22470 Federal Register / Vol. 75, No. 81 / Wednesday, April 28, 2010 / Proposed Rules 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Parts 9 and 63 

[EPA–HQ–OAR–2010–0239; 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 

Source Category List for Standards 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Proposed rule. 

SUMMARY: EPA is proposing to add the 

gold mine ore processing and 

production area source category to the 

list of source categories subject to 

regulation under the hazardous air 

pollutant section of the Clean Air Act 

(CAA) due to their mercury emissions. 

EPA is also proposing national mercury 

emission standards for this category 

based on the emissions level of the best 

performing facilities which are well 

controlled for mercury. EPA is soliciting 

comments on all aspects of this 

proposed rule. 

DATES: Comments must be received on 

or before May 28, 2010 unless a public 

hearing is requested by May 10, 2010. If 

a hearing is requested on this proposed 

rule, written comments must be 

received by June 14, 2010. Under the 

Paperwork Reduction Act, comments on 

the information collection provisions 

must be received by the Office of 

Management and Budget (OMB) on or 

before May 28, 2010. 

ADDRESSES: Submit your comments, 

identified by Docket ID No. EPA–HQ– 

OAR–2010–0239, by one of the 

following methods: 

• Follow the on-line instructions for 

submitting comments at the following 

Web address: http:// 

www.regulations.gov. 

• E-mail: Comments may be sent by 

electronic mail (e-mail) to 

a-and-r-Docket@epa.gov, Attention 

Docket ID No. EPA–HQ–OAR–2010– 

0239. 

• Fax: Fax your comments to: (202) 

566–9744, Attention Docket ID No. 

EPA–HQ–OAR–2010–0239. 

• Mail: Send your comments to: Air 

and Radiation Docket and Information 

Center, Environmental Protection 

Agency, Mailcode: 2822T, 1200 

Pennsylvania Ave., NW., Washington, 

DC 20460, Attention: Docket ID No. 

EPA–HQ–OAR–2010–0239. Please 

include a total of two copies. In 

addition, please mail a copy of your 

comments on the information collection 

provisions to the Office of Information 

and Regulatory Affairs, Office of 

Management and Budget (OMB), Attn: 

Desk Officer for EPA, 725 17th St., NW., 

Washington, DC 20503. 

• 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 Center’s normal hours of 

operation, and special arrangements 

should be made for deliveries of boxed 

information. 

Instructions: Direct your comments to 

Docket ID No. EPA–HQ–OAR–2010– 

0239. EPA’s policy is that all comments 

received will be included in the public 

docket without change and may be 

made available online at http:// 

www.regulations.gov, including any 

personal information provided, unless 

the comment includes information 

claimed to be confidential business 

information (CBI) or other information 

whose disclosure is restricted by statute. 

Do not submit information that you 

consider to be CBI or otherwise 

protected through http:// 

www.regulations.gov or e-mail. The 

http://www.regulations.gov Web site is 

an ‘‘anonymous access’’ system, which 

means that EPA will not know your 

identity or contact information unless 

you provide it in the body of your 

comment. If you send an e-mail 

comment directly to EPA without going 

through http://www.regulations.gov, 

your e-mail address will be 

automatically captured and included as 

part of the comment that is placed in the 

public docket and will be made 

available on the Internet. If you submit 

an electronic comment, EPA 

recommends that you include your 

name and other contact information in 

the body of your comment and with any 

disk or CD–ROM you submit. If EPA 

cannot read your comment due to 

technical difficulties and cannot contact 

you for clarification, EPA may not be 

able to consider your comment. 

Electronic files should avoid the use of 

special characters, any form of 

encryption, and be free of any defects or 

viruses. 

Docket: All documents in the docket 

are listed in the http:// 

www.regulations.gov index. Although 

listed in the index, some information is 

not publicly available (e.g., CBI or other 

information whose disclosure is 

restricted by statute). Certain other 

material, such as copyrighted material, 

will be publicly available only in hard 

copy form. Publicly available docket 

materials are available either 

electronically in http:// 

www.regulations.gov or in hard copy at 

the EPA Docket Center, Public Reading 

Room, EPA West, Room 3334, 1301 

Constitution Ave., NW., Washington, 

DC. The Public Reading Room is open 

from 8:30 a.m. to 4:30 p.m., Monday 

through Friday, excluding legal 

holidays. The telephone number for the 

Public Reading Room is (202) 566–1744, 

and the telephone number for the Air 

Docket is (202) 566–1742. 

FOR FURTHER INFORMATION CONTACT: For 

questions about these proposed 

standards for gold mine ore processing 

and production, contact Mr. Chuck 

French, Sector Policies and Program 

Division, Office of Air Quality Planning 

and Standards (D243–02), 

Environmental Protection Agency, 

Research Triangle Park, North Carolina 

27711, telephone number (919) 541– 

7912; fax number (919) 541–3207, email address: french.chuck@epa.gov. 

SUPPLEMENTARY INFORMATION: The 

information presented in this preamble 

is organized as follows: 

I. General Information 

A. Does this action apply to me? 

B. What should I consider as I prepare my 

comments to EPA? 

C. Where can I get a copy of this 

document? 

D. When would a public hearing occur? 

II. Addition to Section 112(c)(6) Source 

Category List 

III. Background Information 

A. What is the statutory authority and 

regulatory approach for the proposed 

standards? 

B. What source category is affected by the 

proposed NESHAP? 

C. What are the production operations, 

emission sources, and available controls? 

IV. Summary of the Proposed Standards 

A. Do these proposed standards apply to 

my facility? 

B. When must I comply with the proposed 

standards? 

C. What are the proposed standards? 

D. What are the testing and monitoring 

requirements? 

E. What are the notification, recordkeeping, 

and reporting requirements? 

F. What are the title V permit 

requirements? 

G. Emissions of Non-Mercury HAPs 

H. Request for Comments 

V. Rationale for the Proposed Standards 

A. How did we select the affected source? 

B. How did we determine MACT? 

C. How did we select the testing, 

monitoring, and electronic reporting 

requirements? 

VI. Impacts of the Proposed Standards 

A. What are the emissions, cost, economic, 

and non-air environmental impacts? 

B. What are the health benefits of reducing 

mercury emissions? 

VII. Statutory and Executive Order Reviews 

A. Executive Order 12866: Regulatory 

Planning and Review 

B. Paperwork Reduction Act 

C. Regulatory Flexibility Act 

D. Unfunded Mandates Reform Act 


sroberts on DSKD5P82C1PROD with PROPOSALS
Federal Register / Vol. 75, No. 81 / Wednesday, April 28, 2010 / Proposed Rules 22471 

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 

Minority Populations and Low-Income 

Populations 

I. General Information 

A. Does this action apply to me? 

The regulated categories and entities 

potentially affected by the proposed 

standards include: 

Category NAICS Code 1 Examples of regulated entities 

Industry: 

Gold Ore Mining .......... 212221 Establishments primarily engaged in developing the mine site, mining, and/or beneficiating (i.e., 

preparing) ores valued chiefly for their gold content. Establishments primarily engaged in transformation of the gold into bullion or dore bar in combination with mining activities are included 

in this industry. 

1 North American Industry Classification System. 

This table is not intended to be 

exhaustive, but rather provides a guide 

for readers regarding entities likely to be 

affected by this action. To determine 

whether your facility would be 

regulated by this action, you should 

examine the applicability criteria in 40 

CFR 63.11640 of subpart EEEEEEE 

(National Emission Standards for 

Hazardous Air Pollutants: Gold Mine 

Ore Processing and Production Area 

Source Category). If you have any 

questions regarding the applicability of 

this action to a particular entity, consult 

either the air permit authority for the 

entity or your EPA Regional 

representative, as listed in 40 CFR 63.13 

of subpart A (General Provisions). 

B. What should I consider as I prepare 

my comments to EPA? 

Do not submit CBI to EPA through 

http://www.regulations.gov or e-mail. 

Send or deliver information identified 

as CBI only to the following address: 

Roberto Morales, OAQPS Document 

Control Officer (C404–02), Office of Air 

Quality Planning and Standards, 

Environmental Protection Agency, 

Research Triangle Park, NC 27711, 

Attention: Docket ID No. EPA–HQ– 

OAR–2010–0239. Clearly mark the part 

or all of the information that you claim 

to be CBI. For CBI contained in a disk 

or CD–ROM that you mail to EPA, mark 

the outside of the disk or CD–ROM as 

CBI and then identify electronically 

within the disk or CD–ROM the specific 

information that is claimed as CBI. In 

addition to one complete version of the 

comment that includes information 

claimed as CBI, a copy of the comment 

that does not contain the information 

claimed as CBI must be submitted for 

inclusion in the public docket. 

Information so marked will not be 

disclosed except in accordance with 

procedures set forth in 40 CFR part 2. 

C. Where can I get a copy of this 

document? 

In addition to being available in the 

docket, an electronic copy of this 

proposed action will also be available 

on the Worldwide Web (WWW) through 

the Technology Transfer Network 

(TTN). Following signature, a copy of 

the proposed action will be posted on 

the TTN’s policy and guidance page for 

newly proposed or promulgated rules at 

the following address: http:// 

www.epa.gov/ttn/oarpg/. The TTN 

provides information and technology 

exchange in various areas of air 

pollution control. 

D. When would a public hearing occur? 

If anyone contacts EPA requesting to 

speak at a public hearing concerning 

this proposed rule by May 10, 2010, a 

public hearing will be held on May 13, 

2010. If you are interested in attending 

the public hearing, contact Ms. Pamela 

Garrett, Metals and Minerals Group 

(D243–02), Sector Policies and Programs 

Division, U.S. EPA, Research Triangle 

Park, NC 27711, telephone (919) 541– 

7966 e-mail address: 

garrett.pamela@epa.gov to verify that a 

hearing will be held. If a public hearing 

is held, it will be held at EPA’s campus 

located at 109 T.W. Alexander Drive in 

Research Triangle Park, NC, or an 

alternate site. If a hearing is requested 

by May 10, 2010, any persons interested 

in presenting oral testimony at that 

hearing should contact Ms. Pamela 

Garrett at least 2 days in advance of the 

date of the public hearing. 

II. Addition to Section 112(c)(6) Source 

Category List 

Section 112(c)(6) of the CAA requires 

that EPA list categories and 

subcategories of sources assuring that 

sources accounting for not less than 90 

percent of the aggregate emissions of 

each of the seven specified Hazardous 

Air Pollutants (HAP) are subject to 

standards under section 112(d)(2) or 

(d)(4). The seven HAP specified in 

section 112(c)(6) are as follows: 

alkylated lead compounds, polycyclic 

organic matter, hexachlorobenzene, 

mercury, polychlorinated biphenyls, 

2,3,7,9-tetrachlorodibenzofurans, and 

2,3,7,8-tetrachloridibenzo-p-dioxin. 

In 1998, EPA published a list of 

section 112(c)(6) categories (63 FR 

17838, April 10, 1998). At that time, 

there was very little available 

information on mercury emissions from 

gold mine ore production and 

processing. Since the 1998 notice, a 

substantial amount of data and 

information have become available on 

mercury emissions from this source 

category. For example, in 2000, the first 

estimates of mercury emissions from 

this source category were published in 

the Toxics Release Inventory (TRI), 

largely because of the lower TRI 

reporting threshold for mercury that 

went into effect about that time. 

Following this, from 2001 to 2005, 

additional data and information were 

collected through the Voluntary 

Mercury Reduction Program (VMRP), 

which was a collaborative agreement 

between the State of Nevada Division of 

Environmental Protection (NDEP), 

EPA’s Region 9 Office, and four gold 

mining companies. Then, in 2005–2006 

the EPA’s Office of Air Quality Planning 

and Standards (OAQPS) and the NDEP 

sent questionnaires to a number of 

companies seeking additional 

information and data on mercury 

emissions. Moreover, starting in 2007 

the NDEP has been requiring all 

facilities in Nevada to conduct annual 

mercury emissions tests. Based on these 

data collected over the past several 

years, along with information about the 

industry processing and production 

levels and activities in the early 1990s, 

EPA has estimated that the gold mine 

ore processing and production emitted 

about 4.4 tons of mercury during the 


sroberts on DSKD5P82C1PROD with PROPOSALS
22472 Federal Register / Vol. 75, No. 81 / Wednesday, April 28, 2010 / Proposed Rules 

baseline year (i.e., in 1990). These 

estimated mercury emissions in the 

1990 inventory for gold mine ore 

processing and production are based on 

emissions from the following thermal 

processes at gold mine ore processing 

and production facilities: roasters, 

autoclaves, carbon kilns, pregnant 

storage solution tanks (‘‘preg tanks’’), 

electrowinning, melt furnaces, and 

retorts. We have updated our 1990 

baseline emission inventory for section 

112(c)(6) to reflect this contribution of 

mercury from gold mine ore processing 

and production and determined that 

this area source category contributed to 

the 90 percent of the aggregate 

emissions of mercury in 1990. 

Consequently, 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. 

III. Background Information 

A. What is the statutory authority and 

regulatory approach for the proposed 

standards? 

As mentioned above, CAA section 

112(c)(6) requires that EPA set standards 

under section 112(d)(2) or (d)(4). The 

mercury standards for the gold mine ore 

processing and production area source 

category are being established under 

CAA section 112(d)(2), which requires 

MACT level of control. Under CAA 

section 112(d), the MACT standards for 

existing sources must be at least as 

stringent as the average emissions 

limitation achieved by the best 

performing 12 percent of existing 

sources (for which the administrator has 

emissions information) for source 

categories and subcategories with 30 or 

more sources, or the best performing 5 

sources for categories and subcategories 

with fewer than 30 sources (CAA 

section 112(d)(3)(A) and (B)). This level 

of minimum stringency is called the 

MACT floor. For new sources, MACT 

standards must be at least as stringent 

as the emission control that is achieved 

in practice by the best controlled similar 

source (CAA section 112(d)(3)). EPA 

also must consider more stringent 

‘‘beyond-the-floor’’ control options. 

When considering beyond-the-floor 

options, EPA must consider not only the 

maximum degree of reduction in 

emissions of HAP, but must take into 

account costs, energy, and nonair 

quality health and environmental 

impacts when doing so. 

B. What source category is affected by 

the proposed NESHAP? 

The gold mine ore processing and 

production area source category consists 

of facilities engaged in processing gold 

ore to recover gold using one or more of 

the following process units: roasters, 

autoclaves, carbon kilns, melt furnaces, 

mercury retorts, electrowinning, and/or 

pregnant solution tanks. There were 

approximately 21 gold mine ore 

processing and production facilities 

operating these processes in the United 

States (U.S.) in 2008. The majority and 

the largest of these facilities are located 

in Nevada. The other facilities currently 

operating are in Alaska, California, 

Colorado, Montana, and Washington. In 

2007, the U.S. gold mine industry 

produced about 240 metric tons of gold, 

and the value of gold mine production 

was about $5.1 billion. 

C. What are the production operations, 

mercury emission sources, and available 

controls? 

All gold mine operations in the U.S. 

begin by mining ores, generally using 

large earth moving equipment. The ore 

is then subject to crushing operations. 

After crushing, some ore may be pretreated by roasting or autoclaving. 

Subsequent to these operations the ore 

undergoes some type of leaching 

process using a dilute cyanide solution. 

The cyanide binds with the gold (and 

various impurities including mercury) 

to produce a ‘‘pregnant’’ solution. The 

pregnant solutions are further processed 

using various thermal processes (e.g., 

electrowinning, retorts and furnaces) to 

recover gold. The gold mine ore 

processing and production area source 

category covers the thermal processes 

that occur after the crushing, including 

roasting operations (i.e., ore dry 

grinding, ore preheating, roasting, and 

quenching), autoclaves, carbon kilns, 

electrowinning, preg tanks, retorts and 

furnaces. Further details of the gold 

production processes are described in 

section C.2 below. 

1. Historical Background on Mercury 

Emissions 

Mercury, which is naturally present 

in the ores in various concentrations, 

enters the gold recovery processes with 

the gold mine ore. Most of this mercury 

is recovered as a by-product in the form 

of liquid elemental mercury, or as a 

mercury precipitate, placed in closed 

containers, and stored or sold to 

commercial metal companies. In 

addition, a notable amount of mercury 

is currently captured by mercury 

emission control devices (e.g., in carbon 

media) and is not recovered for sale. 

Nevertheless, some portion of the 

mercury in the ore is liberated to the air 

during the thermal processes resulting 

in mercury emissions to the atmosphere. 

Without emissions controls the 

potential for mercury emissions from 

these facilities would be quite high. 

In May 2000, EPA published the first 

estimates of mercury emissions for gold 

mine ore processing and production 

facilities as part of the EPA’s TRI for 

year 1998. Total mercury air emissions 

reported to the TRI in the 1998–2001 

timeframe for this source category were 

about 14,000 pounds per year. However, 

EPA estimated (in the 1999 National 

Emissions Inventory) that total mercury 

emissions from this category were 

higher (about 23,000 pounds in 1999), 

and the mining industry reported 

emissions to be 21,000 pounds in 2001. 

Even at that time, some facilities had 

controls on processes to limit mercury 

emissions. Early efforts to reduce or 

limit mercury emissions were due in 

part to concerns about worker exposure 

to mercury. For example, for years 

facilities that were processing ores with 

higher levels of mercury have been 

using retorts to condense and capture 

the mercury in liquid elemental form. 

Moreover, two of the largest facilities 

have been using mercury specific 

emissions controls on their roasters 

since the mid-1990s. Also, a number of 

facilities had carbon adsorption beds to 

control mercury emissions on various 

thermal process units prior to 2001. We 

estimate that without these early 

controls the potential emissions would 

have been much higher than 23,000 

pounds (at least 37,000 pounds). 

Since 2001, mercury emissions from 

gold mine ore processing and 

production have been further reduced. 

The reductions achieved since 2001 

were obtained through programs 

implemented by the NDEP, EPA, and 

industry. The first program for reducing 

mercury emissions from these facilities 

was the Voluntary Mercury Reduction 

Program (VMRP). The VMRP was a 

voluntary partnership between the 

NDEP, EPA Region 9, and four large 

gold mining companies. The main goal 

of the VMRP, which was officially 

adopted in June 2002, was to achieve 

significant, permanent and rapid 

reductions in mercury air emissions 

from precious metal processing 

operations. The VMRP focused on 5 

large facilities in Nevada that accounted 

for most of the reported emissions in 

2001. Some mercury emission 

reductions were quickly achieved by 

adding emission controls to some of the 

thermal units that emit mercury at these 

facilities. 

To achieve further reductions in 

mercury emissions, the NDEP converted 

the VMRP into a regulatory program, 

called the Nevada Mercury Control 

Program (NMCP). As described on the 

NDEP Web site, the NMCP is a State 


sroberts on DSKD5P82C1PROD with PROPOSALS
Federal Register / Vol. 75, No. 81 / Wednesday, April 28, 2010 / Proposed Rules 22473 

regulatory program that supersedes and 

replaces the VMRP and requires best 

available mercury emissions control 

technology on all thermal units located 

at all precious metal mines in Nevada. 

The NMCP was adopted March 8, 2006 

and made effective May 4, 2006. The 

NMCP is a case-by-case permit program 

in 2 phases. The NMCP also had an 

early reduction program, which 

provided incentives for facilities to add 

controls within the first 2 years of the 

program (by mid-2008). A few facilities 

in Nevada took advantage of the early 

reduction program and added mercury 

specific controls (sulfur impregnated 

carbon filters) in 2007 on various 

thermal units. 

In Phase 1 of the NMCP, which has 

recently been completed, permits were 

issued that require comprehensive work 

practice standards for the proper 

operation of existing mercury controls 

and the operations of the thermal units 

to minimize mercury emissions until 

specific controls are identified later 

under Phase 2 of the program. Phase 1 

also required annual stack testing, site 

inspections and emissions reporting to 

collect data to assist in mercury 

emissions controls determinations in 

Phase 2. Emissions data collected in 

Phase 1 of the NMCP were used in the 

development of this proposed rule. 

