From: "Barbanell, Melissa (Salt Lake City)" < mbarbanell@barrick.com >

To: Steve Fruh/RTP/USEPA/US@EPA, Chuck French/RTP/USEPA/US@EPA

Date: 10/28/2010 07:40 PM

Subject: additional comments

Dear Steve & Chuck,

I am attaching three sets of comments from the Nevada Mining Association. The

first set o f comments addresses a partial exemption under Title V. The next set

of comments addresses the issues that were raised in the comments of the NGOs and shows why mining sources potential to emit HCN remains under 10 tons given EPA’s former guidance.

Finall y, the third set of comments provides a set of possible management practices for HCN that the industry believes to be appropriate.

If you have any questions, please feel free to contact me.

Sincerely,

Melissa Barbanell

(See attached file: partial Title V exemption from MACT for natural minor sources comment.docx) (See attached file: PTE on HCN emission estimates comment.docx) (See attached file: HCN management practices comment.docx)

### 1 

# Partial Title V Exemption for Natural Minor Sources

The Nevada Mining Association and individual gold mining operations have previously submitted comments to EPA during the public comment period on the proposed EPA rulemaking to develop a NESHAP for gold mine ore processing and production area sources. Whi le the comment period has closed, we believe that EPA may find the following additional information to be useful in its efforts to conclude the rulemaking, in particular, relative to determining the extent to which it would be appropriate to include a part ial exemption in the final rule from Title V operating permit requirements.

The Nevada Mining Association and individual gold mining operations have submitted prior comments to EPA regarding the appropriateness of an exemption from title V under section 502(a) of the CAA for area sources covered by the proposed NESHAP. Although a comprehensive title V exemption is still the most appropriate choice for avoiding “unnecessarily burdensome” regulations on facilities that are already subject to comprehensive permitting requirements, at the very least EPA should exempt sources that do not rely on air pollution control devices to stay below major source thresholds. This is an approach that EPA has employed on prior occasions. See e.g., 74 Fed. Reg. 56008 (Oct . 29, 2009) (NESHAP for Chemical Manufacturing Area Sources

– Final Rule); and 75 Fed. Reg. 31896 (June 4, 2010) (NESHAP for Industrial, Commercial and Institutional Boilers

– Proposed Rule). Such a solution is consistent with CAA section 502(a), which pr ovides that the Administrator may exempt an area source category (in

whole or in part ) from title V. See 42 U.S.C. § 7661a(a); 75 Fed. Reg. at 31911.

In cases where EPA determines that at least some area sources covered by a NESHAP should remain subject to title V, it has found it useful to distinguish among three different types of area sources. First, EPA has identified “synthetic area sources” which rely on emission control systems to stay below the major source thresholds. Second, EPA recognizes tha t some synthetic area sources limit their HAP emissions to below the major source thresholds solely by complying with operational limits (e.g., limiting the number of hours a facility can operate) rather than by using emission control equipment. Finally, EPA defines “natural area sources” as sources that require neither emission control equipment nor operational limits to maintain minor source status. See 74 Fed. Reg. at 56013.

In a number of instances, EPA has determined that title V exemptions are ap propriate for natural area sources and those synthetic area sources that only rely on operational limits to avoid major source status while subjecting synthetic minor sources that utilize emission controls to title V. See e.g., 74 Fed. Reg. at 56014; 75 F ed. Reg. at 31913. EPA’s rationale for exempting the natural area sources and synthetic minor area sources that achieve areas source status through operational restrictions is based on its application of the Exemption Rule, the four

- factor balancing test for determining whether title V is unnecessarily burdensome for a particular source category. See 75 Fed. Reg. at 31911

- 12.

