Evaluation of Mercury Emissions from 

U.S. Gold Mining Operations 

August 2007 

Prepared for: 

U.S. Environmental Protection Agency 

Office of Air Quality Planning and Standards 

Research Triangle Park, NC 27711 

Prepared by: 

RTI International 

3040 Cornwallis Road 

Research Triangle Park, NC 27709 

EPA Contract No. EP-D-06-118 

Work Assignment No. 1-20 

Table of Contents 

i 

Table of Contents 

Section Page

Acronyms ...................................................................................................................................v 

1.0 Introduction ....................................................................................................................1 

2.0 Background Information ................................................................................................2 

 2.1 History of Gold Mining in the U.S. ..................................................................2 

 2.2 General Gold Mining Methods ..........................................................................2 

 2.3 Production Amounts and Prices .........................................................................3 

 2.4 Gold Mining Processes Currently Used in the U.S............................................5 

 2.4.1 Extraction, Crushing, and Milling .........................................................5 

 2.4.2 Roasting and Autoclaving ......................................................................6 

 2.4.3 Leaching .................................................................................................6 

 2.4.4 Carbon Stripping and Regeneration .......................................................6 

 2.4.5 Recovery from Solution .........................................................................7 

 2.4.6 Retorting and Smelting ..........................................................................7 

3.0 U.S. Gold Mining Industry Survey ................................................................................8 

 3.1 Description of Industry Survey ..........................................................................8 

 3.2 Summary of Survey Respondents ......................................................................9 

 3.3 Survey Characterization of Current Gold Mining Industry .............................10 

4.0 Mercury Emissions from Gold Mines ..........................................................................13 

 4.1 Gold Mining Mercury Emissions from Industry Surveys ................................13 

 4.1.1 Facility Total Mercury Emissions ........................................................13 

 4.1.2 Thermal Process Mercury Emissions ...................................................13 

 4.1.3 Thermal Process Mercury Emissions Controls ....................................15 

 4.2 Gold Mining Mercury Emissions from the TRI ..............................................17 

 4.3 Gold Mining Mercury Emissions from the NEI ..............................................20 

 4.4 Comparison of Gold Mining Mercury Emissions ............................................20 

 4.5 Uncertainty and Biases in Mercury Emissions Estimates ..............................21 

5.0 Nevada Mercury Control Program ...............................................................................24 

6.0 References ....................................................................................................................25 

Appendix A ........................................................................................................................... A-1 

Appendix B ............................................................................................................................B-1 
Table of Contents 

ii 

List of Figures 

1 United States gold production and price of gold, 1907 to 2005 ....................................4 

2 United States gold production, 2001 to 2005 .................................................................5 

3 Currently operating U.S. gold mines processing mercury-containing ores .................12 

4 Mercury emissions from metals mining in the United States, 1998-2005 

 based on the Toxics Release Inventory ........................................................................19 

List of Tables 

1 Summary of the Type of Mercury Emissions Information Received in the 

 Responses to the Questionnaires ....................................................................................9 

2 Summary of Production and Mercury Emissions from Gold Mining Facilities 

 in the United States, 2004/2005 Timeframe ................................................................10 

3 Tons of Ore Processed by Process Type, 2004/2005 Timeframe ................................11 

4 Summary of Facility-Total Mercury Emissions in the 2004/2005 Timeframe ............14 

5 Summary of Mercury Emissions by Thermal Process (2004/2005 Timeframe) .........14 

6 Summary of Thermal Process Units and Controls Used by Gold Mines 

 in the United States, 2004/2005 Timeframe ................................................................15 

7 Summary of Gold Mining Facilities Using Autoclaves in the United States ..............16 

8 Summary of Gold Mining Facilities Using Roasters in the United States ..................16 

9 Summary of Gold Mining Facilities Using Carbon Regeneration Kilns 

 in the United States ......................................................................................................18 

10 Comparison of Mercury Emission Estimates by Facility ............................................22 

B-1 Summary of Responses to NDEP and U.S. EPA Gold Mines Questionnaire ..........B-3 

B-2 Summary of Controls Used at Top Five Mercury Emitting Gold Mines 

 in the United States ...................................................................................................B-5 

B-3 Summary of Gold Mining Facilities Using Electrowinning in the United States ......B-6 

B-4 Summary of Gold Mining Facilities Using Retorts in the United States ..................B-7 

B-5 Summary of Gold Mining Facilities Using Smelting in the United States ...............B-9 

B-6 Summary of Gold Mining Facilities Using Other Thermal Processes 

 in the United States ..................................................................................................B-11 
Acronyms 

iii 

Acronyms 

CAA Clean Air Act 

CAAA Clean Air Act Amendments 

CalEPA California EPA 

EPA U.S. Environmental Protection Agency 

GIS geographic information systems 

HAPs hazardous air pollutants 

NEI National Emission Inventory 

NDEP Nevada Division of Environmental Protection 

NMA Nevada Mining Association 

NMCP Nevada Mercury Control Program 

NvMACT Nevada Maximum Achievable Control Technology 

OAQPS Office of Air Quality Planning and Standards 

OPTC Operating Permit to Construct 

ppmw parts per million by weight 

TRI Toxics Release Inventory 

VMRP Voluntary Mercury Reduction Program 
Acronyms 

iv 
Section 1.0 Introduction 

1 

1.0 Introduction 

The purpose of the report is to present recent data collected regarding mercury emission 

estimates from gold (and silver) mining operations in the United States (U.S.). In this report we 

refer to these mining operations as gold mining operations because we did not identify any mines 

that produce only silver. That is, there are no silver mines that do not also produce gold. We 

acknowledge, however, that many of these “gold” mining operations also produce a significant 

quantity of silver; they may also produce mercury, copper, and other metal products. 

Nonetheless, in this report, gold mining operations (or gold mines) refer to all mining operations 

that produce gold; mining operations that produce both gold and silver are considered a subset of 

gold mines. 

Because gold and mercury belts can often be found in close proximity, gold ores 

commonly contain mercury in the form of mercury sulfide. The mercury concentrations in gold 

ores varies substantially, from less than 0.1 parts per million by weight (ppmw) to 100 ppmw (or 

0.01 weight %) (Jones and Miller 2005). During gold production, mercury can be liberated from 

the ore. Therefore, gold production processes are potentially significant sources of mercury 

emissions to the atmosphere. The potential for mercury emissions from gold mining activities is 

dependent on the concentration of mercury in the ores along with other factors such as type of 

processes used, control technologies present, and pollution prevention measures applied. 

In addition to mercury being present in the ores, mercury was historically used 

intentionally to extract gold from ores in the U.S., through a process known as mercury 

amalgamation. This amalgamation method is still common among artisanal miners in many 

developing counties in South America, Africa and Asia. However, available information 

indicates that this amalgamation process was largely phased out in the U.S. decades ago and is 

essentially nonexistent in the U.S. today. Therefore, amalgamation is not covered in this report 

other than some historical information presented in the Section 2. 

Section 2 of this report provides background information on the history of gold 

production in the U.S. and an overview of the various gold mining process operations that are 

currently used at active U.S. gold mines. As seen in Section 2, the State of Nevada currently 

dominates the total gold production. Consequently, this report often compares and contrasts the 

gold production and mercury emissions from gold mining activities for the Nevada gold mines 

and all other (non-Nevada) gold mines. Section 3 of this report provides a description of the 

information collection activities conducted to obtain information about current U.S. gold mining 

operations and their estimated mercury emissions, and it summarizes basic information obtained 

about the U.S. gold mines. Section 4 summarizes the mercury emission estimates provided in 

response to the information collection requests and compares these emission estimates with other 

estimates of U.S. gold mining mercury emissions. Finally, Section 5 provides a brief summary 

on the State of Nevada’s Mercury Control Program implemented to reduce mercury emissions 

from Nevada gold (and silver) mines. 
Section 2.0 Background Information 

2 

2.0 Background Information 

 This section provides historical background of U.S. gold mining activities as well as a 

description of the primary gold production processes that are currently used at U.S. gold mines. 

2.1 History of Gold Mining in the U.S. 

The first documented gold mining in the United States occurred in North Carolina during 

the early 19th century, after gold was discovered in 1799 at what would become Reed Gold Mine 

(North Carolina Office of Archives and History 2006). By the late 1820s and early 1830s, 

Georgia, Alabama, Tennessee, and Virginia had also become significant gold producers. With 

the discovery of gold in California in 1848 and the subsequent gold rush, the bulk of gold mining 

activity began to shift to the Western states. At the beginning of the 20th century, there were 

approximately 4,000 gold mines operating in the United States, a number which remained fairly 

stable until the Depression, at which time many small mines were opened in response to a spike 

in the price of gold; by 1934 and 1935 the number of mines had reached over 12,000. However, 

the majority of gold mines were shut down several years later in 1942, in order to focus labor on 

the war effort. After the war, relatively few mines reopened, and until 1970 only two new large 

mines were developed (Butterman and Amey 2005). As of 2005, there were about 19 companies 

in the U.S. producing gold, with a total of roughly 40 operating mines (NMA 2006). 

2.2 General Gold Mining Methods 

Gold mines typically fall into one of two categories: placer mines or lode mines. In 

placer mining, gold is extracted from alluvial deposits of sand and gravel in which it is 

concentrated using various mechanical and hydraulic techniques (Butterman and Amey 2005). 

In the early years of mining in the United States, the majority of gold recovered was from placer 

mines through the use of methods such as gravity separation and amalgamation with mercury. 

By the 1860s, lode mines (surface or underground mines), also known as hard rock mines, had 

also become a significant source of gold. During this time period, mercury amalgamation was 

used to extract gold from the pulverized ore after it was removed from the lode mines; the 

process of cyanidation, also used to chemically recover gold from the ores, was introduced in 

around 1890. With the advent of cyanidation, it became possible to extract a higher percentage 

of gold from the ore, thus making it economically feasible to mine lower-grade ores. The 

development of the flotation process, which began to see widespread use around the 1930s, also 

improved the efficiency with which gold could be extracted. 

In 1986, the last year for which complete data were reported on amalgamation, less than 

1 percent of all lode gold was produced using this process. By the early 1990s, the use of 

mercury amalgamation was largely phased out in the United States; in 1991, cyanidation and 

direct processing (i.e. smelting) were used to process 99 percent of all gold produced (U.S. EPA 

1994). Based on information reviewed for this report, no gold production companies in the U.S. 

currently use the mercury amalgamation process to produce gold. In contrast to the early years 

of mining in the United States, 72 percent of the gold mined between 1900 and 1998 originated 

from precious metal lodes; 14 percent came from placer deposits and 14 percent was recovered 

as a byproduct of base-metal mining. Currently, 93 percent of gold produced in the United 
Section 2.0 Background Information 

3 

States is derived from precious metal mines, with 6 percent coming from base-metal mining and 

just 1 percent from placer mines (Butterman and Amey 2005). 

2.3 Production Amounts and Prices 

Since gold mining began over two hundred years ago in the United States, approximately 

15,200 tons of gold has been produced. Ninety percent of this has originated from seven states: 

Nevada, California, South Dakota, Colorado, Alaska, Utah, and Montana. The remaining 10 

percent of the country’s cumulative gold production was mined in 17 other states, for a total of 

24 gold producing states. Nearly all of South Dakota’s gold production came from Homestake 

Mine, the longest operating mine in the United States, with 1,240 tons of gold produced between 

1876 and 2001 (Butterman and Amey 2005). 

From the beginning of the 20th century to around 1920, gold production in the United 

States ranged between 100 and 150 tons per year. As seen in Figure 1, production then dropped 

to about 70 tons per year and then briefly spiked back up to around 150 tons per year an in the 

late 1930s and early 1940s as a result of the opening of many small mines to provide jobs during 

the Depression (Butterman and Amey 2005). With the advent of World War II, gold production 

declined sharply and continued to decline steadily until it reached around 30 tons per year in 

1979 and 1980. Around 1980, a combination of factors, including strong demand and high 

prices led to a sharp increase in gold production. At this time, the cyanide heap leaching process 

was becoming a primary means for gold extraction. Because the unit cost of gold production is 

largely dependent on the grade of the ore and the efficiency with which the gold can be 

extracted, the development of processes which improve efficiency of removal, such as heap 

leaching, allow for lower-grade ores to be mined without an increase in cost. By the late 1990s, 

yearly gold production in the United States reached over 350 tons (Butterman and Amey 2005); 

of this amount, over 250 tons, or approximately 70 percent, came from mines in Nevada (Figure 

1) (Nevada Division of Minerals 2006). At the beginning of the 21st century, gold production in 

the U.S. began to decline, while prices rose (Figures 2 and 3). In 2005, the United States 

produced about 262 tons of gold, with 217 tons (83 percent) coming from Nevada (NMA 2006); 

at this time, there were about 19 companies producing gold in the United States. The two 

companies with the greatest production were Barrick Gold Corporation and Newmont Mining 

Corporation, which contributed approximately 66 percent of the total gold produced in the U.S. 

(NMA 2006). As of 2001, the top 5 gold producing operations in the country (shown in Table 1) 

were all in Nevada. 

As seen in Figure 1, the gold mining industry is a fairly dynamic one with new mines 

coming on line and old ones being retired. The next few years are expected to continue this 

trend. The richest production reserves occur in an area known as the Carlin Trend in Nevada. 

Development of the Carlin Trend has catapulted Nevada to the top gold mining spot in the U.S. 

This is due in part to the richness of the trend and also due to advances in technology that allow 

for development of reserves hitherto considered uneconomic to develop. Mining reports give the 

Carlin Trend a continued life of about 7-8 years. In the face of declining Carlin Trend reserves, 

the mining industry has understandably been casting further afield in search of new reserves. It 

appears that their efforts have been successful – the Cortez Trend (also in Nevada) is expected to 

be almost as productive as the Carlin Trend. Already, mines are coming online (e.g., Golden 

Phoenix) and others are being permitted. 
Section 2.0 Background Information 

4 

0

50

100

150

200

250

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400

19071912191719221927193219371942194719521957196219671972197719821987199219972002

Year

U.S. gold production (metric tons)

0

100

200

300

400

500

600

700

Price ($) per ounce gold

U.S. gold production

NV gold production

Price

Figure 1. United States gold production and price of gold, 1907 to 2005 (Nevada Division of 

Minerals 2006 and Butterman and Amey 2005).
Section 2.0 Background Information 

5 

0

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350

2001 2002 2003 2004 2005

Year

U.S. gold production (metric tons)

0

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450

Average price ($) per ounce

Total

Nevada

Non-Nevada

Price per ounce

Figure 2. United States gold production and price of gold, 2001 to 2005 (NMA 2006 and 

Nevada Division of Minerals 2006).

2.4 Gold Mining Processes Currently Used in the U.S. 

This section describes current gold mining processes and their potential to emit mercury. 

2.4.1 Extraction, Crushing, and Milling 

The first step in the gold production process is the removal of gold-containing ores from 

the earth. In both surface and underground lode mining, the extraction of ores is typically 

accomplished through calculated blasting and drilling, as well as through the use of earthmoving 

machinery. Placer mines, though currently far less common as gold sources in the U.S., rely on a 

combination of traditional land excavation techniques and hydraulic equipment, including 

dredges and high-pressure water nozzles. After the ore has been removed from the ground, jaw 

and cone crushers are used to reduce the large pieces of ore in size; mills are used next to grind 

ore particles to an even smaller, consistent size (Butterman and Amey 2005). Crushing and 

milling do not represent a significant source for mercury emissions because neither chemical 

reactions nor heat treatments occur in these processes (U.S. EPA 2001b). 
Section 2.0 Background Information 

6 

2.4.2 Roasting and Autoclaving 

If the process of cyanide leaching can extract 88 percent or more of the gold contained in 

a milled ore with no further processing, the ore is referred to as amenable, and if not, the ore is 

described as refractory (Butterman and Amey 2005). Factors such as the presence of organic 

carbon and sulfide mineral grains in refractory ores inhibit the efficiency of gold recovery during 

cyanide leaching; both ore roasters and autoclaves are used to oxidize and remove these 

components. An ore roaster is an industrial furnace in which milled ore is mixed with coal or 

other fuel material and combusted across a fluidized bed. During roasting, mercury sulfide is 

converted to elemental mercury and sulfur dioxide (U.S. EPA 2001b). The elemental mercury is 

emitted in vapor form with the roaster off gas, which is typically vented to air pollution control 

devices such as sulfur dioxide scrubbers, baghouses, and electrostatic precipitators; however, 

removal efficiencies for elemental mercury vapor are low for these devices (e.g., SO2 scrubbers 

provide an average mercury removal of only about 25 percent from roasters based on available 

data) (U.S. EPA 2001a). 

