbers applied to control
PM emissions, it is not related to its mercury emission control performance. We have removed pressure drop monitoring from the final rule for mer cury scrubbers. However, we continue to believe that it is important to monitor the scrubber flow rate to ensure the scrubber solution is being delivered to the system and that the flow is adequate, which is related to the system’s performance. We unders tand that some facilities monitor mercury scrubber solution line pressure (solution header pressure) as an***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **113** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** indicator of flow rate, and we agree this is adequate to ensure proper flow. Consequently, the final rule requires hourly monitoring of scrubber flo w rate (or line pressure) for mercury scrubbers on roasters. As with the inlet temperature operating range, t he minimum flow rate or line pressure must be established by one of the following three ways: (1) during the initial compliance test, (2) from the manufacturer’s specifications, or (3) based on the limits established by the permitting authority . The final rule requires hourly monitoring and that corrective action is triggered if the flow rate or line
pressure falls below the established parameters . Regarding the acceptability of parameter values that were approved by permitting a uthorities prior to this final r ule , such values must be established as specified in the final rule and are not presumed in advance to be acceptable. 5. Exceeding the Opera ting Limits for Roasters
**Comment :**  One commenter was concerned about the consequences of exceeding a parametric monitoring limit . The commenter remarked that shutting down the roaster for exceeding a monitoring parameter without evidence of an ongoing emi ssion limit exceedance is arbitrary and capricious, unnecessarily punitive, and threatens the economic viability of the regulated***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **114** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** sources. The commenter pointed out that the ranges of parameters measured during source testing are not necessarily the only ranges within which the unit can operate effectively
. The parameters proposed by EPA are not the best parameters for monitoring roaster emissions and do not directly correlate to mercury emissions or proper control system operation. The commenter also ob jected to the period of only 45 minutes to investigate and take corrective action. One commenter recommended that the corrective action response time be extended minimally to 48 hours after daily average values are processed, plus an additional 24 hours to verify the daily average parametric value was within limits. For facilities that conduct PS 12B sampling and a daily average parametric deviation persists for 96 hours, the commenter recommended requiring sampling of the roaster’s exhaust using PS
12B within the next 24 hours, then evaluating the mercury concentration results. If the mercury concentration is below the operating limit, then , within 10 days of receiving the analytical results , the facility sho uld be required to either petition the permit ting authority for a change in the parametric limits, or provide the permitting authority with a compliance plan that details corrective actions taken to date and the plan***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **115** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** and schedule for bringing the parameter back within range. The commenter said that , if the mercury concentration is above the operating limit, the facility will be required to schedule an independent source testing firm to perform a compliance test within 45 days using one of the approved methods described in the rule. The commenter not ed that the Nevada State agency requires 30 days to review the testing protocol, and source testing companies typically require 30 days or more advanced notice. For roasters where direct concentration measurements are not required and a daily average para metric deviation persists for 96 hours, the commenter recommended that within 48 hours, the facility sh ould : (1) provide the permitting authority with a compliance plan that details corrective actions taken to date and the plan and schedule for bringing t he parameter back within the limits ; or (2) schedule an independent source testing firm to perform a compliance test within 45 days using one of the approved methods described in the rule. The commenter concluded that , if the test results show that the so urce has exceeded the threshold of 10 lb/million tons of ore, the facility would be required to implement direct mercury concentration measurements. One commenter requested that EPA provide an exception from***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **116** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** the shutdown requirement when it can be demonstr ated that, notwithstanding an exceedance of the parametric operating range, the roaster mercury emissions are less than the operating limit for mercury concentration. The commenter stated that the mercury concentration measurement is a more direct indicat ion of the ultimate mercury emissions that the parametric monitors are designed to address. **Response :**  We have investigated in greater detail the issues associated with monitoring roasters, and we have consulted with NDEP and the owners and operators of roasters to learn more about appropriate roaster monitoring. We believe the requirements of th is final rule provide assurance that timely corrective actions are taken when a monitoring parameter is exceeded, and we have included requirements for testing f or mercury concentration s to determine if the corrective actions were successful or if a deviation has occurred. The final rule includes parametric monitoring of the mercury scrubbers applied to roasters to control mercury. If a parameter is outside of
t he established range or limit, corrective actions are triggered. If corrective actions do not result in the parameter reading being corrected and verified within 48 hours, a mercury concentration measurement (using method 30B, 12B, 29, or OHM)***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **117** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** must be mad e to determine if the operating limit for mercury concentration is being exceeded. The measurement must be performed and the concentration determined within 48 hours (after the initial 48 hours , or a total of 96 hours ). If the measured mercury concentrat ion meets the operating limit for mercury concentration, the corrective actions are deemed successful. In addition, the owner or operator may request approval from the permitting authority to change the parameter range or limit based on measurements of th e parameter at the time the mercury concentration measurement was made. If the operating limit is exceeded, the exceedance must be reported as a deviation and the facility must conduct a full compliance test within 4 0 days to determine if the source is in compliance with the MACT limit
. **Comment :**  For facilities that monitor roasters with a CEMS, one commenter proposed that corrective action be required within 48 hours of receiving and processing the results from the CEMS data, plus an additional 24 hours sh ould be allowed to collect verification data to see if the daily average concentration was restored below the operating limit. The commenter recommended that , if the exceedance persists, the facility sh ould be required to schedule an independent source testing firm to***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **118** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** perform a compliance test within 45 days. For facilities that choose PS 12B monitoring, the commenter recommended that a deviation be considered an exceedance of the operating limit if the average of three consecutive sampling results (thr ee weeks) were above the established limit. The commenter proposed that the facility sh ould then have one week to take corrective actions, an additional week to take the verification sample using PS 12B, with receipt of results the following week (three w eeks total). The commenter stated that if the exceedance persists, the facility sh ould be required to schedule an independent source testing firm to perform a compliance test within 45 days using one of the approved methods described in the proposed rule. **Response :**  After consider ing these comments on the mercury concentration operating limit and the above discussion on parametric monitoring of roasters , we have made several clarifications in the final rule
. If a mercury concentration operating limit is e xceeded from either daily average measurements from a CEMS , continuous sampling using PS 12B, or from sampling twice per month (at least 1 1 days apart) using PS 12B or Method 30B, the exceedance must be reported to the permit authority as a deviation and c orrective actions must be***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **119** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** implemented within 48 hours upon receipt of the sampling results that show the deviation. Moreover, w ithin 96 hours of the exceedance, the owner or operator must measure the concentration again (with the CEMS or Method 12B or 30B ) and demonstrate to the permit authority that the operating limit for mercury concentration has been met, or inform the permit authority that the limit continues to be exceeded
. If the operating limit is still exceeded after these 96 hours, t he owner or operator m ust conduct a full compliance test for the ore pretreatment affected source within 40 days to determine if the affected source is in compliance with the MACT emission standard . If the source is determined to be in compliance, the compliance test may also be used to establish a new operating limit for mercury concentration.
**Comment :**  One commenter requested that EPA provide an exception to the shutdown requirement for facilities that have well

- controlled roasters and elect to monitor under the pro posed Option 3. The commenter believes a facility should have time (45 days) to demonstrate that the roaster’s mercury emissions remain less than 10 lbs of mercury per million tons of ore. The commenter stated that this would be achieved by scheduling an independent source testing firm to perform a compliance test***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **120** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** using methods described in the rule, and calculations that demonstrate compliance with the limit of 10 lbs per million tons of ore. **Response :**  As we have discussed above, the final rule relies i n part on parametric monitoring of mercury scrubbers used on roasters to assure compliance with the applicable emission standards , and when the measured parametric values are out of the established operating range, corrective actions must be taken. This i s no different f or facilities that qualify for the exemption described in §63.11647(a)(5) (i.e., facilities exempt from mercury concentration monitoring by having demonstrated that their roaster emissions are less than 10 lb/million tons of ore ). For thes e facilities , the final rule similarly requires that corrective actions be taken to restore the scrubber operating parameters to the established operating range. If the parameters are not restored to the established range within 48 hours of triggering the corrective actions, the owner or operator must perform mercury concentration sampling of the roaster emissions using PS 12B or Method 30B or Method 29 and determine the mercury concentration within 48 hours following the initial 48 hours (or a total of 96 hours from the time the parameter range was exceeded) . The measured***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **121** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** concentration must be compared to a mercury concentration operating limit that is based on Equation 3 in the final rule, where the value for “C trap ” in Equation 3 is based on the mercury concentration for the roaster measured during the most recent compliance test. If the measured mercury concentration meets the operating limit for mercury concentration, the corrective actions are deemed successful. In addition, the owner or operator ma y request approval from the permitting authority to change the parameter range or limit based on measurements of the parameter at the time the mercury concentration measurement was made. If the operating limit is exceeded, the facility must take correctiv e actions and report it to the permit authority as a deviation. The owner or operator m ust also conduct a compliance test within 40 days to determine if the roaster operations are in compliance with the emission standard
. **Comment :**  One commenter proposed that only the scrubber water flow rate monitoring be required for wet scrubbers on the quenching circuits associated with the roaster. The commenter wanted to confirm that wet scrubber monitoring does not apply to wet scrubbers or condensers on roasters. Another commenter asked that EPA confirm that the term “wet scrubbers” does not include condensers, which are used throughout the mining***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **122** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** processes for gas cooling to condense water or (in the case of retorts) mercury. Another commenter asked EPA to conf irm that wet scrubber monitoring does not apply to wet scrubbers associated with ore preheaters. One commenter noted that continuous readings on wet scrubbers are unreliable and proposed monitoring the water flow rate and pressure drop once per shift. The commenter noted that if any water flow rate or pressure drop reading exceeds the operating limit, the facility should follow the procedures for operating limit exceedances. The commenter stated that many facilities do not have d ata a cquisition s ystems ca pable of recording continuous data and that wet scrubbers are primarily used to control particulates. The commenter concluded by stating that wet scrubbers are not key mercury controls and monitoring once per shift is sufficient to maintain control perfor mance on a continuing basis. One commenter wanted to confirm that the limits established during testing would not be more stringent than the requirements set forth in the Standards of Performance for New Stationary Sources for Metallic Mineral Processing Plants, which allows for plus or minus 30 percent. Another commenter recommended that the operating limit for wet scrubber monitoring be based on***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **123** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** either the lowest average value during any test run or no lower than 10 percent below the average value meas ured during the
test. **Response :**  As discussed above, the scrubber monitoring for roasters applies to the mercury scrubber (located at or near the end of the exhaust gas treatment train) and does not apply to the additional scrubbers that are used to remove PM and SO 2 prior to the mercury scrubber. We are also clarifying in the final rule that when the primary mercury emission control device is a carbon adsorber, which is the last stage of the exhaust gas cleaning treatment train, it is necessary to monitor the carbon adsorber to ensure it is operating properly and controlling mercury emissions, and the rule does not require that scrubbers in the gas treatment train (typically used for control of PM and/or SO 2 ) prior to the carbon adsorber be monitored under this rule for mercury emissions. However, if there is no carbon adsorber or mercury scrubber , and the scrubber in question is the only control device for mercury emissions, the final rule requires that it be monitored once per shift per operating day (e. g., minimum of two times) for pressure drop and flow rate with operating limits that either are established during the initial compliance test, from the manufacturer’s specifications,***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **124** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** or based on approval from the permitting authority (except for
pressure drop for autoclaves as discussed above). This applies to scrubbers on ore preheaters and quenching if there is no carbon adsorber or mercury scrubber in the exhaust gas treatment train. We are clarifying in the final rule that condensers, such as those f ound at roasters and retorts, are not wet scrubbers. We agree that monitoring and recording the pressure drop once per shift is adequate for monitoring these wet scrubbers to ensure they are operating properly. We disagree that a buffer of +/