EPA has concluded that sources that rely on emission controls are more like major sources in many regards than other minor sources

. See 75 Fed. Reg. at 31913; 74 Fed. Reg. at 56014. EPA has also found that the increased burdens of title V are justified for synthetic area sources that are often located in highly populated areas and which have significantly higher emissions potential when uncontrolled than other

sources. See 75 Fed. Reg. at 31913; 74 Fed. Reg. at 56014. Accordingly, EPA has decided that the “additional public participation and compliance benefits of additional informational, monitoring, reporting, certification, and enforcement requirements that exist in title V” should apply to such synthetic

minor sources. 74 Fed. Reg. at 56014. Conversely, the simpler nature of natural area sources and synthetic area sources that maintain minor status through operational restric tions do not merit imposing the burdens of title V on such facilities. The absence of a need for emission controls to keep such

### 2 facilities below minor source thresholds is a sensible basis for distinguishing the potential burdens and benefits of imposing title V.

A similar conclusion applies to the gold mining industry. The application of the Exemption Rule to the gold mining industry has been discussed in comments submitted to EPA by both the Nevada Mining Association and individual gold mining operat ions. If EPA has been unable to conclude that title V would be unnecessarily burdensome for all minor sources covered by the proposed gold mining NESHAP, it should exempt those gold mining sources that are either (i) natural area sources or (ii) synthetic area sources that achieve minor source status through operational limits. Such an approach is especially appropriate for the gold mining source category in view of the remote locations of these operations. Sources that include processes that rely on com plex control systems

— for example, roasters at Goldstrike, Gold Quarry and Jerritt Canyon

— would be subject to Title V operating permit requirements based on s synthetic/natural source distinction. On the other hand, mining sources that do not rely on

contr ol systems to achieve minor source status would not be subject to Title V operating permit requirements. This strikes an appropriate balance for the reasons that EPA has articulated in the

determinations cited above.

### 1 

# PTE Emission Estimates for HCN

The Nevada Mining Association and individual gold mining operations have previously submitted comments to EPA during the public comment period on the proposed EPA rulemaking to develop a NESHAP for gold mine ore processing and production area sources. While the comment period has closed, we believe that EPA may find the following additional information to be useful in its efforts to conclude the rulemaking, in particular, relative to the need to develop regulations of HCN emissions.

EPA is evaluating whether HCN emissions should be addressed in some fashion in the NESHAP standard for gold mining that is currently under consideration. It is neither necessary nor appropriate for EPA to regulate HCN emissions from gold mining operations as part of the gold mining MACT rulemaking.

If EPA were to regulate HCN emissions pursuant to CAA 112, it would have to do so under one of two authorities, neither of which are applicable relative to the gold mining industry based on

EPA’s ru lemaking record: 1



### • EPA would have to find that the gold mining source category contained one or more major sources of HCN pursuant to 112(c)(1), (5). (Assuming that EPA did make such a finding, the MACT standard would be limited to only those sources that were shown to be major .) The existing record does not support such a determination; to the contrary, it supports a conclusion that there are no major sources of HCN emissions in the gold mining source category. See additional discussion below regarding H CN PTE.

**•** The second authority for regulating HCN emissions from gold mining operations would require EPA to make a determination that HCN emissions from the mining industry “presents a threat of adverse effects to human health or the environment.” See CA A 112(c)(3). EPA has not made the requisite finding. In fact, based on extensive ambient air quality monitoring that the industry conducted pursuant to and in accord with EPA approved monitoring plans, EPA concluded that “the results of the fence line mo nitoring for HCN ... showed ambient concentrations below levels of public health and

environmental concerns.” See minutes from February 17, 2010 “Meeting with Industry Representatives, Nevada Division of Environmental Protection (NDEP), and EPA,”

Docket ID No. EPA

- HQ

- OAR

- 2010

- 0239

- 0146.

1 The announced rulemaking is being conducted pursuant to 112(c)(6) for mercury: “we are adding the gold mine ore processing and production area source category to the list of source categories under section 112(c)(6) on the basis of mercury emissions .” 75 Fed. Reg. at 22472, 1 st column. CAA 112(c)(6) is specific to seven HAPs, including mercury.