Autoclaving involves pumping a slurry of milled ore, water, and sulfuric acid into a 

vessel which is highly pressurized with oxygen and heated to 350 to 430o F. The result of this 

process is that at least 95 percent of sulfide minerals in the ore are oxidized to sulfates. During 

autoclaving, mercury sulfide combines with oxygen to form mercury sulfate (HgSO4), which 

dissociates to some degree in the slurry. Consequently, the mercury present in gaseous 

emissions from the autoclave is typically Hg2+ and can be effectively controlled using a venturi 

scrubber system (U.S. EPA 2001b). As described in Section 3, three facilities in U.S. use 

autoclaves, and all three of these facilities are located in Nevada. 

2.4.3 Leaching 

Leaching generally takes place either directly after milling or after roasting and/or 

autoclaving. In heap leaching, ore is stacked on a large impervious pad that drains to a collection 

pond; an alkaline cyanide solution is dispersed over the ore and percolates through the heap, 

which can range in size from less than 50,000 tons to greater than 300,000 tons. As the cyanide 

comes into contact with the gold contained in the ore, a gold-cyanide solution is formed, which 

seeps down to the liner and flows out to the collection pond. During this process, mercury may 

be leached into the gold-cyanide solution; the amount of mercury leached is dependent on the 

concentration of the cyanide solution as well as the presence or absence of additives designed to 

suppress mercury dissolution. The solution containing the precious metals is called the 

“pregnant” cyanide solution. Regional testing performed in Nevada has indicated that around 20 

percent of the mercury in the ore is leached along with the gold (U.S. EPA 2001b). However, 

despite the potential for mercury to leach along with the gold, heap leaching does not represent a 

significant source for mercury emissions, because the mercury remains in either solid or liquid 

form during the process (U.S. EPA 2001b). 

2.4.4 Carbon Stripping and Regeneration 

After leaching, the gold complexes in the pregnant cyanide solution are concentrated 

through adsorption onto activated carbon; if mercury is present in the gold-cyanide solution, it 

too is adsorbed onto the carbon. The adsorbed gold and mercury are then stripped from the 

carbon through desorption under pressurized or atmospheric conditions, typically using a heated 

caustic cyanide solution, resulting in a more concentrated gold-containing solution. Before reuse 
Section 2.0 Background Information 

7 

in the adsorption-desorption process, the carbon is regenerated in a rotary kiln. As the carbon is 

heated, mercury which remained on the carbon after stripping is released as elemental mercury 

vapor and vented, along with steam and carbon monoxide, to pollution control devices or directly 

to the atmosphere. Carbon adsorption filters are the only mercury-specific control device used 

on for carbon regeneration rotary kilns at mines in the United States; particulate control devices 

are ineffective in controlling elemental mercury vapor (U.S. EPA 2001b). 

The carbon adsorption filters used to control mercury emissions from the carbon 

regeneration system or any other gold mining process must be periodically replaced. The spent 

carbon filters may be landfilled or the carbon in the filters may, in turn, be regenerated, typically 

by sending the filters to an off-site carbon regenerator. Unless the off-site regenerator has 

mercury controls, this practice will simply delay and shift the mercury emissions; it will not 

result in true mercury reductions. Therefore, the disposition of the carbon used in carbon 

adsorption control systems is important to consider when evaluating the ultimate mercury 

reduction achieved by the carbon adsorption control system.

2.4.5 Recovery from Solution 

Gold is recovered from solution in one of two ways: electrowinning or precipitation with 

zinc powder. 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. 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. Zinc powder can also be used to recover gold from solution because 

zinc has a higher affinity for cyanide ions than does gold or other metals. Therefore, when zinc 

powder is added to the cyanide solution, the zinc dissolves and the other metals precipitate out 

and are extracted by filtration. Because zinc precipitation typically takes place within a closed 

cell, mercury emissions from this process are limited (U.S. EPA 2001b). 

2.4.6 Retorting and Smelting 

After the separation of gold from solution by electrowinning or precipitation, gold must 

be extracted from other remaining metals. This is accomplished through retorting and then 

smelting. A retort heats the gold and other metals under a vacuum for 12 to 24 hours at 600°C to 

700°C; around 99 percent of the mercury is removed. The majority of this mercury is condensed 

and collected, but a small percentage is emitted as vapor with the off-gas, which is typically 

controlled by a carbon adsorption filter where 95% control efficiency can be expected (U.S. EPA 

2001b). Smelting is the last step in gold production before the gold is sent to a refinery. The 

gold, along with a material with reducing potential known as flux, is heated to around 1500°C, at 

which time most of the remaining mercury is volatilized as elemental mercury. Emissions from 

the smelting furnace are typically vented through a fume hood; venturi scrubbers have been 

applied to reduce mercury emissions from these furnaces (U.S. EPA 2001b). 
Section 3.0 U.S. Gold Mining Industry Survey 

8 

3.0 U.S. Gold Mining Industry Survey 

The U.S. EPA’s Office of Air Quality Planning and Standards (OAQPS) and State of 

Nevada’s Division of Environmental Protection (NDEP) coordinated efforts to develop 

questionnaires designed to gather information on mercury emissions and controls from gold and 

silver production facilities in the U.S. The NDEP administered the survey questionnaires to all 

gold and silver production facilities in Nevada, and the EPA administered the survey 

questionnaire to additional gold and silver production facilities in the United States but not in 

Nevada. Responses to both of these survey questionnaires were compiled. This section 

describes the survey and summarizes general facility information and production data obtained 

from the survey responses. Section 4 summarizes the specific mercury emissions data reported 

in the survey responses. As described in the introduction, we generally refer to the gold and 

silver mines collectively as simply gold mines because all of the respondents produce gold and 

no respondents produce only silver. Therefore, mines that produce silver are a fully included 

subset of gold mines. Also as described in Section 2.3, the gold mining industry is a fairly 

dynamic one with new mines coming on line and old ones being retired. Therefore, it is 

important to understand that the industry survey presented here is merely a snapshot of the 

industry in the 2004/2005 time-frame, and the complexion of the industry may be significantly 

different in 10 years. 

3.1 Description of Industry Survey 

Representatives from the U.S. EPA (including OAQPS, Region 9 and Region 10), the 

NDEP, and industry representatives collaborated in developing a questionnaire to gather 

information about mercury emissions from precious metals mining in general, and gold mining 

in specific. The questionnaire focused on collecting mercury air emissions data from thermal 

operations used to process gold ore. The questionnaires included questions about amount of ore 

processed, mercury content in the ore, types of processes used, control technologies applied, and 

pollution prevention measures used. The questionnaire was divided into three sections: a 

general facility information section; a series of tables specific to thermal gold mining processes; 

and a series of tables specific to mercury emission controls. If a facility did not use thermal 

processes, then only the general information was requested. Additionally, in the EPA version of 

the questionnaire only general information was requested from facilities that processed gold ore 

that contained 0.1 milligram per kilogram (mg/kg) regardless of whether or not thermal 

processes were used. 

The NDEP finalized its questionnaire in January 2006, which was intended for mining 

facilities located within the State of Nevada. The Nevada questionnaire is available on the 

internet at: http://ndep.nv.gov/mercury/mercury_air.htm. The Nevada questionnaire was sent to 

all silver and gold mining production companies with operations in the State of Nevada, and 

requested data specific to their Nevada precious metal mining operations. Fifty-one facilities 

completed and returned the Nevada survey questionnaire. 

The U.S. EPA administered a very similar questionnaire in early 2006. This second 

questionnaire was intended for gold mining operations located in the U.S., but that were outside 

of the State of Nevada. The U.S. EPA questionnaire is shown in Appendix 1 of this report. In 

April 2006, the U.S. EPA sent this questionnaire to seven gold producing companies in the 
Section 3.0 U.S. Gold Mining Industry Survey 

9 

United States that operate mines located outside of Nevada. One company operated two 

facilities outside of Nevada; the other companies either had only one operating facility outside of 

Nevada or no longer operated a mining facility outside of Nevada. 

3.2 Summary of Survey Respondents 

Fifty-one gold mining facilities in Nevada and 8 gold mining facilities outside Nevada 

responded to the survey. The non-Nevada facilities were located in Alaska, California, 

Colorado, Montana, and Washington. Nearly half of the responding facilities in Nevada were 

subsidiaries of either Newmont Mining Corporation or Barrick Gold Corporation; fourteen 

belonged to Newmont and nine to Barrick. Twenty-four of the Nevada facilities are currently 

mining or processing ore, while six of the eight facilities that responded to the survey from the 

rest of the United States are currently operating. In addition, three facilities (two in Nevada and 

one in Washington) indicated that mining operations would begin or resume in the future. 

Table 1 provides the number of respondents for some of the key questions in the survey. 

Note that mercury emissions were requested in two sections of the questionnaire. First, 

facilities were requested to report their total facility-wide mercury air emissions. For facilities 

with thermal operations, mercury emission estimates were also requested individually for each 

thermal process unit. For the EPA version of the survey, individual thermal process unit data 

were not requested for facilities that had low mercury content. A total of 24 facilities reported 

either total facility mercury emissions, process-specific mercury emissions, or both. Eighteen of 

these facilities are located in Nevada and six facilities are located in other states. As shown in 

Table 1, nineteen facilities reported estimates for total mercury emissions (14 Nevada facilities 

and 5 non-Nevada facilities). Nineteen facilities reported mercury emissions by thermal process 

unit; seventeen of these facilities were in Nevada and two were outside of Nevada. Fourteen 

facilities provided mercury emissions estimates on both a facility-total basis and thermal processspecific basis. More details regarding the reported quantity of mercury emissions are provided in 

Section 4.

Table 1. Summary of the Type of Mercury Emissions Information Received in the 

Responses to the Questionnaires. 

Description Nevada U.S. EPA Total 

Number of facilities responding to survey 51 8 59 

Number of facilities currently operating 24 6 30 

Number of facilities producing gold 20 7 27 

Number of facilities producing silver 17 7 24 

Number of facilities producing mercury by-product 13 1 14 

Number of facilities processing mercury-containing 

ore 

25 3 28 

Number of facilities with ore mercury concentrations of 

0.1 mg/kg or greater 18 2 20 

Number of facilities reporting thermal processes 20 4 24 

Number of facilities reporting facility-wide mercury 

emissions 14 5 19 

Number of facilities reporting process-specific mercury 

emissions 17 2 19 

Number of facilities reporting both facility-wide and 

process-specific mercury emissions 13 1 14 
Section 3.0 U.S. Gold Mining Industry Survey 

10 

3.3 Survey Characterization of Current Gold Mining Industry 

Table 2 shows the processing and production quantities for Nevada gold mines compared 

to non-Nevada gold mines. Most survey respondents reported data for 2004 but some facilities 

provided data for 2005. Therefore, the survey data are reported for “the 2004/2005 timeframe.” 

Nevada facilities produced a total of 7,004,270 ounces of gold and 10,532,992 ounces of silver 

annually in the 2004/2005 time frame; mines outside of Nevada produced 944,561 ounces of 

gold and 9,418,246 ounces of silver. Based on these results, Nevada mines represent almost 90 

percent of the U.S. gold production and approximately 50 percent of the U.S. silver production. 

The top gold producer in Nevada was Barrick Goldstrike Mines, which produced 1,942,660 

ounces of gold in 2005, more than twice the gold produced from all Non-Nevada facilities 

combined. Detailed facility-specific information on gold, silver, and mercury production and on 

mercury emissions based on the questionnaire responses is provided in Appendix 2. 

Table 2. Summary of Production and Mercury Emissions from Gold Mining Facilities in 

the United State, 2004/2005 Timeframe.

Nevada Non-Nevada Total 

Tons ore processed (all facilities) 185,132,897 48,308,714 233,441,611

Ounces gold produced 7,004,270 944,561 7,948,831

Ounces silver produced 10,532,992 9,418,246 19,951,238

Pounds elemental mercury produced 202,954 0 202,954

Pounds calomel produced 33,497 0 33,497

In extracting this gold, seventeen Nevada facilities reported processing 185,132,897 tons of ore 

in 2004/2005 timeframe, while seven non-Nevada facilities processed 48,308,714 tons. 

Additional ore processing information is summarized in Table 3. In the EPA survey (nonNevada mines), only facilities processing ore with mercury concentrations greater than or equal 

to 0.1 milligram mercury per kilogram ore (0.1 mg/kg) were asked to report amounts of ore 

processed by process type (e.g. autoclaving, roasting, heap leaching, etc.). As such, only two of 

six operating non-Nevada facilities reported totals for ore processing by process type (i.e. 

autoclaving, roasting, heap leaching, etc.), whereas fifteen of the seventeen Nevada facilities 

reported the process-specific ore processing information. Upon initial calculations, the reported 

amount of total ore processed by these facilities was 140,625,427 tons in Nevada and 4,503,764 

tons outside of Nevada; the calculated amount of total ore processed by these facilities (that is, 

the sum of the amounts processed for each process type) was 174,405,287 tons in Nevada and 

4,503,764 tons in Non-Nevada states. The reported and calculated totals matched for the NonNevada facilities, but the calculated amount of total or processed for Nevada mines was 

significantly higher than the total reported by these facilities. It was apparent that one facility, 

Round Mountain Gold Corporation – Smoky Valley Common Operations, reported a quantity of 

total ore processed (7,801,552 tons) that was lower than the amount reported as being heap 

leached (52,641,580 tons). Given that the total ore processed should include the quantity of ore 

that was heap leached, it was assumed that one of these numbers was reported incorrectly. Based 

on the amount of gold produced at this facility, it was concluded that the total quantity of ore 

processed had been reported incorrectly. Therefore, the total quantity of ore processed was 
Section 3.0 U.S. Gold Mining Industry Survey 

11 

assumed to be equal to the sum of ore heap leached and carbon in leach of milled ore. After this 

correction, the reported amount of total ore processed by Nevada facilities reporting processspecific data was 183,672,254 tons; this figure better corresponded with the calculated amount of 

total ore processed by these facilities (174,405,287 tons) than did the total before the correction. 

The remaining difference between the reported and calculated amounts of total ore processed is 

likely a result of several facilities using processes other than roasting, autoclaving, and heap 

leaching to process ore. 

Table 3. Tons of Ore Processed by Process Type, 2004/2005 Timeframe. 

Nevada Non-Nevada Total 

All facilities 

 Tons ore processed 185,132,897 48,308,714 233,441,611

Facilities reporting amounts by process 

 Tons ore processed 183,672,254 4,503,764 188,176,018

 Tons ore roasted 10,135,483 0 10,135,483

 Tons ore autoclaved 11,356,265 0 11,356,265

 Tons heap leaching 141,423,965 4,225,516 145,649,481

 Tons carbon in leach of milled ore 11,489,574 278,248 11,767,822

 Tons other ore processed 9,266,967 0 9,266,967

Of the ore processed in Nevada, 10,135,483 tons were autoclaved and 11,356,265 tons 

were roasted; no autoclaving or roasting was reported at non-Nevada facilities. In Nevada, 

141,423,965 tons of ore were heap leached, while facilities outside of Nevada processed 

4,225,516 tons of gold through heap leaching. In addition to heap leaching, Nevada facilities 

used carbon in leach to extract gold from 11,489,574 tons of milled ore and 21,501,656 tons of 

roasted/autoclaved ore. Only one non-Nevada facility used the carbon in leach process for gold 

extraction, with 278,248 tons of milled ore processed in this way. 