- 30 percent based on a certain NSPS subpart is appropriate for this NESHAP for mercury. The comment suggesting an option of a +/

- 10 percent buffer around the average value during the performance test has merit as an option to only using the lowest value during any i ndividual run as the operating limit. If the system is so stable that it shows very minimal variability during the performance test, we agree that it is appropriate to add +/

- 10 percent to account for potential future variability
. Consequently, we are in corporating the option in the final rule , as suggested by the commenter. 6 . Carbon Adsorber Temperature Monitoring
**Comment :**  Several commenters stated their concern with the***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **125** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** proposed requirement of monitoring gas st r eam temperature at the inlet to the car bon adsorber and maintaining the inlet temperature below the maximum temperature established during the compliance test. They noted that the primary purpose for monitoring the inlet gas stream temperature of carbon adsorbers is to prevent spontaneous comb ustion of the sulfidized carbon in the adsorber, not to detect excursions in mercury emissions. The commenters also stated that some carbon adsorption systems heat the gas stream prior to the carbon adsorber to prevent moisture buildup and/or subsequent c ondensation in the carbon. The commenters explained that the NMCP already requires that the exit gas temperature of condensers prior to the carbon adsorbers be established to minimize mercury emissions from the condenser. The commenters believe that an i ncrease in inlet gas temperature to a carbon adsorption unit is not indicative of an increase in inlet gas stream mercury emissions because the high operating temperatures of the processes volatilize approximately 100 percent of mercury. The commenters st ated that establishing a maximum operating temperature for inlet gas concentrations by artificially increasing this temperature during compliance testing may destroy mercury control equipment; conflict with NMCP requirements and/or manufacturer’s recommend ed operating***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **126** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** temperatures; artificially increase the reported mercury emissions; or artificially decrease the allowable operating limit for mercury concentration. The commenters continued by stating that, if EPA persisted in requiring the monitoring of the gas stream inlet temperature, the maximum inlet temperature limit should be established by either the manufacturer’s recommendation and/or concurrence with the permitting authority. The commenters proposed monitoring the inlet temperature once per shift as an option to continuously monitoring the inlet temperature and comparing the daily averages rather than the hourly averages to the operating limit. The commenters noted that many facilities do not have d igital a cquisition s ystems capable of recording c ontinuous data, and monitoring once per shift is sufficient to maintain control performance. The commenters suggested that , if corrective action is needed, the facility should be allowed to sample the carbon loading to demonstrate that the effectiveness

o f the carbon adsorber has not been adversely impacted. **Response :**  The purpose of monitoring the inlet temperature to carbon adsorbers is not to provide an indication of higher mercury concentrations in the inlet stream as suggested by the commenters. The purpose is related to the fact that temperature***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **127** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** is a fundamental parameter that affects the efficiency and capacity of carbon adsorbers. Generally, higher temperature s result in lower capacity and earlier breakthrough and , in fact, high temperatures are used to desorb adsorbed pollutants to regenerate carbon. In the extreme of temperature, the carbon adsorber might actually be desorbing rather than acting as a control device. This is particularly important for those carbon adsorbers applied to high temp erature thermal processes, such as carbon kilns and melt furnaces, where it is possible for the exhaust temperature to rise above the normal operating temperature or above the temperature at which the carbon adsorber was designed to operate. For high temp erature
processes ( such as furnaces) , and not those such as electrowinning where the temperature may be near ambient conditions), we continue to require monitoring the inlet temperature . Owners or operators must establish an operating limit for temperatur e based on one of the following : (1) the maximum temperature during the initial compliance test ; (2) from the manufacturer’s specifications ; or (3) based on limits established by the permitting authority . If this established operating limit is exceeded co rrective action must be taken and the exceedance reported as a deviation to the permit authority
.***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **128** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** Further , the final rule requires facilities to monitor inlet temperature once per shift rather than continuously, as was proposed. Because inlet temperature s should not vary greatly over the course of an 8 to 12

- hour period, we believe monitoring once per shift is adequate. We also conclude that if a temperature exceedance has occurred, the carbon bed should be sampled or the outlet concentration determined, depending on the monitoring option chosen, within 48 hours to ensure no permanent damage to the carbon adsorber occurred as a result of the deviation. We believe the temperature exceedance should be reported as a deviation even if the subsequent monitori ng shows that the carbon bed is operating properly because the subsequent monitoring would not necessarily detect if mercury had been desorbed and excess emissions occurred.
7 . Monitoring of Multiple Units Ducted to One Stack
**Comment :**  Commenters requeste d clarification that , for facilities that have two roasters ducted together through a shared mercury control system, the mercury concentration monitoring would be conducted on the combined exhaust stream. The commenters also requested clarification that t he mercury concentration operating limit for two roasters that share a control system would be established during the simultaneous***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **129** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** operation of the roasters in order to account for the combined mercury emissions from both roasters. Commenters also reques ted clarification that , for facilities with multiple process units ducted together through a shared carbon adsorber, the mercury concentration monitoring would be conducted on the combined exhaust stream. The commenters also requested clarification that t he mercury concentration operating limit for a carbon adsorber for multiple units that share the carbon adsorber would be established during the simultaneous operations of all process units in order to account for the combined mercury emissions. **Response :**  We agree with the commenters in general and have made the following clarifications in the final rule. If two roasters share a common control device and stack, the mercury concentration operating limit , as well as stack testing for compliance w ill be ba sed on both roasters operating. However, monitoring for mercury concentration must be performed at the frequency specified in the final rule whether only one or both roasters are operating. We also have clarified that , for multiple process units vented t o a common carbon adsorber, the mercury concentration operating limit and the stack testing for compliance must be based on all units operating if possible
.***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **130** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** However, the ongoing mercury concentration monitoring must be performed at the frequency specified in the final rule for whatever units are operating at the time. 8 . Monitoring Mercury Concentration in Roaster Ore
**Comment :**  One commenter objected to the proposed requirement to conduct additional compliance testing if the mercury concentration in the o re fed to the roaster is higher than any concentration measured in the previous 12 months. The commenter stated that there would not be an increase in the mercury emissions from their roasters because of the extensive series of mercury controls, some of w hich operate more efficiently at higher mercury loadings with unchanged stack emissions. In addition, the commenter noted that the rule does not provide details on how to measure the mercury ore concentration or what threshold of significance would be use d to show an increase in ore mercury content occurred. The commenter concluded that the requirement would only provide extra cost and burden without any environmental benefit. **Response :**  We agree with the commenter and have removed this requirement from t he final rule. We have no data showing that the mercury content of the ore has a significant effect on the performance of mercury scrubbers applied to roasters, which***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **131** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** are designed to handle and operate efficiently for a range of mercury inlet concentratio ns. In addition, roasters condense and recover elemental mercury prior to the mercury scrubber, and any increase in mercury loading would likely result in an increase in the recovery of elemental mercury. We have identified and require the monitoring of parameters associated with the scrubber chemistry, and maintaining these parameters within the established range for which the mercury scrubber was designed . This monitoring approach helps ensure th at the mercury scrubbers are controlling mercury emission independent of variations in ore mercury content . **V. Summary of Environmental, Economic and Health Benefits?** For proposal, we estimated baseline mercury emissions to be 3,119 lb/yr based on the available emissions data and average process data for the p eriod 2007 to 2009. To estimate the impacts of the final rule, we have revised our baseline mercury emissions estimate to account for the recent installation of new mercury emission controls at two facilities and additional test data received since propos al. As a result of these changes, we now estimate baseline mercury emissions to be 2,635 lb/yr. We estimate the final MACT standard will reduce mercury emissions from gold mine ore processing and production by 1,496 lb/yr from***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **132** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** the baseline emissions leve ls of 2,635 lb/yr down to a level of 1,139 lb/yr post

- MACT . The annual emissions expected after MACT (1,139 lb /yr ) represent a n estimated 77 percent reduction from 2007 emissions ( 5,000 lb /yr ), a 95 percent reduction from the emissions level in 2001 (abou t 23,000 lb /yr ) , and more than 97 percent reduction from uncontrolled emissions levels (more than 37,000 lb /yr )
. The capital cost of emission controls is estimated as $ 36 million with a total annualized cost of $ 8.1 million per year. The capital costs fo r monitoring, reporting, and recordkeeping are estimated as $1.0 to $1.3 million with a total annualized cost of $0.8 to $1.5 million per year , depending on the monitoring option that is chosen
. The overall cost effectiveness is estimated to be about $6,4 00 per pound of mercury reduced. The cost of compliance is estimated to be less than 0. 8 percent of sales for all affected firms . We therefore believe that the economic impact on an affected company would be insignificant. Electricity consumption is exp ected to increase by about 12,700 megawatt