Phase 2 has begun issuing permits and 

all permits are scheduled for issuance 

by the end of calendar year 2010. 

Implementation of controls will begin 

shortly after permit issuance. The Phase 

2 permit process is a technology review 

and engineering analysis to determine 

the best available control technology 

and mercury emission limits. Controls 

and mercury emissions limits will be 

determined on a case-by-case analysis 

and will be unique to the individual 

unit (not universal for the unit type). 

The NMCP is a control-based program 

that will require thermal units in 

Nevada to have a best available mercury 

control technology installed. The NDEP 

and EPA have coordinated on the 

review and analyses of data on 

emissions, controls, and monitoring 

approaches for mercury emissions from 

this category, and collaborated to assure 

that the State program could co-exist 

and provide an additional level of 

control for facilities in Nevada while 

working in concert with the proposed 

National standards. 

As described further below, several 

facilities already have effective mercury 

emissions controls in place on various 

thermal units. We expect that a number 

of other facilities will need to add 

mercury controls to comply with 

emissions limits set forth in this 

NESHAP, resulting in further emissions 

reductions from this category. 

2. Description of Gold Mine Ore 

Processing and Production 

The gold mine ore processing and 

production source category consists of 

the following processes: roasting 

operations, autoclaves, carbon 

regeneration kilns, electrowinning cells, 

pregnant solution tanks, mercury 

retorts, and melt furnaces. Each facility 

may not have every one of these 

processes because there are different 

production paths that can be taken to 

recover gold from mine ore. Mercury 

can be emitted from each of these 

thermal processes. Some of these 

processes are already well controlled for 

mercury emissions; however, there are 

some process units at several plants that 

are only partly controlled or 

uncontrolled for mercury. 

The first step in gold mining is 

extracting the gold-containing ores from 

surface or undergrounds mines, 

generally by using large-scale 

earthmoving equipment. Samples of ore 

are examined to determine grade and 

metallurgical characteristics. Broken 

rock is marked by type for efficient 

processing. Based on its metallurgical 

makeup, the ore is delivered to the 

proper processing location. Low grade 

ore is roughly broken into small chunks, 

and high grade ore is delivered to a 

grinding mill, where the ore is 

pulverized to a powder (milled ore). 

Depending on its metallurgical and 

other characteristics, the ore may be 

pretreated in a roaster or autoclave prior 

to leaching, or it may be sent directly to 

a leaching circuit without pretreatment. 

The two main types of ore are oxide ore 

and refractory ore. If the process of 

cyanide leaching can extract most of the 

gold contained in an ore with no 

pretreatment, the ore is referred to as 

oxide ore; otherwise, the ore is 

described as refractory ore. Oxide ore is 

sent directly to the leaching circuit 

where cyanide is used to liberate the 

gold. However, refractory ores contain 

organic carbon and/or sulfide mineral 

grains which inhibit the efficient 

recovery of gold during cyanide 

leaching. Roasters and autoclaves are 

used to oxidize the ore and remove 

these components. Refractory ore 

containing carbon and sulfur is roasted 

to over 1000 °F, burning off the sulfide 

and carbon. The product of this process, 

which is now basically an oxide ore, is 

routed to a leaching circuit. Sulfide 

refractory ore without carbon is 

oxidized in an autoclave to liberate the 

gold from sulfide minerals; then it is 

sent to a leaching circuit. At all 

facilities, the ores are eventually sent to 

some type of cyanide leaching process. 

Lower grade oxide ores generally 

undergo a heap leaching process, 

whereby the ore is spread over large 

areas and dilute cyanide solution is 

slowly dripped through and collected 

on liners and channels. During the 

leaching process, cyanide binds with 

gold and other elements (including 

mercury) producing a ‘‘pregnant’’ 

cyanide solution. At most facilities that 

use this process, the next step involves 

pumping the pregnant cyanide-gold 

solution to tanks with activated carbon 

where the gold is adsorbed (collected) 

out of solution onto the activated 

carbon, and the remaining cyanide 

solution is largely recycled. This carbon 

adsorption step that follows the cyanide 

leaching is generally referred to as the 

‘‘carbon-in-column’’ process. 

Higher grade ores are generally 

milled. If the ore is a higher grade 

‘‘oxide ore,’’ it is milled and then 

generally sent directly to carbon-inleach processes where activated carbon 

is added along with the milled ore and 

cyanide solution in tanks where the 

cyanide-gold complexes adsorb onto 

activated carbon. In these units the 

leaching and carbon adsorption occur 

together. If the higher grade ore is a 

refractory ore, it is roasted or autoclaved 

first, then it is sent to carbon-in-leach 

processes. 

However, a few facilities do not use 

carbon. Instead, these facilities use a 

different, zinc precipitate process, 

which is described later in this 

preamble. 

At all the facilities that use a carbon 

adsorption process, the gold loaded 

carbon (which also contains mercury 

and other constituents) is moved into a 

vessel where the gold is chemically 

stripped from the carbon typically by 

using a concentrated caustic cyanide 

solution, producing a concentrated 

cyanide-gold solution. Gold (along with 

other metals and minerals) is drawn 

from this concentrated solution 

electrolytically (in electrowinning cells). 

The concentrate from the 

electrowinning cells is usually sent to a 

filter press to remove excess moisture 

and then to a retort followed by a melt 

furnace. However, some facilities do not 

have retorts. These facilities dry the 

concentrate and then feed it directly to 

the melt furnace. Either way, the gold is 

melted in furnaces into dore 

(pronounced ‘‘doh-rey’’) bars containing 

up to 90 percent gold. Dore bars are 

subsequently sent to an external refinery 

to be refined to bars of 99.9 percent or 

more pure gold. The processing steps 

are discussed in more detail below. For 

processing steps that emit mercury, the 


sroberts on DSKD5P82C1PROD with PROPOSALS
22474 Federal Register / Vol. 75, No. 81 / Wednesday, April 28, 2010 / Proposed Rules 

discussion below also describes the 

points of mercury emissions and 

available controls for such emissions. 

3. Pretreatment of Refractory Ore 

As mentioned above, refractory ores 

have to be pretreated by furnace 

oxidation (ore roasting) and/or pressure 

oxidation (autoclaving) before they can 

be ready for cyanide leaching. 

Roasting Operations. The roasting 

operations that are sources of mercury 

emissions include ore dry grinding 

where the ore is ground and dried, 

preheating prior to roasting, roasting, 

and quenching. The roaster is by far the 

process unit with the greatest potential 

for mercury emissions because of the 

large quantity of ore processed and the 

high roasting temperatures, which 

readily volatilize available mercury 

from the ore. The mercury 

concentrations in the roasted ores are 

high enough that elemental mercury can 

be recovered from the roaster exhaust 

gas by condensation. The emission 

potential of the ancillary roasting 

operations (dry grinding, pre-heating 

and quenching) are much less than 

those from the roaster because they are 

operated at much lower temperatures. 

Dry grinding of the ore prior to roasting 

is primarily a source of particulate 

matter (PM) emissions; consequently, 

baghouses are used for PM emission 

control. Ore preheaters used to raise the 

ore temperature to facilitate roasting are 

typically equipped with baghouses or 

wet scrubbers, which control particulate 

and some oxidized mercury. Emissions 

from quenching (when the roasted ore is 

cooled) are controlled by wet scrubbers, 

which remove particulate and some 

oxidized mercury. 

Ore roasting is a combustion process 

where the milled ore is oxidized in a 

fluidized bed roaster. During the 

combustion process, ore components 

that interfere with the cyanide leaching 

of gold are oxidized and therefore 

removed. As the ore exits the 

combustion chamber, it typically enters 

a quench process, where the 

temperature is reduced by contact with 

cooling water and the generation of 

steam. The steam from the quench 

process is used as a heat source in other 

processes at the mill, or may be sent 

directly to a cooling tower. 

There are three gold mine ore 

processing and production facilities that 

have a total of six roasters. The mercury 

emissions generated during roasting are 

mainly in gaseous elemental or oxidized 

forms of mercury. A very small portion 

of the mercury emitted is in particulate 

or particulate-bound form. Each of these 

roasters has complex gas treatment 

systems to control not only these forms 

of mercury, but also to control PM, 

sulfur dioxide (SO2), nitrogen oxides 

(NOX), and carbon monoxide (CO). The 

PM control devices remove particulate 

mercury and some oxidized mercury. A 

significant amount of the elemental 

mercury is removed and recovered by 

condensation (either in a condenser or 

gas cooling device), and the three 

facilities with roasters use mercuric 

chloride scrubbers. These scrubbers use 

a mercuric chloride scrubber liquor to 

complex with mercury in the exhaust 

gas to precipitate a mercurous chloride 

byproduct (calomel). These scrubbers 

are also referred to as ‘‘calomel 

scrubbers.’’ The calomel precipitate is 

subsequently removed and is either sent 

to electrowinning to recover the 

mercury, disposed of offsite as a waste 

material, or a portion may be 

chlorinated to create fresh mercuric 

chloride for the calomel scrubber liquor. 

An example of the emissions controls 

and gas treatment train for a roaster 

includes a hot gas electrostatic 

precipitator (ESP), wash tower, gas 

coolers, fluorine tower, wet ESP, 

calomel scrubber, acid plant (for 

removal of SO2 and conversion to 

sulfuric acid product), peroxide 

scrubber (to control NOX), and 

regenerative thermal oxidizer (for CO). 

Autoclaves. Autoclaves are pressure 

oxidation vessels that are used to 

pretreat ores to increase gold recovery 

by cyanide leaching. The milled ore is 

mixed with water to form a slurry, and 

is then acidified with sulfuric acid. The 

acidified slurry is then pumped into the 

autoclave vessel, where oxygen is used 

to increase the vessel pressure to over 

300 pounds per square inch, and the 

slurry is heated to 350 °F to 430 °F. The 

slurry is agitated in the reaction vessel 

and is then discharged to a pressure 

relief chamber. There the liquid content 

is flashed to steam, recovered, and 

returned to the pressurized segment of 

the vessel. 

Most mercury is present in the gold 

ore as mercury sulfide, and during 

autoclaving, the mercury sulfide 

combines with oxygen to form mercury 

sulfate, which dissociates to some 

degree in the slurry. Consequently, the 

mercury present in gaseous emissions 

from the autoclave is mainly in the 

oxidized form. 

Three facilities have a total of eight 

autoclaves. All of the autoclaves are 

equipped with wet venturi scrubbers, 

which remove most of the particulate 

mercury and a significant portion of the 

oxidized mercury present in the 

emissions. Venturi scrubbers have a 

specially designed ‘‘throat’’ that 

increases the gas speed through the 

throat and shears spray droplets to 

smaller sizes, which enhances mixing of 

the droplets and particles and increases 

coagulation and collection. 

4. Leaching 

As mentioned above, leaching 

generally takes place either directly after 

crushing or milling, or after roasting or 

autoclaving. In heap leaching, a dilute 

alkaline cyanide solution is distributed 

onto crushed ore. The solution 

percolates through the ore, and the gold 

reacts with free cyanide to form soluble 

gold-cyanide complexes. The complexes 

migrate with the solution to an 

impermeable liner and flow to a 

collection pond. 

The solution containing the precious 

metals is called the ‘‘pregnant’’ cyanide 

solution. During this process, mercury, 

also present in the ore, may be leached 

into the gold-cyanide solution. 

Refractory ores, which have been 

roasted or autoclaved, are generally 

leached in reaction vessels, referred to 

as vat leaching. Activated carbon 

adsorbent is usually added to the leach 

vessels to improve gold recovery. All 

five facilities in the U.S. that employ 

roasters and/or autoclaves add activated 

carbon to these leach vessels, where the 

leaching and carbon adsorption occur 

simultaneously in the tank. This is 

called the ‘‘carbon-in-leach’’ process. 

5. Carbon Adsorption Process 

As mentioned above, after leaching, 

the most common path for recovering 

gold from the cyanide solution is carbon 

adsorption, where the gold complexes 

in the pregnant solution are 

concentrated through adsorption onto 

activated carbon. If mercury is present 

in the gold-cyanide solution, it is also 

adsorbed onto the carbon. The goldbearing solution may be extracted from 

the leaching process and subsequently 

introduced into a carbon adsorption 

column for concentration of the gold 

content (i.e., the carbon-in-column 

process), or carbon may be added into 

the leach process concurrent with 

leaching from the ore (i.e., the carbonin-leach process). All of these carbon 

adsorption processes produce a ‘‘loaded’’ 

carbon, which contains gold and 

mercury (and some other metals such as 

copper) as adsorbed cyanide complexes. 

6. Carbon Desorption Processes 

The loaded carbon is then separated 

from the rest of the solution or slurry by 

physical separation processes (such as 

with a screen). The remaining cyanide 

solution is now considered ‘‘barren’’ and 

can either be recycled back to the barren 

pond for use in the heap leaching 

process, sent directly to the tailings 

impoundment (if the cyanide 


sroberts on DSKD5P82C1PROD with PROPOSALS
Federal Register / Vol. 75, No. 81 / Wednesday, April 28, 2010 / Proposed Rules 22475 

concentrations are low), or sent to a 

cyanide destruction process and then to 

a tailings impoundment once the 

cyanide levels are sufficiently low. 

The loaded carbon, which contains 

gold-cyanide complexes, mercury, and 

other metals, is stripped in a carbon 

strip tank to recover gold (and other 

metals) typically using a heated caustic 

cyanide solution. Adsorbed gold, as 

well as adsorbed silver, mercury, and 

other metals are stripped from the 

carbon through desorption under 

pressurized or atmospheric conditions, 

resulting in a more concentrated goldcontaining solution. 

7. Description of Thermal Units Used 

After Carbon Desorption 

Carbon kilns. After gold has been 

removed from the activated carbon 

through the stripping process, the 

carbon is usually regenerated and then 

recycled back to the adsorption process. 

Regeneration is performed to regain the 

adsorption capacity of the carbon. 

Rotary kilns known as carbon kilns are 

used to regenerate the spent carbon. 

Because the carbon can be oxidized in 

the kiln if air is present in the heating 

chamber, steam is introduced to the kiln 

to prevent the infiltration of air. As the 

carbon moves through the carbon kiln, 

it is heated, and mercury and other 

remaining components are desorbed 

into the gas stream in the kiln. 

Regenerated carbon exits the kiln and is 

captured and quenched, and the gas 

stream is vented from the process, along 

with combustion gas from heating the 

kiln chamber. The off-gas, containing 

steam and mercury, is discharged to a 

pollution control device, such as a 

carbon adsorber. The potential for 

mercury emissions from carbon kilns is 

directly dependent on the mercury 

content of the stripped carbon and 

whether there is a carbon adsorber or 

other device to control mercury 

emissions. 

There are approximately 16 facilities 

with 18 carbon kilns. Most of these 

carbon kilns have installed carbon 

adsorption units to control mercury 

emissions, and some other facilities in 

Nevada have proposed in their State 

permit applications under the NMCP to 

install carbon adsorbers on their carbon 

kilns. One facility uses a hypochlorite 

scrubber on its carbon kiln which 

oxidizes the elemental mercury to a 

more soluble form and removes it as 

mercuric chloride. 

Pregnant storage solution tanks (‘‘preg 

tanks’’). The concentrated goldcontaining solution that was stripped 

from the carbon is transferred to a preg 

tank, which serves as a storage and feed 

tank to the electrowinning process 

(discussed below). The concentrated 

solution also contains mercury, and 

mercury vapor can be emitted from the 

preg tank vent. Two facilities have 

installed carbon adsorbers on their preg 

tanks. In addition, five facilities in 

Nevada have proposed in their State 

permit applications under the NMCP to 

install carbon adsorbers on their preg 

tanks. 

Electrowinning cells. Recovery of 

gold, along with co-precipitated metals 

such as silver and mercury, from 

concentrated carbon strip solutions is 

performed in one of two ways: 

Electrowinning (the most common 

process) or precipitation with zinc 

powder (discussed below). Separation of 

gold through electrowinning is achieved 

by using an electric potential to plate 

the gold (and other metals present) in 

solution onto a cathode; steel wool is 

typically used as the plating surface 

because of the large surface area it 

provides for gold deposition. The plated 

cathode, or sponge, is then either 

removed from the electrowinning cell, 

so that the gold-bearing sludge-like 

material can be removed from the plated 

cathode, or the plated cathode can be 

left in the electrowinning (EW) cell, but 

the current is turned off and the 

remaining solution is drained out, then 

the material is removed from the plated 

cathode. Either way, once the current 

has stopped, the gold-bearing sludgelike material (known as ‘‘EW 

concentrate’’) is separated from the 

cathode by physical means (such as 

shaking). The gold-bearing EW 

concentrate is then ready for further 

processing. During electrowinning, 

elemental mercury can vaporize and 

escape from the cell with the other gases 

produced in the process; carbon 

adsorption filters are effective in 

controlling these mercury emissions. 

There are approximately 17 

electrowinning units located at 14 

plants. Five facilities have installed 

carbon adsorbers to control mercury 

emissions from electrowinning. In 

addition, four facilities in Nevada have 

proposed in their State permit 

applications under the NMCP to install 

carbon adsorbers on their 

electrowinning units. 

Retorts. The EW concentrate may 

contain up to sixty weight percent gold, 

depending on the mercury content of 

the cyanide solution, the presence of 

other metals and minerals in the 

material, and the configuration of the 

gold recovery process. EW concentrate 

with significant mercury content is 

treated in a retort to remove mercury 

moisture and other impurities. In this 

process, the EW concentrate is placed in 

a pot or tray that is loaded into a heated 

oven under vacuum pressure, usually 

for 12 to 24 hours at 600 °C to 700 °C 

to remove up to 99 percent of the 

mercury. The EW concentrate is heated, 

mercury is vaporized and then pulled 

through a condenser where it condenses 

forming liquid mercury. The liquid 

mercury is recovered and sent through 

a tube into a collection vessel. The 

remaining gold and silver at the end of 

the retorting process typically contains 

less than 1 percent mercury (e.g., 1,000 

to 8,000 mg/kg). The condenser allows 

some mercury to discharge in the off 

gas, and a loss of 0.4 to 0.7 percent of 

the mercury from the condenser has 

been reported. There are approximately 

12 facilities that operate retorts, and all 

operate the retort with a condenser and 

a carbon adsorption filter. A properly 

designed and maintained carbon 

adsorption filter located downstream of 

the condenser is expected to capture 

about 95 percent of the mercury in the 

cooled gas. 

Melt furnaces. Smelting is the last 

step in gold mine ore processing and 

production before the gold is sent to an 

off-site commercial gold refinery. Even 

after retorting, the retorted gold mixture 

still contains some impurities, including 

small concentrations of base and ferrous 

metals, and some residual mercury. 

During this last step, the retorted gold 

mixture (or EW concentrate for facilities 

that do not have retorts) is melted in a 

refinery melt furnace, along with a flux 

material that preferentially absorbs 

impurities, to produce a purified 

commercial mixture of gold known as 

dore. The furnace is heated to 

approximately 1500 °C. Most of the 

remaining mercury is volatilized in the 

melt furnace as elemental mercury or 

oxidized mercury. The dore melt is 

poured into bars, and any flux slag that 

hardens on the bars is removed with a 

mechanical chipper. The bars are then 

shipped to a commercial gold refinery, 

where they are further processed to 

produce gold bullion (99.9 percent pure 

gold). 

There are approximately 24 melt 

furnaces at 17 gold mine ore processing 

and production facilities. All of the melt 

furnaces are equipped with either fabric 

filters, ESPs, wet scrubbers, or a 

combination thereof to control 

emissions of PM. The wet scrubbers also 

remove most of the oxidized mercury, 

but do not remove elemental mercury. 