Twenty-two of the twenty-four currently operating facilities in Nevada process ores that 

contain mercury; eighteen of these have ores with mercury concentrations greater than 0.1 mg/kg 

(Figure 3). Three currently operating non-Nevada facilities process mercury containing ores, and 

both locations have mercury concentrations greater than 0.1 mg/kg in the ore. Nevada mines 

reported producing 202,954 pounds of elemental mercury and an additional 33,497 pounds of 

calomel (mercury chloride) in 2004/2005; facilities in the rest of the United States did not report 

any mercury production. (Note: one of the two non-Nevada mines that have mercury 

containing ores did indicate that they produce mercury, but they did not report a mercury 

production quantity. Mines that do not produce mercury product are expected to have higher 

mercury emissions than those that recovery mercury, all other variables being equal). 
Section 3.0 U.S. Gold Mining Industry Survey 

12 

Figure 3. Currently operating U.S. gold mines processing mercury-containing ores 

Number of currently operating US gold mines 

processing mercury-containing ores

NV, >0.1 mg/kg 

mercury

18

Non-NV, >0.1 

mg/kg mercury

3

NV, ≤0.1 mg/kg 

mercury

4
Section 4.0 Mercury Emissions from Gold Mines

13 

4.0 Mercury Emissions from Gold Mines 

This section presents data on mercury emissions from gold mines. Mercury emissions 

reported in response to the industry survey are first presented, and then they are compared to 

mercury emissions reported in the Toxics Release Inventory (TRI) and the National Emissions 

Inventory (NEI). 

4.1 Gold Mining Mercury Emissions from Industry Surveys 

In the EPA and Nevada questionnaires, facilities were requested to report their total 

mercury air emissions on a facility-wide basis and, for facilities with thermal operations, their 

mercury emissions for each thermal process unit. Respondents to the industry survey did not, as 

a rule, provide information on how these emission estimates were developed. Additionally, 

some respondents did not report any mercury emissions even though they did report processing 

mercury-containing ore. Therefore, the information provided were generally inadequate to 

characterize the uncertainty in the mercury emissions reported. The mercury emission values as 

reported are provided in the following subsections. Additional discussion of the uncertainties 

and potential biases in the reported mercury emission estimates are provided in Section 4.5. 

4.1.1 Facility Total Mercury Emissions 

Table 4 summarizes the reported mercury emissions from the gold and silver mines 

responding to the industry survey. Based on the industry survey responses, Nevada gold and 

silver mines produce approximately 90 percent of the gold, but release approximately 99 percent 

of the mercury emissions from the U.S. gold and silver mines. The annual mercury emissions 

for all facilities in Nevada in the 2004/2005 timeframe were 4,487 pounds per year. Almost half 

of Nevada’s mining mercury emissions came from just one facility, Barrick Gold Corporation’s 

Goldstrike Mines, which emitted an estimated 2,175 pounds of mercury in 2005. The vast 

majority of Nevada’s remaining mining mercury emissions came from four facilities: Newmont 

Mining Corporation’s Gold Quarry Operations; Newmont Mining Corporation’s Twin Creeks 

Mine; Barrick Gold Corporation and Kennecott Minerals, Inc.’s Cortez Gold Mine; and 

Queenstake Resources Ltd.’s Jerritt Canyon Mine (Table 4). Five gold and silver mining 

facilities from the rest of the United States provided total mercury emissions estimates for the 

2004/2005 timeframe; these emissions totaled 41.1 lbs, less than one percent of the emissions 

from the Nevada mines. 

4.1.2 Thermal Process Mercury Emissions 

Gold mining facilities that had thermal process units were requested to estimate their 

mercury emissions on a process-specific basis for each thermal process unit. The number of 

facilities reporting thermal processes and the total mercury emissions by process type as reported 

by the survey respondents are summarized in Table 5. Of the facilities currently operating in the 

United States that reported using thermal processes, twenty were in Nevada and four were 

outside the state of Nevada. Seventeen Nevada facilities reported mercury emissions for the 

2004/2005 timeframe by thermal process unit (of the 20 Nevada facilities reporting to operate 

thermal process units). Mercury emissions from Nevada’s thermal process units were reported to 

be 4,176.3 pounds per year. Autoclaves, roasters, and carbon regeneration kilns were 
Section 4.0 Mercury Emissions from Gold Mines

14 

responsible for 90 percent of these emissions, with 3,760.5 pounds of mercury released from 

these sources. Only two non-Nevada facilities reported emissions by thermal process unit (of the 

4 non-Nevada facilities reporting to operate thermal process units), although a third facility, 

Apollo Gold’s Montana Tunnels, provided information regarding emissions from its refinery 

furnace. No autoclaves or roasters were used by non-Nevada facilities, so these significant 

thermal processes are not present at non-Nevada mines. Non-Nevada mines reported minimal 

mercury emissions from thermal processes (0.6 pounds in 2004/2005). However, it is important 

to note that not all of the non-Nevada mines with thermal processes reported mercury emissions, 

and that we could not verify the basis of the mercury emissions for most of the non-Nevada 

mines. 

Table 4. Summary of Facility-Total Mercury Emissions in the 2004/2005 Timeframe. 

Parent company Facility name 

Quantity of 

Ore 

Processed 

(tons/yr) 

Quantity 

of Gold 

Produced 

(oz/yr) 

Total 

Mercury 

Emissions 

(lbs/yr) 

% of Total 

Mercury 

Emissions

Nevada Gold and Silver Mines 

Barrick Goldstrike Mines 12,809,234 1,942,660 2,174.6 48.0

Newmont Gold Quarry Operations 22,090,847 872,945 658.8 14.5

Newmont Twin Creeks Mine 7,123,665 1,123,755 563.0 12.4

Barrick/Kennecott* Cortez Gold Mines 41,603,701 999,961 492.0 10.9

Queenstake Jerritt Canyon Mine 1,305,833 242,912 461.0 10.2

 Other Nevada mines 100,199,617 1,822,037 137.6 3.0

Subtotal: Nevada mines 185,132,897 7,004,270 4,487.0 99.1

Non-Nevada Gold and Silver Mines 

 All non-Nevada mines 43,308,714 944,561 41.1 0.9

Nationwide Total Based on Survey Responses 228,441,611 7,948,831 4,528.1 100.0

* Barrick 60%, Kennecott 40%

Table 5. Summary of Mercury Emissions by Thermal Process (2004/2005 Timeframe). 

Process # NV facilities 

NV Mercury 

Emissions (lbs) 

# Non-NV 

facilities 

Non-NV 

Mercury 

Emissions (lbs) 

Autoclaving 3 899.4 0 0.0

Roasting 3 1247.9 0 0.0

Carbon regeneration kiln 12 1613.2 3 0.1

Electrowinning 13 80.7 3 0.0

Retorting 13 18.7 0 0.0

Smelting furnace 16 134.9 2 0.4

Other thermal processes 35 181.6 2 0.0

Total 4176.3 0.6
Section 4.0 Mercury Emissions from Gold Mines

15 

4.1.3 Thermal Process Mercury Emission Controls 

Table 6 provides an overview of the types of controls that have been applied to each type 

of thermal processes. As seen in Table 6, thermal process units are used predominately at the 

Nevada mines. Additionally, air emission controls (and specifically mercury air emission 

controls) are used predominately at the Nevada mines. Due to their significance to the total 

annual mercury emissions, process-specific controls and estimated mercury emissions are 

provided for autoclaves, roasters, and carbon regeneration kilns in Tables 7 through 9, 

respectively. 

As seen in Table 7, three Nevada facilities used autoclaving, with a total of nine 

autoclaves used in the state. No non-Nevada mines used autoclaves. Each of the nine autoclaves 

was attached to a wet scrubber, with one unit also attached to an off-gas quencher. Total 

mercury emissions from these units were 899.4 pounds. 

Table 6. Summary of Thermal Process Units and Controls Used by Gold Mines in the 

United States, 2004/2005 Timeframe. 

Process # NV 

facilities 

# NV 

units NV controls 

# NonNV 

facilities 

# NonNV 

units 

Non-NV 

controls 

Autoclave 3 9 Off-gas quencher 

Wet scrubber 0 0 Not applicable 

Roaster 3 8 

Condenser 

Electrostatic precipitator 

Fabric filter 

Off-gas quencher 

Wet scrubber 

0 0 Not 

applicable 

Carbon 

regeneration 

kiln 

12 16 

Carbon adsorption unit 

Condenser 

Wet scrubber 

3 3 Wet scrubber 

Electrowinning 13 13 Carbon adsorption unit 

Wet scrubber 3 6 Wet scrubber 

Retort 13 28 

Carbon adsorption unit 

Condenser 

Cyclone 

Fabric filter 

Mist eliminator 

Wet scrubber 

0 0 Not 

applicable 

Smelting 

furnace 16 23 

Carbon adsorption unit 

Electrostatic precipitator 

Fabric filter 

Wet scrubber 

2 2 Wet scrubber 

Other thermal 

process 

13 127 

Carbon adsorption unit 

Fabric filter 

Wet scrubber 

2 2 Fabric filter 
Section 4.0 Mercury Emissions from Gold Mines

16 

Table 7. Summary of Gold Mining Facilities Using Autoclaves in the United States.

Parent 

company Facility name State 

Total ore 

processed by 

facility (tons) 

Unit 

ID Control technologies 

Estimated mercury 

emissions from unit 

(pounds) 

Newmont Lone Tree Mine NV 6,068,995 01 Wet scrubber (1993)* 

Off-gas quencher (2002) 

No data

Newmont Twin Creeks Mine NV 7,123,665 01 Wet scrubber (1996) 286

Newmont Twin Creeks Mine NV 7,123,665 02 Wet scrubber (1996) 64.93

Barrick Goldstrike Mines NV 12,809,234 01 Wet scrubber (1990) 70.7

Barrick Goldstrike Mines NV 12,809,234 02 Wet scrubber (1992) 97.05

Barrick Goldstrike Mines NV 12,809,234 03 Wet scrubber (1992) 97.05

Barrick Goldstrike Mines NV 12,809,234 04 Wet scrubber (1993) 95.2

Barrick Goldstrike Mines NV 12,809,234 05 Wet scrubber (1993) 94.25

Barrick Goldstrike Mines NV 12,809,234 06 Wet scrubber (1993) 94.25

Total >899.4

* Dates in parentheses indicate the year control unit was installed. 

Three Nevada facilities used roasting, with eight roaster units releasing 1,247.9 pounds of 

mercury (see Table 8). Seven of the roaster units were connected to a wet scrubber, with four 

units also connected to an off-gas quencher. Two units, including the one unit not controlled by 

a wet scrubber, were controlled with a fabric filter; electrostatic precipitators were also used on 

two units. No non-Nevada mines used roasters. 

Table 8. Summary of Gold Mining Facilities Using Roasters in the United States.

Parent 

company Facility name State 

Total ore 

processed 

by facility 

(tons) 

Unit 

ID Control technologies 

Estimated 

mercury 

emissions 

from unit 

(pounds) 

Barrick Goldstrike Mines NV 12,809,234 01 Wet scrubber (1999)* 

Electrostatic precipitator (1999) 

Off-gas quencher (1999) 

Condenser (1999) 

520.5

Queenstake Jerritt Canyon Mine NV 1,305,833 01 Wet scrubber (1999) 

Hypochlorite scrubber (2001) 

Off-gas quencher 

320.5

Queenstake Jerritt Canyon Mine NV 1,305,833 02 Wet scrubber (1999) 

Hypochlorite scrubber (2001) 

Off-gas quencher 

138.31

Newmont Gold Quarry 

Operations 

NV 22,090,847 01 Fabric filter (1994) 0.63

Newmont Gold Quarry 

Operations 

NV 22,090,847 02 Fabric filter (1994) 

Wet scrubber (1994) 

267.05

Newmont Gold Quarry 

Operations 

NV 22,090,847 03 Wet scrubber (1994) 

Electrostatic precipitator (1994) 

Off-gas quencher 

0.75

Newmont Gold Quarry 

Operations 

NV 22,090,847 04 Wet scrubber (1994) 0.065

Newmont Gold Quarry 

Operations 

NV 22,090,847 05 Wet scrubber (1994) 0.065

Total 1,247.9

* Dates in parentheses indicate the year control unit was installed. 
Section 4.0 Mercury Emissions from Gold Mines

17 

As seen in Table 9, twelve Nevada facilities and three non-Nevada facilities used carbon 

regeneration kilns, with a total of 19 units emitting an estimated 1613.3 pounds of mercury. 

Twelve units were connected to a wet scrubber to control emissions, with four of these units also 

using a carbon adsorption unit and one of the units using a hypochlorite scrubber (to enhance 

mercury control). An additional unit used a carbon absorption system alone. One unit using 

both a wet scrubber and a carbon absorption unit was also connected to a condenser. The 

remaining six units used no controls. 

Thirteen Nevada facilities used electrowinning, with thirteen units emitting an estimated 

80.7 pounds of mercury; one of these units had a wet scrubber, one had a carbon adsorption unit, 

and one had both, with rest of the units uncontrolled. Three facilities outside of Nevada had six 

electrowinning units, but no mercury emissions were reported from them; one of these units was 

controlled with a wet scrubber. Thirteen Nevada gold mines used retorting, with 28 retort units 

emitting an estimated 18.7 pounds of mercury; every unit was connected to at least one control 

device, with carbon adsorption units, condensers, cyclones, fabric filters, mist eliminators, and 

wet scrubbers being used. No facilities outside of Nevada reported using retorts. 

Sixteen Nevada mines reported having smelting furnaces, with a total of 23 such furnaces 

emitting an estimated total of 134.9 pounds of mercury. Twenty of the furnaces were connected 

to at least one control, with fourteen connected to a fabric filter and seven connected to a wet 

scrubber; four units also used electrostatic precipitators and one used carbon adsorption unit. 

Two non-Nevada facilities also used one smelting furnace each, but only reported a total of 0.44 

pounds of mercury emissions; one unit was connected to a wet scrubber and one unit had no 

control device. Thirteen Nevada facilities reported using a thermal process other than the 

primary processes listed above, with 127 such units emitting an estimated 181.6 pounds of 

mercury. The two non-Nevada units using other thermal processes reported negligible emissions 

(0.02 pounds) from their two units. 

4.2 Gold Mining Mercury Emissions from the TRI 

The TRI provides yearly estimates of toxic releases into the environment from 1998 to 

2005; data from the TRI was extracted using the basic TRI Explorer queries. The TRI Explorer 

includes a query function for predefined industrial sectors. One of the predefined industry 

sectors is “metal mining” as designated by general standard industrial classification (SIC) code 

of 10. Facility specific data were extracted for the metal mining industry (SIC code = 10) for 

the inventory years of 1998 through 2005. Each facility was designated as either a “Nevada gold 

mining” facility, a “non-Nevada gold mining” facility, or an “other metal mining” facility. The 

“mercury emissions” presented in this section are the sum of the reported on-site air emissions of 

both mercury and mercury compounds. The results of the TRI data analysis are presented in 

Figure 4. 
Section 4.0 Mercury Emissions from Gold Mines

18 

Table 9. Summary of Gold Mining Facilities Using Carbon Regeneration Kilns in the 

United States.