- hours per year due to increased fan capacity for carbon adsorbers and the installation of refrigeration units or condensers on a few process units. Non

hazardous solid waste (spent carbon containing mercury that must***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **133** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** be regenerated or disposed of) would increase by about 7 tons
per year. **VI. Statutory and Executive Order Reviews**
A. This action is a “significant regulatory action” under the terms of Executiv e Order 12866 (58 FR 51735, October 4, 1993) because it may raise novel legal or policy issues. Accordingly, EPA submitted this action to the Office of Management and Budget (OMB) for review under E xecutive Order 12866 , and any changes made in response to OMB recommendations have been documented in the docket for this action. Executive Order 12866: Regulatory Planning and Review

B. The information collection requirements in this final rule have been submitted for approval to OMB under the Paperwork Reduction Act, 44 U.S.C. 3501 Paperwork Reduction Act

et s eq

The recordkeeping and reporting requirements in this final rule are based , in large part, on the information collection requirements in EPA’s NES HAP General Provisions (40 CFR part 63, subpart A). The recordkeeping and reporting requirements in the General Provisions are specifically authorized by section 114 of . The Information Collection Request (ICR) document prepared by EPA has been assigned EPA ICR No. 238 3 .01
.***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **134** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** the CAA (42 U.S.C. 7414). All information other than emissions data submitted to EPA pursuant to the information collection requirements for which a claim of confidentiality is made is safeguarded according to CAA section 114(c) and EPA’s implementing regulations at 40 CFR part 2, subpart B. This final NESHAP will require applicable one

- t ime notifications according to the NESHAP General Provisions. In addition, owners or operators must submit annual notifications of compliance status and report any deviations in each semiannual reporting period. Records of all performance tests,

measurem ents of feed input rates, monitoring data, and corrective actions w ill be required. The average annual burden for this information collection averaged over the first 3 years of this ICR is estimated to total 483 labor hours per year at a cost of approxima tely $ 26,847 per year for the 2 1 facilities that w ill be subject to th is final rule, or approximately 23 hours per year per facility. Capital costs are estimated as $1.3 4 million , operation and maintenance costs are estimated as $6 7 ,000 per year, and tota l annualized cost (including capital recovery) is estimated as $ 417,930 per year for th is final rule ’s information collection requirements. No costs or burden hours are estimated***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **135** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** for new sources because none is projected for the next 3 years. Burden is d efined at 5 CFR 1320.3(b). An agency may not conduct or sponsor, and a person is not required to respond to, a collection of information unless the collection displays a currently valid OMB control number. The OMB control numbers for EPA’s regulations in 40 CFR part 63 are listed in 40 CFR part 9. In addition, EPA is amending the table in 40 CFR part 9 of currently approved OMB control numbers for various regulations to list the regulatory citations for the information requirements contained in this fina l rule.
C. The Regulatory Flexibility Act generally requires an agency to prepare a regulatory flexibility analysis of any rule subject to notice and comment rulemaking requirements under the Administrative Procedure Act or an y other statute unless the agency certifies that th is rule would not have a significant economic impact on a substantial number of small entities. Small entities include small businesses, small not

- for

- profit enterprises, and small governmental jurisdicti ons. Regulatory Flexibility Act

For the purposes of assessing the impacts of th is final NESHAP on small entities, a small entity is defined as: (1) a small business whose parent company meets the Small Business***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **136** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** Administration size standards for small businesses found at 13
CFR 121.201 (less than 500 employees for gold mine ore processing and production facil i ties

– NAICS 212221 ); (2) a small governmental jurisdiction that is a government of a city, county, town, school district, or special district with a population of less than 50,000; and (3) a small organization that is any not

- for

- profit enterprise that is independently owned and operated and is not dominant in its field. After considering the economic impacts of this final rule on small entities, I certify that this action will not have a significant economic impact on a substantial number of small entities. This final rule is estimated to impact about 2 1 gold mine ore processing and production facilities, none of which are owned by small entities. T hus, there are no impac ts to small entities from this final rule. Although this final rule will contain requirements for new sources, EPA expect s few, if any , new sources to be constructed in the next several years.
T herefore, EPA did not estimate the impacts for new affected

sources for this final rule
. Although this final rule will not have a significant economic impact on a substantial number of small entities, EPA nonetheless has tried to reduce the impact of this final rule on***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **137** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** small and large entities. The se standards e stablish emission limits that reflect practices and controls that are used throughout the industry and in many cases are already required by State operating permits. The se standards also require only the essential monitoring, recordkeeping, and reporting needed to verify compliance. The se final standards were developed based on information obtained from industry representatives in our surveys, consultation with business representatives and their trade association and other stakeholders
. D. This final rule does not contain a federal mandate that may result in expenditures of $100 million or more for state, local, and tribal governments, in the aggregate, or to the private sector in any one year. This final rule is not expec ted to impact state, local, or tribal governments. The total nationwide annualized cost of this final rule for affected industrial sources is $ 9.2 million/yr. Thus, this final rule is not subject to the requirements of sections 202 and 205 of the Unfunde d Mandates Reform Act (UMRA). Unfunded Man dates Reform Act

This final rule is also not subject to the requirements of section 203 of UMRA because it contains no regulatory requirements that might significantly or uniquely affect small***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **138** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** governments. This final rule will not apply to s uch governments and will not impose any obligations upon them.
E. This action does not have federalism implications. It will not have substantial direct effects on the States, on the relationship between the national g overnment and the States, or on the distribution of power and responsibilities among the various levels of government, as specified in Executive Order 13132
. This final rule does not impose any requirements on state and local governments. Thus, Executive Order 13132 does not apply to this action
. Executive Order 13132: Federalism

In the spirit of Executive Order 13132, and consistent with EPA policy to promote communications between EPA and State and local governments, EPA specifically solicit ed comment on this proposed action from Stat e and local officials.
F.

This action does not have tribal implications, as specified in Executive Order 13175 (65 FR 67249, November 9, 2000). This final rule imposes no requirements on tribal governments; thus, Executive Order 13175 does not apply to this action. Although Executive Order 13175 does not apply to this action, EPA Executive Order 13175: Consultation and Coordination with Indian Tribal Governments***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **139** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** requested comment from tribal officials in developing this action. However, no comments on the proposal were received from tribal governments
. G.

EPA interprets Executive Order 13045 (62 F.R. 19885, April 22, 1997) as applying only to those regulatory a ctions that are based on health or safety risks, such that the analysis required under section 5

- 501 of the Executive Order has the potential to influence the regulation. This action is not subject to Executive Order 13045 because it is based solely on te chnology performance. Executive Order 13045: Protection of Children from Environmental Health and Safety Risks

H.

This action is not a “significant energy action” as defined in Executive Order 13211 (66 FR 28355, May 22, 2001) because it is not likely to have a significant adverse effect on the supply, distribution, or use of energy. We have concluded that this final rule will not likely have any significant adverse energy effects because energy consumption would increase by o nly 1 2, 7 00 megawatt

- hours per year. Executive Order 13211: Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use

I. National Technology Transfer and Advancement Act***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **140** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** Section 12(d) of the National Technology Transfer and Advancement Act of 1995 (“NTTAA”), Public Law No. 104

- 113 (15 U.S.C. 272 note), directs EPA to use voluntary co nsensus standards (VCS) in its regulatory activities unless to do so would be inconsistent with applicable law or otherwise impractical. VCS are technical standards (e.g., materials specifications, test methods, sampling procedures, business practices) th at are developed or adopted by voluntary consensus standards bodies. NTTAA directs EPA to provide Congress, through OMB, explanations when the Agency decides not to use available and applicable VCS. This final rulemaking involves technical standards. E PA decided to use ASME PTC 19.10

- 1981, “Flue and Exhaust Gas Analyses,” for its manual methods of measuring the oxygen or carbon dioxide content of the exhaust gas. These parts of ASME PTC 19.10

- 1981 are acceptable alternatives to EPA Method 3B. This sta ndard is available from the American Society of Mechanical Engineers (ASME), Three Park Avenue, New York, NY 10016

– 5990.
A n other VCS, ASTM D6784

- 02, “Standard Test Method for Elemental, Oxidized, Particle

- Bound and Total Mercury in Flue Gas Generated from Coal

- Fired Stationary Sources (Ontario Hydro***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **141** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** Method)” is an acceptable alternative to EPA Method 29. This performance test method is available from ASTM International.
See http://www.astm.org/
. EPA has also decided to use EPA Methods 1, 1A, 2, 2A, 2C,
2 D, 2F, 2G, 3, 3A, 3B, 4, 29 , 30B, Method 7471A, “Mercury in Solid or Semisolid Waste (Manual Cold

- Vapor Technique),” and ASTM D6784

– 02, “Standard Test Method for Elemental, Oxidized, Particle

- Bound and Total Mercury in Flue Gas Generated from Coal

- Fired St ationary Sources,” (incorporated by reference

– see 63.14)
. Although the Agency has identified 14 VCS as being potentially applicable to these methods cited in this rule, we have decided not to use these standards in this final rulemaking. The use of the se VCS would have been impractical because they do not meet the objectives of the standards cited in this rule. The search and review results are in the docket for this final rule. Under section 63.7(f) and section 63.8(f) of Subpart A of the General Pro visions, a source may apply to EPA for permission to use alternative test methods or alternative monitoring requirements in place of any required testing methods, performance specifications, or procedures in the final rule.
J. Executive Order 12898: Fede ral Actions to Address***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **142** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** Environmental Justice in Minority Populations and Low

- Income Populations Executive Order 12898 (59 FR 7629, February 16, 1994) establishes federal executive policy on environmental justice. Its main provision directs federal agenci es, to the greatest extent practicable and permitted by law, to make environmental justice part of their mission by identifying and addressing, as appropriate, disproportionately high and adverse human health or environmental effects of their programs, pol icies, and activities on minority populations and low