Six facilities have installed carbon 

adsorbers to control both oxidized and 

elemental mercury emissions from their 

melt furnaces. In addition, three 

facilities in Nevada have proposed in 

their State permit applications under 

NMCP to install carbon adsorbers on 

their melt furnaces. 


sroberts on DSKD5P82C1PROD with PROPOSALS
22476 Federal Register / Vol. 75, No. 81 / Wednesday, April 28, 2010 / Proposed Rules 

8. Non-Carbon Concentrate Process 

After leaching, approximately four 

facilities recover the gold from the 

cyanide solution without using carbon 

by a process commonly known as the 

Merrill-Crowe (MC) method. The 

cyanide solution containing gold is 

separated from the ore by methods such 

as filtration and counter current 

decantation and clarified in special 

filters, usually coated with 

diatomaceous earth to produce a 

clarified solution. Zinc dust is then 

added to the clarified solution. Because 

zinc has a higher affinity for cyanide 

ions than does gold or other metals, zinc 

is dissolved and gold, silver, and 

mercury precipitate as a solid. The fine 

particulate metals are recovered by 

filtration processes. This process is 

performed in deoxygenated, enclosed 

reaction cells. 

The precipitate (also known as MC 

concentrate) is processed in retorts and 

melt furnaces, which are described 

above. The retorts and melt furnaces are 

the sources of mercury emissions at 

facilities that use non-carbon 

concentrate processes, and these 

processes are equipped with carbon 

adsorbers or venturi scrubbers to control 

mercury emissions. These facilities do 

not have carbon kilns since they do not 

use carbon. 

IV. Summary of the Proposed 

Standards 

A. Do these proposed standards apply 

to my facility? 

These proposed mercury standards 

would apply to gold mine ore 

processing and production facilities that 

are area sources that use any of the 

following thermal processes: Roasting 

operations, autoclaves, carbon kilns, 

preg tanks, electrowinning, retorts, and 

melt furnaces. Separate mercury 

standards are proposed for each of the 

following three affected sources: (1) Ore 

pretreatment processes (roasting 

operations and autoclaves), (2) carbon 

processes (carbon kilns, preg tanks, 

electrowinning, retorts, and melt 

furnaces at facilities that use carbon to 

recover the gold from the cyanide 

solution), and (3) non-carbon 

concentrate processes (retorts and melt 

furnaces at facilities that do not use 

carbon to recover gold). 

We are proposing standards for both 

new and existing affected sources. An 

affected source is an existing source if 

construction or reconstruction 

commenced on or before April 28, 2010. 

An affected source is a new source if 

construction or reconstruction 

commenced after April 28, 2010. 

B. When must I comply with the 

proposed standards? 

We are proposing that the owner or 

operator of an existing affected source 

comply with the final rule no later than 

2 years after publication of that rule in 

the Federal Register. The owner or 

operator of a new affected source is 

required to comply by the date of 

publication of the final rule in the 

Federal Register or upon startup of the 

affected source, whichever occurs later. 

C. What are the proposed standards? 

We are soliciting comments on all 

aspects of this proposed rule including, 

but not limited to, the data and 

calculations used to establish the 

emissions limits, the proposed testing 

and monitoring for emissions, and the 

parametric monitoring of control 

devices. 

The proposed standards are 

summarized in Table 1 of this preamble 

and discussed in more detail below. 

These proposed standards establish 

mercury MACT emission limits for three 

affected sources. The proposed MACT 

standard for new and existing ore 

pretreatment processes is 149 pounds of 

mercury per million tons of ore 

processed (149 lb/million tons). The 

proposed MACT standard for existing 

carbon processes is 2.6 pounds of 

mercury per ton of concentrate 

processed (2.6 lb/ton of concentrate), 

and for new carbon processes is 0.14 

pounds of mercury per ton of 

concentrate (0.14 lb/ton of concentrate). 

Concentrate is the gold-bearing sludge 

material that is processed in retorts. For 

facilities without retorts, concentrate is 

the quantity processed in melt furnaces 

before any drying. For new carbon 

processes, we are proposing a 

compliance alternative of 97 percent 

control efficiency. This alternative 

provides at least equivalent HAP 

reductions as the MACT floor. 

TABLE 1—SUMMARY OF PROPOSED MERCURY EMISSION LIMITS

Affected source 

Mercury emission limit 

Existing source New source 

Ore pretreatment processes ............................... 149 lb/ton of ore ............................................... 149 lb/ton of ore. 

Carbon processes .............................................. 2.6 lb/ton of concentrate .................................. 0.14 lb/ton of concentrate or 97 percent reduction in uncontrolled emissions. 

Non-carbon concentrate processes ................... 0.25 lb/ton of concentrate ................................ 0.20 lb/ton of concentrate. 

The proposed MACT standard for 

existing non-carbon concentrate 

processes is 0.25 pounds of mercury per 

ton of concentrate processed (0.25 lb/ 

ton of concentrate processed), and for 

new non-carbon concentrate processes 

is 0.20 lb/ton of concentrate processed. 

D. What are the testing and monitoring 

requirements? 

1. Testing for Compliance With 

Emission Limits 

Any stack that is a discharge point for 

any thermal process at a gold mine ore 

processing and production facility 

would be tested for mercury emissions 

based on the average of a minimum of 

three runs per stack at least once 

annually (i.e., once every four 

successive calendar quarters) using EPA 

Method 29 in Appendix A–8 to part 60, 

the Ontario Hydro Method (ASTM 

D6784–02, ‘‘Standard Test Method for 

Elemental, Oxidized, Particle-Bound 

and Total Mercury in Flue Gas 

Generated from Coal-Fired Stationary 

Sources’’), EPA Method 30A, or EPA 

Method 30B, both in Appendix A–8 to 

part 60. 

We are proposing that the initial 

compliance test for new sources be 

conducted within 180 days of the 

compliance date. The emissions for each 

process stack (in lb/hr) would be 

multiplied by the number of hours the 

process operated in the 6-month period 

following the compliance date to 

determine the total mercury emissions 

for the initial 6-month period. The 

process inputs used in the denominator 

of the emission limit, including ore and 

concentrate, would be measured and 

summed for each month to provide the 

total input (in tons) for the initial 6- 


sroberts on DSKD5P82C1PROD with PROPOSALS
Federal Register / Vol. 75, No. 81 / Wednesday, April 28, 2010 / Proposed Rules 22477 

month period following the compliance 

date. The sum of the emissions (in lbs) 

for the 6-month period for all process 

units included in the affected source 

would be divided by the total input for 

the 6-month period to determine 

compliance with the emission limit. 

After the initial 6-month period, all the 

stacks for the thermal process units 

would be tested for mercury emissions 

annually. 

We are proposing that existing 

sources also conduct their initial 

compliance test within 180 days of their 

compliance date. The emissions for each 

process stack (in lb/hr) would be 

multiplied by the number of hours the 

process operated in the 6-month period 

following the initial compliance date to 

determine the emissions for the 6-month 

period. The emissions for each process 

stack would be recorded in total pounds 

of mercury for the 6-month period. The 

total mercury emissions for the affected 

source for the 6 months would be 

determined by summing the emissions 

for each process stack included in the 

affected source. The total emissions for 

the 6-month period for the affected 

source would be divided by the process 

input (concentrate or ore) for the 6- 

month period to determine compliance 

with the emission limit. 

After the initial 6-month period, all of 

the stacks for the thermal process units 

at new and existing sources would be 

tested for mercury emissions annually. 

The total mercury emissions and 

process inputs for each 12-month period 

would be calculated as described below 

to determine compliance with the 

emissions limit. 

The process inputs used in the 

denominator of the emission limit, 

including ore and concentrate, would be 

measured and summed to provide the 

total input (in tons) for each month. For 

facilities with ore pretreatment 

processes, the daily quantity of ore (in 

tons) would be determined either by 

calibrated weigh scales or by measuring 

volumetric flow rate and density and 

multiplying the two measurements. The 

daily totals would be summed for each 

calendar month to provide a monthly 

total for ore input. For facilities with 

carbon and/or non-carbon processes 

affected sources, each batch of 

concentrate would be weighed by 

scales, and the total of all batches would 

be summed for each calendar month to 

produce monthly weights of 

concentrate. 

Emissions in lb/million tons of ore for 

each affected source of ore pretreatment 

processes would be determined by 

summing the emissions for all units in 

the pre-treatment processes affected 

source for the appropriate time period 

(e.g., a 6-month period initially for new 

and existing sources and the 12-month 

periods thereafter) and dividing this 

sum of the emissions by the sum of the 

total ore processed (expressed in 

millions tons) in all processes at the 

affected source for the appropriate time 

period (i.e., 6 months or 12 months). 

Emissions in lb/ton of concentrate for 

each affected source of carbon processes 

would be determined by dividing the 

sum of the emissions from all carbon 

processes at the affected source for the 

appropriate time period by the sum of 

the tons of concentrate processed at the 

affected source for each time period. 

Emissions in lb/ton of concentrate for 

each non-carbon concentrate process 

affected source would be determined by 

dividing the sum of the emissions from 

all non-carbon concentrate process units 

at the affected source for each 

appropriate time period by the sum of 

the concentrate (expressed in tons) 

processed in all process units at the 

affected source for each time period. 

Mercury testing at both the inlet and 

outlet of all mercury emissions control 

devices is proposed for new affected 

sources with carbon processes that 

choose to demonstrate a 97 percent 

reduction in emissions. The inlet and 

outlet of every process unit’s control 

device would be sampled, and the 

mercury emissions before and after 

control (in lb/hr) would be multiplied 

by each process unit’s operating hours 

for the appropriate time period to 

determine the mercury emissions for the 

time period. The initial tests would be 

done within 180 days of the compliance 

date. For the first 6 months of operation, 

the inlet emissions for all process units 

would be calculated and summed and 

compared to the sum of the calculated 

outlet emissions for the 6-month period. 

After the initial 6 months, annual tests 

would be conducted and the 

calculations would be based on each 12 

month period to determine the percent 

reduction in mercury emissions. 

We have also considered other 

procedures for calculating the mercury 

emission rate in pounds per ton of input 

to determine compliance for the ore 

pretreatment group and possibly for the 

carbon and non-carbon affected sources 

as well. For example, one approach for 

the ore pre-treatment processes would 

be to divide the measured emission rate 

(in pounds per hour) from the 

compliance test for each autoclave and 

roasting operation by the ore throughput 

(in tons per hour) for each autoclave and 

roasting operation as measured during 

the performance tests. The result would 

be emissions in pounds per ton of ore 

for each autoclave and roasting 

operation. Then the fraction of the total 

ore processed in the previous 12 months 

would be calculated for each roasting 

operation and autoclave, and the 

emissions from all autoclaves and 

roasting operations in the group would 

be calculated as the weighted average 

pounds per ton of ore to determine 

compliance (i.e., the sum of fraction of 

total ore throughput times the pounds 

per ton for each roasting operation and 

autoclave). With this approach, it would 

not be necessary to monitor, record, and 

use the annual operating hours for each 

unit to calculate emissions. A similar 

approach could possibly also be used 

for the carbon and non-carbon groups. 

We are requesting comment and 

supporting information on the 

advantages and disadvantages of this 

possible alternative procedure and the 

proposed procedure for determining 

compliance from the ore pretreatment 

processes and the other process groups. 

2. Monitoring Requirements 

Roasters. We are proposing two 

options for monitoring roaster 

emissions: (1) Integrated sorbent trap 

mercury monitoring coupled with 

parametric monitoring of scrubbers and 

(2) monitoring using a continuous 

emission monitoring system (CEMS) for 

mercury. Both proposed monitoring 

options would require establishment of 

operating limits to detect and correct 

problems as soon as possible. An 

exceedance of an operating limit would 

trigger immediate corrective action and 

would require that the problem be 

corrected within 48 hours or that the 

feed of ore to the roaster be stopped. 

The first option for monitoring 

emissions from roasters would be to use 

the EPA Performance Specification (PS) 

12B for integrated sorbent trap mercury 

monitoring on a periodic basis coupled 

with parametric monitoring of mercury 

scrubbers. We propose that under this 

option the facility will sample and 

analyze weekly for mercury 

concentration according to PS 12B. To 

determine appropriate sampling 

duration, we propose that the owner or 

operator 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, the facility 

would 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, the facility 

would re-sample using a shorter 

sampling duration. 

We are proposing that the owner or 

operator of an affected source would 

establish an operating limit for mercury 


sroberts on DSKD5P82C1PROD with PROPOSALS
22478 Federal Register / Vol. 75, No. 81 / Wednesday, April 28, 2010 / Proposed Rules 

concentration for PS 12B monitoring 

during the initial compliance test and 

maintain the mercury emissions below 

the established operating limit. The 

specific method and equation to be used 

to establish the operating limit are 

described in the proposed rule. If the 

operating limit is exceeded, the facility 

would report the exceedance as a 

deviation and take corrective actions 

within 48 hours to return the emissions 

control system back to proper operation. 

In addition, we are proposing as part 

of this first monitoring option (i.e., 

sorbent trap monitoring) that facilities 

with roasters and calomel-based 

mercury control systems (also referred 

to as ‘‘mercury scrubbers’’) also establish 

operating limits for various control 

parameters described below during their 

annual mercury compliance stack test. 

We are proposing that each mercury 

scrubber be equipped with devices to 

monitor the scrubber liquor flow rate, 

scrubber pressure drop, and inlet gas 

temperature. Minimum operating limits 

for the scrubber liquor flow rate and 

pressure drop would be established 

based on the lowest average value 

measured during any of the three runs 

of a compliant performance test. A 

maximum inlet temperature would be 

established based on the highest 

temperature measured during any of the 

three runs of the compliance test. In 

addition to the parameters described 

above, we are proposing that the facility 

must also monitor the mercuric ion 

concentration and the chloride ion 

concentration four times per day or 

continuously monitor the oxidation 

reduction potential and pH. These 

monitored parameters would be 

maintained within the range specified 

by the scrubber’s manufacturer or 

within an alternative range approved by 

the permitting authority. If any of the 

parameters are outside the specified 

range or limit, corrective action would 

be taken to bring the parameters back to 

the operating range or limit or else the 

facility would commence shutdown of 

the roaster. 

As mentioned above, we are including 

an alternative option for monitoring 

emissions from roasters, which is to 

install and operate a continuous 

emission monitoring system (CEMS) for 

mercury. Under this alternative option, 

facilities would not be required to do 

the parametric monitoring of the 

mercury scrubbers described above 

under the first option. A facility 

choosing the CEMS option would 

operate the mercury CEMS according to 

EPA Performance Specification (PS) 

12A (except that calibration standards 

traceable to the National Institute of 

Standards and Technology (NIST) are 

not required). This exception is 

necessary because the mercury 

concentrations in the exhaust gases from 

roasters can be higher than the range of 

concentrations that are covered with the 

existing calibration standards traceable 

to NIST. 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 from roasters. However, 

calibration standards are available from 

the manufacturers of mercury CEMS 

which can be used to calibrate these 

CEMS for monitoring of roasters. 

In addition to following PS 12A, the 

facility would perform a data accuracy 

assessment of the CEMS according to 

section 5 of Appendix F in part 60. We 

are proposing that the owner or operator 

would establish an operating limit for 

mercury concentration for the CEMS 

during a compliance test for the roaster 

stack and monitor the daily average 

mercury concentration in the roaster 

stack exhaust gas with the CEMS. The 

specific method and equation to be used 

to establish the operating limit are 

described in the proposed rule. If any 

daily average concentration as measured 

with the CEMS exceeds the operating 

limit, the facility would report the 

exceedance as a deviation and take 

corrective actions within 48 hours to 

return the emission control system back 

to proper operation. Regardless of 

whether deviations occur, the owner or 

operator of any facility with a roaster 

would submit a monitoring plan that 

includes quality assurance and quality 

control (QA/QC) procedures sufficient 

to demonstrate the accuracy of the 

CEMS. At a minimum, the QA/QC 

procedures would include daily 

calibrations and an annual accuracy test 

for the CEMS. 

For facilities that control roaster 

mercury emissions with mercury 

scrubbers, we are proposing not to 

require sorbent traps or mercury CEMs 

monitoring if a facility demonstrates 

that the mercury emissions from its 

roasters are consistently low and well 

controlled. Specifically, if a facility can 

demonstrate that mercury emissions 

from the roaster are less than 10 pounds 

of mercury per million tons of ore, then 

the facility would be allowed to 

discontinue the use of the sorbent trap 

or CEMS as described above. To 

demonstrate this, the facility would 

conduct three or more consecutive 

independent performance tests for 

mercury at least one month apart on the 

roaster exhaust stacks and show that 

emissions are less than 10 pounds per 

million tons of ore during normal 

operations for all tests. However, such a 

facility would be required to perform 

the parametric monitoring for mercury 

scrubbers and maintain parameters 

within the operating ranges established 

in accordance with the proposed rule. 

Also, the facility would continue to 

perform annual compliance tests of the 

roaster stack. Moreover, if there is an 

increase in the mercury concentration in 

the ore processed by the roaster that is 

higher than any concentration measured 

during the previous 12 months, then the 

facility would need to perform a 

compliance test within 30 days of the 

first day that the new ore is processed 

to determine whether the mercury 

emissions are still below 10 lbs per 

million tons of ore. If any subsequent 

performance compliance test indicates 

that the roaster is emitting more than 10 

pounds of mercury per million tons of 

ore input, then the facility would be 

required to monitor the roaster 

emissions using the sorbent trap method 

or CEMS. 

Carbon Adsorbers. For process units 

(such as furnaces, kilns, retorts, 

electrowinning, and autoclaves) that 

control mercury emissions with a 

carbon adsorber, we are proposing three 

emissions monitoring options. One 

proposed option involves monitoring 

the mercury concentration at the exit of 

the carbon bed. A second option is 

based on sampling the carbon bed for 

mercury. The third option is based on 

changing out the carbon bed after a 

fixed period of time determined based 

on historical operating experience. 

For the first option (i.e., the exit 

concentration monitoring option), the 

mercury concentration would be 

measured periodically using a sorbent 

trap according to EPA Method 30B. An 

operating limit would be established 

through sorbent trap measurements 

obtained during the initial compliance 

test. The mercury concentration would 

be measured during each annual 

performance compliance test of each of 

the stacks for the carbon processes using 

Method 30B. An operating limit would 

be calculated from the average mercury 

concentration measured during the 

compliance test multiplied by a factor. 

The factor is the MACT emission limit 

for carbon processes divided by the sum 

of results of the compliance test for all 

units within the carbon processes 

affected source. Thereafter, if the 

established operating limit is exceeded, 

the exceedance would be reported as a 

deviation and corrective action would 

be triggered (e.g., replace the carbon in 

the bed). The specific equations to 

calculate the operating limit are 

described in the proposed rule. Initially, 

the facility would measure mercury 

concentration in the exit gas monthly 

using Method 30B. Once mercury 


sroberts on DSKD5P82C1PROD with PROPOSALS
Federal Register / Vol. 75, No. 81 / Wednesday, April 28, 2010 / Proposed Rules 22479 

1For the factors that EPA considers in evaluating 

whether to exercise the Agency’s discretion to 

exempt area sources from title V, please see 

National Emission Standards for Hazardous Air 

Pollutants for Area Sources: Clay Ceramic 

Manufacturing, Glass Manufacturing, and 

Secondary Nonferrous Metal Processing; Proposed 

rule, 72 FR 53838, 53849–53853 (September 20, 

2007). 

concentrations reach 50 percent of the 

operating limit, the facility would then 

need to perform weekly sampling and 

analysis using Method 30B. When the 

concentration reaches 90 percent of the 

operating limit, to prevent an 

exceedance, the owner or operator 

would be expected to replace the carbon 

in the control device within 30 days (or 

before the operating limit is actually 

exceeded). 