Parent 

company Facility name State 

Total ore 

processed 

by facility 

(tons) 

Unit 

ID Control technologies 

Estimated 

mercury 

emissions 

from unit 

(pounds) 

Newmont Lone Tree Mine NV 6,068,995 01 None No data

Newmont Lone Tree Mine NV 6,068,995 02 Wet scrubber (1992)* No data

Florida 

Canyon/ 

Jipangu 

International 

Florida Canyon Mine NV 6,256,953 01 None No data

Newmont Battle Mountain Gold, 

Reona and Phoenix 

Projects 

NV 1,940,439 01 Wet scrubber (2005) No data

Kinross/ 

Barrick 

Round Mountain Gold, 

Smoky Valley 

Common Operation 

NV 7,801,552 01 None 13.6

Barrick/ 

Kennecott 

Cortez Gold Mines Mill 

#2 (Pipeline Mill) 

NV 41,603,701 01 Wet scrubber (2005) 230

Barrick/ 

Kennecott 

Cortez Gold Mines Mill 

#2 (Pipeline Mill) 

NV 41,603,701 02 Wet scrubber (2005) 231

Golden 

Phoenix 

Mineral Ridge Mine NV 280,000 01 No data No data

Barrick Homestake Mining, 

Ruby Hill Mine 

NV 0 01 Wet scrubber (1997) No data

Newmont Twin Creeks Mine NV 7,123,665 02 Wet scrubber No data

Newmont Twin Creeks Mine NV 7,123,665 01 Wet scrubber (1987/1996) 

Hypochlorite scrubber (2003) 

21.78

Barrick Goldstrike Mines NV 12,809,234 01 Wet scrubber (1998/1999) 

Carbon adsorption unit 

(1998/1999) 

Condenser (1999) 

1064

Queenstake Jerritt Canyon Mine NV 1,305,833 01 Wet scrubber (2002) 

Carbon adsorption unit (2002) 

0.26

Newmont Gold Quarry 

Operations 

NV 22,090,847 01 Wet scrubber (1989) 

Carbon adsorption unit (1989) 

38.54

Newmont Gold Quarry 

Operations 

NV 22,090,847 02 Wet scrubber (1993) 

Carbon adsorption unit (1993) 

5.98

Barrick/ 

Placer Dome 

Bald Mountain Mine 

(including Mooney 

Basin) 

NV 2,225,405 01 Carbon adsorption unit (2004) 8.06

Barrick Golden Sunlight Mines MT 2,600,000 01 Wet scrubber 0.12

Kinross Echo Bay Minerals, 

Kettle River 

Operations 

WA 278,248 01 None No data

Western 

Goldfields 

Western Mesquite 

Mine 

CA 4,225,516 01 None No data

Total >1,613.3

* Dates in parentheses indicate the year control unit was installed. Two dates in parentheses indicate the years 

control unit was installed/rebuilt. 
Section 4.0 Mercury Emissions from Gold Mines

19 

0

2000

4000

6000

8000

10000

12000

14000

16000

1998 1999 2000 2001 2002 2003 2004 2005

Year

Total air emissions of mercury (lbs)

Total U.S. metal mining

Nevada gold mining

Non-Nevada gold mining

Other metal mining

Jerritt Canyon Mine

Barrick Goldstrike Mines

 

Figure 4. Mercury emissions from metals mining in the United States, 1998-2005 based on 

the Toxics Release Inventory. 

As seen in Figure 4, TRI’s on-site air emissions of mercury from gold mines steadily 

decreased from 1998 to 2005, dropping from 13,612 pounds in 1998 to about 4,908 pounds in 

2005. The majority of this decrease is attributable to emission reduction activities conducted at 

gold mines in the state of Nevada. The Nevada gold mines decreased their mercury emissions 

from 13,576 pounds in 1998 to about 4,681 pounds in 2005. Gold mines in the rest of the United 

States had some decrease in reported on-site air emissions during this time, with total on-site 

mercury air emissions of 271 pounds in 1998 and 71 pounds in 2005. As mercury emissions 

decreased more rapidly within Nevada than in other states, the percentage of total metal mining 

mercury emissions in the US that is attributable to Nevada gold mines decreased from 99.7% in 

1998 to about 95% in 2005. 

Between 1998 and 2001, Jerritt Canyon Mine, owned by Queenstake Resources USA, 

Inc., emitted approximately 4 tons per year (tpy) of mercury, well over 50 percent of total 

mercury emissions from the U.S. metal mining industry. With the installation of mercury 

emission control systems in 2001 and 2002, emissions from Jerritt Canyon dropped to just over 

790 pounds in 2003 or about 15 percent of total U.S. metal mining mercury emissions. As seen 

in Figure 4, the total metal mining industry emissions mirror the emissions reductions achieved 

by Jerritt Canyon. When Jerritt Canyon’s mercury emissions plunged in 2003, Barrick 

Goldstrike Mines became the highest emitting facility. As detailed in Table 8 in Section 4.1.3, 

Barrick had installed mercury controls in 1998 and 1999. Therefore, mercury emissions from 
Section 4.0 Mercury Emissions from Gold Mines

20 

Barrick were relatively stable at approximately 1,500 pounds per year between 1998 and 2003. 

In 2004, Goldstrike’s mercury emissions increased to 2,205 pounds, presumably due to changes 

in production level and/or mercury content in the ore; these emissions represented 43 percent of 

all mercury air emissions from the U.S. gold mining industry. In 2005, Goldstrike’s emissions 

decreased to 1701 pounds, representing 35 percent of all mercury air emissions from the gold 

mining in the United States. 

4.3 Gold Mining Mercury Emissions from the NEI 

Unlike the TRI which provides yearly data, the NEI only provides a snapshot of the 

emissions once every three years. The most recent inventory year for which NEI data are 

available is 2002. Data from the 2002 National Emissions Inventory corresponds reasonably 

well to data from the 2002 Toxics Release Inventory, with one exception. In the 2002 TRI, total 

mercury emissions from Barrick Goldstrike Mines are reported as 1,300 pounds, while the 2002 

NEI reported 5,920 pounds of mercury emissions from Barrick Goldstrike Mines. Consequently, 

the 2002 NEI’s total reported mercury emissions from gold mines reported were 13,010 pounds, 

4,140 pounds more than the 2002 TRI mercury emissions value of 8,870 pounds. 

4.4 Comparison of Reported Gold Mining Mercury Emissions 

Table 10 provides a comparison of the mercury emissions from the EPA/NDEP survey 

(2004/2005 timeframe), the 2004 TRI, and the 2002 NEI for gold mining facilities. A seen in 

Table 1, the 2002 NEI provides much higher mercury emissions for Barrick Goldstrike Mines 

and the Jerritt Canyon Mine. The higher mercury emissions estimate in the 2002 NEI for the 

Jerritt Canyon Mine agrees reasonable well with the 2002 TRI data, and the difference between 

the 2002 NEI and the other estimates are due to the emissions reductions achieved by Jerritt 

Canyon Mine through the application of mercury emission control systems. It is unclear why the 

2002 NEI mercury emission estimate for Barrick Goldstrike Mines is so much higher than the 

2004 TRI or NDEP survey estimates, especially noting the increase in emissions from the 

Barrick Goldstrike Mines between 2002 and 2004 as seen in Figure 4. 

The NDEP survey identifies Newmont’s Gold Quarry Operations as a significant 

mercury emissions producer; mercury emissions from these operations appear to be reported in 

the 2004 TRI and 2002 NEI under “South Operations” and “North Operations.” Even so, the 

NDEP mercury emission estimate for the Gold Quarry Operations a factor of two higher than the 

emissions reported in the 2004 TRI and almost 20 percent higher than the 2002 NEI estimate. 

On the other hand, the NDEP survey showed significantly lower mercury emissions from 

the Barrick/Kennecott Cortez Gold Mines than were reported in the TRI or NEI. The mercury 

emission estimate provided for the Cortez Gold Mines was specifically reported to be for 2004, 

so this discrepancy cannot be attributed to mercury emission reduction achieved by the 

installation of wet scrubber control systems on their carbon regeneration kilns in 2005. 

There is one non-Nevada gold mine, CR Briggs in California, that reported 62.5 pounds 

per year of mercury emissions in both the 2004 TRI and the 2002 NEI. This facility did not 

receive the EPA questionnaire, so the EPA/NDEP survey results do not include mercury 

emissions from this mine. While the NDEP questionnaire was sent to all Nevada mines, the EPA 

questionnaire was only sent to a handful of mines and is therefore only a survey of non-Nevada 
Section 4.0 Mercury Emissions from Gold Mines

21 

mines. Additional discussion of the uncertainties and biases of the survey results are discussed 

in the next section. 

4.5 Uncertainty and Biases in Mercury Emissions Estimates 

As mentioned previously, there are a few companies and facilities in the U.S. that 

produce gold and/or silver to which EPA did not send a questionnaire. For example, based on 

the 2004 TRI, there are 3 gold and/or silver production facilities that reported mercury releases. 

However, two of these facilities reported 0 pounds air emissions in the 2004 TRI and the third 

facility (CR Briggs, California) reported mercury air emissions of 62.5 pounds. Based on 

information received from a technical contact at CR Briggs, the facility operated from 1996 to 

2004 and is now in the reclamation phase. For 2005, this facility had estimated emissions of 

about 29 pounds. Thus, based on information in the TRI and other available information (e.g., 

from states), it appears that the questionnaires were sent to all significant gold producing 

operations, covering over 99 percent of total current mercury emissions from gold mines in the 

U.S.. Nonetheless, the lack of complete coverage of all non-Nevada gold mines does create a 

negative bias to the nationwide mercury emission estimates. 

Additionally, the lack of reporting of mercury emissions from gold mines that process 

mercury-containing ore, especially those that have thermal process units (as was the case for 

some non-Nevada mines), is expected to create a small negative bias. For one non-Nevada 

facility that did provide information on how they derived their mercury emissions, we considered 

the approach to be technically flawed. For this facility (Kinross – Fort Knox Mine), the reported 

mercury emissions per ton of gold produced was orders of magnitude lower than any other 

facility. Although they suggest that their TRI reported value is based on an assumption of 100 

percent mercury emissions, we believe the reported 2004/2005 TRI values are much more 

realistic. Nonetheless, even though we believe the mercury emissions reported by this factility in 

the EPA survey may be orders of magnitude too low, using a high-end emission estimate for this 

facility does not significantly alter the nationwide mercury emissions. Therefore, although there 

appears to be high uncertainty or bias for the emissions from the non-Nevada mines, the 

emissions from these facilities still appears to make little impact on the nationwide estimates for 

gold mining mercury emissions. These findings are consistent with the lower mercury content in 

the gold ores and the lack of autoclaves and roasters (primary emission sources) at the nonNevada gold mines. 

In addition to the bias discussed regarding non-Nevada gold mines, there is also a 

negative bias in the survey results caused by Nevada facilities not reporting their mercury 

emissions. Most notably, the Newmont Lone Tree Mine, which operates an autoclave and two 

carbon regeneration units, did not provide any mercury emission estimates. The TRI and NEI 

suggest nominal mercury emissions from this mine. However, this mine has mercury in its ore, 

produces a significant amount of gold, and has several thermal processing units, one of which is 

uncontrolled. As such, this mine is expected to have appreciable mercury emissions and the lack 

of mercury estimates for this mine creates a negative bias in the reported mercury emissions. 
Section 4.0 Mercury Emissions from Gold Mines

22 

Table 10. Comparison of Mercury Emission Estimates by Facility. 

Parent company Facility name State 

2004/2005 

EPA/NDEP 

Survey 

(lbs/year) 

2002 NEI 

(lbs/year) 

2004 TRI 

mercury 

emissions 

(lbs/year) 

2005 TRI 

mercury 

emissions 

(lbs/year) 

Barrick Goldstrike Mines NV 2174.6 5919.97 2205.24 1701

Barrick / Kennecott 

Cortez Gold Mines Mill #2 

(Pipeline Mill) NV 492 1052.9506 1342.6 851.5

Newmont South Operations Area NV - 507.998 262 690

Newmont Gold Quarry Operations NV 658.8 - - -

Newmont Twin Creeks Mine NV 563 524.001 327 592

Queenstake Jerritt Canyon NV 461 4737.99953 461.78 381.46

Glamis Glamis Marigold Mine NV - 0.9 184.9 327.6

Barrick / Placer 

Dome 

Bald Mountain Mine 

(including Mooney Basin) NV 53.25 0.3 51.8 83.5

 CR Briggs Corp CA Not surveyed 62.5 62.5 28.85465

Anglogold Ashanti / 

Golden Cycle 

Cripple Creek & Victor Gold 

Mining Company CO 34.3 37 34.3 34.3

Golden Phoenix Mineral Ridge Mine NV 33 - - -

Kinross / Barrick 

Round Mountain Gold - 

Smoky Valley Common 

Operation NV 22.6 0.6 0.12 23.3

Barrick Placer Turquoise Ridge Inc. NV - - 23.1 0.2

Newmont North Operations Area NV - 22.4 23.1 18.7

Newmont Midas Operations NV 12.97 - - -

Coeur d'Alene Coeur Rochester, Inc. NV 4.9 - 7.5 8

Kennecott/ Hecla 

Kennecott Greens Creek 

Mining Company AK 5.43 - 6.05 5.43

Florida Canyon / 

Jipangu Florida Canyon Mine NV 5.52 1.79 1.491 0.07

Newmont Lone Tree Mine NV - 9 4 2

Barrick Ruby Hill Mine NV 3 0.4 0 0

GoldSprings Plum Mining Company LLC NV 1.89 - - -

Barrick Golden Sunlight Mines, Inc. MT 0.12 0.1 0.4 1.7

Western Goldfields Mesquite Mine CA 1.2 - - -

Newmont McCoy/Cove Mine NV 0.5 - 0.5 -

Kinross Fort Knox Mine AK 0.0000111 113 0.12 0.13

Kennecott Barneys Canyon 

Mining Co UT Not surveyed 0.09 0.05 0.003

Homestake Mining 

Company CA Not surveyed 16.9033161 - -

Newmont Trenton Canyon Project NV - 1 0 -

Viceroy Gold Corp Castle 

Mountain CA Not surveyed 0.575786 0 -

 Ken Snyder Mine NV Not surveyed 0.2 - -

Newmont Rain Mill Mine NV - 0.2 0 -

 Glamis Rand Mine CA Not surveyed 0.1 0 -

Nevada mercury 

emissions 4487.0 12779.7 4895.1 4679.3

Non-Nevada mercury 

emissions 41.1 230.3 103.4 70.4

Total U.S. mercury 

emissions 4528.1 13010.0 4998.6 4749.7

* Kennecott 70%, Hecla 30% 
Section 4.0 Mercury Emissions from Gold Mines

23 

 

It is important to note that there is considerable uncertainty when estimating mercury 

emissions from gold mines. Until recently, few sources actually tested their process emissions 

for mercury. Without specific data, some facilities assumed 100 percent of the mercury in the 

process ore was emitted, while others assumed little, if any, of the mercury was emitted. 

Consequently, both under- and over-reporting of mercury emissions have been documented in 

recent years. As of August 2007, several facilities have revised the estimates of mercury 

emissions that were submitted for the TRI between 2001 and 2005. The 2004 estimated mercury 

emissions from one facility were revised from 6.6 pounds to 184.9 pounds; another facility 

revised its mercury emissions reported in the 2004 TRI from 121 pounds (based on 100 percent 

emissions) to 0.12 pounds, after performing emissions testing of several key process units. From 

2001 to 2004, the net effect of all revisions was an increase in total mercury emissions each year. 

The largest increase due to revision was 166.9 pounds for 2003’s reported mercury emissions. 

There remains a significant lack of emissions test data from a variety of gold mining 

processes. While stack test data are becoming available from thermal processes as a result of the 

Nevada Mercury Control Program (described in the Section 5), fugitive emission sources are 

more difficult to characterize. There is incredible uncertainty regarding the significance of 

fugitive sources, such as grinding and milling operations, heap leaching, and tailing ponds, on a 

facility’s overall mercury emissions. Due to the large quantity of ore processed, the relatively 

low and variable concentrations of mercury in the ore, it is difficult to accurately account for all 

the mercury contained in the processed ore. When facilities perform emissions testing on their 

process stacks, they often use these data estimate their mercury emissions. While these test data 

improve the emission estimate for the tested process, there is a potential to underestimate 

mercury emissions if the test data are used as the only emissions from the mining operations, 

thereby neglecting to include inventory estimates for the fugitive emission sources. 
Section 5.0 Nevada Mercury Control Program 

24 

5.0 Nevada Mercury Control Program 

In the 1998-99 timeframe, gold production facilities were identified by U.S. EPA and the 

State of Nevada as significant sources of mercury emissions. As previously described, most of 

the emissions were coming from five facilities in Nevada. The Nevada DEP and U.S. EPA (and 

other stakeholders) immediately started to address this issue and explore options to reduce 

emissions. These efforts lead to establishing the Voluntary Mercury Reduction Program 

(VMRP) in June 2002 with the goal to achieve significant, permanent and rapid reductions in 

mercury air emissions from precious metal processing operations. As seen by the reported TRI 

emissions, mercury emission reductions were quickly achieved by adding emission controls to 

thermal units that emit mercury. The VMRP resulted in over 75 percent reduction in mercury 

emissions from these gold production facilities (NV DEP, 2006). 