- income populations in the United States. EPA has determined that this final rule will not have disproportionately high and adverse human health or environmental effects on minority or low

- income popula tions because it will increase the level of environmental protection for all affected populations without having any disproportionately high and adverse human health or environmental effects on any population, including any minority or low

- income populatio n. This final rule is expected to reduce mercury emissions from gold mine ore processing and production facilities and thus decrease the amount of such emissions to which all affected populations are exposed
.***E.O. 12866 Review

– Draft

– Do Not Cite, Quote, or Release During Review*** Page **143** of **187**

**Draft –**  **Deliberative Document**  **for Internal EPA**  **Review (11/2/10)** K. The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the Small Business Regulatory Enforcement Fairness Act of 1996, generally provides that before a rule may take effect, the agency promulgating the rule must submit a rule report, which includes a copy of the r ule, to each House of the Congress and to the Comptroller General of the United States. EPA will submit a report containing this final rule and other required information to the U.S. Senate, the U.S. House of Representatives, and the Comptroller General o f the United States prior to publication of this final rule in the Congressional Review Act

Federal Register
. A major rule cannot take effect until 60 days after it is published in the Federal Register
. This action is a “major rule” as defined by 5 U.S.C. 804(2). This final rul e will be effective on [INSERT DATE 60 DAYS AFTER PUBLICATION IN THE FEDERAL REGISTER].**National Emission Standards for Hazardous Air Pollutants: Gold**  **Mine Ore Processing and Production Area Source Category; and**  **Addition to Source Category List for Standa rds**  **Page 144**  **of 187** 

**List of Subjects in 40 CFR Part s 9 and**  **63** Environmental protection, Air pollution control, Hazardous substances, Incorporations by reference, Reporting and recordkeep ing requirements.

___________ Dated:

____________________________ Lisa P. Jackson, Administrator.145
For the reasons stated in the preamble, title 40, chapter I, of the Code of Federal Regulations is amended as follows: **PART 9 —**  **[AMENDED]** 1. The authorit y citation for part 9 continues to read as follows: **Authority:** 7 U.S.C. 135, et seq ., 136

– 136y; 15 U.S.C. 2001, 2003, 2005, 2006, 2601

– 2671; 21 U.S.C. 331j, 346a, 348; 31 U.S.C. 9701; 33 U.S.C. 1251, et seq ., 1311, 1313d, 1314, 1318, 1321, 1326, 1330, 134 2, 1344, 1345(d) and (e), 1361; E.O. 11735, 38 FR 21243, 3 CFR, 1971

– 1975 Comp. p. 973; 42 U.S.C. 241, 242b, 243, 246, 300f, 300g, 300g

– 1, 300g

– 2, 300g

– 3, 300g

– 4, 300g

– 5, 300g

– 6, 300j

– 1, 300j

– 2, 300j

– 3, 300j

– 4, 300j

– 9, 1857, et seq

**Subpart A —**  **[Amended]** ., 6901

– 6992k, 7401

– 7671q , 7542, 9601

– 9657, 11023, 11048.

* * * * * 2. The table in § 9.1 is amended by adding an entry in numerical order for “ 63.11647

– 63.11648 ” under the heading “National Emission Standards for Hazardous Air Pollutants for Source Categories” to read as follows: **§9.1 OMB Approvals under the Paperwork Reduction Act.**
* * * * *
40 CFR citation OMB control No. * * * * * National Emission Standards for Hazardous Air Pollutants for146
Source Categories 3 * * * * * 63.11647

– 63.11648 2060

– NEW * * * * * * * * * *

3 The ICRs referenced in this section of the table encompass the applicable general provisions contained in 40 CFR part 63, subpart A, which are not independent information collection requirements.
* * * * * **PART 63 —**  **[AMENDED]** 3 . The autho rity citation for part 63 continues to read as follows: **Authority** : 42 U.S.C. 7401 et seq **Subpart A —**  **[Amended]** .

4 . Section 63.14 is amended by revising paragraph s (b)(35) and (i)(1) and by adding paragraph (k)(1)(v) to read as follows: **§ 63.14 Incorporati**  **on by reference.**
* * * * * ( b ) * * * (35) ASTM D6784

– 02, Standard Test Method for Elemental, Oxidized, Particle

- Bound and Total Mercury in Flue Gas Generated from Coal

- Fired Stationary Sources (Ontario Hydro Method), IBR approved for §63.11646(a)(1)(v) an d table 5 to subpart DDDDD of this part.
* * * * *147
(i) * * * (1) ANSI/ASME PTC 19.10

– 1981, “Flue and Exhaust Gas Analyses [Part 10, Instruments and Apparatus],” IBR approved for §§63.309(k)(1)(iii), 63.865(b), 63.3166(a)(3), 63.3360(e)(1)(iii), 63.3545(a )(3), 63.3555(a)(3), 63.4166(a)(3), 63.4362(a)(3), 63.4766(a)(3), 63.4965(a)(3), 63.5160(d)(1)(iii), 63.9307(c)(2), 63.9323(a)(3), 63.11148(e)(3)(iii), 63.11155(e)(3), 63.11162(f)(3)(iii) and (f)(4), 63.11163(g)(1)(iii) and (g)(2), 63.11410(j)(1)(iii), 63. 11551(a)(2)(i)(C), 63.11646(a)(1)(iii), table 5 to subpart DDDDD of this part, and table 1 to subpart ZZZZZ of this part.
* * * * * (k) * * * (1) * * * (v) Method 7471A, “Mercury in Solid or Semisolid Waste (Manual Cold

- Vapor Technique),” IBR approved f or §63.11647( f )(2).
* * * * * 5 . Part 63 is amended by adding subpart EEEEEEE to read as follows: **Subpart EEEEEEE —**  **National Emission Standards for Hazardous Air Pollutants: Gold Mine Ore Processing and Production**  **Area Source Category** 148
**Applicability and C ompliance Dates**  Sec. 63.11640 Am I subject to this subpart? 63.11641 What are my compliance dates? **Standards and Compliance Requirements** 63.11645 What are my mercury emission standards? 63.11646 What are my compliance requirements? 63.11647 What are my m onitoring requirements? 63.11648 What are my notification, reporting, and recordkeeping requirements? **Other Requirements and Information** 63.11650 What General Provisions apply to this subpart? 63.11651 What definitions apply to this subpart? 63.11652 Who implements and enforces this subpart? 63.11653 [Reserved] **Tables to Subpart EEEEEEE of Part 63** Table 1 to Subpart EEEEEEE of Part 63

— Applicability of General Provisions to Subpart EEEEEEE **Subpart EEEEEEE —**  **National Emission Standards for Hazardous Air**
**Po llutants: Gold Mine Ore Processing and Production**  **Area Source Category**  **Applicability and Compliance Dates** §63.11640 Am I subject to this subpart (a) You are subject to this subpart if you own or operate a gold mine ore processing and production facili ty as defined in §63.11651 , that is an area source
. ?

(b) This subpart applies to each new or existing affected

source. The affected sources are each collection of “ ore pretreatment processes ” at a gold mine ore processing and149
production facility , each co llection of “ carbon processes with
mercury retorts ” at a gold mine ore processing and production facility , each collection of “carbon processes without mercury retorts” at a gold mine ore processing and production facility, and each collection of “ non - carb on concentrate processes " at a gold mine ore processing and production facility, as defined in §63.11651
. (1) An affected source is existing if you commenced construction or reconstruction of the affected source on or before April 28, 2010
. (2) An affe cted source is new if you commenced construction or reconstruction of the affected source after April 28, 2010
. (c) This subpart does not apply to research and development facilities, as defined in section 112(c)(7) of the Clean Air Act (CAA). (d) If y ou own or operate a source subject to this subpart, you must have or you must obtain a permit under 40 CFR part 70 or 40 CFR part 71
. §63.11641 What are my compliance dates (a) If you own or operate an existing affected source, you
must comply with the applicable provisions of this subpart no later than [INSERT DATE 3 YEARS AFTER PUBLICATION OF THIS FINAL RULE IN THE FEDERAL REGISTER]
. ?150
(b) If you own or operate a new affected source , and the initial startup of your affected source is on or before [INS ERT DATE OF PUBLICATION OF THIS FINAL RULE IN THE FEDERAL REGISTER] , you must comply with the provisions of this subpart no later than [INSERT DATE OF PUBLICATION OF THIS FINAL RULE IN THE FEDERAL REGISTER]
. (c) If you own or operate a new affected sourc e , and the initial startup of your affected source is after [INSERT DATE OF PUBLICATION OF THIS FINAL RULE IN THE FEDERAL REGISTER] , you
must comply with the provisions of this subpart upon startup of your affected source. **Standards and Compliance Requirem ents**  § 63.11645 What are my mercury emission standards (a) For existing ore pretreatment processes, you must emit no more than 12 7 pounds of mercury per million tons of ore processed
. ?