The second proposed monitoring 

option, which is based on sampling the 

carbon bed for mercury, would require 

conducting an initial sampling of the 

carbon in the carbon bed 90 days after 

the replacement of the carbon to 

determine mercury loading. A 

representative sample would be 

collected from the carbon bed and 

analyzed using EPA Method 7471A, and 

the depth to which the sampler is 

inserted would be recorded. Based upon 

sample results, a carbon loading would 

be calculated for the system, and 

sampling would be performed quarterly 

thereafter. When the carbon loading 

reaches 50 percent of the design 

capacity of the carbon, monthly 

sampling would be performed until 90 

percent of the carbon loading capacity is 

reached. The carbon would be removed 

and replaced with fresh carbon no later 

than 30 days after reaching 90 percent 

of capacity to ensure that the maximum 

mercury loading as recommended by 

the manufacturer is not exceeded. 

The third proposed option would start 

with one of the two previous options. 

After collecting at least two years of data 

under one of the options described 

above, a facility would establish a 

change out time for the carbon based on 

the two years of monitoring and could 

implement this periodic change out 

instead of sampling and analysis after 

approval by the permitting authority. 

However, if there is any significant 

change in the process, input materials, 

or mercury control system (e.g., an 

increase in operating rates or processing 

different ores with higher mercury 

levels) then sampling and analysis 

(according to the procedures in option 

1 or option 2 described above) would be 

required within 30 days to re-establish 

the carbon change out time. 

We are also proposing that the inlet 

stream to carbon adsorbers applied to 

autoclaves, carbon kilns, melt furnaces, 

and retorts be monitored for 

temperature and that the inlet 

temperature be maintained below the 

maximum temperature established 

during the compliance tests. If the 

maximum temperature is exceeded, the 

owner or operator would analyze the 

outlet concentration using Method 30B 

within 30 days as described above. If the 

concentration is below 90 percent of the 

operating limit, the owner or operator 

could set a new temperature operating 

limit 10 °F above the previous operating 

limit. On the other hand, if the 

concentration is more than 90 percent of 

the operating limit, the facility would 

take corrective action to reduce the 

temperature back down to below the 

maximum temperature recorded during 

compliance tests and then retest 

emissions using Method 30B. If the 

concentration is more than 90 percent of 

the operating limit based on this 

subsequent test, then the facility must 

replace the carbon. 

Wet scrubbers. For each wet scrubber, 

we are proposing that pressure drop and 

water flow rate be maintained at a 

minimum level based on measurements 

during the initial or subsequent 

compliance test(s). 

E. What are the notification, 

recordkeeping, and reporting 

requirements? 

The owner or operator of an existing 

or new affected source would be 

required to comply with certain 

notification, recordkeeping, and 

reporting requirements of the NESHAP 

General Provisions (40 CFR part 63, 

subpart A), which are identified in 

Table 1 of this proposed rule. Each 

owner or operator of an affected source 

would submit an Initial Notification 

according to the requirements in 40 CFR 

63.9(a) through (d) and a Notification of 

Compliance Status according to the 

requirements in 40 CFR 63.9(h). 

Each owner or operator of an existing 

or new affected source would be 

required to keep records to document 

compliance with the mercury emission 

limits. Owners or operators of new and 

existing affected sources would 

maintain records of all monitoring data. 

Other records include monthly totals of 

ore quantity for ore pretreatment 

affected sources, monthly quantities of 

concentrate for all other affected 

sources, and monthly hours of operation 

for each process unit at each affected 

source. 

If a deviation from this rule’s 

requirements occurs, an affected source 

would be required to submit a 

compliance report for that reporting 

period. The proposed rule specifies the 

information requirements for such 

compliance reports. 

We are also proposing to require 

electronic reporting of performance 

evaluation data collected using methods 

compatible with EPA’s Electronic 

Reporting Tool (ERT). After December 

31, 2011, within 60 days after the date 

of completing each performance 

evaluation conducted to demonstrate 

compliance, the owner or operator 

would submit the test data to EPA by 

entering the data electronically into 

EPA’s WebFIRE database through EPA’s 

Central Data Exchange. The owner or 

operator of an affected facility would 

enter the test data into EPA’s database 

using the ERT or other compatible 

electronic spreadsheet. Only 

performance evaluation data collected 

using methods compatible with ERT 

would be subject to this requirement to 

be submitted electronically into EPA’s 

WebFIRE database. 

F. What are the title V permit 

requirements? 

Under section 502(a) of the CAA, all 

major sources and certain other sources, 

including sources subject to section 112 

standards, are required to operate in 

compliance with a title V permit. 

Today’s proposal requires that gold 

mine ore processing and production 

area sources comply with the title V 

permitting requirements. However, 

section 502(a) of the CAA provides that 

the Administrator may exempt an area 

source category (in whole or in part) 

from title V if she/he determines that 

compliance with title V requirements is 

‘‘impracticable, infeasible, or 

unnecessarily burdensome’’ on such 

category. We are therefore soliciting 

comment on whether such an 

exemption is appropriate under section 

502(a) for any particular sources in this 

category. Commenters should provide 

supporting data and rationale to explain 

the bases for their comments.1

G. Emissions of Non-Mercury HAPs 

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). However, a few 

facilities are close to the major source 

threshold due to hydrogen cyanide 

(HCN). For example, the largest facility 

emits an estimated 5 to 9 tons of HCN 

per year. Emissions of all other HAPs, 

including mercury, are individually 

significantly lower than the 10 ton per 

year threshold for a single HAP and the 

25 ton per year threshold for a 


sroberts on DSKD5P82C1PROD with PROPOSALS
22480 Federal Register / Vol. 75, No. 81 / Wednesday, April 28, 2010 / Proposed Rules 

combination of HAP. However, 

depending on how facilities manage 

their cyanide processes, EPA believes 

that cyanide emissions could potentially 

change a facility’s status from area 

source to major source. Although EPA 

would develop MACT standards if it 

ever identified any major sources of 

gold mine ore processing and 

production, the MACT standards in 

today’s proposal apply only to area 

sources because those are the only gold 

mine ore processing and production 

sources EPA has identified. 

In light of the above, we are 

considering including in today’s 

NESHAP a provision under which 

sources may certify and demonstrate 

that they are area sources of gold mine 

ore processing and production. We 

would include in this area source 

NESHAP management practices for 

cyanide processes that we believe 

would effectively limit cyanide 

emissions and thus assure that sources 

maintain their area source status. To the 

extent sources were concerned about 

their HCN emissions, they could 

implement the management practices 

for cyanide processes specified in this 

rule and certify to the Agency that they 

had done so. Some management 

practices we are considering include: 

maintaining pH of cyanide leach 

solutions greater than nine; burying 

leach lines whenever practical and 

feasible; monitoring cyanide 

concentrations at the perimeter and in a 

downwind direction of main emission 

sources; not allowing puddles to form 

that are greater than 1 square meter on 

leach pads; and 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). 

We request comment on whether we 

should include the proposal described 

above or some modification of it. We 

also request comment on effective 

management practices to limit cyanide 

emissions, including the practices 

described above as well as other 

approaches to manage cyanide 

emissions. 

H. Request for Comments 

As mentioned previously, we are 

soliciting comments on all aspects of 

this proposed rule, including, but not 

limited to, the data and calculations 

used to establish the emissions limits 

for mercury, the proposed requirements 

and options for emissions testing and 

monitoring, the parametric monitoring 

options for control devices, title V 

permit requirements, and emissions of 

non-mercury HAPs. 

V. Rationale for the Proposed 

Standards 

A. How did we select the affected 

source? 

We are proposing individual MACT 

standards for each of the following three 

affected sources in the gold mine ore 

processing and production source 

category: ore pretreatment processes, 

carbon processes, and non-carbon 

concentrate processes. These three 

affected sources reflect the three 

primary different types of processes 

used in this source category to produce 

gold. Moreover, many gold mine ore 

processing and production facilities 

combine the emissions from multiple 

process units within a single affected 

source and route them to a single 

mercury emission control system and 

stack. Because we cannot determine the 

mercury emissions from individual 

process units that share a stack, it is 

difficult to establish emission standards 

for each process unit within an affected 

source. Setting MACT standards for 

each of the three affected sources 

accommodates the various stack and 

control configurations for the process 

units within an affected source. 

Emissions from all process units in the 

affected source would be summed to 

determine compliance with the 

proposed MACT standard for that 

affected source. 

As described above, the three affected 

sources differ in process operations, the 

sources of mercury entering the 

processes, and the nature of the 

emissions. Ore pretreatment processes 

include roasting operations (roasters, 

ore dryers, ore pre-heaters, and 

quenchers) and autoclaves that are used 

to pretreat refractory ore, which 

contains organic carbon and/or sulfide 

mineral grains that prevent the initial 

use of cyanide leaching to extract the 

gold effectively from the ore. Mercury 

enters these processes with the ore. The 

potential for mercury emissions from 

this affected source is directly related to 

the amount of ore processed in the 

autoclaves and roasters; the proposed 

standard for this affected source is 

therefore expressed in pounds of 

mercury emissions per million tons of 

ore processed (lb/million tons of ore). 

Carbon processes include carbon 

kilns, electrowinning cells, melt 

furnaces, retorts, and preg tanks at 

facilities that use carbon to recover gold 

from pregnant cyanide solution. In 

developing a proposed format for the 

emission limit for carbon processes, we 

examined the use of loaded carbon, 

concentrate, and gold production in the 

denominator of a pound per ton format. 

In other NESHAPs, we have typically 

used the amount of feed throughput or 

the amount of product produced in the 

denominator of the emission limit. For 

example, in the proposed revisions to 

the Portland cement NESHAP (74 FR 

21136, May 6, 2009), we analyzed the 

data and developed the MACT floor in 

terms of pounds per million tons of feed 

to the kiln and subsequently converted 

the emission limit to a format of pounds 

per million tons of clinker (i.e., the 

product from the kiln). Although loaded 

carbon can be considered the ‘‘primary 

feed,’’ we discovered there were 

potential issues with its measurements 

(e.g., default values were used for 

density), we were unsure that the data 

from different facilities were 

comparable, and it was not a quantity 

that has been required to be reported 

under existing State regulatory 

programs. We rejected the use of gold 

produced because some facilities do not 

produce gold (they send the 

intermediate product to offsite 

refineries), some facilities produce more 

silver than gold, and the quantity of 

gold varies depending on the percent of 

gold in the product. The primary 

intermediate product that is common to 

all of the facilities with these carbon 

processes is the gold-bearing EW 

concentrate, which is the input to 

retorts or melt furnaces. Further, 

concentrate is closely related to the final 

product because it contains about 60 

percent gold, and because of its value, 

it is carefully and accurately weighed 

and records of the quantities are kept. 

Concentrate is also required to be 

reported under the NDEP program, so 

we had comparable and reliable data 

from the different gold mine ore 

processing and production facilities. 

Consequently, we decided that the most 

appropriate format of the emission limit 

for the carbon processes is lb/ton of 

concentrate. 

For the reasons discussed above, we 

are proposing the concentrate format. 

However, we also considered using the 

amount of loaded carbon for the 

denominator of the emission limit 

format for carbon processes instead of 

concentrate, and we believe there may 

be merit in using loaded carbon as the 

denominator. Therefore, we are 

soliciting comments on the merits of 

both formats. In particular, we seek 

comments on whether loaded carbon or 

concentrate would be the better format 

for compliance determinations (e.g., 

accuracy and reliability of the 

measurements, availability of records) 

or for other reasons or factors, such as 

the processes present at a given plant, 

operating layout, or offsite shipments 

for processing. We are also requesting 


sroberts on DSKD5P82C1PROD with PROPOSALS
Federal Register / Vol. 75, No. 81 / Wednesday, April 28, 2010 / Proposed Rules 22481 

2More details on the calculation of the MACT 

floor limits are given in the technical memo in the 

docket. 

comment on whether the quantity of 

concentrate should be determined on an 

‘‘as fed’’ or dry basis, and if a dry basis, 

what methods could be used to 

determine dry weight accurately and 

reproducibly. 

Non-carbon concentrate processes 

include retorts and melt furnaces at 

facilities that use the Merrill Crowe 

process to produce gold. These affected 

sources do not use carbon to recover 

gold and the only thermal process units 

used to recover gold ore are retorts and 

furnaces. As described above, during the 

non-carbon processes, zinc dust is 

added to the cyanide solution after 

leaching to precipitate gold and other 

metals (including mercury). The 

precipitate (or ‘‘MC concentrate’’) is then 

processed in retorts and metal furnaces, 

liberating mercury from the concentrate. 

The potential mercury emissions are 

therefore directly related to the amount 

of concentrate processed; consequently 

for this reason and the merits of using 

concentrate as discussed above, the 

proposed standard for this affected 

source is expressed in lb/ton of 

concentrate. 

B. How did we determine MACT? 

1. Selection of MACT Floors for Existing 

Sources for the Three Affected Sources 

CAA section 112(d)(3)(B) requires that 

the MACT standards for existing sources 

be at least as stringent as the average 

emission limitation achieved by the best 

performing five sources (for which the 

Administrator has or could reasonably 

obtain emissions information) in a 

category with fewer than 30 sources. 

The gold mine ore processing and 

production source category consists of 

fewer than 30 sources. As mentioned 

above, we are proposing MACT 

standards for each of the following three 

affected sources: ore pretreatment 

processes, carbon processes, and noncarbon concentrate processes. We have 

mercury emissions data on ore 

pretreatment processes for all five 

facilities in the United States with ore 

pretreatment processes. We have 

mercury emissions data on carbon 

processes for 11 facilities and mercury 

emissions data on non-carbon 

concentrate processes for two facilities. 

Pursuant to section 112(d)(3), the MACT 

floor limits for existing ore pretreatment 

processes and carbon processes are 

based on the average emission 

limitation achieved by the best 

performing five facilities for each of 

these two affected sources, and the 

MACT floor limit for existing noncarbon concentrate processes are based 

on the average emission limitation 

achieved by the two facilities with such 

processes. 

To calculate the MACT floor limit for 

each of the affected sources, we 

established and ranked sources’ 

emissions from lowest to highest. The 

data on which we based the limits are 

expressed in terms of pounds of 

mercury emitted per ton of input, where 

the gold mine ore is the input for the ore 

pretreatment processes and concentrate 

is the input for the carbon processes and 

the non-carbon concentrate processes. 

We used the emissions data for those 

best performing affected sources to 

determine the emission limits to be 

proposed, with an accounting for 

variability. EPA must exercise its 

judgment, based on an evaluation of the 

relevant factors and available data, to 

determine the level of emissions control 

that has been achieved by the best 

performing sources under variable 

conditions. The Court has recognized 

that EPA may consider variability in 

estimating the degree of emission 

reduction achieved by best-performing 

sources and in setting MACT floors. See 

Mossville Envt’l Action Now v. EPA, 370 

F.3d 1232, 1241–42 (DC Cir 2004) 

(holding EPA may consider emission 

variability in estimating performance 

achieved by best-performing sources 

and may set the floor at a level that a 

best-performing source can expect to 

meet ‘‘every day and under all operating 

conditions’’). 

To calculate the achieved emission 

limit, including variability, we used the 

equation: 2

UPL = xp + t * (vT) 0.5

Where: 

UPL = upper prediction limit (99 percent), 

xp = average of the best performing MACT 

pool sources, 

t = Student’s t-factor evaluated at 99 percent 

confidence, and 

vT = total variance determined as the sum of 

the within-source variance and the 

between-source variance. 

The between-source variance is the 

variance of the average of the best 

performing source averages. The withinsource variance is the variance of the 

MACT source average considering ‘‘m’’ 

number of future individual test runs 

used to make up the average to 

determine compliance. We are 

proposing that a compliance test would 

be based on the average of three runs; 

consequently, the value of ‘‘m’’ used in 

the statistical analysis is 3. This value 

of ‘‘m’’ is used to reduce the variability 

to account for the lower variability 

when averaging of individual runs is 

used to determine compliance in the 

future. For example, if the average of 

three test runs is used to determine 

compliance (m=3), the variability based 

on 3-run averages is lower than the 

variability of the single run 

measurements in the data base, which 

results in a lower UPL for the 3-run 

average. 

Our MACT floor limit calculations are 

based primarily on mercury emissions 

data from annual testing that was 

required by NDEP for 2007 and 2008. 

However, we used data from 2006 for an 

autoclave at a Nevada facility that was 

not tested in 2007 and did not operate 

in 2008. We also used data from 2009 

to replace 2008 test data at one Nevada 

facility that was invalidated due to not 

following the procedures in the State’s 

testing protocol. In addition, we used 

2010 test data for a Nevada facility that 

installed new mercury emission 

controls on its roasters and resumed 

operation in late 2009. The tests that 

generated the data described above 

generally consisted of three runs per test 

per process at each facility. There were 

cases where 2007 results represent 

emissions before a control device was 

installed, and 2008 test results were 

after a mercury emission control device 

had been installed. In those cases, we 

used only the 2008 (controlled) test 

results to determine the top performing 

facilities. Emissions from the tests (in 

lb/hr) were multiplied by the number of 

hours the process operated in the 

calendar year and then divided by the 

process input rate for the year (in tons) 

to calculate the facility’s performance 

for an affected source (expressed as lbs 

of mercury emissions per ton of input 

material). 

Source performance and the resulting 

MACT floor limits are summarized in 

Tables 2, 3, and 4, for ore pretreatment, 

carbon, and non-carbon concentrate 

processes, respectively. 

TABLE 2—MACT FLOOR RESULTS FOR

ORE PRETREATMENT

Facility 

Average 

performance 

(lb/million 

tons ore) 

A ........................................... 62 

B ........................................... 64 

C ........................................... 69 

E ........................................... 90 

D ........................................... 211 

Average of top 5 ................... 99 

99% UPL existing (MACT 

Floor) ................................. 175 

99% UPL new (MACT Floor) 163 


sroberts on DSKD5P82C1PROD with PROPOSALS
22482 Federal Register / Vol. 75, No. 81 / Wednesday, April 28, 2010 / Proposed Rules 

TABLE 3—MACT FLOOR RESULTS FOR

CARBON PROCESSES

Facility 

Average 

performance 

(lb/ton 

concentrate) 

M ......................................... 0 .06 

N ......................................... 0 .60 

A ......................................... 1 .5 

H ......................................... 1 .8 

D ......................................... 2 .9 

F .......................................... 3 .1 

C ......................................... 3 .7 

I ........................................... 6 .9 

G ......................................... 9 .7 

B ......................................... 21 

J .......................................... 39 

Average of top 5 ................. 1 .4 

99% UPL existing (MACT 

Floor) ............................... 2 .6 

99% UPL new (MACT 

Floor) ............................... 0 .14 

TABLE 4—MACT FLOOR RESULTS FOR

NON-CARBON CONCENTRATE PROCESSES

Facility 

Average 

performance 

(lb/ton 

concentrate) 

K ........................................... 0.07 

L ............................................ 0.11 

Average of top 2 ................... 0.09 

99% UPL existing ................. 0.25 

99% UPL new ....................... 0.20 

The average emission rates for ore 

pretreatment and carbon processes from 

the top five facilities performing these 

processes are 99 lbs/million tons ore 

and 1.4 lb/ton of concentrate, 

respectively. The average emission rate 

for non-carbon concentrate processes 

from the top two facilities performing 

these processes is 0.09 lb/ton of 

concentrate. As previously discussed 

above, we account for variability in 

setting floors, not only because 

variability is an element of performance, 

but also because it is reasonable to 

assess best performance over time. Here, 

for example, we know that the 2 to 5 

lowest emitting affected sources’ 

emission estimates are averages and we 

expect that the actual emissions will 

vary over time. If we do not account for 

this variability, we would expect that 

even the sources that perform better 

than the floor on average would 

potentially exceed the floor emission 

levels part of the time. 