Even though the VMRP proved to be successful, the NDEP decided to convert the 

VMRP into a mandatory program, called the Nevada Mercury Control Program (NMCP). The 

NMCP is a State mandatory regulatory Program that supersedes and replaces the VMRP. The 

NMCP was adopted March 8, 2006 and made effective May 4, 2006. The Program achieves 

mercury reduction via add-on control technologies by implementing Nevada Maximum 

Achievable Control Technology (or “NvMACT”). The NvMACT is “...a standard, method of 

control or any other limitation which is applied to an existing, new or modified thermal unit that 

emits mercury” (NDEP, 2006). 

The “starting point” or “baseline” for NvMACT is the “Presumptive NvMACT.” The 

Presumptive NvMACT “...is technologies to control mercury emissions which have been 

implemented before May 4, 2006 and associated with Tier-1 units.” Tier-1 units are the units 

that were included in the VMRP. NvMACT is based on each discrete thermal mercury emission 

unit at a facility (NDEP, 2006). 

For new/modified emission units, NvMACT is at minimum the emission control that is 

achieved in practice by the best controlled similar emission unit within the precious metals 

mining industry. A determination of similar emission units may take into account ore mercury 

concentration, size of process units and other relevant factors. NDEP will use the principles of 

MACT consistent with Section 112(d) of the Federal Clean Air Act of 1990 in establishing 

NvMACT (NDEP, 2006). 

Pursuant to the Nevada regulations (NAC 445B.3625), owners or operators that operate, 

construct or modify a thermal unit that emits mercury must apply for, and obtain, a Mercury 

Operating Permit to Construct (Mercury OPTC) to apply the NvMACT. Construction of a new 

or modified thermal unit that emits mercury requires a permit before construction begins. Those 

emission units subject to NvMACT must install controls no later than 24 months after final 

Phase-2 permit issuance, unless deferred 48 months with the Director designated Early 

Reduction Credit (NDEP, 2006). More information on the NV program is available in a paper 

titled: “Nevada Mercury Control Program (NMCP), Overview and Guidance, July 2006”, which 

is available at: http://ndep.nv.gov/bapc/download/mercury/white_sheet.pdf. Additional 

information, including the detailed regulation, is available at: 

http://ndep.nv.gov/mercury/index.htm. 
Section 6.0 References 

25 

6.0 References 

Butterman, W.C. and Earle B. Amey III, 2005. Mineral Commodity Profiles – Gold. U.S. 

Geological Survey. 

Jones, Greg and Glenn Miller, 2005. Mercury and Modern Gold Mining in Nevada. U.S. 

Environmental Protection Agency. 

NMA 2006, National Mining Association. 2005 Statistics. Available at: 

http://www.nma.org/statistics/pub_gold_silver.asp 

NV Division of Minerals, Commission on Mineral Resources, 2006. “Nevada Gold and Silver 

Prices, Productions, and Value.” December 2006. Available at: 

http://minerals.state.nv.us/programs/min_AUAG.htm. 

NV DEP, 2006. “Nevada Mercury Control Program (NMCP), Overview and Guidance”. 

Nevada Department of Environmental Protection (NV DEP). July 2006. Available at:

http://ndep.nv.gov/bapc/download/mercury/white_sheet.pdf. 

U.S. Environmental Protection Agency, 1994. Technical Resource Document: Extraction and 

Beneficiation of Ores and Minerals: Volume 2: Gold. Office of Solid Waste. 

U.S. Environmental Protection Agency, 2001a. Mercury Mass Balance and Emissions Factor 

Estimates for Gold Ore Processing Facilities. Region 9. 

U.S. Environmental Protection Agency, 2001b. Process Descriptions and Material Flows for 

Gold Ore Processing Facilities. Region 9. 
Section 6.0 References 

26 
Appendix A U.S. EPA Questionnaire 

A-1 

Appendix A 

U.S. EPA Questionnaire 

Appendix A contains a copy of the mercury air emissions questionnaire sent to United States 

precious metal mines outside the state of Nevada by the U.S. EPA. The questionnaire sent to 

Nevada gold and silver mines by the NDEP is available on the internet at: 

http://ndep.nv.gov/mercury/mercury_air.htm. 
Appendix A U.S. EPA Questionnaire 

A-2 
Appendix A U.S. EPA Questionnaire 

A-3 

PRECIOUS METALS MINING 

MERCURY AIR EMISSIONS QUESTIONNAIRE 

(for facilities outside Nevada) 

1. Instructions: 

We request that this questionnaire is completed for operations that comprise the

"Primary Extraction and Processing of Gold and Silver” industry at your facility. This 

industry includes all facilities and processes that are part of primary extraction, processing, and 

production of gold and silver, and the production of particular by-products (such as mercury), 

including, but not limited to, grinding, leaching, roasting, autoclaving, carbon stripping, carbon 

regeneration, electrowinning, retorting, smelting and waste disposal. The subject operations are 

generally conducted under Standard Industrial Classification (SIC) Codes 1041 and 1042, Gold 

and Silver Ores or under North American Industry Classification System (NAICS) Codes 

212221 and 212222. We are seeking the information requested by this questionnaire pursuant to 

section 114 of the Clean Air Act. 

 

 We are requesting information regarding mercury air emissions from your primary 

extraction and processing operations, the use of air pollution control (APC) devices in those 

operations, and their effectiveness in reducing mercury emissions. The information requested is 

described in Sections 2 through 10 of this questionnaire and the Annexes. 

 Please satisfy this request as completely as possible from existing information. No 

additional monitoring or emission testing is required by your company to respond to this request. 
Appendix A U.S. EPA Questionnaire 

A-4 

 If you have any questions regarding this request, please contact me at phone number: 

919-541-7912, or by e-mail at e-mail address: french.chuck@epa.gov 

 

 Please return this questionnaire along with any additional relevant information to me by 

June 16, 2006 by e-mail, or by regular mail to the mailing address shown below. 

 Thank You. 

 Mr. Chuck French 

 Environmental Scientist 

Metals and Minerals Group 

 U.S. Environmental Protection Agency (EPA) 

 

Mailing Address for Responses: 

 Mr. Chuck French 

 Environmental Scientist 

U.S. EPA, Office of Air Quality 

 109 TW Alexander Drive (D243-02) 

 Research Triangle Park, NC 27711 
Appendix A U.S. EPA Questionnaire 

A-5 

2. Facility General Information:

a. Plant-specific facility name: 

b. Mailing address: 

c. Street address or physical location of facility: 

d. Longitude and latitude (or UTM coordinates) for primary processing/refinery 

area: 

e. Names and telephone numbers of contact persons who are able to answer 

technical questions about this questionnaire: 

f. Are you a subsidiary or affiliate of another company or other organization? If 

yes, please provide the name of parent company and/or other organization. 

3. Facility Operation Information:

a. Total tons of ore processed in 2005 (or most recent year for which data are available, 

such as 2004): 

Tons of Ore Processed = _________ for year: __________ 

b. Total quantity (ounces) of precious metals produced in 2005 (or most recent year for 

which data are available, such as 2004): 

i. Ounces of Gold = _________ for year: _________ 

ii. Ounces of Silver = ________ for year: _________ 

iii. Other: _________________ for year: _________ 

c. Does the facility process ore containing mercury at concentrations of 0.1 milligram 

mercury per kilogram ore (0.1 mg/kg) or higher? If no, please provide ore 

characterization data or other evidence supporting this answer. If the answer is “no” and 
Appendix A U.S. EPA Questionnaire 

A-6 

adequate supporting evidence is provided, then you do not need to complete the 

remaining questions in section 3, and you do not need to complete the questions in 

sections 4, 6, 7, 10 or the Annexes. However, please complete the questions in section 2, 

5, 8, and 9, to the extent feasible given available information. On the other hand, if the 

answer to this question (3c) is “yes” or “unknown”, please complete the questions in all 

sections of the questionnaire, as appropriate and applicable to your facility. 

____________________________________________________________________

____________________________________________________________________

__________________________________

d. Does the facility use thermal operations in its precious metals processing? (Note: 

Thermal operations include: pre-dryers, drying, roasting, autoclaving, electrowinning, 

retorting, smelting, carbon regeneration kilns, drying, and any other processes that 

involve units with the potential to emit mercury generated by direct or indirect sources of 

heat energy.) If yes, proceed to Question 3e and complete the remaining questions 3e to 

10 and the Annexes, as applicable for your facility. If no, please provide explanation of 

plant precious metals processing operations with a flow diagram and basis for 

determination that no thermal processes are used. If the answer is “no” to this question, 

you can skip questions 4, 6, 7 and 10 and the Annexes, but please complete the remaining 

questions in sections 3, 5, 8 and 9, as applicable for your facility. 

e. Please provide a flow diagram and description of the precious metals processing 

operations at your facility, with identification on the diagram of where mercury is 

expected to be present. Include a description of how mercury is typically liberated from 

the ore and its flow for eventual recovery, release to the atmosphere or deposition in 

tailings or waste streams. 
Appendix A U.S. EPA Questionnaire 

A-7 

f. If roasting is utilized, total tons of ore roasted in 2005 (or most recent year for which data 

are available, such as 2004): 

Tons of Ore Roasted = _________ for year __________ 

g. If autoclaving is utilized, total tons of ore autoclaved in 2005 (or most recent year for 

which data are available, such as 2004): 

Tons of Ore Autoclaved = _________ for year __________ 

h. Please provide the total tons of ore processed that are subject to cyanide leaching 

(provide quantity by the following categories): 

i. heap leaching: ______ tons for year ______ 

ii. carbon in leach of milled ore: ______ tons for year ______ 

iii. carbon in leach of roasted or autoclaved ore: ____ tons for year: _____ 

i. Do you produce mercury as a product or byproduct? If yes, please provide amount 

(pounds) of mercury produced in 2005 (or most recent year for which data are available) 

by type of product/byproduct produced: 

i. _______ pounds elemental mercury produced, for year: ____ 

ii. _______ pounds calomel produced, for year: _______. 

 
Appendix A U.S. EPA Questionnaire 

A-8 

4. Emission Unit Identification: 

For each thermal operation emission unit with the potential to emit mercury, please 

complete the questions in Annexes 1 to 7, as applicable and appropriate for your facility. 

See Annexes 1 to 7. 

5. Estimated Total Mercury Emissions From the Facility: 

a. Please provide an estimate of the total actual mercury air emissions (in pounds) released 

from the entire facility (including fugitive emissions) for year 2005 (or most recent year 

for which data are available) and a description of the basis of such estimate. Please use 

the following hierarchy of data, for reporting such estimate: 

• Direct testing and measurement. 

• Based on engineering calculations that take into account the average mercury 

content of the ore processed, the amount of ore processed and the potential 

for mercury releases from the specific processes utilized to recover gold. 

Total estimated mercury emissions = _____ pounds, for year: ____ 

b. If ambient mercury monitoring has been conducted at the facility, please attach 

information regarding the monitoring program (number, placement, sampling duration, 

collection method of monitors) and the monitoring results. 

c. If any studies have been conducted to assess fugitive mercury emissions from various 

process units (including heap leach pads, carbon in leach tanks, and tailings ponds), 

please attach information regarding the processes evaluated, the methods used, and 

results of each study performed. 

 
Appendix A U.S. EPA Questionnaire 

A-9 

6. Mercury Emissions Control Information as of 2005 (or most recent year for which data are 

available):

For each air emissions control device that has some effect on mercury emissions, please 

complete the questions in Annexes 8 to 12, as applicable and appropriate for your 

facility. See Annexes 8 to 12. Also, please describe any additional control measures, 

improved work place practices, pollution prevention measures, or other actions being 

implemented at the time. 

7. Modifications to Existing Mercury Controls and Additional Controls:

Please describe any post-2005 modifications to existing mercury controls, additional control 

measures, improved work place practices, pollution prevention measures, or other actions, if 

any, that have been installed or implemented post-2005 or are planned by the facility to be 

installed or implemented within the next 24 months to further reduce mercury emissions: 

_____________________________________________________________________________

_____________________________________________________________________________

______________________
Appendix A U.S. EPA Questionnaire 

A-10 

8. Process Changes and Future Operations: 

a. Please describe any process or equipment changes implemented post-2005, or planned for 

future years, that could significantly increase the potential for mercury emissions (for example, 

installing a roaster, carbon kiln, or other thermal process, or processing different ores that have 

higher mercury content): 

______________________________________________________________________________

______________________________________________________________________________

________________________

b. Please describe your facility’s expected number of future years of operation: 

______________________________________________________________________________

__________________________________________

9. Permit Conditions and other Commitments/Agreements:

Please provide a summary of air emission permit conditions or provide a copy of your air permit. 

Also, please provide a summary of any voluntary agreements/commitments, especially with 

regard to pollution prevention measures, control equipment and emissions levels, and compliance 

schedules: 

______________________________________________________________________________

______________________________________________________________________________

______________________

10. Mercury Control Device Cost Information: Please complete Annex 13, as applicable and 

appropriate for your facility. 
Appendix A U.S. EPA Questionnaire 

A-11 

ANNEX 1. AUTOCLAVING

1. Please provide an identification of each such unit, including a process description and the 

mechanism by which mercury emissions are released. (Note: if facility has more than 1 

autoclave, copy this Annex 1 and complete a separate copy for each such unit.) 

Autoclaving process description: 

______________________________________________________________ 

_____________________________________________________________________

_______________________________________________________ 

2. Please provide the following information about the process described in Item 1: 

 a. Process capacity: tons ore per hour 

 b. Annual hours this process was operated in 2005 (or most recent year for which data are 

available): hours for year _____ 

 c. Typical process operating temperature: oF 

3. Provide an estimate of the actual mercury air emissions released from this unit for 2005 

(or most recent year for which data are available) and the basis of such estimate, in 

accordance with the following hierarchy of data: 

a. Direct testing and measurement. 

b. Based on engineering calculations that take into account the average mercury content of 

the ore processed, the amount of ore processed and the potential for mercury releases from 

the specific processes utilized to recover gold. 

Estimated mercury emissions from autoclave = _____ pounds for year ____ 

Basis of estimate: 

____________________________________________________________________

____________________________________________________________________

________________________________________________
Appendix A U.S. EPA Questionnaire 

A-12 

4. Circle the code numbers for the type of air pollution control (APC) devices and the type 

of fume capture systems used: 

 APC device: Fume capture system: 

0 No device is used 0 None 

1 Fabric/cartridge filter 1 Side-draft or canopy hood 

2 Wet scrubber 2 Close-fitting hood or direct process vent 

 3 Off-gas quencher 3 Other: ________________ 

4 Electrostatic precipitator 

5 Carbon adsorption unit 

 6 Other: ______________ 

5. Provide exit exhaust vent (or stack) parameters (for gaseous streams): 

 height: __________________ feet 

 diameter: ________________ feet 

 flow rate: ________________ acfm (actual cubic feet per minute) 

 temperature: ______________ EF 

6. Describe any work practices or other measures that prevent mercury emissions from 

autoclaving operations. 

___________________________________________________________

 _____________________________________________________

7. Have tests been conducted for mercury air emissions on these autoclaving operations? 

 0 No 

 1 Yes [Enclose summary measurement data, including data on mercury 

speciation, if available, the test methods used, information on actual 

production or processing rates and on process conditions at the time the 

measurements were made, and a statement that any APC devices (if 

present) were operating normally during the test, or if not, what the 

abnormal operating conditions were.]

8. Additional comments and information: 

________________________________________________________________________

______________________________________________
Appendix A U.S. EPA Questionnaire 

A-13 

ANNEX 2. ROASTING OPERATIONS 

1. Please provide an identification of each such unit, including a process description and the 

mechanism by which mercury emissions are released. (Note: if facility has more than 1 roasting 

operation, copy this Annex 2 and complete a separate copy). 

Description: 

______________________________________________________________ 

_____________________________________________________________________

_______________________________________________________ 

2. Please provide the following information about the process described in Item 1: 

 a. Process capacity: tons ore per hour 

b. Annual hours this process was operated in 2005 (or most recent year for which data are 

available): hours for year: _____ 

 c. Typical process operating temperature: oF 

 d. Type of fuel used: . 

3. Provide an estimate of the actual mercury air emissions released from this unit for 2005 

(or most recent year for which data are available) and the basis of such estimate, in 

accordance with the following hierarchy of data: 

• Direct testing and measurement. 

• Based on engineering calculations that take into account the average mercury content of the 

ore processed, the amount of ore processed and the potential for mercury releases from the 

specific processes utilized to recover gold. 