### 2 The record currently supports the conclusion that there are no major sources of HCN based on PTE: “EPA recently gathered data and evaluated emissions of other HAP, including cyanide and

non

- mercury metals. The data indicate that the gold mining processing and production category consists of only area sources (i.e., facilities that emit less than ten tons per year of any one HAP and less than 25 tons per year of any combination of HAP).” 2 

### An “area source” by definition has

a potential to emit of less than the 10/25 tpy major source thresholds. 3



### “Potential to emit” is defined to mean “the maximum capacity of a stationary source to emit a pollutant under its physical and operational design. Any physical or operational limitat ion on the capacity of the stationary source to emit a pollutant, including air pollution control equipment and restrictions on hours of operation or on the type or amount of material combusted, stored, or processed, shall be treated as part of its design if the limitation or the effect it would have on emissions is federally enforceable.” 4



### Sierra Club and Earthjustice incorrectly assume that EPA’s emission estimates are not based on “the maximum capacity” of the mines to emit HCN under their “physical an d operational design.” While the HCN estimates are based on specific operating parameters for each of the several mines, those operating parameters are based on management practices that are inherent to those operations. There are reasons unrelated to ai r pollution control that dictate those measures.

EPA guidance has clearly acknowledged that certain measures that are inherent to an operation and that have the effect of limiting emissions are properly accounted for in PTE determinations.

The actions t aken to manage CN usage and concentrations, as discussed above, constitute such measures. EPA has consistently recognized that “there are sources for which inherent physical limitations for the operation restrict the potential emissions of individual emis sion units. Where such inherent limitations can be documented by a source and confirmed by the permitting agency, EPA believes that States have the authority to make such judgements and factor them into estimates of a stationary source's potential to emit .” 5

2 75 Fed. Reg. at 22479

- 80.

3 CAA 112(a)(1) and (2).

4 40 CFR 63.2.

5 EPA Memorandum, Options for Limiting the Potential to Emit (PTE) of a Stationary Source Un der Section 112 and Title V of the Clean Air Act (Act) (Jan. 25, 1995). As an example, EPA explained that it did not believe that the “maximum capacity” language in the PTE definition required that owner of a paint spray booth at a small auto body shop mu st assume operation year

- round (8760 hours per year) in cases where there are inherent physical limitations on the number of cars that can be painted within any given period of time. (In estimating HCN emissions from mining operations, year

- round operatio n was assumed.) See also, e.g. , EPA Memorandum, Calculating Potential to Emit (PTE) for Emergency Generators (Sept. 6, 1995) (in which EPA explained that its previous guidance was intended to “clarif[y] that inherent physical limitations, and operational design features which restrict the potential emissions of individual emission units, can be taken into account” when assessing PTE in those cases “for which the theoretical use of equipment is much higher than could ever actually occur in practice.” EPA a lso noted that while sources “could in most cases readily accept enforceable [permit] limitations restricting the operation to its designed level, EPA believes this administrative requirement for such sources to be unnecessary and burdensome.”).

### 3 Further, EPA has specifically addressed the appropriateness of accounting for “inherent” control measures when assessing PTE. 6 

### EPA has explained that “control measures . . . can be taken into account where those control devices and measures are subj ect to enforceable [permit] limits or are inherent to the operation of the facility.” 7

Control measures that are “inherent” are those which are always being operated and maintained for reasons other than community air quality protection . Examples of inherent control measures would include (a) product collection devices for which the value of the product collected greatly exceeds the cost of the collection device, and (b) devices for which the primary purpose is to improve product quality control, to recover product, or to enhance production operating efficiency . . . . 