For the lowest emitting sources (2 to 

5 sources, depending on the affected 

source), we calculated an average 

emission rate using the data from 

multiple test runs for multiple 

processes. The results are shown in 

Tables 2, 3, and 4 and represent the 

average performance of each source 

from the sum of the average emissions 

from all process units within the 

affected source. We then calculated the 

average performance of the lowest 

emitting sources and the variances of 

the emission rates for each process unit, 

which is a direct measure of the 

variability of the data set. This 

variability includes the run-to-run and 

year-to-year variability in the total 

mercury input to each process unit and 

variability of the sampling and analysis 

methods over the testing period, and it 

includes the variability resulting from 

site-to-site differences for the lowest 

emitters. We calculated the MACT floor 

based on the UPL (upper 99th percent) 

as described earlier from the average 

performance of the lowest emitting 

sources, Students t-factor, and the total 

variability, which was adjusted to 

account for the lower variability when 

using 3-run averages to determine 

compliance. Our calculations yield the 

following MACT floor limits for existing 

sources: 175 lbs/million tons of ore for 

ore pretreatment processes, 2.6 lb/ton of 

concentrate for carbon processes, and 

0.25 lbs/ton of concentrate for noncarbon concentrate processes. 

The technologies for achieving the 

MACT floor for existing ore 

pretreatment processes include mercury 

scrubbers on roasters and venturi 

scrubbers on autoclaves and ancillary 

roaster operations. The roasters and 

autoclaves at Facilities A, B, C, and E 

shown in Table 2 above are already 

equipped with these controls. Our 

MACT floor analysis indicates that these 

facilities are achieving the MACT floor 

average of 99 lb/million tons of ore. The 

analysis also indicates that an emission 

reduction will be needed for Facility D 

to achieve the MACT floor. Currently 

Facility D also has venturi scrubbers on 

its autoclaves; however, the emission 

control performance of these scrubbers 

will need to be improved to achieve the 

MACT floor. 

To achieve the MACT floor for 

existing carbon processes, we expect 

that facilities would need to install 

carbon adsorbers on all process units 

that do not already have them (i.e., 

carbon adsorbers for carbon kilns, 

electrowinning, preg tanks, retorts, and 

melt furnaces). Our MACT floor analysis 

indicates that only Facilities M and N in 

Table 3 are achieving the MACT floor 

level of control; consequently, the other 

nine facilities in Table 3 are expected to 

have to install carbon adsorbers on all 

process units that do not already have 

them. The two top performing facilities 

(M and N) are fully equipped with 

carbon adsorbers (i.e., all of their 

process units are controlled by carbon 

adsorbers). Facility M also processes ore 

which has significantly lower mercury 

concentrations compared to the ore 

processed at most other facilities. We 

believe the combination of processing 

ore with low mercury content and the 

use of state-of-the-art mercury emission 

controls result in emissions at Facility 

M that are considerably lower than the 

other facilities. 

For the non-carbon concentrate 

processes, the MACT floor technology is 

the use of carbon adsorbers on retorts 

and melt furnaces. We expect that 

Facility L would probably need to 

install a carbon adsorber on their melt 

furnace to achieve the MACT floor. 

2. Selection of New Source Floors for 

the Three Affected Sources 

CAA section 112(d)(3) requires that 

the MACT floor limit for new sources 

not be less stringent than the emission 

control that is achieved in practice by 

the best controlled similar source. Table 

2 above shows that Facility A has the 

lowest emission rate for ore 

pretreatment processes and is therefore 

considered the ‘‘best controlled similar 

source’’ for such processes. As 

previously mentioned, this facility is 

equipped with calomel scrubbers on 

roasters and venturi scrubbers on 

autoclaves. The emission rate for orepretreatment processes at Facility A is 

62 lbs/million tons ore, not accounting 

for variability. Applying the UPL 

formula discussed earlier to account for 

variability based on the emission test 

runs for all affected process units at the 

best performing ore pretreatment 

affected source (Facility A), we 

calculated the 99th percentile of 

performance, which results in a new 

source MACT level of 163 lb/million 

tons of ore for ore pre-treatment 

processes. 

Table 3 shows that Facility M has the 

lowest emission rate for carbon 

processes and is therefore considered 

the ‘‘best controlled similar source’’ for 

such processes. As previously 

mentioned, all carbon process units at 

Facility M are well controlled with 

carbon absorbers. The emission rate for 

carbon processes at Facility M is 0.06 

lb/ton of concentrate. After applying the 

UPL formula as described above to 

account for variability, the new source 

floor for carbon processes based on the 

99th percentile of performance is 0.14 

lb/ton of concentrate. 

For carbon processes at new sources, 

we are proposing a compliance 

alternative to provide flexibility in 

determining compliance because of the 

wide variety of process combinations 

and variations in input material that 


sroberts on DSKD5P82C1PROD with PROPOSALS
Federal Register / Vol. 75, No. 81 / Wednesday, April 28, 2010 / Proposed Rules 22483 

may be present at future new carbon 

process sources. A well-established and 

conventional metric for expressing the 

degree of emission control is the percent 

control of the target pollutant. As 

mentioned above, Facility M is 

considered the ‘‘best controlled similar 

source’’ for carbon processes. Test data 

were available for 2007 for Facility M 

when the processes were uncontrolled, 

for 2008 when the controls were newly 

installed, and from 2009 after over one 

year of operation. The test results 

showed a 99.6 percent mercury 

emission reduction in 2008 and 93.5 

percent reduction in 2009. Based on 

these results and considering variability 

over time, we are proposing a 

compliance alternative of 97 percent 

reduction in mercury emissions for new 

carbon processes. This compliance 

alternative was calculated based on the 

average reduction achieved by the best 

performing source in 2008 and 2009. 

Table 4 shows that Facility K has the 

lowest emission rate for non-carbon 

concentrate processes and is therefore 

considered the ‘‘best controlled similar 

source’’ for such processes. The 

emission rate for non-carbon 

concentrate processes at Facility K is 

0.07 lb/ton of concentrate (not 

accounting for variability). Again 

applying the UPL formula as described 

above to account for variability, the new 

source floor for non-carbon concentrate 

processes based on the 99th percentile 

of performance is 0.20 lb/ton of 

concentrate. 

3. Beyond the Floor Determination 

To evaluate opportunities for 

emission reductions beyond those 

provided by the MACT floor, we 

typically identify control techniques 

that have the ability to achieve an 

emissions limit more stringent than the 

MACT floor. As mentioned above, the 

facilities with ore pretreatment 

processes would have installed mercury 

scrubbers and venturi scrubbers on their 

roasters and autoclaves, respectively, to 

achieve the MACT floor for ore 

pretreatment processes. To achieve 

further reductions in mercury beyond 

what can be achieved using mercury 

scrubbers and venturi scrubbers, we 

identified as a beyond-the-floor option 

the installation of both a refrigeration 

unit (or condenser) and a carbon 

adsorber on autoclaves. This additional 

control system would follow the 

existing venturi scrubbers to further 

reduce mercury emission from 

autoclaves. Because the exhaust is 

saturated with water, a refrigeration unit 

or condenser would be needed to 

remove water that would otherwise 

adversely affect the adsorptive capacity 

of the carbon adsorber. With this 

additional control system, all facilities 

with ore pretreatment processes could 

achieve an average performance of 90 

lb/million tons of ore or less. This is 

lower than the average emission rate of 

99 lbs/million tons ore for ore 

pretreatment processes from the top five 

facilities performing these processes. 

In determining whether to control 

emissions ‘‘beyond-the-floor,’’ we must 

consider the costs, non-air quality 

health and environmental impacts, and 

energy requirements of such more 

stringent control. See CAA Section 

112(d)(2). We estimate that the capital 

cost for the additional controls on the 

autoclaves would be $890,000 with a 

total annualized cost of $720,000/yr. 

Mercury emissions would be reduced by 

543 lbs, resulting in an estimated cost 

effectiveness of $1,300/lb. Energy 

consumption would increase by about 

730 megawatt-hours per year, primarily 

due to the refrigeration unit. Solid waste 

generation and disposal (spent carbon 

loaded with mercury) would increase by 

about 3 tons per year. (See Section VI.A 

for additional discussion of our 

consideration of emissions, cost, and 

non-air impacts in developing MACT 

standards for this source category.) After 

considering the costs and the abovementioned impacts associated with the 

use of a refrigeration unit (or condenser) 

and a carbon adsorber on autoclaves, we 

believe that the emission reduction that 

can be achieved with this additional 

control system is justified under section 

112(d) of the CAA. Applying the UPL 

formula discussed earlier to account for 

variability, the 99th percent UPL would 

be 149 lb/million tons of ore. We 

therefore propose that the beyond-thefloor performance level of 149 lb/ 

million tons of ore is MACT for new and 

existing ore pretreatment processes. 

For the carbon processes, we estimate 

that 9 of the 11 facilities for which we 

have data will need to improve control 

to meet the floor limits because these 9 

plants have an average emission control 

performance that is above the MACT 

floor average performance. There are a 

few facilities in the middle of the 

rankings that will probably only need 

marginal improvements, but several 

facilities (especially those at the bottom 

of the ranking that average several times 

the floor average) will need significant 

improvements in mercury emission 

control. We estimate that the MACT 

floor limit for the carbon processes will 

reduce emissions by about 1,100 lbs per 

year, a reduction of 89 percent from 

current levels. Our estimates of impacts 

for the MACT floor indicate that most of 

the carbon processes currently have or 

will have carbon adsorbers installed to 

effectively control mercury emissions at 

the MACT floor level. Considering the 

very low mercury concentrations when 

the carbon processes are performing at 

the MACT level of control, it is difficult 

to identify a technology that can obtain 

efficient additional percent reductions 

from low concentration streams. For a 

beyond-the-floor analysis, we assumed 

that theoretically a second carbon 

adsorption system could be installed in 

series with the first one and would get 

an additional 90 percent reduction from 

the very low mercury concentrations 

that result from the MACT floor level of 

control. We acknowledge that there is 

uncertainty as to the additional percent 

reduction the second control system 

might achieve. Nevertheless, we 

estimate that the emission reduction 

would only be 12 lbs per year. The 

capital cost was estimated as $3.2 

million with a total annualized cost of 

about $1.2 million/yr and a cost 

effectiveness of $100,000/lb. 

Considering the significant cost and the 

small additional reduction in emissions 

associated with a second carbon 

adsorption system and the uncertainty 

that even that small reduction might be 

achieved, we believe that the additional 

emission reduction from this beyondthe-floor control option is not warranted 

under section 112(d). 

For the non-carbon concentrate 

processes, we expect that Facility L 

would probably need to add a carbon 

adsorber to its melt furnace to achieve 

the MACT floor level of control. For 

beyond the floor, we again assumed that 

the existing carbon adsorbers would be 

supplemented by adding a second 

control system of carbon adsorbers in 

series for all of the melt furnaces. We 

estimated the capital cost for the second 

set of control systems as $0.7 million 

and a total annualized cost of $306,000/ 

year. Emissions would be reduced by 7 

lb/year, which results in a cost 

effectiveness of $44,000/lb. Considering 

the very small emission reduction from 

a second carbon adsorber system, and 

its high capital and operating costs, we 

believe that the emission reduction 

associated with this additional control 

system is not warranted under section 

112(d) of the CAA. 

C. How did we select the testing, 

monitoring and electronic reporting 

requirements? 

We are proposing testing and 

monitoring requirements to assure 

compliance with the emission standards 

set forth in this proposed rule. These 

compliance assurance provisions are 

based, in part, on requirements that 

have been applied to this source 

category in State operating permits, EPA 


sroberts on DSKD5P82C1PROD with PROPOSALS
22484 Federal Register / Vol. 75, No. 81 / Wednesday, April 28, 2010 / Proposed Rules 

requirements applied to other industries 

that emit mercury, and an 

understanding of how control devices 

and processes perform and can be 

effectively monitored. 

We are proposing initial compliance 

stack tests for mercury (using Method 

29) within the first 180 days of the 

compliance date and annual compliance 

tests thereafter for all thermal process 

units to determine compliance with the 

proposed emission limits. The testing 

frequency and procedures would be 

essentially the same as the NDEP 

requirements for the facilities that are 

located in Nevada partly because the 

stack test data that we used to develop 

the proposed emission limits were 

based on the test methods applied in 

Nevada. To provide additional 

flexibility, we propose to allow the use 

of the Ontario Hydro Method, Method 

30A, or Method 30B as alternatives to 

EPA Method 29. 

We also propose the following 

monitoring requirements to assure 

compliance with the proposed MACT 

standards. 

Roasters. In addition to the annual 

stack test, we are proposing two options 

for monitoring roaster emissions: (1) 

Integrated sorbent trap mercury 

monitoring coupled with parametric 

monitoring of scrubbers and (2) 

monitoring using a continuous emission 

monitoring system (CEMS) for mercury. 

Both proposed monitoring options 

would require establishment of 

operating limits to detect and correct 

problems as soon as possible. An 

exceedance of an operating limit for the 

sorbent trap or CEMS monitoring would 

trigger immediate corrective action and 

would require that the problem be 

corrected within 48 hours or that the 

feed of ore to the roaster be stopped. 

As part of this first monitoring option 

(i.e., sorbent trap monitoring), we are 

also proposing that facilities with 

roasters and mercury scrubbers establish 

operating limits for various parameters 

during their compliance test (i.e., the 

annual stack test for mercury 

emissions). The proposed parametric 

monitoring provides additional 

compliance assurance by ensuring that 

the process and control devices are 

operating properly. The proposed 

parameters for monitoring mercury 

scrubbers are similar to those currently 

required to be monitored in the title V 

operating permits issued by NDEP for 

roasters. We are proposing that each 

mercury scrubber be equipped with 

devices to monitor the scrubber liquor 

flow rate, scrubber pressure drop, and 

inlet gas temperature. Minimum 

operating limits for the scrubber liquor 

flow rate and pressure drop would be 

established based on the lowest average 

value measured during any of the three 

runs of a compliant performance test. A 

maximum inlet temperature would be 

established based on the highest 

temperature measured during any of the 

three runs of the compliance test. In 

addition to the parameters described 

above, we are proposing that the facility 

would also monitor the mercuric ion 

concentration and the chloride ion 

concentration four times per day or 

continuously monitor the oxidation 

reduction potential and pH. These 

monitored parameters would be 

maintained within the range specified 

by the scrubber’s manufacturer or 

within an alternative range approved by 

the permitting authority. If any of the 

parameters are outside the specified 

range or limit, corrective action would 

be taken to bring the parameters back 

within the operating range or the facility 

would commence shutdown of the 

roaster. 

As mentioned above, we are including 

a mercury CEMS as an alternative for 

monitoring of mercury emissions from 

roasters. This monitoring option would 

not require parametric monitoring of the 

mercury scrubbers. Mercury CEMS have 

been applied at other industrial sources 

that emit mercury, such as coal-fired 

power plants and cement production 

plants, and these devices yield valuable 

information regarding continuous 

emissions performance. We realize that 

mercury CEMs have not yet been 

demonstrated on roasters at gold 

production facilities and that there are 

currently no calibration standards 

traceable to NIST within the range of 

mercury concentrations from roasters. 

However, calibration standards are 

available from the manufacturers of 

mercury CEMS. Based on the Agency’s 

understanding and experience relative 

to continuous mercury monitoring at 

other industrial facilities, such as coalfired power plants and cement plants, as 

well as research experience, EPA 

believes that the CEMS can be 

adequately calibrated with 

manufacturers’ standards and be used as 

a valuable tool to monitor roasting 

operations to detect deviations in 

performance. We therefore believe that 

it is appropriate to propose the use of 

mercury CEMS as a monitoring option 

for roasters. However, we believe that it 

is appropriate to also propose an 

alternative monitoring approach based 

on frequent (weekly) monitoring using a 

sorbent trap method. 

We request comments on the viability 

of using mercury CEMs, specifically for 

monitoring mercury emissions from 

roasters at gold ore processing and 

production facilities. We request 

comments on calibration methods, 

costs, reliability and other aspects of the 

CEMs. We also request similar 

comments on the sorbent trap method. 

For facilities that control roaster 

mercury emissions with mercury 

scrubbers, we are proposing that if a 

facility demonstrates, in accordance 

with the demonstration requirements in 

the proposed rule, that mercury 

emissions from the roaster are less than 

10 pounds of mercury per million tons 

of input ore, they can cease monitoring 

via either the sorbent trap or the 

mercury CEMS. Such a facility would be 

required to conduct the parametric 

monitoring for mercury scrubbers as 

described above (under option one) and 

maintain parameters within the 

operating ranges established in 

accordance with the proposed rule. 

Also, the facility would continue to 

perform annual compliance tests of the 

roaster stack to demonstrate emissions 

continue to be less than 10 pounds of 

mercury per million tons of input ore. 

We believe that for roasters that are 

effectively controlled with mercury 

scrubbers (i.e., emitting less than 10 

pounds per million tons of ore during 

normal operations), parametric 

monitoring of the scrubbers would be 

sufficient. This monitoring option 

provides additional incentive for 

facilities to reduce emissions from 

roasters. However, if any subsequent 

compliance tests indicate that the 

roaster is emitting more than 10 pounds 

of mercury per million tons of ore input, 

then the facility would be required to 

monitor the roaster emissions using a 

sorbent trap method or CEMS. 

We are specifically requesting 

comments on the advantages and 

disadvantages of the two options for 

monitoring emissions from roasters 

along with any supporting data and 

documentation to support one or both of 

the options. We are also requesting 

comment on the proposed daily 

averaging time when using the mercury 

CEMS option and the frequency of 

sampling when using the sorbent trap 

option. In addition, we are requesting 

comments on the proposed monitoring 

approach for low-emitting roasters with 

mercury scrubbers, as described in the 

paragraph above, and possible 

alternatives to this approach. Moreover, 

we are requesting comments on the 

parametric monitoring methods. 

Carbon Adsorbers. For process units 

(such as furnaces, kilns, retorts, 

electrowinning, and autoclaves) that 

control mercury emissions with a 

carbon adsorber, we are proposing three 

options. One option involves 

monitoring the mercury concentration at 

the exit of the carbon bed. A second 


sroberts on DSKD5P82C1PROD with PROPOSALS
Federal Register / Vol. 75, No. 81 / Wednesday, April 28, 2010 / Proposed Rules 22485 

option, adopted from requirements in 

some NDEP permits, is based on 

sampling the carbon bed for mercury. 

The third option is based on changing 

out the carbon bed after a fixed period 

of time determined based on historical 

operating experience. 

We believe that all three options 

could provide reasonable assurance that 

the carbon adsorber is operating 

properly on a continuing basis and that 

the carbon is replaced before 

breakthrough occurs. Our current 

preference among the three proposed 

monitoring options for carbon beds 

described above is the option of 

sampling the exit gas from the carbon 

bed using EPA Method 30B along with 

continuous temperature monitoring 

because this option provides a direct 

measurement of the amount of mercury 

exiting the control device. We are 

specifically requesting comments on the 

advantages and disadvantages of the 

three options along with any supporting 

data and documentation. Based on 

public comments, we intend to 

promulgate one or more of these options 

or a modified version as necessary. 

We are also proposing that the inlet 

stream to carbon adsorbers applied to 

autoclaves, carbon kilns, melt furnaces, 

and retorts be monitored for 

temperature and that the inlet 

temperature be maintained below the 

maximum temperature established 

during the compliance tests. We believe 

the temperature monitoring is needed to 

detect any excursions in mercury 

emissions caused by excessively high 

temperatures. We are also considering a 

reduction in frequency of the sampling 

and analysis based on historical data on 

the life of a new carbon bed (e.g., 

quarterly sampling when the carbon bed 

is fresh and monthly sampling after a 

specified period of time) and for 

processes that are very small sources of 

mercury emissions. We are requesting 

comments and supporting data on these 

options and others that may be 

appropriate for monitoring carbon beds. 

