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Date: June 28, 2010

Subject: Minutes of the June 23, 2010 Conference Call with representatives from Alaska 

Tribes

EPA Contract No. EP-D-06-118; EPA Work Assignment No. 4-06

RTI Project No. 0210426.004.006

From: Chuck French

OAQPS/SPPD/MMG (D243-02)

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

To: Docket ID No. EPA-HQ-OAR-2010-0239

I. Introduction

A conference call with representatives from Alaskan Tribes was held on June 23, 2010. 

The purpose of the meeting was for EPA to introduce the proposed National Emission Standards 

for Hazardous Air Pollutants: Gold Mine Ore Processing and Production Area Source Category 

and Addition to Source Category List for Standards to the Alaskan Trives. This memorandum 

summarizes the major topics discussed during the meeting.

II. Attendees

Representatives from Alaskan Tribes

Chuck French, U.S. EPA, OAQPS

Tami Fordham, U.S. EPA, Region 10

Mahri Lowinger, U.S. EPA, Region 10

Marvin Branscome, RTI International

Gabrielle Raymond, RTI International

III. Discussion

The EPA presented their webinar from May 25, 2010 that covers an overview of the 

background information and the proposed gold mine ore processing and production rule. The 

EPA answered general questions about the proposed rule. 

Attachment 1 contains the fact sheet for the proposed rule. Attachment 2 contains the 

presentation from the May 25, 2010 webinar.
Attachment 1
PROPOSED RULE TO REDUCE MERCURY EMISSIONS FROM GOLD ORE 

PROCESSING AND PRODUCTION SOURCES

FACT SHEET

ACTION 

• On April 15, 2010 the U.S. Environmental Protection Agency (EPA) proposed National 

Emissions Standards for Hazardous Air Pollutants for gold ore processing and production 

facilities, the sixth largest source of mercury air emission in the United States. 

• The proposed standards would cut mercury emissions from this industry by more than 70 

percent from 2007 levels. 

• Gold ore processing and production facilities extract gold from mined ore. About 20 gold ore 

processing facilities in the United States will be subject to the proposed rule. 

• Some facilities in Nevada already, including some of the nation’s largest gold ore processing 

facilities, are making significant progress toward the proposed reductions under the Nevada 

Mercury Air Emissions Control Program, which requires controls at precious metal mining 

facilities. 

• At full implementation, the proposed rule is estimated to reduce mercury emissions to 0.7 tons 

per year (1,390 pounds), a 73 percent reduction from 2007 levels. 

• EPA estimates capital costs of this proposed rule at $6.2 million, with annual costs of $3.8 

million a year. 

• Mercury is the only air toxic that would be regulated under this proposed rule. Gold processing 

and production facilities have not been identified as major sources of hazardous air pollutants, 

also known as air toxics. A “major source” emits 10 or more tons a year of a single air toxic, or 

25 or more tons a year of a combination of toxics. 

• However, because gold ore processing and production is a significant source of mercury 

emissions, it falls under a section of the Clean Air Act that requires EPA to establish standards 

known as maximum achievable control technology (MACT) for sources of seven air toxics 

known as persistent, bioaccumulative pollutants, including mercury. 

• Mercury in the air eventually deposits into water, where it transforms into methylmercury, a 

highly toxic form that builds up in fish. Americans are primarily exposed to mercury by eating 

contaminated fish. 

• Because methylmercury can damage children’s developing brains and nervous systems, even 

before they are born, women of childbearing age and children are the population of greatest 

concern. 
• EPA will accept comments on this proposed rule for 30 days following publication of the 

proposed rule in the Federal Register. The Agency will hold a public hearing if requested; 

requests for a hearing must be made within 10 days after the rule is published. (If a hearing is 

requested, the comment period will be extended by 15 days.) 

WHAT THE PROPOSED RULE WOULD REQUIRE

• The proposed rule would establish mercury emissions limits for three types of processes found 

at gold production facilities: ore-pretreatment processes (primarily heating processes used to 

prepare ore for gold extraction); and two other processes known as carbon and non-carbon 

concentrate processes (both separate gold from ore). The proposed emissions limits are based 

on the existing emissions level of the best-performing U.S. facilities, which are well controlled 

for mercury. 