Estimated mercury emissions from roaster = ______ pounds for year: _____. 

Basis of estimate: ________________________________________ 

________________________________________________________________________

________________________________________________
Appendix A U.S. EPA Questionnaire 

A-14 

4. Circle the code numbers for the type of air pollution control (APC) device and the type of 

fume capture system used: 

 APC device: Fume capture system: 

0 No device is used 0 None 

1 Fabric/cartridge filter 1 Side-draft or canopy hood 

2 Wet scrubber 2 Close-fitting hood or direct process vent 

 3 Off-gas quencher 3 Other: ________________ 

4 Electrostatic precipitator 

5 Carbon adsorption unit 

 6 Other: ______________ 

5. Provide exit exhaust vent (or stack) parameters (for gaseous streams): 

 height: __________________ feet 

 diameter: ________________ feet 

 flow rate: ________________ acfm (actual cubic feet per minute) 

 temperature: ______________ EF 

6. Describe any work practices or other measures that prevent mercury emissions from this 

roasting operation: 

________________________________________________________________________

______________________________________________

7. Have tests been conducted for mercury air emissions on these roasting operations? 

 0 No 

 1 Yes [Enclose summary measurement data, including data on mercury 

speciation, if available, the test methods used, information on actual 

production or processing rates and on process conditions at the time the 

measurements were made, and a statement that any APC devices (if 

present) were operating normally during the test, or if not, what the 

abnormal operating conditions were.]

 

8. Additional comments and information: 

 ________________________________________________________________________

________________________________________________________________________

___________________________________
Appendix A U.S. EPA Questionnaire 

A-15 

ANNEX 3. CARBON REGENERATION KILN 

1. Please provide an identification of each such unit, including a process description and the 

mechanism by which mercury emissions are released. (Note: if facility has more than 1 carbon 

regeneration kiln, copy this Annex 3 and complete a separate copy for each such unit).

Description: __________________________________________________ 

______________________________________________________________ 

____________________________________________________________ 

2. Please provide the following information about the process described in Item 1: 

 a. Process capacity: tons carbon per hour 

b. Annual hours this process was operated in 2005 (or most recent year for which data are 

available): hours for year: ______ 

 c. Typical process operating temperature: oF 

 d. Type of regeneration process used: .

3. An estimate of the actual mercury air emissions released from this unit for 2005 (or most 

recent year for which data are available) and the basis of such estimate, in accordance 

with the following hierarchy of data: 

• Direct testing and measurement. 

• Based on engineering calculations that take into account the average mercury content of the 

ore processed, the amount of ore processed and the potential for mercury releases from the 

specific processes utilized to recover gold. 

Estimated mercury emissions from carbon regeneration kiln = ________ pounds for year _____. 

Basis of estimate: ___________________________________________ 

________________________________________________________________________

________________________________________________
Appendix A U.S. EPA Questionnaire 

A-16 

4. Circle the code numbers for the type of air pollution control (APC) device and the type of 

fume capture system used: 

 APC device: Fume capture system: 

0 No device is used 0 None 

1 Fabric filter 1 Side-draft or canopy hood 

2 Wet scrubber 2 Close-fitting hood or direct process vent 

 3 Selenium filter 3 Other: _________________

 4 Carbon adsorption unit

 5 Other: ________________ 

5. Provide exit exhaust vent (or stack) parameters (for gaseous streams): 

 height: __________________ feet 

 diameter: ________________ feet 

 flow rate: ________________ acfm (actual cubic feet per minute) 

 temperature: ______________ EF 

6. Describe any work practices or other measures that prevent mercury emissions from this 

carbon regeneration operation: 

________________________________________________________________________

______________________________________________

7. Have tests been conducted for mercury air emissions on these carbon regeneration 

operations? 

 0 No 

 1 Yes [Enclose summary measurement data, including data on mercury 

speciation, if available, the test methods used, information on actual 

production or processing rates and on process conditions at the time the 

measurements were made, and a statement that any APC devices (if 

present) were operating normally during the test, or if not, what the 

abnormal operating conditions were.] 

8. Additional comments and information: 

_________________________________________________________________ 

_________________________________________________________________ 

 ___________________________________________________________
Appendix A U.S. EPA Questionnaire 

A-17 

ANNEX 4. ELECTROWINNING 

1. Please provide an identification of each such unit, including a process description and the 

mechanism by which mercury emissions are released. (Note: if facility has more than 1 

electrowinning process, copy this Annex 4 and complete a separate copy for each such unit.) 

Description: ___________________________________________________ 

_____________________________________________________________________

_______________________________________________________ 

2. Please provide the following information about the process described in Item 1: 

 a. Process capacity: gallons per minute of preg solution 

b. Annual hours this process was operated in 2005 (or most recent year for which data are 

available): hours for year: _______ 

 c. Typical process operating temperature: oF 

3. An estimate of the actual mercury air emissions released from this unit for 2005 (or most 

recent year for which data are available) and the basis of such estimate, in accordance 

with the following hierarchy of data: 

• Direct testing and measurement. 

• Based on engineering calculations that take into account the average mercury content of the 

ore processed, the amount of ore processed and the potential for mercury releases from the 

specific processes utilized to recover gold. 

Estimated mercury emissions from electrowinning unit = ________ pounds for year: _____. 

Basis of estimate: 

______________________________________________________________________________

______________________________________________________________________________

_____________________
Appendix A U.S. EPA Questionnaire 

A-18 

4. Circle the code numbers for the type of air pollution control (APC) device and the type of 

fume capture system used: 

 APC device: Fume capture system: 

0 No device is used 0 None 

1 Fabric filter 1 Side-draft or canopy hood 

2 Wet scrubber 2 Close-fitting hood or direct process vent 

 3 Carbon adsorption unit 3 Other: ________________ 

4 Other: ______________ 

5. Provide exit exhaust vent (or stack) parameters (for gaseous streams): 

 height: __________________ feet 

 diameter: ________________ feet 

 flow rate: ________________ acfm 

 temperature: ______________ EF 

6. Describe any work practices or other measures that prevent mercury emissions from this 

electrowinning operation: 

__________________________________________________________

 ____________________________________________________

7. Have tests been conducted for mercury air emissions on these electrowinning operations? 

 0 No 

 1 Yes [Enclose summary measurement data, including data on mercury 

speciation, if available, the test methods used, information on actual 

production or processing rates and on process conditions at the time the 

measurements were made, and a statement that any APC devices (if 

present) were operating normally during the test, or if not, what the 

abnormal operating conditions were.] 

8. Additional comments and information: 

________________________________________________________________________

________________________________________________________________________

___________________________________
Appendix A U.S. EPA Questionnaire 

A-19 

ANNEX 5. RETORT

1. Please provide an identification of each such unit, including a process description and the 

mechanism by which mercury emissions are released. (Note: if facility has more than 1 retort 

process, copy this Annex 5 and complete a separate copy for each such unit). 

Description: 

_____________________________________________________________________

_____________________________________________________________________

_________________________________________________ 

2. Please provide the following information about the process described in Item 1: 

 a. Process capacity: tons sludge per cycle 

b. Annual hours this process was operated in 2005 (or most recent year for which data are 

available): hours for year: _____ 

 c. Typical process operating temperature: oF 

 d. Typical cycle time: hours 

3. An estimate of the actual mercury air emissions released from this unit for 2005 (or most 

recent year for which data are available) and the basis of such estimate, in accordance 

with the following hierarchy of data: 

• Direct testing and measurement. 

• Based on engineering calculations that take into account the average mercury content of the 

ore processed, the amount of ore processed and the potential for mercury releases from the 

specific processes utilized to recover gold. 

Estimated mercury emissions from retort = ______ pounds for year: ______ 

Basis of estimate: 

_________________________________________________________________________________

_________________________________________________________________________________

__________________________

4. Do you recover mercury? ____________________ 
Appendix A U.S. EPA Questionnaire 

A-20 

5. Is it processed further onsite? ___________________________

6. Circle the code numbers for the type of air pollution control device and the type of fume 

capture system used: 

 APC device: Fume capture system: 

0 No device is used 0 None 

1 Fabric filter 1 Side-draft or canopy hood 

2 Wet scrubber 2 Close-fitting hood or direct process vent 

 3 Carbon adsorption unit 3 Other: ________________

 4 Other: ________________ 

7. Provide exit exhaust vent (or stack) parameters (for gaseous streams): 

 height: __________________ ft 

 diameter: ________________ ft 

 flow rate: ________________ acfm 

 temperature: ______________ EF 

8. Describe any work practices or other measures that prevent mercury emissions from this 

retort operation. 

________________________________________________________________________

________________________________________________

9. Have tests been conducted for mercury air emissions on these retort operations? 

 0 No 

 1 Yes [Enclose summary measurement data, including data on mercury 

speciation, if available, the test methods used, information on actual 

production or processing rates and on process conditions at the time the 

measurements were made, and a statement that any APC devices (if 

present) were operating normally during the test, or if not, what the 

abnormal operating conditions were.] 

10. Additional comments and information: 

____________________________________________________________ 

____________________________________________________________

____________________________________________________________
Appendix A U.S. EPA Questionnaire 

A-21 

ANNEX 6. SMELTING FURNACE 

1. Please provide an identification of each such unit, including a process description and the 

mechanism by which mercury emissions are released. (Note: if facility has more than 1 smelting 

furnace, copy this Annex 6 and complete a separate copy for each such unit.) 

Description: _________________________________________________ 

___________________________________________________________ 

____________________________________________________________ 

2. Please provide the following information about the process described in Item 1: 

 a. Process capacity: tons total charge per cycle 

b. Annual hours this process was operated in 2005 (or most recent year for which data are 

available): hours for year: ______ 

 c. Typical process operating temperature: oF 

 d. Typical cycle time: hours 

3. An estimate of the actual mercury air emissions released from such unit for 2005 (or most 

recent year for which data are available) and the basis of such estimate, in accordance 

with the following hierarchy of data: 

• Direct testing and measurement. 

• Based on engineering calculations that take into account the average mercury content of the 

ore processed, the amount of ore processed and the potential for mercury releases from the 

specific processes utilized to recover gold. 

Estimated mercury emissions from furnace = _____ pounds for year _____

Basis of estimate: 

__________________________________________________________________________

__________________________________________________________________________

________________________________________
Appendix A U.S. EPA Questionnaire 

A-22 

4. Circle the code number(s) for materials added for smelting: 

1 Lime 

2 Fluxing materials (e.g., magnesium chloride, calcium chloride, etc.) 3

 Inhibitive gases 

4 Alloying agents (describe): _______________

5 Other (describe): _______________________

5. Circle code which describes how molten material is transferred to molds for casting: 

1 Hand ladling 

2 Pumping 

3 Tilt pouring 

4 Other (describe): ______________________

6. For charging, melting, and tapping operations associated with this furnace, circle the code 

numbers for the types of air pollution control devices and fume capture systems used. 

Charging:

 APC device: Fume capture system: 

0 No device is used 0 None 

1 Fabric filter 1 Side-draft or canopy hood 

2 Wet scrubber 2 Close-fitting hood or direct process vent 

 3 Carbon adsorption unit 3 Other: _____________________

 4 Other: ________________

Melting:

 APC device: Fume capture system: 

0 No device is used 0 None 

1 Fabric filter 1 Side-draft or canopy hood 

2 Wet scrubber 2 Close-fitting hood or direct process vent 

 3 Carbon adsorption unit 3 Other: _____________________

 4 Other: ________________

 

Tapping:

 APC device: Fume capture system: 

0 No device is used 0 None 

1 Fabric filter 1 Side-draft or canopy hood 

2 Wet scrubber 2 Close-fitting hood or direct process vent 

 3 Carbon adsorption unit 3 Other: _____________________

 4 Other: ________________
Appendix A U.S. EPA Questionnaire 

A-23 

7. Provide exit exhaust vent (or stack) parameters (for gaseous streams): 

 height: __________________ feet 

 diameter: ________________ feet 

 flow rate: ________________ acfm 

 temperature: ______________ EF 

8. Describe any work practices or other measures that prevent mercury emissions from this 

furnace operation: 

__________________________________________________________

 ______________________________________________________

9. Have tests been conducted for mercury air emissions on this furnace? 

 0 No 

 1 Yes [Enclose summary measurement data, including data on mercury 

speciation, if available, the test methods used, information on actual 

production or processing rates and on process conditions at the time the 

measurements were made, and a statement that any APC devices (if 

present) were operating normally during the test, or if not, what the 

abnormal operating conditions were.] 

10. Additional comments and information: 

________________________________________________________________________

________________________________________________________________________

___________________________________
Appendix A U.S. EPA Questionnaire 

A-24 

ANNEX 7. OTHER THERMAL PROCESS UNITS 

1. Please provide an identification of other thermal process units, including a process description 

and the mechanism by which mercury emissions are released. (Note: if facility has more than 1 

“other thermal process” process, copy this Annex 7 and complete a separate copy for each such 

unit.)

Description: ___________________________________________________ 

_____________________________________________________________________

_________________________________________________________ 

2. Please provide the following information about the process described in Item 1: 

 a. Process capacity: (specify units)

b. Annual hours this process was operated in 2005 (or most recent year for which data are 

available): hours for year: _____ 

 c. Typical process operating temperature: oF 

 d. Typical cycle time, if applicable: hours 

3. An estimate of the actual mercury air emissions released from such unit for 2005 (or most 

recent year for which data are available) and the basis of such estimate, in accordance 

with the following hierarchy of data: 

• Direct testing and measurement. 

• Based on engineering calculations that take into account the average mercury content of the 

ore processed, the amount of ore processed and the potential for mercury releases from the 

specific processes utilized to recover gold. 

Estimated mercury emissions from unit = _____ pounds for year: ____ 

Basis of estimate: 

__________________________________________________________ ______________

__________________________________________
Appendix A U.S. EPA Questionnaire 

A-25 

4. Circle the code numbers for the type of air pollution control device and the type of fume 

capture system used: 

 APC device ID no.: __________ Fume capture system: 

0 No device is used 0 None 

1 Fabric filter 1 Side-draft or canopy hood 

2 Wet scrubber 2 Close-fitting hood or direct process vent 

 3 Carbon adsorption unit 3 Other: _______________________

 4 Other: ________________ 

5. Provide exit exhaust vent (or stack) parameters (for gaseous streams): 

 height: __________________ ft 

 diameter: ________________ ft 

 flow rate: ________________ acfm 

 temperature: ______________ EF 

6. Describe any work practices or other measures that prevent mercury emissions from this 

operation: 

________________________________________________________________________

_______________________________________________

7. Have tests been conducted for mercury air emissions on this unit? 

 0 No 

 1 Yes [Enclose summary measurement data, including data on mercury 

speciation, if available, the test methods used, information on actual 

production or processing rates and on process conditions at the time the 

measurements were made, and a statement that any APC devices (if 

present) were operating normally during the test, or if not, what the 

abnormal operating conditions were.] 

8. Additional comments and information: 

______________________________________________________________________________

______________________________________________________________________________

_______________________
Appendix A U.S. EPA Questionnaire 

A-26 

ANNEX 8. FABRIC FILTER DESCRIPTION 

1. Please describe the fabric filters including an explanation of the mechanism for mercury 

removal (for example physical or chemical adsorption). (Note: if facility has more than 1 fabric 

filter, copy this Annex 8 and complete a separate copy for each fabric filter.)

Device description: 

___________________________________________________________ 

________________________________________________________________________

______________________________________________ 

2. Year installed/rebuilt: /______________ 

3. The estimated control efficiency with an explanation as to how that was calculated: 

________________________________________________________________________

________________________________________________________________________

____________________________________

4. Describe the chemical and physical form of the mercury generated by the control (for 

example, elemental mercury, calomel scrubber solution, carbon loaded with mercury, 

etc.) and the handling, storage and disposition of same: 

________________________________________________________________________

________________________________________________________________________

___________________________________

5. Circle the code number for device type: 

 1 Fabric filter 2 Cartridge collector 

6. Circle the code number for pressure mode of operation: 

 1 Positive pressure 2 Negative pressure 
Appendix A U.S. EPA Questionnaire 

A-27 

7. Circle the code number for bag cleaning method: 

 1 Pulse jet 

 2 Shaker 

 3 Reverse air 

 4 Other (describe): 

8. Circle the code number for bag cleaning mode: 

 1 On line 2 Off line 

9. Cloth type: 

10. Number of compartments: 

11. Gas inlet temperature: EF

12. Gas flow rate: acfm

13. Gross filtering area: square feet 

14. Net filtering area: square feet

15. Air to cloth ratio: fpm (Note: fpm = foot/minute = actual cubic feet 

per minute per square foot of filter area = ft3/min/ft2) 

16. Referring to the processes described in Annexes 1 through 7, identify each process served 

by this device. 