Wet scrubbers. For each wet scrubber, 

we are proposing that pressure drop and 

water flow rate be maintained at a 

minimum level based on measurements 

during the initial or subsequent 

compliance test(s). These parameters are 

the typical monitoring parameters 

required by other MACT standards and 

by State operating permits for wet 

scrubbers at gold mine ore processing 

and production facilities. Monitoring 

these parameters ensures that wet 

scrubbers are operating properly. 

Electronic reporting. The EPA must 

have performance test data to conduct 

effective reviews of CAA Section 112 

and 129 standards, as well as for many 

other purposes including compliance 

determinations, emissions factor 

development, and annual emissions rate 

determinations. In conducting these 

required reviews, we have found it 

ineffective and time consuming not only 

for us but also for other regulatory 

agencies and source owners and 

operators to locate, collect, and submit 

emissions test data because of varied 

locations for data storage and varied 

data storage methods. One improvement 

that has occurred in recent years is the 

availability of stack test reports in 

electronic format as a replacement for 

cumbersome paper copies. 

In this action, we are taking a step to 

improve data accessibility. Owners and 

operators of affected facilities would be 

required to submit to an EPA electronic 

database an electronic copy of reports of 

certain performance tests required 

under this rule. Data entry would be 

through an electronic emissions test 

report structure called the Electronic 

Reporting Tool (ERT) that will be used 

by the staff as part of the emissions 

testing project. The ERT was developed 

with input from stack testing companies 

who generally collect and compile 

performance test data electronically and 

offices within State and local agencies 

which perform field test assessments. 

The ERT is currently available, and 

access to direct data submittal to EPA’s 

electronic emissions database 

(WebFIRE) will become available by 

December 31, 2011. 

The requirement to submit source test 

data electronically to EPA would not 

require any additional performance 

testing and would apply to those 

performance tests conducted using test 

methods that are supported by ERT. The 

ERT contains a specific electronic data 

entry form for most of the commonly 

used EPA reference methods. The Web 

site listed below contains a listing of the 

pollutants and test methods supported 

by ERT. In addition, when a facility 

submits performance test data to 

WebFIRE, there would be no additional 

requirements for emissions test data 

compilation. Moreover, we believe 

industry would benefit from 

development of improved emissions 

factors, fewer follow-up information 

requests, and better regulation 

development as discussed below. The 

information to be reported is already 

required for the existing test methods 

and is necessary to evaluate the 

conformance to the test method. 

One major advantage of submitting 

source test data through the ERT is that 

it provides a standardized method to 

compile and store much of the 

documentation required to be reported 

by this rule while clearly stating what 

testing information we require. Another 

important benefit of submitting these 

data to EPA at the time the source test 

is conducted is that it will substantially 

reduce the effort involved in data 

collection activities in the future. 

Specifically, because EPA would 

already have adequate source category 

data to conduct residual risk 

assessments or technology reviews, 

there would likely be fewer or less 

substantial data collection requests (e.g., 

CAA Section 114 letters). This results in 

a reduced burden on both affected 

facilities (in terms of reduced manpower 

to respond to data collection requests) 

and EPA (in terms of preparing and 

distributing data collection requests). 

State/local/Tribal agencies may also 

benefit in that their review may be more 

streamlined and accurate as the States 

will not have to re-enter the data to 

assess the calculations and verify the 

data entry. Finally, another benefit of 

submitting these data to WebFIRE 

electronically is that these data will 

improve greatly the overall quality of 

the existing and new emissions factors 

by supplementing the pool of emissions 

test data upon which the emissions 

factor is based and by ensuring that data 

are more representative of current 

industry operational procedures. A 

common complaint we hear from 

industry and regulators is that emissions 

factors are outdated or not 

representative of a particular source 

category. Receiving and incorporating 

data for most performance tests will 

ensure that emissions factors, when 

updated, represent accurately the most 

current operational practices. In 

summary, receiving test data already 

collected for other purposes and using 

them in the emissions factors 

development program will save 

industry, State/local/Tribal agencies, 

and EPA time and money and work to 

improve the quality of emissions 

inventories and related regulatory 

decisions. 

As mentioned earlier, the electronic 

data base that will be used is EPA’s 

WebFIRE, which is a Web site accessible 

through EPA’s Technology Transfer 

Network (TTN). The WebFIRE Web site 

was constructed to store emissions test 

data for use in developing emissions 

factors. A description of the WebFIRE 

data base can be found at http:// 

cfpub.epa.gov/oarweb/ 

index.cfm?action=fire.main. 

The ERT will be able to transmit the 

electronic report through EPA’s Central 

Data Exchange (CDX) network for 

storage in the WebFIRE data base. 

Although ERT is not the only electronic 

interface that can be used to submit 

source test data to the CDX for entry 


sroberts on DSKD5P82C1PROD with PROPOSALS
22486 Federal Register / Vol. 75, No. 81 / Wednesday, April 28, 2010 / Proposed Rules 

3United Nations Environment Programme/Arctic 

Monitoring and Assessment Program (UNEP/ 

AMAP). Study on mercury-emitting sources, 

including emissions trends and cost and 

effectiveness of alternative control measures: 

‘‘UNEP Paragraph 29 study.’’ 2008. Available at: 

http://www.chem.unep.ch/mercury/Paragraph29/ 

Zero%20Draft%20Report%20March%208.doc. 

4The National Study of Chemical Residues in 

Lake Fish Tissue. U.S. Environmental Protection 

Agency Office of Water Office of Science and 

Technology September 2009. Available at: http:// 

www.epa.gov/waterscience/fish/study/index.htm. 

5Scudder, B., L. Chasar, D. Wentz, N. Bauch, M. 

Brigham, P. Moran, and D. Krabbenhoft. (United 

States Geological Survey). Mercury in Fish, Bed 

Sediment, and Water from Streams Across the 

United States, 1998–2005. 2009. Available at: 

http://pubs.usgs.gov/sir/2009/5109/. 

6For more information see http://www.epa.gov/ 

mercury/about.htm. 

into WebFIRE, it makes submittal of 

data very straightforward and easy. A 

description of the ERT can be found at 

http://www.epa.gov/ttn/chief/ert/ 

ert_tool.html. 

VI. Impacts of the Proposed Standards 

A. What are the emissions, cost, 

economic, and non-air environmental 

impacts? 

We estimate the proposed MACT 

standard will reduce mercury emissions 

from gold mine ore processing and 

production by 1,650 lb/year from 

current emissions levels down to a level 

of 1,390 lb/year post-MACT. The annual 

emissions expected after MACT (of 

1,390 lbs) represent a 73 percent 

reduction from 2007 emissions (5,000 

pounds), more than 90 percent 

reduction from the emissions level in 

2001 (about 23,000 pounds), and more 

than 96 percent reduction from 

uncontrolled emissions levels (more 

than 37,000 pounds). The capital cost of 

emission controls is estimated as $5 

million with a total annualized cost of 

$2.3 million per year. The capital costs 

for 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 cost of compliance 

is estimated to be less than 0.3 percent 

of sales. We therefore believe that the 

economic impact on an affected 

company would be insignificant. 

Electricity consumption is expected to 

increase by about 2,100 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 be regenerated or disposed of) 

would increase by about 7 tons per year. 

B. What are the health benefits of 

reducing mercury emissions? 

Mercury is emitted to the air from 

various man-made and natural sources. 

These emissions transport through the 

atmosphere and eventually deposit to 

land or water bodies. This deposition 

can occur locally, regionally, or 

globally, depending on the form of 

mercury emitted and other factors such 

as the weather. The form of mercury 

emitted varies depending on source type 

and other factors. Available data 

indicate that the majority of air 

emissions from gold mine ore 

processing and production facilities are 

in the form of gaseous elemental 

mercury. This form of mercury can be 

transported very long distances, even 

globally, to regions far from the 

emissions source (becoming part of the 

global ‘‘pool’’) before deposition occurs. 

However, this source category also emits 

some gaseous inorganic ionic mercury 

forms (such as mercuric chloride), and 

smaller amounts of particulate bound 

mercury. These forms have a shorter 

atmospheric lifetime and can deposit to 

land or water bodies closer to the 

emissions source. Furthermore, 

elemental mercury in the atmosphere 

can undergo transformation into ionic 

mercury, providing a significant 

pathway for deposition of emitted 

elemental mercury. 

As mentioned previously, the gold 

mine ore processing and production 

source category emitted about 2.5 tons 

of mercury to the air in 2007 in the U.S. 

Based on the EPA’s National Emission 

Inventory, about 103 tons of mercury 

were emitted from all anthropogenic 

sources in the U.S. in 2005. Moreover, 

the United Nations has estimated that 

about 2100 tons were emitted 

worldwide by anthropogenic sources in 

2005.3 We believe that total mercury 

emissions in the U.S. and globally in 

2007 were about the same magnitude as 

in 2005. Therefore, we estimate that in 

2007 the gold mine ore processing and 

production source category emitted 

about 2.5 percent of the total 

anthropogenic mercury emissions in the 

U.S. and about 0.12 percent of the global 

emissions. 

Potential exposure routes to mercury 

emissions include both direct 

inhalation, and consumption of fish 

containing methylmercury. The primary 

route of human exposure to mercury 

emissions from industrial sources is 

generally indirectly through the 

consumption of fish containing 

methylmercury. As described above, 

mercury that has been emitted to the air 

eventually settles into water bodies or 

onto land where it can either move 

directly or be leached into water bodies. 

Once deposited, certain microorganisms 

can change it into methylmercury, a 

highly toxic form that builds up in fish, 

shellfish and animals that eat fish. 

Consumption of fish and shellfish are 

the main sources of methylmercury 

exposure to humans. Methylmercury 

builds up more in some types of fish 

and shellfish than others. The levels of 

methylmercury in fish and shellfish 

vary widely depending on what they 

eat, how long they live and how high 

they are in the food chain. Most fish, 

including ocean species and local 

freshwater fish, contain some 

methylmercury. For example, in recent 

studies by EPA and the United States 

Geological Survey (USGS) of fish 

tissues, every fish sampled contained 

some methylmercury.4, 5

Research shows that most people’s 

fish consumption does not cause a 

mercury-related health concern. 

However, certain sub-populations may 

be at higher risk because of their 

routinely high consumption of fish (e.g., 

Tribal and other subsistence fishers and 

their families who rely heavily on fish 

for a substantial part of their diet). It has 

been demonstrated that high levels of 

methylmercury in the bloodstreams of 

unborn babies and young children may 

harm the developing nervous system, 

making the child less able to think and 

learn. Moreover, mercury exposure at 

high levels can harm the brain, heart, 

kidneys, lungs, and immune system of 

people of all ages.6

The majority of the fish consumed in 

the U.S. are ocean species. The 

methylmercury concentrations in ocean 

fish species are primarily influenced by 

the global mercury pool. However, the 

methylmercury found in local fish can 

be due, at least partly, to mercury 

emissions from local sources. 

Overall, this regulation will reduce 

mercury emissions from the gold ore 

processing and production source 

category by about 1,650 pounds per year 

from current levels and, therefore, 

contribute to reductions in mercury 

exposures and health effects. 

VII. Statutory and Executive Order 

Reviews 

A. Executive Order 12866: Regulatory 

Planning and Review 

This action is a ‘‘significant regulatory 

action’’ under the terms of Executive 

Order 12866 (58 FR 51735, October 4, 

1993) because it may raise novel legal or 

policy issues. Accordingly, EPA 

submitted this action to the Office of 

Management and Budget (OMB) for 

review under Executive Order 12866, 

and any changes made in response to 

OMB recommendations have been 


sroberts on DSKD5P82C1PROD with PROPOSALS
Federal Register / Vol. 75, No. 81 / Wednesday, April 28, 2010 / Proposed Rules 22487 

documented in the docket for this 

action. 

B. Paperwork Reduction Act 

The information collection 

requirements in this proposed rule have 

been submitted for approval to OMB 

under the Paperwork Reduction Act, 44 

U.S.C. 3501 et seq. The Information 

Collection Request (ICR) document 

prepared by EPA has been assigned EPA 

ICR No. 2383.01. 

The recordkeeping and reporting 

requirements in this proposed rule are 

based, in large part, on the information 

collection requirements in EPA’s 

NESHAP General Provisions (40 CFR 

part 63, subpart A). The recordkeeping 

and reporting requirements in the 

General Provisions are specifically 

authorized by section 114 of the CAA 

(42 U.S.C. 7414). All information other 

than emissions data submitted to EPA 

pursuant to the information collection 

requirements for which a claim of 

confidentiality is made is safeguarded 

according to CAA section 114(c) and 

EPA’s implementing regulations at 40 

CFR part 2, subpart B. 

This proposed NESHAP would 

require applicable one-time 

notifications according to the NESHAP 

General Provisions. In addition, owners 

or operators must submit annual 

notifications of compliance status and 

report any deviations in each 

semiannual reporting period. Records of 

all performance tests, measurements of 

feed input rates, monitoring data, and 

corrective actions would be required. 

The average annual burden for this 

information collection averaged over the 

first 3 years of this ICR is estimated to 

total 4,225 labor hours per year at a cost 

of approximately $213,726 per year for 

the 21 facilities that would be subject to 

this proposed rule, or approximately 

201 hours per year per facility. Capital 

costs are estimated as $1.3 million, 

operation and maintenance costs are 

estimated as $65,000 per year, and total 

annualized cost (including capital 

recovery) is estimated as $256,000 per 

year for this proposed rule’s information 

collection requirements. No costs or 

burden hours are estimated for new 

sources because none is projected for 

the next 3 years. Burden is defined at 5 

CFR 1320.3(b). 

An agency may not conduct or 

sponsor, and a person is not required to 

respond to, a collection of information 

unless the collection displays a 

currently valid OMB control number. 

The OMB control numbers for EPA’s 

regulations in 40 CFR part 63 are listed 

in 40 CFR part 9. 

To comment on the Agency’s need for 

this information, the accuracy of the 

provided burden estimates, and any 

suggested methods for minimizing 

respondent burden, EPA has established 

a public docket for this rule, which 

includes this ICR, under Docket ID 

number EPA–HQ–OAR–2010–0239. 

Submit any comments related to the 

ICR to EPA and OMB. See ADDRESSES

section at the beginning of this notice 

for where to submit comments to EPA. 

Send comments to OMB at the Office of 

Information and Regulatory Affairs, 

Office of Management and Budget, 725 

17th Street, NW., Washington, DC 

20503, Attention: Desk Office for EPA. 

Since OMB is required to make a 

decision concerning the ICR between 30 

and 60 days after April 28, 2010, a 

comment to OMB is best assured of 

having its full effect if OMB receives it 

by May 28, 2010. The final rule will 

respond to any OMB or public 

comments on the information collection 

requirements contained in this proposal. 

C. Regulatory Flexibility Act 

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 any 

other statute unless the agency certifies 

that this 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 jurisdictions. 

For the purposes of assessing the 

impacts of this proposed NESHAP on 

small entities, a small entity is defined 

as: (1) A small business whose parent 

company meets the Small Business 

Administration size standards for small 

businesses found at 13 CFR 121.201 

(less than 500 employees for gold mine 

ore processing and production 

facilities—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-forprofit enterprise that is independently 

owned and operated and is not 

dominant in its field. 

After considering the economic 

impacts of this proposed rule on small 

entities, I certify that this action will not 

have a significant economic impact on 

a substantial number of small entities. 

This proposed rule is estimated to 

impact about 21 gold mine ore 

processing and production facilities, 

none of which are owned by small 

entities. Thus, there are no impacts to 

small entities from this proposed rule. 

Although this proposed rule will 

contain requirements for new sources, 

EPA expects few, if any, new sources to 

be constructed in the next several years. 

Therefore, EPA did not estimate the 

impacts for new affected sources for this 

proposed rule. 

Although this proposed 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 proposed rule on small 

and large entities. These standards 

establish emission limits that reflect 

practices and controls that are used 

throughout the industry and in many 

cases are already required by State 

operating permits. These standards also 

require only the essential monitoring, 

recordkeeping, and reporting needed to 

verify compliance. These proposed 

standards were developed based on 

information obtained from industry 

representatives in our surveys, 

consultation with business 

representatives and their trade 

association and other stakeholders. We 

continue to be interested in the 

potential impacts of this proposed rule 

on small entities and welcome 

comments on issues related to such 

impacts. 

D. Unfunded Mandates Reform Act 

This proposed 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 proposed rule is 

not expected to impact State, local, or 

Tribal governments. The nationwide 

annualized cost of this proposed rule for 

affected industrial sources is $3.8 

million/yr. Thus, this proposed rule is 

not subject to the requirements of 

sections 202 and 205 of the Unfunded 

Mandates Reform Act (UMRA). 

This proposed 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 governments. This 

proposed rule will not apply to such 

governments and will not impose any 

obligations upon them. 

E. Executive Order 13132: Federalism 

This action does not have federalism 

implications. It will not have substantial 

direct effects on the States, on the 

relationship between the national 

government and the States, or on the 

distribution of power and 

responsibilities among the various 

levels of government, as specified in 

Executive Order 13132. This proposed 

rule does not impose any requirements 

on State and local governments. Thus, 


sroberts on DSKD5P82C1PROD with PROPOSALS
22488 Federal Register / Vol. 75, No. 81 / Wednesday, April 28, 2010 / Proposed Rules 

Executive Order 13132 does not apply 

to this action. 

In the spirit of Executive Order 13132, 

and consistent with EPA policy to 

promote communications between EPA 

and State and local governments, EPA 

specifically solicits comment on this 

proposed action from State and local 

officials. 

F. Executive Order 13175: Consultation 

and Coordination With Indian Tribal 

Governments 

This action does not have Tribal 

implications, as specified in Executive 

Order 13175 (65 FR 67249, November 9, 

2000). This proposed rule imposes no 

requirements on Tribal governments; 

thus, Executive Order 13175 does not 

apply to this action. EPA specifically 

solicits additional comment on this 

proposed action from Tribal officials. 

G. Executive Order 13045: Protection of 

Children From Environmental Health 

and Safety Risks 

EPA interprets Executive Order 13045 

(62 FR 19885, April 22, 1997) as 

applying only to those regulatory 

actions that are based on health or safety 

risks, such that the analysis required 

under section 5–501 of the Executive 

Order has the potential to influence the 

regulation. This action is not subject to 

Executive Order 13045 because it is 

based solely on technology 

performance. 

H. Executive Order 13211: Actions 

Concerning Regulations That 

Significantly Affect Energy Supply, 

Distribution, or Use 

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 proposed rule will 

not likely have any significant adverse 

energy effects because energy 

consumption would increase by only 

2,100 megawatt-hours per year. 

I. National Technology Transfer and 

Advancement Act 

Section 12(d) of the National 

Technology Transfer and Advancement 

Act of 1995 (‘‘NTTAA’’), Public Law 

104–113 (15 U.S.C. 272 note), directs 

EPA to use voluntary consensus 

standards (VCS) in its regulatory 

activities unless to do so would be 

inconsistent with applicable law or 

otherwise impractical. VCS are 

technical standards (e.g., materials 

specifications, test methods, sampling 

procedures, business practices) that are 

developed or adopted by voluntary 

consensus standards bodies. NTTAA 

directs EPA to provide Congress, 

through OMB, explanations when the 

Agency decides not to use available and 

applicable VCS. 