### EPA explains that:

8



### The concept of an inherent control measure is that the source employs such a measure not

In particular, mining operations are required to manage CN exposure from tailings areas and heap leaches

— the predominant sources of HCN at gold mining operations

— so as to be protective of wildlife and worker safety. This requires that mea sures be taken to prevent wildlife access to these areas or requires CN concentrations to be maintained at levels that are protective of birds and other wildlife. In Nevada, for example, the Nevada Department of Wildlife requires, among other measures, th at “any chemical

- laden fluids that are the result of any process and that are impounded in a pond that is too large to cover or contain (e.g., mill tailings ponds)

must be rendered non

- lethal to wildlife.” Accordingly, steps are taken to neutralize CN or otherwise manage CN concentrations in these areas. because it is required pursuant to air regulatory requirements, but due to other c onsiderations.

For wildlife protection purposes, used leach solution from the mill leach circuit is treated by a CN neutralization process prior to discharge to the mill tailing impoundment. This practice

reduces the we ak acid dissociable (WAD) CN in the discharge water to non

- lethal levels (i.e., to levels safe for birds that will inevitably come in contact with the discharged water). Mine personnel routinely sample the WAD CN concentration in the tailings impoundment water to ensure safe levels are achieved. As per the International Cyanide Code, cyanide solution that is open to the environment must be operated below 50 mg/L WAD CN. Additionally, per the Nevada Department of Wildlife, mine personnel are required to r eport “all wildlife mortalities

that are associated with chemical

- containing tanks or impoundments by the beginning of the next day following the occurrence...” This CN neutralization practice has the benefit of minimizing the potential for HCN off gassing from the tailings impoundment. The low WAD CN levels achieved by this practice significantly reduce the potential for the formation of HCN in the tailings impoundment water and its subsequent evaporation to the atmosphere.

In addition to wildlife protecti on measures, mining companies manage CN usage and concentrations for worker safety reasons. Miners are routinely required to work on top of leach pads and around open leach solution ponds and tanks. These areas are rendered safe through the

6 EPA Memo randum, Calculating Potential to Emit (PTE) and Other Guidance for Grain Handling Facilities (Nov. 14, 1995).

7 Id.

8 Id.

### 4 practice of m aintaining high solution pH’s and minimizing cyanide concentrations in the leach solutions. This practice minimizes the potential for HCN off gassing in order to comply with MSHA HCN exposure limits. Mining companies have a further economic incentive to not over utilize CN chemical due to the significant operating cost associated with its use. For instance, at one Nevada gold mine with heap leaching operation, the amount spent on cyanide exceeds $12 million per year

– an overuse of 10% would cost the mine an additional $1.2 million per year.

In another EPA guidance letter, EPA elaborated upon inherent controls and limitations that may be taken into account when estimating a source’s PTE. 9

1. Is the primary purpose of the equipment to control air pollution? 

### In this guidance, EPA provides a test for determining whether equipm ent constitutes “air pollution equipment” or air pollution control

measures

**** which can be taken into account in assessing PTE only if the equipment/measures are required by an air quality permit

**** or “process equipment” or process measures

**** which can be

taken into account in assessing PTE even if not required by a permit if the equipment/measures are determined to be an inherent part of the process. EPA offers the following list of questions for consideration in making case

- by

- case judgments as to whether cert ain devices or practices should be treated as air pollution controls or as inherent to the process:

2. Where the equipment is recovering product, how do the cost savings from the produc t recovery compare to the cost of the equipment?

3. Would the equipment be installed if no air quality regulations are in place?



### In the case then under consideration, EPA determined that the primary purpose of the equipment

at issue was to increase the availability of the process, to minimize safety hazards and to prevent impurities from entering the process; not to control air pollution. Additionally, EPA found that air quality regulations were not the reason for installation of the equipment. (EPA fo und that the equipment was not used for recovering product and so the second criterion was not relevant to the analysis.) Based on this analysis, EPA concluded that the equipment at issue was “inherent to the process and can be considered in potential emi ssion calculations without federally enforceable requirements.”

This is analogous to measures that mines utilize to manage CN usage and concentrations and prevent chemical loss. Although these measures have the effect of reducing air emissions, the primar y purpose of these measures is not to control air pollution and they would be in place if even if no air quality regulations were in place. The CN control measures are for other purposes (protect wildlife, minimize chemical usage, address worker safety, e tc.). Because they are inherent, they are properly accounted for in determining PTE regardless of whether they are specifically enumerated in an air quality permit.