Annex No. Process Description Operation 

 

 

17. Amount of particulate matter collected by this device: 

A. Tons of dust material collected: _________________ tons 

B. Time period for which dust material was collected: _____________ hours of 

operation 

C. Amount of metal or material processed or treated: _____________ tons 
Appendix A U.S. EPA Questionnaire 

A-28 

18. Has this material been analyzed? 

 0 No 1 Yes [Enclose analysis (but not TCLP data).]

19. Have tests been conducted for mercury air emissions on this device? 

 0 No 

 1 Yes [Enclose summary measurement data, including data on mercury 

speciation, if available, the test methods used, information on actual 

production or processing rates and on process conditions at the time the 

measurements were made, and a statement that any APC devices (if 

present) were operating normally during the test, or if not, what the 

abnormal operating conditions were.] 

 

20. Additional comments and information: 

________________________________________________________________________

________________________________________________________________________

____________________________________
Appendix A U.S. EPA Questionnaire 

A-29 

ANNEX 9. WET SCRUBBER DESCRIPTION

1. Please describe the wet scrubber system including an explanation of the mechanism for 

mercury removal (for example physical or chemical adsorption). (Note: if facility has 

more than 1 wet scrubber, copy this Annex 9 complete a separate copy for each.)

 Device description: 

____________________________________________________________ 

________________________________________________________________________

________________________________________________ 

2. Year installed/rebuilt: /___________ 

3. a.) Estimated control efficiency: _________________ 

b.) Basis of estimated control efficiency (circle appropriate code number): 

 1 Performance source test 

 2 Vendor performance guarantee 

 3 Engineering design efficiency 

 4 Other (specify): _________________________________

4. What is the chemical and physical form of the mercury generated by the control (circle 

all that apply)? 

 1 Elemental mercury 

 2 Calomel scrubber solution (mercurous chloride; Hg2Cl2) 

 3 Hypochlorite scrubber solution 

 4 Carbon loaded with mercury 

 5 Other (specify): _________________________________

5. Specify the handling, storage and disposition of mercury generated from Item 4; if 

multiple forms/dispositions are used, indicate the approximate percent of total mercury 

generated attributable to each? 

 1 Elemental mercury collected in containers and sold off-site 

2 Scrubber solution sent to tailings pond 

3 Scrubber solution regenerated; mercury precipitated as solid; sent off-site for land 

disposal 

 4 Scrubber solution regenerated; mercury precipitated as solid; sent to on-site 

landfill 

5 Mercury remaining on processed ore; disposed of in tailings pond 

6 Other (specify): ____________________________________ 
Appendix A U.S. EPA Questionnaire 

A-30 

6. Circle the code number for scrubber type: 

 1 Venturi 

 2 Mercurous Chloride Scrubber 

 3 Vertical packed bed 

 4 Horizontal packed bed 

 5 Tray Tower 

 6 Spray Chamber 

 7 Other (specify): 

7. Circle the code number for pressure mode of operation: 

 1 Positive pressure 2 Negative pressure 

8. Gas flow rate: acfm

9. Typical gas inlet temperature: EF

10. Typical gas outlet temperature: EF

11. Pressure drop: ____ inches water column

12. Liquid to gas ratio: gallons per 1,000 actual cubic feet

13. Chemical usage rate (specify chemical and typical usage rate): 

Chemical Added Usage Rate Units for Usage Rate 

 

14. Referring to the processes described in Annexes 1 through 7, identify each process served 

by this device. 

Annex No. Process Description Operation 

 
Appendix A U.S. EPA Questionnaire 

A-31 

15. Have tests been conducted for mercury air emissions on this device? 

 0 No 

 1 Yes [Enclose summary measurement data, including data on mercury 

speciation, if available, the test methods used, information on actual 

production or processing rates and on process conditions at the time the 

measurements were made, and a statement that any APC devices (if 

present) were operating normally during the test, or if not, what the 

abnormal operating conditions were.]

16. Additional comments and information: 

________________________________________________________________________

________________________________________________________________________

___________________________________
Appendix A U.S. EPA Questionnaire 

A-32 

ANNEX 10. ELECTROSTATIC PRECIPITATOR (ESP) DESCRIPTION 

1. Please describe the ESP system including an explanation of the mechanism for mercury 

removal (for example physical or chemical adsorption). (Note: if facility has more than 

1 ESP, copy this Annex 10 and complete a separate copy for each.)

 Device description: 

____________________________________________________________ 

________________________________________________________________________

________________________________________________ 

2. Year installed/rebuilt: /_______________ 

3. The estimated control efficiency with an explanation as to how that was calculated: 

________________________________________________________________________

________________________________________________________________________

___________________________________

4. The chemical and physical form of the mercury generated by the control (for example, 

elemental mercury, calomel scrubber solution, carbon loaded with mercury, etc.) and the 

handling, storage and disposition of same: 

________________________________________________________________________

________________________________________________________________________

____________________________________

5. Circle the code number for the device type: 

 1 High-voltage, single-stage 2 Low-voltage, two-stage 

6. Collection plate surface area: _______________________ 

7. Gas inlet temperature: _____________ EF 

8. Voltage: _____________ kV 

9. Gas inlet flow rate: ___________________ acfm 

10. Pressure drop: _______________ inches H2O 
Appendix A U.S. EPA Questionnaire 

A-33 

11. Referring to the processes described in Annexes 1 through 7, identify each process served 

by this device. 

Annex No. Process Description Operation 

 

12. Have tests been conducted for mercury air emissions on this device? 

 0 No 

 1 Yes [Enclose summary measurement data, including data on mercury 

speciation, if available, the test methods used, information on actual 

production or processing rates and on process conditions at the time the 

measurements were made, and a statement that any APC devices (if 

present) were operating normally during the test, or if not, what the 

abnormal operating conditions were.]

13. Additional comments and information: 

________________________________________________________________________

________________________________________________
Appendix A U.S. EPA Questionnaire 

A-34 

ANNEX 11. CARBON ADSORPTION UNITS 

1. Please describe the carbon adsorption units including an explanation of the mechanism 

for mercury removal (for example physical or chemical adsorption). (Note: if facility 

has more than 1 carbon adsorption unit, copy this Annex 11 and complete a separate 

copy for each such unit.)

 Device description: 

________________________________________________________________________

________________________________________________________________________

____________________________________ 

2. Year installed/rebuilt: /____________ 

3. The estimated control efficiency with an explanation as to how that was calculated: 

4. The chemical and physical form of the mercury generated by the control (for example, 

elemental mercury, calomel scrubber solution, carbon loaded with mercury, etc.) and the 

handling, storage and disposition of same: 

5. Circle the code for the type of stream treated: 

 1 Gaseous 2 Aqueous/liquid 

6. Flow rate: __________________ acfm or gallons/min (circle appropriate units) 

7. Inlet temperature: ________________ EF 

8. Circle the code for the type of carbon adsorption system: 

 1 Canisters (nonregenerative) 

 2 Regenerative 

 3 Other (specify): ___________________

9. Total number of beds in system: ___________________ 

10. Total number of beds used (actively adsorbing) in parallel at any given time: _________ 

11. Total number of beds used in series: ___________________ 
Appendix A U.S. EPA Questionnaire 

A-35 

12. Carbon bed dimensions (in feet): 

 length: _____________

 width: _____________

13. Superficial carbon bed velocity: ____________________ 

14. Adsorbtion bed temperature (if different than inlet): ____________________ EF 

15. Mass of carbon per bed: ______________ lbs 

16. Type of carbon used: ____________________________ 

17. Disposition of carbon: 

1 Regenerated on-site: 

 a steam 

 b chemical 

 c other: _________________

2 Reactivated by carbon supplier

 3 Land disposed 

4 Incinerated 

5 Other: ___________________

18. For your regenerable systems: 

 Method of carbon regeneration: 

 1 steam 

 2 chemical leaching 

 3 other: _______________

 Length of the adsorbtion cycle: ______________________

 Length of desorption cycle: ______________________

 Number of beds desorbing at one time: ______________________
Appendix A U.S. EPA Questionnaire 

A-36 

19. Method of monitoring breakthrough: 

1 Monitor for mercury at system outlet 

2 Monitor for mercury within adsorption bed near outlet 

3 Monitor for mercury outlet of first bed in a system with beds in series 

4 Do not monitor/replace beds at fixed intervals 

 Replacement frequency __________ months

 5 Do not monitor/replace beds at fixed volume of gas processed 

 Gas processing set point __________ scf/bed 

6 Other: _______________________________

20. If monitoring mercury breakthrough: 

Sampling and Analytic method used: 

 1 EPA Method 29 

 2 EPA Method 101, 101A, 102, 105 

 3 Ontario Hydro Method 

 4 Other atomic adsorption spectroscopy method: ______________

 5 Other: ____________________

 Frequency of monitoring: 

 1 Continuous (sample at least once every 15 minutes) 

 2 Periodic _______________ times per month 

21. Referring to the processes described in Annexes 1 through 7, identify each process served 

by this device. 

Annex No. Process Description Operation 

 
Appendix A U.S. EPA Questionnaire 

A-37 

22. Have tests been conducted for mercury air emissions on this device? 

 0 No 

 1 Yes [Enclose summary measurement data, including data on mercury 

speciation, if available, the test methods used, information on actual 

production or processing rates and on process conditions at the time the 

measurements were made, and a statement that any APC devices (if 

present) were operating normally during the test, or if not, what the 

abnormal operating conditions were.]

23. Additional comments and information: 

________________________________________________________________________

________________________________________________
Appendix A U.S. EPA Questionnaire 

A-38 

ANNEX 12. OTHER AIR POLLUTION CONTROL (APC) DEVICE DESCRIPTION 

1. Please describe the other APC devices (such as condensers, or other controls) including 

an explanation of the mechanism for mercury removal (for example physical or chemical 

adsorption). (Note: if facility has more than 1 “other APC device”, copy this Annex 12 

and complete a separate copy for each such device.) 

Device description: 

________________________________________________________________________

________________________________________________________________________

___________________________________ 

2. Year installed/rebuilt: /_____________ 

3. The estimated control efficiency with an explanation as to how that was calculated: 

4. The chemical and physical form of the mercury generated by the control (for example, 

elemental mercury, calomel scrubber solution, carbon loaded with mercury, etc.) and the 

handling, storage and disposition of same: 

 

5. Relevant design and operating data (e.g., refrigerated non-contact water-cooled 

condenser; water recirculation set to achieve outlet gas temperature of _____ EF): 

________________________________________________________________________

________________________________________________________________________

____________________________________
Appendix A U.S. EPA Questionnaire 

A-39 

6. Exit Exhaust Vent (or Stack) Parameters (for gaseous streams): 

 height: __________________ ft 

 diameter: ________________ ft 

 flow rate: ________________ acfm 

 temperature: ______________ EF 

7. Referring to the processes described in Annexes 1 through 7, identify each process served 

by this device. 

Annex No. Process Description Operation 

 

8. Have tests been conducted for mercury air emissions on this device? 

 0 No 

 1 Yes [Enclose summary measurement data, including data on mercury 

speciation, if available, the test methods used, information on actual 

production or processing rates and on process conditions at the time the 

measurements were made, and a statement that any APC devices (if 

present) were operating normally during the test, or if not, what the 

abnormal operating conditions were.]

9. Additional comments and information: 

 __________________________________________________________

__________________________________________________________
Appendix A U.S. EPA Questionnaire 

A-40 

ANNEX 13. MERCURY CONTROL DEVICE COST INFORMATION 

1. Do you have recent (within the last 10 years) cost data for a control device described in a 

prior Annex installed specifically to reduce mercury emissions or produces a mercury 

product/byproduct? 

 0 No [You do not need to complete the rest of this Annex.]

 1 Yes [Please complete this Annex for each such control device.] 

2. Mercury control device description for which costs are provided. (Note: if cost 

information is available for more than 1 control device, copy this Annex 13 and complete 

a separate copy for each such unit) 

________________________________________________________________________

________________________________________________

Annex Number in which this control device was described: ________________

3. Please provide available cost information for this control device by completing the 

Control Cost Table on the following page. Engineering estimates and vendor quotes are 

acceptable. Where available, please provide the cost breakdown. If only total costs are 

available, indicate which costs are “Included in Total” (to the best of your knowledge) by 

placing a check in the appropriate box. If a given cost item is unavailable or not 

included, place a check under “Not known.” 

4. Please provide the basis of the costs provided by circling the appropriate code number: 

 1 Actual 

 2 Vendor quote 

 3 Engineering estimate 

 4 Other (specify) .
Appendix A U.S. EPA Questionnaire 

A-41 

Control Cost Table

(For control device described in Annex ) 

Cost Item Description Cost ($) Year of 

Cost

Included 

in Total

Not 

Known

1. Total Installed Cost of APCD 

a. Cost of APCD equipment 

b. Cost of auxiliary equipment1 

c. Cost of monitoring/instrumentation 

d. Direct installation costs2 

e. Indirect installation costs3 

2. Annual O&M Cost for APCD4 

a. Operating labor 

b. Maintenance labor 

c. Utilities (electric, water, natural gas) 

d. Waste disposal 

e. Monitoring, recordkeeping & reporting 

f. Indirect annual costs4,5 

 1Auxiliary equipment includes: fan, pumps, motors, duct work, stack 

 2

Direct installation costs include: foundation, supports, installation, electrical, piping 

 3

Indirect installation costs include: engineering selection, start-up, testing, contingencies 

 4

Do not include capital recovery in the annual operating and maintenance (O&M) costs 

 5Indirect annual costs include: overhead, administration, taxes, and insurance.
Appendix B U.S. EPA Survey Responses 

B-1 

Appendix B 

U.S. EPA Survey Responses 

Appendix B contains detailed results of the questionnaire responses that were not provided in 

Section 3.0. 
Appendix B U.S. EPA Survey Responses 

B-2 
. 

B-3 

Table B-1. Summary of Responses to NDEP and U.S. EPA Gold Mines Questionnaire.

Parent 

company Facility name State Currently operating 

Ore 

mercury 

conc. ≥

0.1 mg/kg 

Thermal 

operations 

Gold 

produced 

(oz) 

Silver 

produced 

(oz) 

Ore 

processed 

(tons) 

Ore roasted 

(tons) 

Newmont Lone Tree Mine NV Yes Yes Yes 412,364 - 6,068,995 - Coeur d'Alene Coeur Rochester, Inc. NV Yes Yes Yes 69,456 5,669,073 12,435,346 - Florida Canyon/ Jipangu 

Florida Canyon Mine NV Yes Yes Yes 73,082 60,405 6,256,953 - 

Glamis Glamis Marigold Mine NV Yes Unknown Yes 155,010 2,435 9,858,024 - Newmont Reona and Phoenix 

Projects 

NV Yes Yes Yes 7,664 - 1,940,439 - 

Glamis Glamis Dee Gold Mine NV No - - - - - - Barrick Placer Turquoise Ridge 

Inc. 