This proposed rulemaking involves 

technical standards. EPA proposes to 

use ASME PTC 19.10–1981, ‘‘Flue and 

Exhaust Gas Analyses,’’ for its manual 

methods of measuring the oxygen or 

carbon dioxide content of the exhaust 

gas. These parts of ASME PTC 19.10– 

1981 are acceptable alternatives to EPA 

Method 3B. This standard is available 

from the American Society of 

Mechanical Engineers (ASME), Three 

Park Avenue, New York, NY 10016– 

5990. 

Another VCS, ASTM D6784–02, 

‘‘Standard Test Method for Elemental, 

Oxidized, Particle-Bound and Total 

Mercury in Flue Gas Generated From 

Coal-Fired Stationary Sources (Ontario 

Hydro Method)’’ is an acceptable 

alternative to EPA Method 29. This 

performance test method is available 

from ASTM International. See http:// 

www.astm.org/. 

EPA has also decided to use EPA 

Methods 1, 1A, 2, 2A, 2C, 2D, 2F, 2G, 

3, 3A, 3B, 4, 29, 30A, 30B, Method 

7471A, ‘‘Mercury in Solid or Semisolid 

Waste (Manual Cold-Vapor Technique),’’ 

and ASTM D6784–02, ‘‘Standard Test 

Method for Elemental, Oxidized, 

Particle-Bound and Total Mercury in 

Flue Gas Generated From Coal-Fired 

Stationary Sources,’’ (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 proposed 

rulemaking. The use of these VCS 

would have been impractical because 

they do not meet the objectives of the 

standards cited in this rule. The search 

and review results are in the docket for 

this proposed rule. 

EPA welcomes comments on this 

aspect of this proposed rulemaking and, 

specifically, invites the public to 

identify potentially applicable voluntary 

consensus standards and to explain why 

such standards should be used in this 

regulation. 

Under section 63.7(f) and section 

63.8(f) of Subpart A of the General 

Provisions, a source may apply to EPA 

for permission to use alternative test 

methods or alternative monitoring 

requirements in place of any required 

testing methods, performance 

specifications, or procedures in the 

proposed rule. 

J. Executive Order 12898: Federal 

Actions To Address 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 agencies, to the greatest extent 

practicable and permitted by law, to 

make environmental justice part of their 

mission by identifying and addressing, 

as appropriate, disproportionately high 

and adverse human health or 

environmental effects of their programs, 

policies, and activities on minority 

populations and low-income 

populations in the United States. 

EPA has determined that this 

proposed rule will not have 

disproportionately high and adverse 

human health or environmental effects 

on minority or low-income populations 

because it will increase the level of 

environmental protection for all affected 

populations without having any 

disproportionately high and adverse 

human health or environmental effects 

on any population, including any 

minority or low-income population. 

This proposed 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. 

List of Subjects in 40 CFR Parts 9 and 

63 

Environmental protection, Air 

pollution control, Hazardous 

substances, Incorporations by reference, 

Reporting and recordkeeping 

requirements. 

Dated: April 15, 2010. 

Lisa P. Jackson, 

Administrator. 

For the reasons stated in the 

preamble, title 40, chapter I, of the Code 

of Federal Regulations is proposed to be 

amended as follows: 

PART 9—[AMENDED] 

1. The authority citation for part 9 

continues to read as follows: 

Authority: 7 U.S.C. 135, et seq., 136–136y; 

15 U.S.C. 2001, 2003, 2005, 2006, 2601–2671; 

21 U.S.C. 331j, 346a, 348; 31 U.S.C. 9701; 33 

U.S.C. 1251, et seq., 1311, 1313d, 1314, 1318, 

1321, 1326, 1330, 1342, 1344, 1345(d) and 

(e), 1361; E.O. 11735, 38 FR 21243, 3 CFR, 

1971–1975 Comp. p. 973; 42 U.S.C. 241, 

242b, 243, 246, 300f, 300g, 300g–1, 300g–2, 

300g–3, 300g–4, 300g–5, 300g–6, 300j–1, 

300j–2, 300j–3, 300j–4, 300j–9, 1857, et seq., 

6901–6992k, 7401–7671q, 7542, 9601–9657, 

11023, 11048. 


sroberts on DSKD5P82C1PROD with PROPOSALS
Federal Register / Vol. 75, No. 81 / Wednesday, April 28, 2010 / Proposed Rules 22489 

Subpart A—[Amended] 

* * * * * 

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 for Source Categories 3

* * * * * * * 

63.11647–63.11648 .......................................................................................................................................................................... 2060–NEW 

* * * * * * * 

* * * * * * * 

3The 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 authority citation for part 63 

continues to read as follows: 

Authority: 42 U.S.C. 7401 et seq. 

Subpart A—[Amended] 

4. Section 63.14 is amended by 

revising paragraphs (b)(35) and (i)(1) 

and by adding paragraph (k)(1)(v) to 

read as follows: 

§ 63.14 Incorporations by reference. 

* * * * * 

(b) * * * 

(35) ASTM D6784–02, Standard Test 

Method for Elemental, Oxidized, 

Particle-Bound and Total Mercury in 

Flue Gas Generated from Coal-Fired 

Stationary Sources (Ontario Hydro 

Method), IBR approved for 

§ 63.11646(a)(1)(v) and table 5 to 

subpart DDDDD of this part. 

* * * * * 

(i) * * * 

(1) ANSI/ASME PTC 19.10–1981, 

‘‘Flue and Exhaust Gas Analyses [Part 

10, Instruments and Apparatus],’’ IBR 

approved for §§ 63.309(k)(1)(iii), 

63.865(b), 63.3166(a)(3), 

63.3360(e)(1)(iii), 63.3545(a)(3), 

63.3555(a)(3), 63.4166(a)(3), 

63.4362(a)(3), 63.4766(a)(3), 

63.4965(a)(3), 63.5160(d)(1)(iii), 

63.9307(c)(2), 63.9323(a)(3), 

63.11148(e)(3)(iii), 63.11155(e)(3), 

63.11162(f)(3)(iii) and (f)(4), 

63.11163(g)(1)(iii) and (g)(2), 

63.11410(j)(1)(iii), 63.11551(a)(2)(i)(C), 

63.11646(a)(1)(iii), table 5 to subpart 

DDDDD of this part, and table 1 to 

subpart ZZZZZ of this part. 

* * * * * 

(k) * * * 

(1) * * * 

(v) Method 7471A, ‘‘Mercury in Solid 

or Semisolid Waste (Manual Cold-Vapor 

Technique),’’ IBR approved for 

§ 63.11647(f)(2). 

* * * * * 

5. Part 63 is amended by adding 

subpart EEEEEEE to read as follows: 

Subpart EEEEEEE—National Emission 

Standards for Hazardous Air Pollutants: 

Gold Mine Ore Processing and Production 

Area Source Category 

Applicability and Compliance Dates 

Sec. 

63.11640 Am I subject to this subpart? 

63.11641 What are my compliance dates? 

Standards and Compliance Requirements 

63.11645 What are my mercury emission 

standards? 

63.11646 What are my compliance 

requirements? 

63.11647 What are my monitoring 

requirements? 

63.11648 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 

Pollutants: Gold Mine Ore Processing 

and Production Area Source Category 

Applicability and Compliance Dates 

§ 63.11640 Am I subject to this subpart? 

(a) You are subject to this subpart if 

you own or operate a gold mine ore 

processing and production facility as 

defined in § 63.11651, that is an area 

source. 

(b) This subpart applies to each new 

or existing affected source. The affected 

sources are each collection of ‘‘ore 

pretreatment processes’’ at a gold mine 

ore processing and production facility, 

each collection of ‘‘carbon processes’’ at 

a gold mine ore processing and 

production facility, and each collection 

of ‘‘non-carbon concentrate processes’’ at 

a gold mine ore processing and 

production facility, as defined in 

§ 63.11651. 

(1) An affected source is existing if 

you commenced construction or 

reconstruction of the affected source on 

or before April 28, 2010. 

(2) An affected source is new if you 

commenced construction or 

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 you own or operate a source 

subject to this subpart, you must have 

or you must obtain a permit under 40 

CFR part 70 or 40 CFR part 71. 

§ 63.11641 What are my compliance 

dates? 

(a) If you own or operate an existing 

affected source, you must comply with 

the applicable provisions of this subpart 


sroberts on DSKD5P82C1PROD with PROPOSALS
22490 Federal Register / Vol. 75, No. 81 / Wednesday, April 28, 2010 / Proposed Rules 

no later than 2 years after the date of 

publication of the final rule in the 

Federal Register. 

(b) If you start up a new affected 

source on or before the date of 

publication of the final rule in the 

Federal Register, you must comply with 

the provisions of this subpart no later 

than the date of publication of the final 

rule in the Federal Register. 

(c) If you start up a new affected 

source after the date of publication of 

the final rule in the Federal Register, 

you must comply with the provisions of 

this subpart upon startup of your 

affected source. 

Standards and Compliance 

Requirements 

§ 63.11645 What are my mercury emission 

standards? 

(a) For existing ore pretreatment 

processes, you must emit no more than 

149 pounds of mercury per million tons 

of ore processed. 

(b) For existing carbon processes, you 

must emit no more than 2.6 pounds of 

mercury per ton of concentrate 

processed. 

(c) For existing non-carbon 

concentrate processes, you must emit no 

more than 0.25 pounds of mercury per 

ton of concentrate processed. 

(d) For new ore pretreatment 

processes, you must emit no more than 

149 pounds of mercury per million tons 

of ore processed. 

(e) For new carbon processes, you 

must either: 

(1) Emit no more than 0.14 pounds of 

mercury per ton of concentrate 

processed, or 

(2) Achieve a 97-percent reduction in 

mercury emissions as measured before 

and after the mercury emission control 

devices. 

(f) For new non-carbon concentrate 

processes, you must emit no more than 

0.2 pounds of mercury per ton of 

concentrate processed. 

(g) The standards set forth in this 

section apply at all times. 

§ 63.11646 What are my compliance 

requirements? 

(a) Except as provided in paragraph 

(b) of this section, you must conduct a 

mercury compliance emission test 

within 180 days of the compliance date 

for all process units at new and existing 

affected sources according to the 

requirements in paragraphs (a)(1) 

through (13) of this section. This 

compliance testing must be repeated 

annually thereafter (i.e., once every four 

successive calendar quarters). 

(1) You must determine the 

concentration of mercury and the 

volumetric flow rate of the stack gas 

according to the following test methods 

and procedures: 

(i) Method 1 or 1A (40 CFR part 60, 

appendix A–1) to select sampling port 

locations and the number of traverse 

points in each stack or duct. Sampling 

sites must be located at the outlet of the 

control device (or at the outlet of the 

emissions source if no control device is 

present) and prior to any releases to the 

atmosphere. 

(ii) Method 2, 2A, 2C, 2D, 2F (40 CFR 

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), 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)’’ (incorporated by 

reference—see § 63.14); Method 30A (40 

CFR part 60, appendix A–8); or Method 

30B (40 CFR part 60, appendix A–8) to 

determine the concentration of mercury. 

If you use Method 29, the acetone rinse 

procedures in Section 8.2.6 of the 

method must be followed and are not 

optional (i.e., quantitative removal of 

particulate matter and any condensate 

from the sampling apparatus (probe 

nozzle, fitting, holder) and front half of 

the filter holder must be performed 

using acetone). 

(vi) The absence of cyclonic flow 

must be determined prior to or during 

the test. For retorts and other narrow 

stacks where sampling is done at a 

single point with a standard pitot tube, 

a ‘‘null’’ check must be performed prior 

to sampling. 

(2) A minimum of three test runs must 

be conducted for each performance test 

of each process unit. Each test run must 

be conducted for at least two hours and 

collect a minimum sample volume of 

1.7 dry standard cubic meters (60 dry 

standard cubic feet). 

(3) Tests must be conducted under 

operating conditions (including process 

or production throughputs) that are 

based on representative performance. 

Record and report the process 

throughput for each test run. 

(4) Calculate the mercury emission 

rate 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 milligrams per dry standard cubic 

meter (mg/dscm); 

Qs = volumetric flow rate of the stack gas, in 

dry standard cubic feet per hour; and 

K = conversion factor from mg/dscm to 

pounds per dry standard cubic foot, 6.23 

× 10¥ 8. 

(5) Monitor and record the number of 

hours 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 the 6-month period 

following the compliance date by 

multiplying the emission rate in lb/hr 

for each process unit by the number of 

hours each process unit operated during 

the 6-month period. After the initial 6 

months following the compliance date, 

determine the annual mercury mass 

emissions 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, determine the 

total mercury mass emissions for each 

process unit for the 12-month period 

preceding the performance test by 

multiplying the emission rate in lb/hr 

for each process unit by the number of 

hours each process unit operated during 

the 12-month period preceding the 

completion of the performance tests. 

(8) You must install, calibrate, 

maintain and operate an appropriate 

weight measurement device or 

densitometers and volumetric flow 


sroberts on DSKD5P82C1PROD with PROPOSALSEP28AP10.022</MATH>
Federal Register / Vol. 75, No. 81 / Wednesday, April 28, 2010 / Proposed Rules 22491 

meters to measure ore throughput for 

each roasting operation and autoclave 

and calculate hourly, daily and monthly 

totals in tons of as fed ore. 

(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 carbonin-leach tanks. 

(ii) Measure the weight or the density 

and volumetric flow rate of the ore 

slurry as it is fed to the autoclave(s). 

(9) Measure the weight of concentrate 

processed (by electrowinning, Merrill 

Crowe process, gravity feed, or other 

methods) using weigh scales for each 

batch prior to retorting. The concentrate 

must be weighed in the same State and 

condition as it is when fed to the retort. 

For facilities without retorts, the 

concentrate must be weighed prior to 

being fed to the melt furnace before 

drying in any ovens. For facilities that 

ship concentrate offsite, measure the 

weight of concentrate as shipped offsite. 

You must keep accurate records of the 

weights of each batch of concentrate 

processed and calculate and record the 

total weight of concentrate processed 

each month. 

(10) You must maintain the systems 

for measuring density, volumetric flow 

rate, and weight within ±5 percent 

accuracy. You must describe the 

specific equipment used to make 

measurements at your facility and how 

that equipment is periodically 

calibrated. You must also explain, 

document, and maintain written 

procedures for determining the accuracy 

of the measurements and make these 

written procedures available to your 

permitting authority upon 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. 

(11) Record the weight in tons of ore 

for ore pretreatment processes and 

concentrate for carbon processes and for 

non-carbon concentrate processes on a 

daily and monthly basis. 

(12) Calculate the emissions from 

each new and existing affected source 

for the 6-month period following the 

compliance date in pounds of mercury 

per ton of process input using the 

procedures in paragraphs (a)(12)(i) 

through (iii) of this section to determine 

initial compliance with the emission 

standards in § 63.11645. After the initial 

6-month period, determine annual 

compliance using the procedures in 

paragraph (a)(13) of this section for 

existing sources. 

(i) For ore pretreatment processes, 

divide the sum of mercury mass 

emissions from all roasting operations 

and autoclaves during the initial 6- 

month period following the compliance 

date by the sum of the total amount of 

gold mine ore processed in these 

process units during the 6-month period 

following the compliance date. 

(ii) For carbon processes, divide the 

sum of mercury mass emissions from all 

carbon kilns, preg tanks, 

electrowinning, retorts, and melt 

furnaces during the initial 6-month 

period following the compliance date by 

the total amount of concentrate 

processed in these process units during 

the initial 6-month period following the 

compliance date. 

(iii) For non-carbon concentrate 

processes, divide the sum of mercury 

mass emissions from retorts and melt 

furnaces during the initial 6-month 

period following the compliance date by 

the total amount of concentrate 

processed in these process units during 

the 6-month period following the 

compliance date. 

(13) After the initial compliance test, 

calculate the emissions from each new 

and existing affected source for each 12- 

month period preceding each 

subsequent compliance test in pounds 

of mercury per ton of process input 

using the procedures in paragraphs 

(a)(13)(i) through (iii) of this section to 

determine compliance 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 that 12-month period. 

(ii) For carbon processes, divide the 

sum of mercury mass emissions from all 

carbon kilns, preg tanks, 

electrowinning, retorts, and melt 

furnaces in the 12-month period 

preceding a compliance test by the total 

amount of concentrate processed in 

these process units in that 12-month 

period. 

(iii) For non-carbon concentrate 

processes, divide the sum of mercury 

mass emissions from 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) If you have a new carbon processes 

affected source and elect to comply with 

the percent reduction standard in 

§ 63.11645(e)(2), you must perform 

annual tests of the inlet and outlet to 

each control device used in the new 

affected source and calculate emissions 

at the inlet and outlet using the methods 

and procedures in paragraphs (a)(1) 

through (7) of this section. The sampling 

and analysis of inlet emissions for 

retorts must be performed following the 

mercury condenser and before the 

carbon adsorber. Calculate the percent 

reduction in mercury emissions based 

on the difference in emission rates at the 

inlet and outlet to each control device. 

Perform a compliance determination for 

the initial 6-month period following the 

compliance date using the procedures in 

paragraph (a)(6) of this section. Perform 

compliance determinations annually 

following the initial 6-month period 

using the procedures in paragraph (a)(7) 

of this section. 

(c) 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. 

§ 63.11647 What are my monitoring 

requirements? 

(a) Except as provided in paragraph 

(a)(4) of this section, you must monitor 

each roaster for mercury emissions 

using one of the procedures in 

paragraphs (a)(1) or (2) of this section 

and establish operating limits for 

mercury concentration as described in 

paragraph (a)(3) of this section. 

(1) Perform sampling and analysis of 

the roaster’s exhaust for mercury 

concentration using EPA Performance 

Specification 12B each week and 

maintain the daily average 

concentration below the operating limit 

established in paragraph (a)(3) of this 

section. 

(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 resample within 30 days using a shorter 

sampling duration. 

(ii) If you measure a daily average 

concentration above the operating limit, 

you must take corrective action and 

correct the problem within 48 hours of 

the exceedance or stop the feed of ore 

to the roaster, and report the exceedance 

as a deviation. 

(2) Install, operate, calibrate, and 

maintain a continuous emissions 

monitoring system (CEMS) to 

continuously measure the mercury 

concentration in the final exhaust 

stream from each roaster according to 


sroberts on DSKD5P82C1PROD with PROPOSALS
22492 Federal Register / Vol. 75, No. 81 / Wednesday, April 28, 2010 / Proposed Rules 

the requirements of Performance 

Specification 12A (40 CFR part 60, 

appendix B) except that calibration 

standards traceable to the National 

Institute of Standards and Technology 

are not required. You must perform a 

data accuracy assessment of the CEMS 

according to section 5 of Appendix F in 

part 60 and follow the monitoring 

requirements in § 63.8. 

(i) You must continuously monitor 

the daily average mercury concentration 

from the roaster and maintain the daily 

average concentration below the 

operating limit established in paragraph 

(a)(3) of this section. If you measure a 

daily average concentration above the 

operating limit, you must take corrective 

action and correct the problem within 

48 hours of the exceedance or stop the 

feed of ore to the roaster, and report the 

exceedance as a deviation. 

(ii) You must submit a monitoring 

plan that includes quality assurance and 

quality control (QA/QC) procedures 

sufficient to demonstrate the accuracy of 

the CEMS to your permitting authority 

for approval 180 days prior to your 

initial compliance test. At a minimum, 

the QA/QC procedures must include 

daily calibrations and an annual 

accuracy test for the CEMS. 

(3) 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) or (2) of this section concurrently 

while you are also doing your annual 

compliance performance stack test 

according to the procedures in 

§ 63.11646(a). 

OLR C CT Eq = ∗ test ( / ) (. 149 2)

Where: 

OLR = mercury concentration operating limit 

for the roaster (in micrograms per cubic 

meter); 

Ctest = average mercury concentration 

measured by the monitoring procedures 

(PS 12A or PS 12B) during the annual 

performance stack test (in micrograms 

per cubic meter); 

149 = emission limit for ore pretreatment 

processes (in lb/million tons of ore); 

CT = compliance test results for ore 

pretreatment processes (in lb/million 

tons of ore). 