• The proposed mercury limits are as follows: 

Proposed Emissions 

Limit 

Pre-treatment 

processes (in pounds 

per million tons of 

ore) 

Carbon processes 

(in pounds per ton of 

concentrate) 

Non-carbon 

concentrate processes 

(in pounds per ton of 

concentrate) 

Existing sources 149 lb 2.6 lb 0.25 lb 

New sources 149 lb 0.14 lb 0.20 lb 

• For new carbon processes, we are proposing a compliance alternative of 97 percent control 

efficiency. 

• At full implementation, these limits are estimated to reduce mercury emissions to 0.7 tons per 

year, a 73 percent reduction from 2007 levels. 

• Today’s action also proposes several requirements for monitoring. These include requiring 

each facility to conduct annual mercury emissions tests at all emissions stacks. In addition, 

EPA is seeking comment on two options for continuous or frequent (weekly) testing at 

facilities using roasters to pretreat ore. 

BACKGROUND 

• The Clean Air Act requires EPA to identify and, develop regulations for, the sources of 90 

percent of the air emissions of seven pollutants known as persistent, bioaccumulative 

pollutants. The seven pollutants are: mercury, alkylated lead compounds, polycyclic organic 

matter (POM), hexachlorobenzene, polychlorinatedbiphenyls (PCBs), 2,3,7,8-

tetrachlorodibenzofurans (TCDF) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). 

• EPA identified gold processing and production as one of these sources in 2008. 
• The State of Nevada and the gold processing and production industry have made significant 

progress in reducing mercury emissions in that state, under a combination of voluntary and 

regulatory programs. Fifteen of the gold ore production and processing facilities in the U.S. are 

located in Nevada. Emissions have been reduced from about 11.5 tons in 1999 down to about 

2.5 tons in 2007. Today’s proposed rule would further reduce emissions from those facilities, 

in addition to limiting emissions from gold ore processing and production facilities in other 

states. 

HOW TO COMMENT 

• EPA will accept comment on the proposal for 30 days after publication in the Federal Register. 

Comments, identified by Docket ID No. EPA-HQ-OAR-2010-0239, may be submitted by one 

of the following methods: 

o www.regulations.gov: Follow the on-line instructions for submitting comments. 

o E-mail: Comments may be sent by electronic mail (e-mail) to a-and-rDocket@epa.gov. 

o Fax: Fax your comments to: 202-566-1741. 

o Mail: Send your comments to: Air and Radiation Docket and Information Center, 

Environmental Protection Agency, Mail Code: 2822T, 1200 Pennsylvania Ave., NW, 

Washington, DC, 20460. 

o Hand Delivery or Courier: Deliver your comments to: EPA Docket Center, Room 

3334, 1301 Constitution Ave., NW, Washington, DC, 20460. Such deliveries are only 

accepted during the Docket’s normal hours of operation, and special arrangements 

should be made for deliveries of boxed information. 

FOR MORE INFORMATION 

• To download a copy the proposed rule, go to EPA's Web site at 

http://www.epa.gov/ttn/oarpg/new.html 

• For more information about the proposed rule for gold ore processing, contact Chuck French of 

EPA’s Office of Air Quality Planning and Standards at (919) 541-7912 or french.chuck@epa.gov. 
Attachment 2
Summary of the Proposed 

National Emissions Standard 

for Gold Mine Ore Processing 

and Production

Webinar

May 25, 2010

Presentation by Chuck French, U.S. EPA

Metals and Minerals Group

Office of Air Quality and Planning and Standards

Email: french.chuck@epa.gov

Phone: 919-541-7912

Outline

 Background 

 Summary of the proposed regulation for 

mercury emissions

 Discussion of Non-mercury HAPs

 Schedule/next steps

 Questions?