The PTE estimates of HCN emissions from the gold mining industry that EPA has made are

ba sed on parameters that are reflective of the manner in which the various mines are designed and operated for purposes other than air pollution control; they are inherent to the mines’

9 EPA Letter Detailing Criteria for Determining Whether Equipment is Air Pollution Control Equipment or Process Equipment (Nov. 27, 19 95).

### 5 operations and their inclusion allows for a realistic

- worst case estimat e of emissions. In fact, we would argue that EPA has significantly overestimated HCN emissions by not accounting for the large surface correction factor (F A 

### ) that is necessary to account for the effect that ambient

concentrations will have on emissions fo r large surface areas. This (not including F A 

### ) results in a very conservative (high) estimate of HCN emissions. By accounting for the effect of the large surfaces over which the emission is taking place, HCN emissions are estimated to range from

3.7

- 4.5 tpy for the larger mines compared to the 5

- 9 tpy estimate without accounting for large surfaces. Accordingly, EPA’s estimate in the preamble to the proposed rule is very conservative and provides for a realistic (if not excessive) upper bound estimate of HCN emissions. 10

10 “[P]otential to emit does not refer to the maximum emissions that can be generated by a source hypothesizing the worst conceivable operation. Rather, the concept contemplates the maximum emissions that can be generated while operating the source as it is intended to be operated and as it is normally operated. * * * Alabama Power stands for the proposition that hypothesizing the worst possible emissions from the worst possible operation is the wrong way to calculate potential to emit. 893 F.2d ___, 917 (7th Cir. 1990) (emphasis added) (quoting U.S. v. Louisiana

Pacific Corp., 682 F. Supp. 1141, 1158).4837

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- 8631.2 

# HCN Management Practices

October 28, 2010

The Nevada Mining Association and individual gold mining operations previously submitted comments to EPA during the public comment period on the proposed EPA rulemaking to develop a NESHAP for gold mine ore processing and production area sources. While the comment period has closed, we believe that EPA may find the following additional information to be useful in its efforts to conclude the

rulema king, in particular, relative to comments received on HCN emissions.

There does not currently exist a legal basis for regulating HCN emissions from the gold mining source category. The rulemaking being proposed for the gold mine ore processing and produ ction area source category is being conducted pursuant to 112(c)(6) specifically for mercury. Further, the current administrative record and related legal authority 1

Notwithstanding the absence of a legal basis for regulating HCN emissions, th e proposed rulemaking indicates that EPA evaluated several approaches to manage CN emissions. Following are the potential management practices that EPA listed in the proposed rule and a brief response regarding the potential utility and practicality of ea ch practice. support EPA’s conclusion in the proposed rule that there are no major HCN sources in the gold mine ore processing and production source category. Finally, EPA has concluded that ambient HCN concentrations are below levels of public health and environmental

concerns.

2

**•** Maintaining pH of cyanide leach solutions greater than nine.

While mining operations do monitor and maintain pH levels for several reasons, it is not possible to specify a single pH value that will be appropriate for all mines for all time s. Because of the difference in mineralogy at each mine, scaling can occur at different pH levels. This results in each mine having a different maximum pH level at which the cyanide solutions can be maintained. Moreover, while it may be possible to mana ge pH at the CN addition point for each process, it is not possible to control the downstream chemistry and the resulting pH. Further, establishing a single, enforceable, pH level would likely result in a pH number that is lower than the level at which m uch of the processes actually operate over the annual period. Such a lower number could be misleading in terms of the overall pH management that is employed at the majority of mines and suggest higher HCN emissions than actually occur.

**•** Burying leach lin es whenever practical and feasible.

Some mines may be able to bury leach solution emitters on some leach pads; however, other mines deal with larger and more varied sized rock, which is not suited for burying emitters. While the proposed management practice to bury leach lines “whenever practical and feasible” is, on its face, reasonable, there is good deal of ambiguity in the measure; for example, what criteria will be used to determine if it is practical and feasible to bury leach lines?