(b) For existing carbon processes with mercury retorts , you must em it no more than 2.2 pounds of mercury per ton of
concentrate processed
. (c) For existing carbon processes without mercury retorts, you must emit no more than 0.1 7 pounds of mercury per ton of concentrate processed. ( d ) For existing non

- carbon concentra te processes, you must emit no more than 0. 2 pounds of mercury per ton of151

concentrate processed
. ( e ) For new ore pretreatment processes, you must emit no more than 84 pounds of mercury per million tons of ore processed
. ( f ) For new carbon processes wit h mercury retorts , you
must emit no more than 0.8 pounds of mercury per ton of concentrate processed. (g) For new carbon processes without mercury retorts, you must emit no more than 0. 14 pounds of mercury per ton of concentrate processed. ( h ) For ne w non - carbon concentrate processes, you must emit no more than 0.1 pounds of mercury per ton of concentrate processed
. ( i ) The standards set forth in this section apply at all times.
§ 63.11646 What are my compliance requirements (a) Except as provi ded in paragraph (b) of this section, you must conduct a mercury compliance emission test within 180 days of the compliance date for all process units at new and existing affected sources according to the requirements in paragraphs (a)(1) through (1 3 ) of t his section. This compliance testing must be repeated annually thereafter , with no two consecutive annual compliance tests occurring less than 3 months apart or more than 15 months apart
. ?152
(1) You must determine the concentration of mercury and the volume tric flow rate of the stack gas according to the following test methods and procedures: (i) Method 1 or 1A (40 CFR part 60, appendix A

- 1) to select sampling port locations and the number of traverse points in each stack or duct. Sampling sites must be lo cated at the outlet of the control device (or at the outlet of the emissions source if no control device is present) and prior to any releases to the atmosphere. (ii) Method 2, 2A, 2C, 2D, 2F (40 CFR part 60, appendix A

1), or Method 2G (40 CFR part 60, appendix A

- 2) to determine the volumetric flow rate of the stack gas. (iii) Method 3, 3A, or 3B (40 CFR part 60, appendix A

- 2) to determine the dry molecular weight of the stack gas. You may use ANSI/ASME PTC 19.10

- 1981, “Flue and Exhaust Gas Analyses” (incorporated by reference

- see §63.14) as an alternative to EPA Method 3B. (iv) Method 4 (40 CFR part 60, appendix A

- 3) to determine the moisture content of the stack gas. (v) Method 29 (40 CFR part 60, appendix A

- 8) to determine the concentration of me rcury , except as provided in paragraphs (a)(1)(vi) and (vii) of this section. (vi) Upon approval by the permitting authority , ASTM D6784

– 02 ; “Standard Test Method for Elemental, Oxidized,153
Particle

- Bound and Total Mercury in Flue Gas Generated from Coal

- Fi red Stationary Sources (Ontario Hydro Method)” (incorporated by reference

– see §63.14) may be used as an alternative to Method 29 to determine the concentration of
mercury . (vii) Upon approval by the permitting authority, Method 30B (40 CFR part 60, appe ndix A

- 8 ) may be used as an alternative to Method 29 to determine the concentration of mercury for those process units with relatively low particulate

- bound mercury as specified in Section 1.2 of Method 30B
. (2) A minimum of three test runs must be cond ucted for each performance test of each process unit . Each test run conducted with Method 29 must collect a minimum sample volume of 0.85 dry standard cubic meters ( 30 dry standard cubic feet)
. If conducted with Method 30B or Ontario Hydro Method, determ ine sample time and volume according to the testing criteria set forth in the relevant method. If the emission testing results for any of the emission points yields a non

- detect value, then the minimum detection limit (MDL) must be used in calculating the emissions for that emission point and, in turn, for calculating the sum of the mass emissions for all emission points subject to the emission standard for determining compliance. If the resulting mercury mass emissions rate is greater than the allowable emission standard , the owner or154
operator may use procedures that produce lower MDL results and repeat the mercury emissions testing one additional time for any emission p o int for which the measured result was below the MDL. If this additional testing is p erformed, the results from that testing must be used to determine compliance (i.e., ther e are no additional opportunities allowed to lower the MDL). (3) Tests must be conducted under operating conditions (including process or production throughputs) that are based on representative performance. Record and report to the permit authority the process throughput for each test run. For sources with multiple emission units (e.g., two roasters) ducted to a common control device and stack, c ompliance testin g must be performed with all affected emissions units in operation if possible
. If it is not possible to test all sources ducted to a common control device simultaneously, the sources can be tested separately. In such cases, any source that is not tested initially must be tested as soon as is practicable. (4) Calculate the mercury emission rate , based on the average of 3 test run values, for each process unit using Equation (1) of this section: E = Cs * Qs * K (Eq. 1) Where:
E = mercury emissions in lb/hr; Cs = concentration of mercury in the stack gas, in grains per dry standard cubic foot (gr/dscf) ;155
Qs = volumetric flow rate of the stack gas, in dry standard cubic feet per hour; and K = conversion factor f or grains (gr) to pounds (lb), 1.43 x 10 - 4

. (5) Monitor and report to the permit authority the number of one - hour periods each process unit operates during each month. (6) For the initial compliance determination for both new and existing sources, determine the total mercury emissions for all the full calendar month s between the compliance date and the date of the initial compliance test by multiplying the emission rate in lb/hr for each process unit by the number of hours each process unit operated during t h ose full calendar month s prior to th e initial compliance test
. After the initial compliance test , for subsequent compliance tests, determine the mercury mass emissions for the 12 month period prior to the compliance test in accordance with the procedures in paragraph (a)(7) of this section. Existing sources may use a previous emission test for their initial compliance determination in lieu of conducting a new test if the test was conducted within one year of the compliance date using the methods specified in paragraphs (a)(1) through (4) of this section, and the tests were representative of current operating processes and conditions. ( 7 ) For compliance determinations following the initial compliance test for new and existing sources, d etermine the total mercury mass emissions for each proc ess unit for the 12

-156
month period preceding the performance test by multiplying the emission rate in lb/hr for each process unit by the number of hours each process unit operated during the 12 full calendar months preceding the completion of the performance tests. ( 8 ) You must install, calibrate, maintain and operate an appropriate weight measurement device , mass flow meter, or densitometer and volumetric flow meter to measure ore throughput for each roast ing operation and autoclave and calculate hourly, daily and monthly totals in tons of ore according to paragraphs (a)(8)(i) and (ii) of this section
. (i) Measure the weight or the density and volumetric flow rate of the oxidized ore slurry as it exits the roaster oxidation circuit and before the carbon

- i n - leach tanks. (ii) Measure the weight or the density and volumetric flow rate of the ore slurry as it is fed to or as it exits the autoclave(s). ( 9 ) Measure the weight of concentrate ( produced by electrowinning, Mer r ill Crowe process, gravity feed, or o ther methods) using weigh scales for each batch prior to processing in mercury retort s or melt furnaces . The concentrate must be weighed in the same state and condition as it is when fed to the
mercury retort. F or facilities without mercury retorts, the concentrate must be weighed prior to being fed to the melt furnace before drying in any ovens. For facilities that ship157
concentrate offsite , measure the weight of concentrate as shipped offsite. You must keep accurate records of the weights of each batch of concentrate processed and calculate , record , and report to the permit authority the total weight of concentrate processed each month. ( 10 ) You must maintain the systems for measuring density, volumetric flow rate, and weight within ±5 percent accurac y. You must describe the specific equipment used to make measurements at your facility and how that equipment is periodically calibrated. You must also explain, document, and maintain written procedures for determining the accuracy of the
measurements an d make these written procedures available to your permitting authority upon request. You must determine, record, and maintain a record of the accuracy of the measuring systems before the beginning of your initial compliance test and during each subsequent quarter of affected source operation. (1 1 ) R ecord the weight in tons of ore for ore pretreatment processes and concentrate for carbon processes with mercury retorts, carbon processes without mercury retorts, and for non

carbon concentrate processes on a daily and monthly basis and report the monthly values to the permit authority
. (1 2 ) Calculate the emissions from each new and existing affected source for the sum of all full month s between the compliance date and the date of the initial compliance test i n158
pounds of mercury per ton of process input using the procedures in paragraphs (a)(1 2 )(i) through (i v ) of this section to determine initial compliance with the emission standards in §63.11645. After th is initial compliance test period, d etermine annual c ompliance using the procedures in paragraph (a)(13) of this section for existing sources. (i) For o re pretreatment processes, divide the sum of
mercury mass emissions from all roasting operations and autoclaves during the number of full months between th e compliance date and the initial compliance test by the sum of the total amount of gold mine ore processed in these process units during th ose same full month s following the compliance date
. (ii) For carbon processes with mercury retorts , divide the

su m of mercury mass emissions from all carbon kilns, preg tanks, electrowinning, mercury retorts, and melt furnaces during the initial number of full months between the compliance date and the initial compliance tests by the total amount of concentrate
proce ssed in these process units during those same full months following the compliance date. (ii i ) For carbon processes without mercury retorts , divide the sum of mercury mass emissions from all carbon kilns, preg tanks, electrowinning, and melt furnaces duri ng the initial number of full months between the compliance date and the159
initial compliance tests by the total amount of concentrate processed in these process units during those same full months following the compliance date
. (i v ) For non

- carbon concentr ate processes, divide the sum of mercury mass emissions from mercury retorts and melt furnaces during the initial number of full months between the compliance date and the initial compliance tests by the total amount of concentrate processed in these proce ss units during those same full months fol lowing the compliance date
. (1 3 ) After the initial compliance test, c alculate the emissions from each new and existing affected source for each 12

- month period preceding each subsequent compliance test in pounds o f mercury per ton of process input using the procedures in paragraphs (a)(1 3 )(i) through (i v ) of this section to determine c ompliance with the emission standards in §63.11645. (i) For ore pretreatment processes, divide the sum of
mercury mass emissions from all roasting operations and autoclaves in the 12

- month period preceding a compliance test by the sum of the total amount of gold mine ore processed in th at 12

- month period
. (ii) For carbon processes with mercury retorts , divide the sum of mercury mas s emissions from all carbon kilns, preg tanks, electrowinning, mercury retorts, and melt furnaces in the 12

- month period preceding a compliance test by the total amount of160
concentrate processed in these process units in that 12

- month period
. (ii i ) For car bon processes without mercury retorts , divide the sum of mercury mass emissions from all carbon kilns, preg tanks, electrowinning, and melt furnaces in the 12

- month period preceding a compliance test by the total amount of concentrate processed in these pr ocess units in that 12

- month period
. (i v ) For non

- carbon concentrate processes, divide the sum of mercury mass emissions from mercury retorts and melt furnaces in the 12

- month period preceding a compliance test by the total amount of concentrate processed in these process units in that 12

- month period
. ( b ) At all times, you must operate and maintain any affected source, including associated air pollution control equipment and monitoring equipment, in a manner consistent with safety and good air pollution control practices for minimizing emissions.