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Background

 23 facilities in U.S. (15 in Nevada and 8 in other Western States) 

 Gold Mines were identified in the 1999 National Emissions Inventory as a 

source of mercury emissions (estimated 11.5 tons per year)

 Most emissions were from facilities located in Nevada

 Initial Nevada Voluntary Program (2001-04) achieved some reductions

 Targeted 5 large facilities 

 In 2006 Nevada DEP established a mandatory Mercury Control Program to 

achieve further reductions:

 covers all gold and silver production operations in Nevada 

 requires best available control technology at facilities in Nevada

 In 2007, Gold Mines emitted an estimated 2.5 tons of mercury nationwide 

 In 2008, EPA determined that mercury emissions from Gold Mines should 

be regulated under the National MACT program

 Pursuant to Section 112(c)(6) of the Clean Air Act 

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Summary of Gold Mine Production 

Processes in U.S.A.

 All facilities:

 mine, crush ores.....

 conduct various other processes, depending on ore type, etc.

 5 facilities use high temperature ore pre-treatment 

(roasters or autoclaves) before cyanide leaching.

 About 18 facilities process ores without pre-treatment 

(no roaster or autoclave), but have other thermal 

processes: 

 About 14 facilities add carbon to leaching, therefore have carbon kilns 

and 2-4 other processes (e.g., electrowinning, retorts, furnaces).

 About 4 facilities use no carbon (therefore no kiln), but have other 

processes (e.g., furnaces, retorts).

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CARBON

ADSORPTION

& DESORPTION

CARBON REGENERATION

KILN

PREGNANT

TANK

BARREN

TANK

EW CELL

ELECTROWINNING

FURNACE

RETORT

RETORTING & SMELTING

CARBON

ORE

MINING

GOLD

LEACHING

Overview of Gold Mine 

Production Processes

ROASTERS &

AUTOCLAVES

FURNACE

RETORT

RETORTING & SMELTING

MERRILL-CROWE

Hg

Hg

Hg

Hg

Hg Hg Hg

Hg

Hg

Hg

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Gold Mine Ore Processing - 

Mercury Emissions in 2007 by 

Process Type

Roasters 

(1.15 tons, 48%)

Autoclaves 

(0.41 tons, 17%)

Melt Furnaces

(0.36 tons, 15%)

Carbon Kilns

(0.27 tons, 11%)

Preg Tanks 

(0.1 ton, 4%)

Electrowinning 

(0.1 ton, 4%)

Retorts

(0.01 ton, 1%)

Total = about 2.5 tons

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Summary of Mercury Controls 

for Gold Production Facilities

 A number of facilities already have effective mercury 

controls on many units.

 Facilities apply various control technologies and 

pollution prevention measures to limit mercury 

emissions, including:

 gas condensers

 carbon adsorption units 

 wet scrubbers

 fabric filters

 mercurous chloride scrubbers (calomel scrubbers) 

 wet venturi scrubbers 

 chemical additives to improve mercury capture.

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Summary of the Proposed 

National Emissions Standard

 Coordinated with Nevada DEP and other stakeholders in development 

of the proposal

 We believe the proposed requirements are compatible with the 

Nevada Mercury Control Program 

 Emissions limits are proposed for mercury, based on Maximum 

Achievable Control Technology (MACT), for the 3 types of affected 

processes:

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Ore-pretreatment 

Processes

Carbon Processes Non-carbon 

Processes

Existing 

sources

149 lb/million tons of 

ore

2.6 lb/ton of concentrate 0.25 lb/ton of 

concentrate

New 

Sources

149 lb/million tons of 

ore

0.14 lb/ton of concentrate 

or 97% reduction

0.20 lb/ton of 

concentrate
CARBON

ADSORPTION

& DESORPTION

CARBON REGENERATION

KILN

PREGNANT

TANK

BARREN

TANK

EW CELL

ELECTROWINNING

FURNACE

RETORT

RETORTING & SMELTING

CARBON

ORE

MINING

GOLD

LEACHING

Gold Ore Processing – 3 Process Groups -

Proposed Approach for MACT limits

ROASTERS &

AUTOCLAVES

FURNACE

RETORT

RETORTING & SMELTING

MERRILL-CROWE

Hg

Hg

Hg

Hg

Hg Hg Hg

Hg

Hg

Hg

Ore pre-treatment group

Non-carbon

group

Carbon group

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Proposed Compliance Testing and 

Monitoring Requirements

 For all thermal units, annual stack tests for mercury (using method 

29, 30A, 30B, or the Ontario Hydro method).