1 See additional comment on “PTE Emission Estimates for HCN.”

2 Our comment and discussion relative to CN management practices should not be construed as an endorsement by the mining industry of the need for such measures to be included in the NESHAP; as we have indicated repeatedly, there is neither a basis nor need for doing so.

### - 2

- 4837

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- 8631.2 **•** Monito ring cyanide concentrations at the perimeter and in a downwind direction of main

emission sources. The industry has conducted extensive ambient monitoring of HCN emissions and EPA has concluded that “the results of the fence line monitoring for HCN ... show ed ambient concentrations below levels of public health and environmental concerns.” While additional monitoring would be costly and burdensome, EPA may want to consider allowing mines to elect this option in lieu of implementing a site specific plan conc erning HCN work practices, as discussed further below.

**•** Not allowing puddles to form that are greater than 1 square meter on leach pads. While application systems are designed to avoid puddles, the aerial extent of the pads can be quite large making cont rol to this specified level burdensome, if not impossible to achieve.

**•** In locations that have the highest potential for concentrated emissions (e.g., mixing tanks, CIL tanks, loading stations) maintain HCN air concentrations below a prescribed level (e.g ., 5 ppm). In fact, MSHA imposes an HCN exposure limit of 10 ppm. This is for worker protection purposes, not ambient air protection. Concentrations in the “ambient air” will generally be much lower due to the dispersion and dilution that will occur.

As we have indicated in a companion submission, 3

Because of the above concerns with the specific work practice measures set forth in the proposed rule, a more feasible option would be to have each gold mining operation develop a site

- specific plan with work practices designed to limit HCN emissions. These work practices could include elements contained in the International Cyanide Management Code, a comprehensive, peer

- reviewed set of measures designed to

red uce cyanide use in the gold mining industry. The following, based on principles derived from the International Cyanide Management Code, provides examples of measures that would be addressed in the

site

- specific plan. gold mining operations currently employ a number of measures in order to manage CN usage and concentrations and prevent chemical loss. These measures are inherent to the mines’ operations and are required for worker safety, wildlife protection and cost management reasons. Additionally, the measures are customized to each mine based on ore mineralogy, gold recovery processes employed, etc. To the extent a rule were to include CN management practices, such pra ctices would necessarily need to account for the unique operating characteristics of each mine.

**•** Implement management and operating syst ems to minimize cyanide use, thereby limiting concentrations of cyanide in mill tailings.

**•** Implement a water management program to protect against unintentional releases.

**•** Implement measures to protect birds, other wildlife and livestock from adverse effects of cyanide process solutions.

**•** Implement measures to protect fish and wildlife from direct and indirect discharges of cyanide process solutions to surface water.

**•** Implement measures designed to manage seepage from cyanide facilities to protect the beneficial uses of ground water.

**•** Provide spill prevention or containment measures for process tanks and pipelines.

3 See additional comment on “PTE Emission Estimates for HCN.”

### - 3

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- 8631.2 **•** Implement monitoring programs to evaluate the effects of cyanide use on wildlife, surface and ground water quality.

These measures provide effective cyanide management practices and while they are focused on issues such as wildlife, surface, and groundwater protection, they have the effect of managing HCN emissions as well. These measures may be tailored according to t he particular operating circumstances of individual mining operations. Mines would need to be given latitude to design their measures and plans. Compliance would be based on a determination that a mine had a plan in place, the plan contained

measures des igned to manage and limit CN use, and that the mine was implementing such a plan, and not on the specific measures that the mine has determined to be appropriate for its site

- specific operations.

To the extent that a mine is complying with permits which address these issues, the permit provisions and compliance with these permits could constitute compliance with this requirement. As an alternative compliance method to developing and implementing a plan, mines may obtain and maintain certification

under t he International Cyanide Management Code.