(a) Except as provided in paragraph (a)( 5 ) of this section, you must monitor each roaster for mercury emissions using one of the procedures in paragraphs (a)(1) , (2) , or (3) of this section and establish operating limits for mercury concentration as described in paragraph (a)( 4 ) of this section. §63.11647 What are my monitoring requirements?

( 1 ) Perform sampling and analysis of the roaster’s exhaust161
for mercury concentration using EPA Performance Specification
12B or EPA Method 30B at least twice per month . A minimum of two measurements must be taken per month that are at least 11 days apart from other consecutive tests. T he mercury concentration must be maintained below the operating limit established in par agraph (a)( 4 ) of this section. The results of the sampling must be obtained within 72 hours of the time the sample is taken. (i) To determine the appropriate sampling duration, you must review the available data from previous stack tests to determine the upper 99th percentile of the range of mercury concentrations in the exit stack gas. Based on this upper end of expected concentrations, select an appropriate sampling duration that is likely to provide a valid sample and not result in breakthrough of the sampling tubes. If breakthrough of the sampling tubes occurs, you must re - sample within 30 days using a shorter sampling duration. (ii) If the any mercury concentration measurement from the twice per month sampling with method 12B or 30B is higher than the operating limit, the exceedance must be reported to the permit authority as a deviation and corrective actions must be implemented within 48 hours upon receipt of the sampling results. Moreover, w ithin 96 hours of the exceedance, the owner or operato r must measure the concentration again (with method162
12B or 30B) and demonstrate to the permit authority that the mercury concentration is no higher than the operating limit , or inform the permit authority that the limit continues to be exceeded. If the op erating limit is still exceeded after these 96 hours, t he owner or operator m ust conduct a full compliance
test for the ore

- pretreatment affected source within 40 days to determine if the affected source is in compliance with the MACT emission standard . I f the source is determined to be in compliance, the compliance test may also be used to e stablish a new operating limit for mercury concentration ( in accordance with paragraph (e) of this section )
. ( 2 ) Install, operate, calibrate, and maintain a continuou s emissions monitoring system (CEMS) to continuously measure the mercury concentration in the final exhaust stream from each roaster according to the requirements of Performance Specification 12A (40 CFR part 60, appendix B) except that calibration standar ds traceable to the National Institute of Standards and Technology are not required. You must perform a data accuracy assessment of the CEMS according to section 5 of Appendix F in part 60 and follow the monitoring requirements in §63.8
. (i) You must co ntinuously monitor the daily average mercury concentration from the roaster and maintain the daily average concentration below the operating limit established in163
paragraph (a)( 4 ) of this section. (ii) If the daily average mercury concentration from the CEMs is higher than the operating limit, the exceedance must be reported to the permit authority as a deviation and corrective actions must be implemented within 48 hours upon receipt of the sampling results. Moreover, w ithin 96 hours of the exceedance,
t he owner or operator must measure the concentration again (with the CEMs) and demonstrate to the permit authority that the mercury concentration is no higher than the operating limit , or inform the permit authority that the limit continues to be exceeded. If the operating limit is still exceeded after these 96 hours, t he owner or operator m ust conduct a full compliance
test for the ore

- pretreatment affected source within 40 days to determine if the affected source is in compliance with the MACT emission st andard . If the source is determined to be in compliance, the compliance test results may also be used to

e stablish a new operating limit for mercury concentration ( in accordance with paragraph (e) of this section )
. (ii i ) You must submit a monitoring pla n that includes quality assurance and quality control (QA/QC) procedures sufficient to demonstrate the accuracy of the CEMS to your permitting authority for approval 180 days prior to your initial compliance test. At a minimum, the QA/QC procedures must i nclude daily calibrations and an annual accuracy test for the164

CEMS. (3) Continuously measure the mercury concentration in the final exhaust stream from each roaster using EPA Performance Specification 12B
. (i) You must continuously measure the mercury

co ncentration in the roaster exhaust and maintain the average daily mercury concentration below the operating limit established in paragraph (a)( 4 ) of this section. To determine the appropriate sampling duration, you must review the available data from prev ious stack tests to determine the upper 99th percentile of the range of mercury concentrations in the exit stack gas. Based on this upper end of expected concentrations, select an appropriate sampling duration that is likely to provide a valid sample and not result in breakthrough of the sampling tubes. If breakthrough of the sampling tubes occurs, you must re - sample within 30 days using a shorter sampling duration. (ii) If the daily average mercury concentration is higher than the operating limit, the e xceedance must be reported to the permit authority as a deviation and corrective actions must be implemented within 48 hours upon receipt of the sampling results. Moreover, w ithin 96 hours of the exceedance, the owner or operator must measure the concentr ation again with method 12B or 30B and demonstrate to the permit authority that the mercury165
concentration is no higher than the operating limit , or inform the permit authority that the limit continues to be exceeded. If the operating limit is still exceed ed after these 96 hours,
t he owner or operator m ust conduct a full compliance test for the ore

- pretreatment affected source within 40 days to determine if the affected source is in compliance with the MACT emission standard . If the source is determined to be in compliance, the compliance test results may also be used to e stablish a new operating limit for mercury concentration ( in accordance with paragraph (e) of this section )
. ( 4 ) Use Equation (2) of this section to establish an upper operating limit for mercury concentration as determined by using the procedures in paragraphs (a)(1) , (2) , or (3) of this section concurrently while you are conducting your annual compliance performance stack test according to the procedures in §63.11646(a)
. OLR = C test * ( EL /CT) (Eq 2) where
OLR = mercury concentration operating limit for the roaster ( in micrograms per cubic meter); C test = average mercury concentration measured by the monitoring procedures (PS 12A or PS 12B or 30B ) during the annual performance sta ck test ( in micrograms per cubic meter); EL = emission standard for ore pretreatment processes ( in lb/ million tons of ore); CT = compliance test results for ore pretreatment processes ( in lb/ million tons of ore).166
( 5 ) For r oaster s that utilize calomel

- based mercury control systems for emissions controls , y ou are not required to perform the monitoring for mercury emissions in paragraphs (a)(1) , (2) , or (3) of this section if you demonstrate to the satisfaction of your permitting authority that mercury em issions from the roaster are less than 10 pounds of mercury per million tons of ore throughput. If you make this demonstration , you must conduct the parametric monitoring as described below in paragraphs (b) and (c) of this section. (i) The initial demo nstration must include three or more consecutive independent stack tests for mercury at least one month apart on the roaster exhaust stacks . Subsequent demonstrations may be based upon the single stack test required in paragraph (a) of section § 63.11646
. The results of each of the tests must be less than 10 pounds of mercury per million tons of ore. The testing must be performed according to the procedures in §63.11646(a)(1) through (4) to determine mercury emissions in pounds per hour. (ii) Divide th e mercury emission rate in pounds per hour by the ore throughput rate during the test expressed in millions of tons per hour to determine the emissions in pounds per million tons of ore. (b) For facilities with roasters and a calomel

- based mercury contr ol system that choose to monitor for mercury167
emissions using the procedures in paragraph (a)( 1 ) of this section or that qualify for and choose to follow the requirements in paragraph (a)( 5 ) of this section , you must establish operating parameter limit s for scrubber liquor flow (or line pressure) and scrubber inlet gas temperature and monitor these parameters. You may establish your operating parameter limit s from the initial compliance test, according to the manufacturer’s specifications, or based on limit s established by the permitting authority. If you choose to establish your operating parameter limit s from the initial compliance test, m onitor the scrubber liquor flow (or line pressure) and scrubber inlet gas temperature during each run of your initial compliance test. The minimum operating limit for scrubber liquor flow rate (or line pressure) is the lowest value during any run of the initial compliance test, and your maximum scrubber inlet temperature limit is the highest measured during any run of th e initial compliance test. Y ou must monitor the scrubber liquor flow rate (or line pressure) and scrubber inlet gas temperature hourly and maintain the scrubber liquor flow (or line pressure) at or above the established operating parameter and maintain th e inlet gas temperature below the established operating parameter limit
. ( c ) For facilities with roasters and a calomel

- based mercury control system that choose to monitor for mercury168
emissions using the procedures in paragraph (a)(1) of this section or that qualify for and follow the requirements in paragraph (a)( 5 ) of this section , you must establish operating parameter range s for mercuric ion and chloride ion concentrations or for oxidation reduction potential and pH using the procedures in paragraph ( c)(1) or (2) of this section respectively
. (1) Establish the mercuric ion concentration and chloride ion concentration range s for each calomel

- based mercury control system. The mercuric ion concentration and chloride ion concentration ranges for each ca lomel

- based mercury control system must be based on the manufacturer’s specifications. Alternatively, the mercuric ion concentration and chloride ion concentration range s for each calomel

- based mercury control system may be based on approv al by your p ermi tting a uthority. Measure the mercuric ion concentration and chloride ion concentrations at least once during each run of your initial compliance test. T he measurements must be within the established concentration range for mercuric ion concentration and chloride ion concentration. Subsequently, you must sample at least once daily and maintain the mercuric ion concentration and chloride ion concentrations within their established range. (2) Establish the oxidation reduction potential and pH range for eac h calomel

- based mercury control system. The169
oxidation reduction potential and pH range for each calomel

based mercury control system must be based on the manufacturer’s specifications. Alternatively, the oxidation reduction potential and pH range for eac h calomel

- based mercury control system may be based on approv al by your p ermitting a uthority. Install monitoring equipment to continuously monitor the oxidation reduction potential and pH of the calomel