 For carbon beds, facilities need to monitor temperatures and do one 

of the following to prevent breakthrough:

 weekly test with method 30B, and as mercury concentrations 

approach an “operating limit” established during the 

performance test, facility must change carbon;

 periodic sampling of carbon bed at specified depths, and when 

carbon reaches 90% capacity, carbon must be changed; or

 replace carbon at specified frequency based on knowledge of 

bed life demonstrated by one of the above methods.

 Wet Scrubbers:

 Monitor water flow rate and pressure drop. 10
Proposed Monitoring 

Requirements for Roasters

 Continuous emissions monitoring for mercury using either:

 Hg CEMS (daily average), or

 Method 30B (sorbent trap) with weekly sampling and analysis 

 Concentrations would be compared to an “operating limit” established 

during the performance test to assure that controls are working, but not 

used to demonstrate compliance to the MACT emission limit.

 Any deviation must be reported to permitting authority and corrective 

action taken.

 We also propose that for roasters that are not monitored with a Hg 

CEMS that facilities must monitor various parameters of the calomel 

scrubbers including: scrubber liquid flow; pressure drop; inlet 

temperature; and chloride ion concentration or oxidation reduction 

potential and pH

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Affected 

Processes

Uncontrolled 

emissions 

(lb/yr)

2007 

emissions 

(lb/yr)

Reductions due to 

Federal MACT and 

Nevada Hg Program 

(lb/yr)

% Reduction 

from 2007 

emissions

% Reduction 

from 

uncontrolled 

emissions

Ore Pretreatment 

processes 18,976 3,383 2,150 64% 94%

Carbon 

processes 14,465 1,537 1,397 91% 99%

Non-carbon 

processes 768 139 125 90% 98%

Total 34,209 5,059 3,672 73% 96%

Estimated Mercury Emissions Reductions

Estimates of Costs and Cost Effectiveness

Case

Capital 

cost

Total annualized 

cost

MACT emission 

reduction (lb/yr)

Average cost 

effectiveness

Hg controls only $4.8 million $2.3 million/year 1,650 $1,400/lb Hg

With monitoring $6.0 million $3.4 million/year 1,650 $2,100/lb Hg

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Non-Mercury HAP

 In 2009, we requested that industry conduct emissions tests for 

non-mercury HAPs, including cyanide and non-mercury metals

 Cyanide is mainly emitted from large non-point sources (e.g., leach pads, tailings 

ponds), and non-mercury metals are mainly emitted from stacks

 Testing was completed, and all data submitted to EPA in early 2010

 Results indicate there are no major sources

 The largest facility emits an estimated 5 to 9 tons of cyanide per year

 All other HAPs are individually significantly lower than the 10 tons per year (tpy) 

threshold for a single HAP and the 25 tpy threshold for a combination of HAP. 

 The proposed rule text has no requirements for non-mercury HAPs.

 However, the preamble discusses cyanide and requests comments on possible 

management practices or other approaches to limit cyanide emissions.

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Seeking comments on several 

specific topics, including:

 Title V:

 About 6 of the 15 facilities currently have Title V permits

 We are soliciting comment on whether an exemption is 

appropriate for any particular sources in this category. 

 Hg CEMs:

 Technology not yet demonstrated on these facilities.

 We request comments on the viability of using mercury CEMs, 

specifically for monitoring mercury emissions from roasters.

 Carbon vs concentrate metric for “Carbon Group”

 The proposed emissions limits for this group are in units of 

pounds of mercury per ton of concentrate.

 We seek comment on whether “loaded carbon” might be 

another option worth further consideration as the denominator 

(e.g., pounds of mercury per ton of loaded carbon)

 Cyanide Emissions - Management Practices?

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Schedule

 April 15, 2010 – Proposed rule was signed by 

EPA Administrator

 April 28, 2010 – Proposed rule published in 

Federal Register

 May 20, 2010 – Published Notice of extension 

of comment period to 6/28/2010

 June 28, 2010 – Public Comment period ends

 December 16, 2010 – Final rule deadline 

(court-ordered)

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