(4) For roasters that utilize calomelbased mercury control systems for 

emissions controls, you are not required 

to perform the monitoring for mercury 

emissions in paragraphs (a)(1) or (2) of 

this section if you demonstrate to the 

satisfaction of your permitting authority 

that mercury emissions from the roaster 

are less than 10 pounds of mercury per 

million tons of ore throughput. If you 

make this demonstration, you must 

conduct the parametric monitoring as 

described below in paragraphs (b) and 

(c) of this section. 

(i) The initial demonstration must 

include three or more consecutive 

independent stack tests for mercury at 

least one month apart on the roaster 

exhaust stacks. Subsequent 

demonstrations may be based upon the 

single stack test 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 the mercury emission rate 

in pounds per hour by the ore 

throughput rate during the test 

expressed in millions of tons per hour 

to determine the emissions in pounds 

per million tons of ore. 

(iii) You must continue to perform 

annual compliance tests of the roaster 

stack as required in § 63.11646(a). In 

addition, if the mercury concentration 

in the ore processed in the roaster 

increases to a level higher than any 

mercury concentration measured in the 

previous 12 months, you must perform 

a compliance test within 30 days of the 

first day that the ore with higher 

mercury levels is processed to 

determine whether the mercury 

emissions are still below 10 lbs per 

million tons of ore. If any subsequent 

compliance tests indicate that the 

roaster is emitting more than 10 pounds 

of mercury per million tons of ore input, 

then you must implement the 

monitoring required in paragraphs (a)(1) 

or (2) of this section within 30 days. 

(b) For facilities with roasters and a 

calomel-based mercury control system 

that choose to monitor for mercury 

emissions using the procedures in 

paragraph (a)(1) of this section or that 

qualify for and choose to follow the 

requirements in paragraph (a)(4) of this 

section, you must establish operating 

parameters for scrubber liquor flow, 

scrubber pressure drop and scrubber 

inlet gas temperature and monitor these 

parameters. Monitor the scrubber liquor 

flow, scrubber pressure drop and 

scrubber inlet gas temperature during 

each run of your initial compliance test. 

The minimum operating rate for 

scrubber liquor flow and pressure drop 

are the lowest values during any run of 

the initial compliance test, and your 

maximum scrubber inlet temperature 

limit is the highest measured during any 

run of the initial compliance test. 

Subsequently, you must monitor the 

scrubber liquor flow, scrubber pressure 

drop and scrubber inlet gas temperature 

hourly and maintain the scrubber liquor 

flow and scrubber pressure drop at or 

above the operating parameters 

established during the initial 

compliance test and maintain the inlet 

gas temperature below the operating 

parameters established during the initial 

compliance test. 

(c) For facilities with roasters and a 

calomel-based mercury control system 

that choose to monitor for mercury 

emissions using the procedures in 

paragraph (a)(1) of this section or that 

qualify for and follow the requirements 

in paragraph (a)(4) of this section, you 

must establish operating parameters for 

mercuric ion and chloride ion 

concentrations or for oxidation 

reduction potential and pH using the 

procedures in either paragraph (c)(1) or 

(2) of this section. 

(1) Establish the mercuric ion 

concentration and chloride ion 

concentration range for each calomelbased mercury control system. The 

mercuric ion concentration and chloride 

ion concentration for each calomelbased mercury control system must be 

based on the manufacturer’s 

specifications. Alternatively, the 

mercuric ion concentration and chloride 

ion concentration range for each 

calomel-based mercury control system 

may be approved by your permitting 

authority. Measure the mercuric ion 

concentration and chloride ion 

concentrations at least once during each 

run of your initial compliance test. The 

measurements must be within the 

established concentration range for 

mercuric ion concentration and chloride 

ion concentration. Subsequently, you 

must sample four times daily and 

maintain the mercuric ion concentration 

and chloride ion concentrations within 

their established range. 

(2) Establish the oxidation reduction 

potential and pH range for each 

calomel-based mercury control system. 

The oxidation reduction potential and 

pH range for each calomel-based 

mercury control system must be based 

on the manufacturer’s specifications. 


sroberts on DSKD5P82C1PROD with PROPOSALSEP28AP10.023</MATH>
Federal Register / Vol. 75, No. 81 / Wednesday, April 28, 2010 / Proposed Rules 22493 

Alternatively, the oxidation reduction 

potential and pH range for each 

calomel-based mercury control system 

may be approved by your permitting 

authority. Install monitoring equipment 

to continuously monitor the oxidation 

reduction potential and pH of the 

calomel-based mercury control system 

scrubber liquor. Measure the oxidation 

reduction potential and pH of the 

scrubber liquor during each run of your 

initial compliance test. The 

measurements must be within the 

established range for oxidation 

reduction potential and pH. 

Subsequently, you must monitor the 

oxidation reduction potential and pH of 

the scrubber liquor continuously and 

maintain it within the established 

operating range. 

(d) If you have an exceedance of an 

operating limit or range in paragraphs 

(b) or (c) of this section, you must take 

corrective action and bring the system 

operations back into the specified 

operational range or limit within 45 

minutes or commence shutdown of the 

roaster. 

(e) You may submit a request to your 

permitting authority for approval to 

change the operating limits established 

under paragraph (a)(3) of this section for 

the monitoring required in paragraph 

(a)(1) or (2) of this section. In the 

request, you must demonstrate that the 

proposed change to the operating limit 

detects changes in levels of mercury 

emission control. An approved change 

to the operating limit under this 

paragraph only applies until a new 

operating limit is established during the 

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), (2), or 

(3) of this section. 

(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 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 

Equation (3) of this section. 

OLC C EL CT Eq = ∗ trap ( / ) ( .) 3

Where: 

OLC = mercury concentration operating limit 

for the process as measured using the 

sorbent trap, (micrograms per cubic 

meter); 

Ctrap = average mercury concentration 

measured using the sorbent trap during 

the week that includes the performance 

test, (micrograms per cubic meter); 

EL = emission limit for the affected sources 

(lb/ton of concentrate); 

CT = compliance test results for the affected 

sources (lb/ton of concentrate). 

(ii) Sample and analyze the exhaust 

stream from the carbon adsorber for 

mercury at least monthly using Method 

30B (40 CFR part 60, appendix A–8). 

When the mercury concentration 

reaches 50 percent of the operating 

limit, begin weekly sampling and 

analysis. When the mercury 

concentration reaches 90 percent of the 

operating limit, replace the carbon in 

the carbon adsorber within 30 days. 

(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 top of the bed and the 

exit of the bed and analyzed using EPA 

Method 7471A (incorporated by 

reference—see § 63.14). The depth to 

which the sampler is inserted must be 

recorded. Calculate an average carbon 

loading from the two measurements. 

Sampling and analysis of the carbon bed 

for mercury must be performed 

quarterly thereafter. When the carbon 

loading reaches 50 percent of the design 

capacity of the carbon, monthly 

sampling must be performed until 90 

percent of the carbon loading capacity is 

reached. The carbon must be removed 

and replaced with fresh carbon no later 

than 30 days after reaching 90 percent 

of capacity. 

(3) Calculate the change out rate for 

the carbon in the carbon adsorber based 

on the carbon lifetime as determined 

from at least 2 years of data for the 

process unit from following the 

procedures in paragraphs (f)(1) or (2) of 

this section. You must submit 

supporting data and request approval 

from your permitting authority to 

periodically change out the carbon 

instead of monitoring. After approval 

from your permitting authority, change 

out the carbon in the carbon adsorber no 

less frequently than the established 

lifetime. If you change the process or 

inputs in such a manner that mercury 

emissions might increase (e.g., increase 

throughput), you must re-establish the 

change out period based on two years of 

historical data as described in this 

paragraph. 

(g) You must monitor gas stream 

temperature at the inlet to the carbon 

adsorber for each autoclave, carbon kiln, 

melt furnace, and retort equipped with 

a carbon adsorber during the annual 

performance test required in 

§ 63.11646(a) and establish a maximum 

value for the inlet temperature. 

Establish the temperature operating 

limit based on either the highest reading 

during the test or at 10 °F higher than 

the average temperature measured 

during the performance test. 

Continuously monitor the inlet 

temperature thereafter. If an hourly 

average inlet temperature exceeds the 

temperature operating limit, you must 

follow the requirements for outlet 

concentration measurement in 

paragraph (f)(1) of this section. If the 

concentration is below 90 percent of the 

operating limit, you may set a new 

temperature operating limit 10 °F above 

the previous operating limit. If the 

concentration is above 90 percent of the 

operating limit, you must take 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 section. If the concentration 

is still above 90 percent of the operating 

limit, then you must change the carbon 

in the bed within 30 days. 

(h) For each wet scrubber at each new 

and existing affected source, you must 

monitor the water flow rate and 

pressure drop during the performance 

test required in § 63.11646(a) and 

establish a minimum value as the 

operating limit based on either the 

lowest average value during any test run 

or as no lower than 10 percent of the 

average value measured during the test. 

You must continuously monitor the 

water flow rate and pressure drop and 

take corrective action within 24 hours if 

any daily average is less than the 

operating limit. 

(i) You may conduct additional 

compliance tests according to the 

procedures in § 63.11646 and reestablish the operating limits required 

in paragraphs (a) through (c) and (f) 

through (h) of this section at any time. 

§ 63.11648 What are my notification, 

reporting, and recordkeeping 

requirements? 

(a) You must submit the Initial 

Notification required by § 63.9(b)(2) no 

later than 120 calendar days after the 

date of publication of the final rule in 

the Federal Register or within 120 days 


sroberts on DSKD5P82C1PROD with PROPOSALSEP28AP10.024</MATH>
22494 Federal Register / Vol. 75, No. 81 / Wednesday, April 28, 2010 / Proposed Rules 

after the source becomes subject to the 

standard. The Initial Notification must 

include the information specified in 

§ 63.9(b)(2)(i) through (b)(2)(iv). 

(b) You must submit an initial 

Notification of Compliance Status as 

required by § 63.9(h). 

(c) If a deviation occurs during a 

semiannual reporting period, you must 

submit a deviation report to your 

permitting authority according to the 

requirements in paragraphs (c)(1) and 

(2) of this section. 

(1) The first reporting period covers 

the period beginning on the compliance 

date specified in § 63.11641 and ending 

on June 30 or December 31, whichever 

date comes first after your compliance 

date. Each subsequent reporting period 

covers the semiannual period from 

January 1 through June 30 or from July 

1 through December 31. Your deviation 

report must be postmarked or delivered 

no later than July 31 or January 31, 

whichever date comes first after the end 

of the semiannual reporting period. 

(2) A deviation report must include 

the information in paragraphs (c)(2)(i) 

through (iv) of this section. 

(i) Company name and address. 

(ii) Statement by a responsible 

official, with the official’s name, title, 

and signature, certifying the truth, 

accuracy and completeness of the 

content of the report. 

(iii) Date of the report and beginning 

and ending dates of the reporting 

period. 

(iv) Identification of the affected 

source, the pollutant being monitored, 

applicable requirement, description of 

deviation, and corrective action taken. 

(d) If you had a malfunction during 

the reporting period, the compliance 

report must include the number, 

duration, and a brief description for 

each type of malfunction which 

occurred during the reporting period 

and which caused or may have caused 

any applicable emission limitation to be 

exceeded. The report must also include 

a description 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 paragraphs (e)(1) through 

(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 semiannual compliance 

certifications that you submitted. 

(2) You must keep the records of all 

performance tests, 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 

activity; 

(v) Results, including the date, time, 

and duration of the period from the time 

the monitoring indicated a problem 

(e.g., VE) to the time that monitoring 

indicated proper operation; and 

(vi) Maintenance or corrective action 

taken (if applicable). 

(3) You must keep records of 

operating hours for each process 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 action according 

to § 63.10(b)(1). You may keep the 

records offsite for the remaining 3 years. 

(g) After December 31, 2011, within 

60 days after the date of completing 

each performance evaluation conducted 

to demonstrate compliance with this 

subpart, the owner or operator of the 

affected facility must submit the test 

data to EPA by entering the data 

electronically into EPA’s WebFIRE data 

base 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 this requirement to be 

submitted electronically into EPA’s 

WebFIRE database. 

Other Requirements and Information 

§ 63.11650 What General Provisions apply 

to this subpart? 

Table 1 to this subpart shows which 

parts of the General Provisions in 

§§ 63.1 through 63.16 apply to you. 

§ 63.11651 What definitions apply to this 

subpart? 

Terms used in this subpart are 

defined in the Clean 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). 

Sometimes these scrubbers are also 

referred to as ‘‘mercury scrubbers.’’ 

Carbon kiln means a kiln or furnace 

where carbon is regenerated by heating, 

usually in the presence of steam, after 

the gold has been stripped from the 

carbon. 

Carbon processes means the affected 

source that includes carbon kilns, preg 

tanks, electrowinning cells, mercury 

retorts, and melt furnaces at gold mine 

ore processing and production facilities 

that use activated carbon 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 retorts, or for facilities 

without retorts, as the input to melt 

furnaces before any drying takes place. 

For facilities without retorts or melt 

furnaces, concentrate is measured as the 

quantity shipped. 

Deviation means any instance where 

an affected source subject to this 

subpart, or an owner or operator of such 

a 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) Fails to meet any term or condition 

that is adopted to implement an 

applicable requirement in this subpart 

and that is included in the operating 

permit for any affected source required 

to obtain such a permit; or 

(3) Exceeds any operating limit 

established under this subpart. 

Electrowinning means a process that 

uses induced voltage on anode and 


sroberts on DSKD5P82C1PROD with PROPOSALS
Federal Register / Vol. 75, No. 81 / Wednesday, April 28, 2010 / Proposed Rules 22495 

cathode plates to remove metals from 

the continuous flow of solution, where 

the gold in solution is plated onto the 

cathode. Steel wool is typically used as 

the plating surface. 

Electrowinning Cells means a tank in 

which the electrowinning takes place. 

Gold mine ore processing and 

production facility means any facility 

engaged in the processing of gold mine 

ore that uses any of the following 

processes: roasting operations, 

autoclaves, carbon kilns, preg tanks, 

electrowinning, retorts, or melt 

furnaces. A facility that produces 

primarily copper (where copper is 95 

percent or more of the total metal 

production) that may also recover some 

gold as a byproduct is not a gold mine 

ore processing and production facility. 

Melt furnace means a furnace 

(typically a crucible furnace) that is 

used for smelting the gold-bearing 

material recovered from retorting, or the 

gold-bearing material from 

electrowinning, the Merrill-Crowe 

process or other processes for facilities 

without retorts. 

Merrill-Crowe process means a 

precipitation technique using zinc oxide 

for removing gold from a cyanide 

solution. Zinc dust is added to the 

solution, and gold is precipitated to 

produce a concentrate. 

Non-carbon concentrate processes 

means the affected source that includes 

retorts and melt furnaces at gold mine 

ore processing and production facilities 

that use the Merrill-Crowe process or 

other processes and do not use carbon 

to recover (adsorb) gold from the 

pregnant cyanide solution. 

Ore dry grinding means a process in 

which the gold ore is ground and heated 

(dried) prior to additional preheating or 

prior to entering the roaster. 

Ore preheating means a process in 

which ground gold ore is preheated 

prior to entering the roaster. 

Ore 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. 

Pregnant solution tank (or preg tank) 

means a storage tank for pregnant 

solution, which is the cyanide solution 

that contains gold-cyanide complexes 

that is generated from leaching gold ore 

with cyanide solution. 

Pregnant cyanide solution means the 

cyanide solution that contains goldcyanide 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. 

Retort means a vessel that is operated 

under a partial vacuum at 

approximately 1,100 to 1,300 °F to 

remove mercury and moisture from the 

gold bearing sludge material that is 

recovered from electrowinning, the 

Merrill-Crowe process or other 

processes. Retorts are usually equipped 

with condensers that recover liquid 

mercury during the processing. 

Roasting operation means a process 

that uses an industrial furnace in which 

milled ore is combusted across a 

fluidized bed to oxidize and remove 

organic carbon and sulfide mineral 

grains in refractory gold ore. The 

emissions points of the roasting 

operation subject to this subpart include 

ore dry grinding, ore preheating, the 

roaster stack, and quenching. 

§ 63.11652 Who implements and enforces 

this subpart? 

(a) This subpart can be implemented 

and enforced by the U.S. EPA or a 

delegated authority, such as your State, 

local, or Tribal agency. If the U.S. EPA 

Administrator has delegated authority to 

your State, local, or Tribal agency, then 

that 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 in § 63.11641, and the 

applicable standards in § 63.11645. 

(2) Approval of an alternative 

nonopacity emissions standard under 

§ 63.6(g). 

(3) Approval of a major change to a 

test method under § 63.7(e)(2)(ii) and (f). 

A ‘‘major change to test method’’ is 

defined in § 63.90(a). 

(4) Approval of a major change to 

monitoring under § 63.8(f). A ‘‘major 

change to monitoring’’ is defined in 

§ 63.90(a). 

(5) Approval of a waiver of 

recordkeeping or reporting requirements 

under § 63.10(f), or another major 

change to recordkeeping/reporting. A 

‘‘major change to recordkeeping/ 

reporting’’ is defined in § 63.90(a). 

§ 63.11653 [Reserved] 

Tables to Subpart EEEEEEE of Part 63 

TABLE 1 TO SUBPART EEEEEEE OF PART 63—APPLICABILITY OF GENERAL PROVISIONS TO SUBPART EEEEEE 

[As stated in § 63.11650, you must comply with the applicable General Provisions requirements according to the following table] 

Citation Subject 

Applies to 

subpart 

EEEEEEE 

Explanation 

§ 63.1(a)(1), (a)(2), (a)(3), (a)(4), (a)(6), 

(a)(10)–(a)(12), (b)(1), (b)(3), (c)(1), 

(c)(2), (c)(5), (e).

Applicability ............................................... Yes.

§ 63.1(a)(5), (a)(7)–(a)(9), (b)(2), (c)(3), 

(c)(4), (d).

Reserved ................................................... No.

§ 63.2 ........................................................... Definitions ................................................. Yes.

§ 63.3 ........................................................... Units and Abbreviations ............................ Yes.

§ 63.4 ........................................................... Prohibited Activities and Circumvention ... Yes.

§ 63.5 ........................................................... Preconstruction Review and Notification 

Requirements.

Yes.

§ 63.6(a), (b)(1)–(b)(5), (b)(7), (c)(1), (c)(2), 

(c)(5), (e)(1)(iii), (f)(2), (f)(3), (g), (i), (j).

Compliance with Standards and Maintenance Requirements.Yes.

§ 63.6(e)(1)(i) and (ii), (e)(3), and (f)(1) ...... Startup, Shutdown and Malfunction Requirements (SSM).No ............ Subpart EEEEEEE standards apply at all 

times. 


sroberts on DSKD5P82C1PROD with PROPOSALS
22496 Federal Register / Vol. 75, No. 81 / Wednesday, April 28, 2010 / Proposed Rules 

TABLE 1 TO SUBPART EEEEEEE OF PART 63—APPLICABILITY OF GENERAL PROVISIONS TO SUBPART EEEEEE— 

Continued 

[As stated in § 63.11650, you must comply with the applicable General Provisions requirements according to the following table] 

Citation Subject 

Applies to 

subpart 

EEEEEEE 

Explanation 

§ 63.6(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 visible 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 .......................... Yes.

§ 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] ................................................. No.

§ 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.

[FR Doc. 2010–9363 Filed 4–27–10; 8:45 am] 

BILLING CODE 6560–50–P 


sroberts on DSKD5P82C1PROD with PROPOSALS