- based mercury control system scrubber liquor. Measu re the oxidation reduction potential and pH of the scrubber liquor during each run of your initial compliance test. T he measurements must be within the established range for oxidation reduction potential and pH. Subsequently, you must monitor the oxidati on reduction potential and pH of the scrubber liquor continuously and maintain it within the established operating range. (d) If you have an exceedance of a control device operating parameter range provided in paragraphs (b) or (c) of this section, you mu st take corrective action and bring the parameters back into the established parametric range s . I f the corrective actions taken following an exceedance do not result in the operating parameter value being returned within the established range within 48 ho urs, a mercury concentration
measurement (with method 12B or 30B) must be made to determine if the operating limit for mercury concentration is being exceeded. The measurement must be performed and the mercury170
concentration determined within 48 hours (aft er the initial 48 hours , or a total of 96 hours from the time the parameter range was exceeded ). If the measured mercury concentration meets the operating limit for mercury concentration established under
§ 63.11647(a)(4) , the corrective actions are deemed successful , and the owner or operator can request the permit authority to establish a new limit or range for the parameter . If the measured mercury concentration exceeds the operating limit for mercury concentration after these 96 hours , the exceedance m ust be reported as a deviation within 24 hours to the permitting authority . The owner or operator must conduct a compliance test pursuant to §63.1164 6 ( a ) within 40 days to determine if the roaster operations are in compliance with the MACT emission standa rd
. If the source is determined to be in compliance with the MACT emission standard, the compliance test may also be used
to e stablish a new operating limit for mercury concentration ( see paragraph ( e) of this section )
. ( e ) You may submit a request to your permitting authority for approval to change the operating limit s established under paragraph (a)( 4 ) of this section for the monitoring required in paragraph (a)(1) , (2) , or (3) of this section. In the request, you must demonstrate that the proposed ch ange to the operating limit detects changes in levels of mercury emission control. An approved change to the operating limit under this paragraph only171
applies until a new operating limit is established during the next annual compliance test. ( f ) You must monitor each process unit at each new and existing affected source that uses a carbon adsorber to control mercury emissions using the procedures in paragraphs ( f )(1) or (2) of this section. A carbon adsorber may include a fixed carbon bed, carbon filter p acks or modules, carbon columns, and other variations. (1) Continuously sample and analyze the exhaust stream from the carbon adsorber for mercury using Method 30B (40 CFR part 60, appendix A

- 8) for a duration of at least the minimum sampling time specifi ed in Method 30B and up to one week that includes the period of the annual performance test. (i) Establish an upper operating limit for the process as determined using the mercury concentration measurements from the sorbent trap as calculated from Equatio n (3) of this section.
OLC = C trap * (EL/CT) (Eq 3) where
OLC = mercury concentration operating limit for the carbon adsorber control device on the process as measured using the sorbent trap, (micrograms per cubic meter); C trap = average mercury conc entration measured using the sorbent trap during the week that includes the performance test, (micrograms per cubic meter); EL = emission standard for the affected sources (lb/ton of concentrate); CT = compliance test results for the affected sources (lb/ ton of concentrate).172

(ii) Sample and analyze the exhaust stream from the carbon adsorber for mercury at least monthly using Method 30B (40 CFR part 60, appendix A

- 8). When the mercury concentration reaches
75 percent of the operating limit, begin weekly sampling and analysis. When the mercury concentration reaches 9 0 percent of the operating limit, replace the carbon in the carbon adsorber within 30 days. If mercury concentration exceeds the operating limit, change the carbon in the carbon adsorber wit hin 30 days and report the deviation to your permitting authority. (2) Conduct an initial sampling of the carbon in the carbon bed for mercury 90 days after the replacement of the carbon. A representative sample must be collected from the inlet of the be d and the exit of the bed and analyzed using EPA Method 7471A (incorporated by reference

- see §63.14). The depth to which the sampler is inserted must be recorded. The design capacity is established by c alculat ing the average carbon loading from the inl et and outlet measurements. Sampling and analysis of the carbon bed for mercury must be performed quarterly thereafter. When the carbon loading reaches 50 percent of the design capacity of the carbon, monthly sampling must be performed until 90 percent o f the carbon loading capacity is reached. The carbon must be removed and replaced with fresh carbon no later than 30 days after reaching 90173
percent of capacity. For carbon designs where there may be multiple carbon columns or beds, a representative sampl e may be collected from the first and last column or bed instead of the inlet or outlet. If the carbon loading exceeds the design capacity of the carbon, change the carbon within 30 days and report the deviation to your permitting authority. ( g ) You mu st monitor gas stream temperature at the inlet to the carbon adsorber for each autoclave, carbon kiln, melt furnace, and mercury retort equipped with a carbon adsorber
. E stablish a maximum value for the inlet temperature either during the annual performa nce test as required in §63.11646(a) , according to the manufacturer’s specifications, or as approved by your permitting authority
. If you choose to establish the temperature operating limit during the performance test,

e stablish the temperature operating limit based on either the highest reading during the test or a t 10°F higher than the average temperature measured during the performance test
. M onitor the inlet temperature once per shift . If a n inlet temperature exceeds the temperature operating limit, you must follow the requirements for outlet concentration measurement in paragraph ( f )(1) of this section. If the concentration is below 90 percent of the operating limit, you may set a new temperature operating limit 10°F above the previous operating lim it. If the concentration is above 90 percent of the operating limit, you174

must take corrective action to reduce the temperature back below the temperature operating limit and again measure the outlet concentration according to paragraph ( f )(1) of this sect ion. If the concentration is still above 90 percent of the operating limit , then you must change the carbon in the bed within 30 days and report the deviation to your permitting authority
. ( h ) For each wet scrubber at each new and existing affected sou rce not followed by a mercury control system , you must monitor the water flow rate (or line pressure) and pressure drop
. E stablish a minimum value as the operating limit either during the performance test required in §63.11646(a) , according to the manufac turer’s specifications, or as approved by your permitting authority. If you choose to establish the operating limit based on the results of the performance test, the new operating limit must be establish ed based on either the lowest average value during a ny test run or no lower than 10 percent of the average value measured during the test. For wet scrubbers on an autoclave , establish the range according to manufacturer’s specifications. You must monitor the water flow rate and pressure drop once per shif t and take corrective action within 24 hours if any daily average is less than the operating limit. If the parameters are not in range within 72 hours, the owner or operator must report the deviation to the permitting authority and perform a compliance te st within 4 0 days to determine if the175
source is in compliance with the MACT limit
. ( i ) You may conduct additional compliance tests according to the procedures in § 63.11646 and re

- establish the operating limits required in paragraphs (a) through (c) and ( f ) through ( h ) of this section at any time. You must submit a request to your permitting authority for approval to re - establish the operating limits. In the request, you must demonstrate that the proposed change to the operating limit detects changes in levels of mercury emission control. An approved change to the operating limit under this paragraph only applies until a new operating limit is established during the next annual compliance
test. § 63.11648 What are my notification, reporting, and recordke eping requirements (a) You must submit the Initial Notification required by §63.9(b)(2) no later than 120 calendar days after the date of publication of the final rule in the ?

Federal Register

(b) You must submit an initial Notification of Compliance Status as required by §63.9(h). or within 120 days after the source becomes subject to the st andard. The Initial Notification must include the information specified in §63.9(b)(2)(i) through (b)(2)(iv).

(c) If a deviation occurs during a semiannual repor ting period, you must submit a deviation report to your permitting176
authority according to the requirements in paragraphs (c)(1) and (2) of this section. (1) The first reporting period covers the period beginning on the compliance date specified in §63.11 641 and ending on June 30 or December 31, whichever date comes first after your compliance date. Each subsequent reporting period covers the semiannual period from January 1 through June 30 or from July 1 through December 31. Your deviation report must b e postmarked or delivered no later than July 31 or January 31, whichever date comes first after the end of the semiannual reporting period. (2) A deviation report must include the information in paragraphs (c)(2)(i) through (iv) of this section. (i) Com pany name and address. (ii) Statement by a responsible official, with the official’s name, title, and signature, certifying the truth, accuracy and completeness of the content of the report. (iii) Date of the report and beginning and ending dates of the reporting period. (iv) Identification of the affected source, the pollutant being monitored, applicable requirement, description of deviation, and corrective action taken. (d) If you had a malfunction during the reporting period, the compliance report mus t include the number, duration, and a brief description for each type of malfunction which occurred177
during the reporting period and which caused or may have caused any applicable emission limitation to be exceeded. The report must also include a descripti on of actions taken by an owner or operator during a malfunction of an affected source to minimize emissions in accordance with §63.11646(c), including actions taken to correct a malfunction. ( e ) You must keep the records specified in par agraphs ( e )(1) t hrough (3) of this section. (1) As required in §63.10(b)(2)(xiv), you must keep a copy of each notification that you submitted to comply with this subpart and all documentation supporting any Initial Notification, Notification of Compliance Status, and s emiannual compliance certifications that you submitted. (2) You must keep the records of all performance tests, measurements, monitoring data, and corrective actions required by §§63.11646 and 63.11647, and the information identified in paragraphs (c)(2) (i) through (vi) of this section for each corrective action required by §63.11647. (i) The date, place, and time of the monitoring event requiring corrective action; (ii) Technique or method used for monitoring; (iv) Operating conditions during the a ctivity; (v) Results, including the date, time, and duration of the period from the time the monitoring indicated a problem to the178
time that monitoring indicated proper operation; and (vi) Maintenance or corrective action taken (if applicable). (3) Yo u must keep records of operating hours for each process as required by §63.11646(a)( 5 ) and records of the monthly quantity of ore and concentrate processed as required by §63.11646(a)( 10 ). ( f ) Your records must be in a form suitable and readily available for expeditious review, according to §63.10(b)(1). As specified in §63.10(b)(1), you must keep each record for 5 years following the date of each recorded action. You must keep each record onsite for at least 2 years after the date of each recorded acti on according to §63.10(b)(1). You may keep the records offsite for the remaining 3 years. ( g ) After December 31, 2011, within 60 days after the date of completing each performance evaluation conducted to demonstrate compliance with this subpart, the owne r or operator of the affected facility must submit the test data to EPA by entering the data electronically into EPA’s WebFIRE data base through EPA’s Central Data Exchange. The owner or operator of an affected facility shall enter the test data into EPA’ s data base using the Electronic Reporting Tool or other compatible electronic spreadsheet. Only performance evaluation data collected using methods compatible with ERT are subject to this179
requirement to be submitted electronically into EPA’s WebFIRE data base. **Other Requirements and Information** §63.11650 What General Provisions apply to this subpart Table 1 to this subpart shows which parts of the General Provisions in §§63.1 through 63.16 apply to you. ?

§63.11651 What definitions apply to this subpart Terms used in this subpart are defined in the Clean Air Act, in §63.2, and in this section as follows: ?

Autoclave means a pressure oxidation vessel that is used to treat gold ores (primarily sulfide refractory ore) and involves pumping a slurry of milled ore into the vessel which is highly pressurized with oxygen and heated to temperatures of approximately 350 ° to 430°F. Calomel

- based mercury control system means a mercury emissions control system that uses scrubbers to remove mercury from the gas stream of a roaster or combination of roasters by complexing the mercury from the gas stream with mercuric chloride to form mercurous chloride (calomel). T hese scrubbers are also referred to as “mercury scrubbers.” Carbon adso r ber means a control device consisti ng of a single fixed carbon bed, multiple carbon beds or columns, carbon filter packs or modules, and other variations that uses activated carbon to remove pollutants from a gas stream
.180
Carbon kiln means a kiln or furnace where carbon is regenerated by hea ting, usually in the presence of steam, after the gold has been stripped from the carbon. Carbon processes with mercury retorts means the affected source that includes carbon kilns, preg tanks, electrowinning cells , mercury retorts, and melt furnaces at go ld mine ore processing and production facilities that use activated carbon to recover (adsorb) gold from the pregnant cyanide solution. Carbon processes without mercury retorts means the affected source that includes carbon kilns, preg tanks, electrowinnin g cells, and melt furnaces , but has no retorts , at gold mine ore processing and production facilities that use activated carbon to recover (adsorb) gold from the pregnant cyanide solution.
Concentrate means the sludge

- like material that is loaded with gold along with various other metals (such as silver, copper, and mercury) and various other substances , that is produced by electrowinning, the Merrill

- Crowe process, flotation and gravity separation processes. Concentrate is measured as the input to mercury retorts, or for facilities without mercury retorts, as the input to melt furnaces before any drying takes place. For facilities without mercury retorts or melt furnaces,
concentrate is measured as the quantity shipped. Deviation means any instance wher e an affected source subject to this subpart, or an owner or operator of such a181

source: (1) Fails to meet any requirement or obligation established by this subpart, including but not limited to any emissions limitation or work practice standard; (2) Fa ils to meet any term or condition that is adopted to implement an applicable requirement in this subpart and that is included in the operating permit for any affected source required to obtain such a permit ; or (3) Exceeds any operating limit established under this subpart. Electrowinning means a process that uses induced voltage on anode and cathode plates to remove metals from the continuous flow of solution, where the gold in solution is plated onto the cathode. Steel wool is typically used as the pl ating surface. Electrowinning Cells means a tank in which the electrowinning takes place. Gold mine ore processing and production facility means any industrial facility engaged in the processing of gold mine ore that uses any of the following processes: roasting operations, autoclaves, carbon kilns, preg tanks, electrowinning, mercury retorts, or melt furnaces. An operation that processes or produces less than 50 pounds of concentrate per year is not a gold mine ore processing and production facility
. A facility that produces primarily metals other than gold, such as copper ,182
lead, zinc, or nickel (where these metals other than gold comprise 95 percent or more of the total metal production) that may also recover some gold as a byproduct is not a gold mi ne ore processing and production facility. Those facilities whereby 95 percent or more of total mass of metals produced are metals other than gold, whether final metal production is onsite or offsite , are not part of the gold mine or processing and produc tion source category
. Melt furnace means a furnace (typically a crucible furnace) that is used for smelting the gold

- bearing material recovered from mercury retorting , or the gold

- bearing material from electrowinning , the Merrill

- Crowe process , or other processes for facilities without mercury retorts. Mercury r etort means a vessel that is operated under a partial vacuum at approximately 1100 ° to 1300oF to remove
mercury and moisture from the gold bearing sludge material that is recovered from electrowi nning , the Merrill

- Crowe process , or other processes
. Mercury r etorts are usually equipped with condensers that recover liquid mercury during the processing. Merrill

- Crowe process means a precipitation technique using zinc oxide for removing gold from a c yanide solution . Z inc dust is added to the solution , and gold is precipitated to produce a
concentrate.
Non

- carbon concentrate processes means the affected source18 3
that includes mercury retorts and melt furnaces at gold mine ore processing and production f acilities that use the Merrill

- Crowe
process or other processes and do not use carbon to recover (adsorb) gold from the pregnant cyanide solution. Ore dry grinding means a process in which the gold ore is ground and heated (dried) prior to additional prehe ating or prior to entering the roaster. Ore preheating means a process in which ground gold ore is preheated prior to entering the roaster. Ore pretreatment processes means the affected source that includes roasting operations and autoclaves that are used to
pre - treat gold mine ore at gold mine ore processing and production facilities prior to the cyanide leaching process. Preg nant solution tank (or preg tank) means a storage tank for pregnant solution, which is the cyanide solution that contains gold

- cyani de complexes that is generated from leaching gold ore with cyanide solution. Pregnant cyanide solution means the cyanide solution that contains gold

- cyanide complexes that are generated from leaching gold ore with a dilute cyanide solution. Quenching means a process in which the hot calcined ore is cooled and quenched with water after it leaves the roaster. Roasting operation means a process that uses an industrial furnace in which milled ore is combusted across a fluidized bed184
to oxidize and remove organi c carbon and sulfide mineral grains in refractory gold ore. The emissions points of the roasting operation subject to this subpart include ore dry grinding, ore preheating, the roaster stack, and quenching.
§ 63.11652 Who implements and enforces this sub part (a) This subpart can be implemented and enforced by the U.S. EPA or a delegated authority, such as your state, local, or tribal agency. If the U.S. EPA Administrator has delegated authority to your state, local, or tribal agency, then that
agency has the authority to implement and enforce this subpart. You should contact your U.S. EPA Regional Office to find out if this subpart is delegated to your state, local, or tribal
agency. ?

(b) In delegating implementation and enforcement authority of this subpart to a state, local, or tribal agency under 40 CFR part 63, subpart E, the authorities contained in paragraph (c) of this section are retained by the Administrator of the U.S. EPA and are not transferred to the state, local, or tribal
agency. (c) The authorities that will not be delegated to state, local, or tribal agencies are listed in paragraphs (c)(1) through (4) of this section. (1) Approval of alternatives to the applicability requirements in §63.11640, the compliance date requirements in185

§ 63.11641, and the applicable standards in §63.11645. (2) Approval of an alternative nonopacity emissions standard under §63.6(g). (3) Approval of a major change to a test method under §63.7(e)(2)(ii) and (f). A “major change to test method” is define d in §63.90(a). (4) Approval of a major change to monitoring under §63.8(f). A “major change to monitoring” is defined in §63.90(a). (5) Approval of a waiver of recordkeeping or reporting requirements under §63.10(f), or another major change to recordk eeping/reporting. A “major change to recordkeeping/reporting” is defined in §63.90(a). §63.11653 **[Reserved] Tables to Subpart EEEEEEE of Part 63**  Table 1 to Subpart EEEEEEE of Part 63

— Applicability of General Provisions to S ubpart EEEEEE
As stated in §6 3.11 650 , you must comply with the applicable General Provisions requirements according to the following table :

**Citation Subject**  **Applies to**  **subpart EEEEEEE**  **Explanation** §63.1(a)(1), (a)(2), (a)(3), (a)(4), (a)(6), (a)(10)

– (a)(12), (b)(1), (b)(3), (c)(1), Applicability Yes186

( c)(2), (c)(5), (e) §63.1(a)(5), (a)(7)

– (a)(9), (b)(2), (c)(3), (c)(4), (d) Reserved No

§63.2 Definitions Yes §63.3 Units and Abbreviations Yes §63.4 Prohibited Activities and Circumvention Yes
§63.5 Preconstruction Review and No tification Requirements Yes

§63.6(a), (b)(1)

– (b)(5), (b)(7), (c)(1), (c)(2), (c)(5), (e)(1)(iii), (f)(2), (f)(3), (g), (i), (j) Compliance with Standards and Maintenance Requirements Yes

§63.6 (e)(1)(i) and (ii), (e)(3), and (f)(1) Startup, Shutdown and M alfunction Requirements (SSM) No Subpart EEEEEEE standards apply at all times
. §63.6(h)(1), (h)(2), (h)(4),(h)(5)(i), (ii), (iii) and (v), (h)(6)

– (h)(9) Compliance with Opacity and Visible Emission Limits No Subpart EEEEEEE does not contain opacity or vis ible emission limits. §63.6(b)(6), (c)(3), (c)(4), (d), (e)(2), (e)(3)(ii), (h)(3), (h)(5)(iv) Reserved No

§63.7 , except (e)(1) Applicability and Performance Test Dates Yes
§ 63.7(e)(1) Performance Testing Requirements Related to SSM No

§63.8(a)(1) , (b)(1), (f)(1)

- (5), (g) Monitoring Requirements Yes187

§63.8(a)(2), (a)(4), (b)(2)

- (3), (c), (d), (e), (f)(6), (g) Continuous Monitoring Systems Yes Except cross references to SSM requirements in §63. 6 ( e)(1) and (3) do not apply §63.8(a)(3) [Reserved] N o §63.9(a), (b)(1), (b)(2)(i)

- ( v ), (b)(4), (b)(5), (c), (d), (e), (g), (h)(1)

– (h)(3), (h)(5), (h)(6), (i), (j) Notification Requirements Yes

§63.9(f) No §63.9(b)(3), (h)(4) Reserved No §63.10(a), (b)(1), (b)(2)(vi)

– (xiv) , (b)(3), (c), (d)(1)

- ( 4 ), ( e ), (f) Recordkeeping and Reporting Requirements Yes

§ 63.10(b)(2)(i)

- (v), (d)(5) Recordkeeping/Reporting Associated with SSM No
§63.10(c)(2)

– (c)(4), (c)(9) Reserved No
§63.11 Control Device Requirements No
§63.12 State Authority and Delegations Yes
§§63.13

– 63.16 Addresses, Incorporations by Reference, Availability of Information, Performance Track Provisions Yes