NV Yes Yes Yes - - - - 

Vista Hycroft Mine NV No Unknown Yes 61 1 - - Anglogold Ashanti 

Big Springs Project NV No - - - - - - 

Silver Standard Candelaria Mining 

Company 

NV Yes No - - - - - 

Newmont North Operations Area NV Yes Yes No - - 4,144,930 - - Rain Mill Mine NV No - - - - - - Kinross/ Barrick Round Mountain Gold - 

Smoky Valley Common Operation 

NV Yes Yes Yes 762,966 764,992 55,352,143 - 

- South Operations Area NV No - - - - - - U.S. Gold Tonkin Springs Mine NV No - - - - - - - Northumberland Mine NV No - - - - - - Newmont Mule Canyon NV No - - - - - - Newmont McCoy/Cove Mine NV No - - - - - - Barrick/ Kennecott 

Cortez Gold Mines Mill #2 (Pipeline Mill) 

NV Yes Yes Yes 999,961 58,458 41,603,701 - 

Kinross Kinross Goldbanks 

Mining 

NV No - - - - - - 

Newmont Trenton Canyon Project NV Yes Yes No 17,243 - 1,052,658 - - Mineral Ridge Mine NV No Unknown Yes 3,484 2,927 280,000 - Barrick Ruby Hill Mine NV Yes Yes Yes 1,695 694 - - Newmont Twin Creeks Mine NV Yes Yes Yes 1,123,755 305,034 7,123,665 - Barrick Goldstrike Mines NV Yes Yes Yes 1,942,660 253,480 12,809,234 5,789,417 
. 

B-4 

Table B-1. Summary of Responses to NDEP and U.S. EPA Gold Mines Questionnaire (Continued) Parent company Facility name State Currently operating Ore mercury conc. ≥ 0.1 mg/kg Thermal operations Gold produced (oz) Silver produced (oz) Ore processed (tons) Ore roasted (tons) Newmont Midas Operations NV Yes Yes Yes 214,538 2,334,764 407,985 - - Jerritt Canyon NV Yes Yes Yes 242,912 6,454 1,305,833 1,305,833 Newmont Gold Quarry Operations NV Yes Yes Yes 872,945 527,049 22,090,847 3,040,233 Barrick Gold Exploration NV No - - - - - - - Columbus S M LLC NV No - - - - - - GoldSprings Plum Mining Company LLC NV Yes Unknown Yes 2,836 12,695 176,739 - Kennecott Goldwedge Gravity Mill NV Yes No Yes - - - - - Willow Creek Mine NV No No - 195 89 - - Hew Sleeper Sleeper Mining Company LLC NV No - - - - - - Metallic Ventures Esmeralda Mine NV No - - - - - - Newmont Ames Construction, Inc. - Newmont Project NV No - - - - - - Hecla Hollister Development Block Project NV No - - - - - - Barrick/ Placer Dome Bald Mountain Mine - Mooney Basin Project NV Yes Yes No - - - - Barrick/ Placer Dome Bald Mountain Mine (including Mooney Basin) NV Yes Yes Yes 46,685 27,635 2,225,405 - - Imlay Mine NV Yes Unknown No - - - - Newmont Midas Borrow NV No - - - - - - Newmont Midas Exploration NV No - - - - - - Kennecott Denton-Rawhide Mine NV Yes Unknown Yes 54,758 506,806 - - Standard Gold/ Jipangu Standard Mine NV Yes Yes - - - - - Altenberg Window Peak Trace Minerals NV No - - - - - - Newmont Double Deck Screen Plant NV No - - - - - - Barrick/ Kennecott Cortez Gold Mines Mill #1 NV No - - - - - - Atna Pinson Exploration 

Project 

NV No - - 

- 

 - - - 
. 

B-5 

Table B-1. Summary of Responses to NDEP and U.S. EPA Gold Mines Questionnaire (Continued) 

Parent 

company Facility name State Currently operating 

Ore 

mercury 

conc. ≥

0.1 mg/kg 

Thermal 

operations 

Gold 

produced 

(oz) 

Silver 

produced 

(oz) 

Ore 

processed 

(tons) 

Ore roasted 

(tons) 

Newmont Emigrant Mine NV No - - 

- 

 - - - 

Newmont Copper Basin Landfill NV No - - 

- 

 - - - 

- Geodesy Resources, Ltd. NV No - - 

- 

 - - - 

Apollo Montana Tunnels Mining, 

Inc. 

MT Yes No - 46,938 659,536 4,955,302 - 

Anglogold Ashanti/ Golden Cycle 

Cripple Creek & Victor Gold Mining Company 

CO Yes No - 

329,625 

 169,189 21,157,243 - 

Kennecott/ Hecla 

Kennecott Greens Creek Mining Company 

AK Yes - Yes 60,873 8,482,752 717,564 - 

Barrick Golden Sunlight Mines, 

Inc. 

MT Yes Yes Yes 88,592 32,388 2,600,000 - 

Kinross Fort Knox Mine AK Yes No - 329,598 25,391 14,374,841 - Kinross Echo Bay Minerals Co., 

Kettle River Operations 

WA No Unknown Yes 65,117 46,442 278,248 - 

Western Goldfields 

Mesquite Mine CA Yes Yes Yes 23,818 2,548 4,225,516 - 

Nevada Total 7,004,270 10,532,992 185,132,897 10,135,483 

Non-Nevada Total 944,561 9,418,246 48,308,714 - 

U.S. Total 7,948,831 19,951,238 233,441,611 10,135,483 
. 

B-6 

Table B-2. Summary of Controls Used at Top Five Mercury Emitting Gold Mines in the United States.

Controls 

Thermal Process 

Goldstrike Mines 

(Barrick) 

Gold Quarry Operations 

(Newmont) 

Twin Creeks Mine 

(Newmont) 

Cortez Gold Mine

(Barrick/Kenneco

Autoclave 

Fabric filter (1988/1993) Venturi scrubbers (1990, 1992, and 1993) 

Not applicable Venturi scrubbers (1996) Not applicable 

Roaster 

Wet scrubber, calomel (1999) Electrostatic precipitator (1999) Off-gas quencher (1999) Off-gas condenser (1999) 

Fabric filters (1994) Wet scrubber, caustic (50% NaOH, 1994) Wet scrubber, calomel (1994) Wet scrubber, peroxide (1994) Electrostatic precipitators (1994) Waste heat boiler (1994) Wash tower (1994) Gas cooler (1994) Fluorine tower (1994) 

Not applicable Not applicable 

Carbon regeneration kiln 

Venturi scrubber (1998/1999) Carbon adsorption unit (1998/1999) Condenser (2005) 

Venturi scrubbers (1989, 1993) Carbon adsorption units (1989, 1993) 

Wet scrubbers (1987/1996, 1990/1997, 2003) 

Venturi scrubber (20

Electrowinning 

Carbon adsorption unit (2001) Wet scrubber (1986) Carbon adsorption unit (1998) None None 

Retort 

Wet scrubbers (1988, 1990, and 1993) Carbon adsorption units (1988, 1990, and 1993) 

Fabric filter (1993) Carbon adsorption units (1985, 1993) Condensers (1985) 

Carbon adsorption units Not applicable 

Smelting furnace 

Carbon adsorption unit (2001) Fabric filters (1990, 1992) Carbon adsorption unit (1992) Fabric filter (1987) Fabric filter (1996) 
. 

B-7 

Table B-3. Summary of Gold Mining Facilities Using Electrowinning in the United States. 

Parent company Facility name State 

Total ore processed by facility (tons) 

Unit ID Control technologies 

Estimated meemissions frounit (tons) 

Newmont Lone Tree Mine NV 6,068,995 01 None NFlorida Canyon/ Jipangu 

Florida Canyon Mine NV 6,256,953 01 None N

Glamis Glamis Marigold Mine NV 9,858,024 01 None Newmont Reona and Phoenix Projects NV 1,940,439 01 None NKinross/ Barrick Round Mountain Gold - 

Smoky Valley Common Operation 

NV 55,352,143 01 None 

Barrick/ Kennecott Cortez Gold Mines Mill #2 

(Pipeline Mill) 

NV 41,603,701 01 None de m

Golden Phoenix Mineral Ridge Mine NV 280,000 01 None NBarrick Ruby Hill Mine NV 0 01 Wet scrubber de mNewmont Twin Creeks Mine NV 7,123,665 01 None Barrick Goldstrike Mines NV 12,809,234 01 Carbon adsorption unit Queenstake Jerritt Canyon NV 1,305,833 01 None Newmont Gold Quarry Operations NV 22,090,847 01 Carbon adsorption unit 

Wet scrubber 

Barrick/ Placer Dome 

Bald Mountain Mine (including Mooney Basin) 

NV 2,225,405 01 None N

Barrick Golden Sunlight Mines, Inc. MT 2,600,000 01 None Barrick Golden Sunlight Mines, Inc. MT 2,600,000 02 None Barrick Golden Sunlight Mines, Inc. MT 2,600,000 03 None Barrick Golden Sunlight Mines, Inc. MT 2,600,000 04 None Kinross Echo Bay Minerals Co., Kettle 

River Operations 

WA 278,248 01 None N

Western Goldfields Mesquite Mine CA 4,225,516 01 Wet scrubber N

Total 
. 

B-8 

Table B-4. Summary of Gold Mining Facilities Using Retorts in the United States. 

Parent company Facility name State 

Total ore processed by facility (tons) 

Unit ID Control technologies 

Estimated meemissions fro(tons) 

Coeur d'Alene Coeur Rochester, Inc. NV 12,435,346 01 Carbon adsorption unit 

Condenser 

0.

Coeur d'Alene Coeur Rochester, Inc. NV 12,435,346 02 Carbon adsorption unit 

Condenser 

0.

Florida Canyon/ Jipangu 

Florida Canyon Mine NV 6,256,953 01 Condenser 

Florida Canyon/ Jipangu 

Florida Canyon Mine NV 6,256,953 02 Condenser 

Glamis Glamis Marigold Mine NV 9,858,024 01 Condenser Newmont Reona and Phoenix Projects NV 1,940,439 01 Carbon adsorption unit NVista Hycroft Mine NV 0 01 Condenser NVista Hycroft Mine NV 0 02 Condenser NVista Hycroft Mine NV 0 03 Condenser NBarrick Ruby Hill Mine NV 0 01 Carbon adsorption unit 

Condenser 

N

Newmont Twin Creeks Mine NV 7,123,665 01 Carbon adsorption unit 

Condenser Mist eliminator 

Newmont Twin Creeks Mine NV 7,123,665 02 Carbon adsorption unit 

Condenser Mist eliminator 

Newmont Twin Creeks Mine NV 7,123,665 03 Carbon adsorption unit 

Condenser Mist eliminator 

Newmont Twin Creeks Mine NV 7,123,665 04 Carbon adsorption unit 

Condenser Mist eliminator 

Barrick Goldstrike Mines NV 12,809,234 01 Carbon adsorption unit 

Condenser Cyclone 

Barrick Goldstrike Mines NV 12,809,234 02 Carbon adsorption unit 

Condenser Cyclone 
. 

B-9 

Table B-4. Summary of Gold Mining Facilities Using Retorts in the United States (Continued)Parent company Facility name State Total ore processed by facility (tons) Unit ID Control technologies Estimated me

emissions fro(tons) Barrick Goldstrike Mines NV 12,809,234 03 Carbon adsorption unit Condenser Cyclone 

Newmont Midas Operations NV 407,985 01 Carbon adsorption unit Wet scrubber Newmont Midas Operations NV 407,985 02 Carbon adsorption unit Wet scrubber Queenstake Jerritt Canyon NV 1,305,833 01 Carbon adsorption unit Condenser Wet scrubber NNewmont Gold Quarry Operations NV 22,090,847 01 Carbon adsorption unit Condenser Fabric filter Newmont Gold Quarry Operations NV 22,090,847 02 Carbon adsorption unit Condenser Fabric filter Newmont Gold Quarry Operations NV 22,090,847 03 Carbon adsorption unit Condenser Fabric filter Newmont Gold Quarry Operations NV 22,090,847 04 Carbon adsorption unit Condenser Fabric filter Newmont Gold Quarry Operations NV 22,090,847 05 Carbon adsorption unit Condenser Fabric filter Newmont Gold Quarry Operations NV 22,090,847 06 Carbon adsorption unit Condenser Fabric filter Barrick / Placer Dome Bald Mountain Mine (including Mooney Basin) NV 2,225,405 01 Carbon adsorption unit Kennecott Denton-Rawhide Mine NV 0 01 Carbon adsorption unit 

Total 
. 

B-10 

Table B-5. Summary of Gold Mining Facilities Using Smelting in the United States.

Parent company Facility name State 

Total ore processed by facility (tons) 

Unit ID Control technologies 

Coeur d'Alene Coeur Rochester, Inc. NV 12,435,346 01 Electrostatic precipitator 

Wet scrubber 

Florida Canyon/ Jipangu Florida Canyon Mine NV 6,256,953 01 Fabric filter Florida Canyon/ Jipangu Florida Canyon Mine NV 6,256,953 02 Fabric filter Glamis Glamis Marigold Mine NV 9,858,024 01 None Vista Hycroft Mine NV 0 01 Wet scrubber Vista Hycroft Mine NV 0 02 Wet scrubber Vista Hycroft Mine NV 0 03 Wet scrubber Barrick/ Kennecott Cortez Gold Mines Mill #2 NV 41,603,701 01 Fabric filter Barrick/ Kennecott Cortez Gold Mines Mill #2 NV 41,603,701 02 Fabric filter Golden Phoenix Mineral Ridge Mine NV 280,000 01 Wet scrubber Barrick Ruby Hill Mine NV 0 01 Wet scrubber Newmont Twin Creeks Mine NV 7,123,665 01 Fabric filter Newmont Twin Creeks Mine NV 7,123,665 02 Fabric filter Barrick Goldstrike Mines NV 12,809,234 01 Carbon adsorption unit 

Fabric filter 

Barrick Goldstrike Mines NV 12,809,234 02 Carbon adsorption unit 

Fabric filter 

Newmont Midas Operations NV 407,985 01 Carbon adsorption unit 

Wet scrubber 

Queenstake Jerritt Canyon NV 1,305,833 01 Fabric filter Newmont Gold Quarry Operations NV 22,090,847 01 Carbon adsorption unit 

Fabric filter 

Newmont Gold Quarry Operations NV 22,090,847 02 Carbon adsorption unit 

Fabric filter 

GoldSprings Plum Mining Company LLC NV 176,739 01 None Kennecott Goldwedge Gravity Mill NV 0 01 None Barrick/ Placer Dome Bald Mountain Mine NV 2,225,405 01 Fabric filter Kennecott Denton-Rawhide Mine NV 0 01 Fabric filter Barrick Golden Sunlight Mines, Inc. MT 2,600,000 01 Wet scrubber Western Goldfields Mesquite Mine CA 4,225,516 01 None  Total 
. 

B-11 

Table B-6. Summary of Gold Mining Facilities Using Other Thermal Processes in the United States.

Parent company Facility name State 

Total ore processed by facility (tons) Process Control technologie

Newmont Lone Tree Mine NV 6,068,995 Pregnant/barren solution tank None Newmont Lone Tree Mine NV 6,068,995 Drying oven None Newmont Lone Tree Mine NV 6,068,995 Drying oven None Newmont Lone Tree Mine NV 6,068,995 Drying oven None Newmont Lone Tree Mine NV 6,068,995 Drying oven None Newmont Lone Tree Mine NV 6,068,995 Fire assay furnace Fabric filter Newmont Lone Tree Mine NV 6,068,995 Fire assay furnace Fabric filter Newmont Lone Tree Mine NV 6,068,995 Fire assay furnace Fabric filter Newmont Lone Tree Mine NV 6,068,995 Fire assay furnace Fabric filter Newmont Lone Tree Mine NV 6,068,995 Lime slaker None Newmont Lone Tree Mine NV 6,068,995 LECO furnace Fabric filter Newmont Lone Tree Mine NV 6,068,995 LECO furnace Fabric filter Coeur d'Alene Coeur Rochester, Inc. NV 12,435,346 Drying oven None Coeur d'Alene Coeur Rochester, Inc. NV 12,435,346 Drying oven None Coeur d'Alene Coeur Rochester, Inc. NV 12,435,346 Drying oven None Coeur d'Alene Coeur Rochester, Inc. NV 12,435,346 Drying oven None Coeur d'Alene Coeur Rochester, Inc. NV 12,435,346 Fire assay furnace None Coeur d'Alene Coeur Rochester, Inc. NV 12,435,346 Fire assay furnace None Coeur d'Alene Coeur Rochester, Inc. NV 12,435,346 Fire assay furnace None Coeur d'Alene Coeur Rochester, Inc. NV 12,435,346 Fire assay furnace None Coeur d'Alene Coeur Rochester, Inc. NV 12,435,346 Miscellaneous assay processes None Coeur d'Alene Coeur Rochester, Inc. NV 12,435,346 Miscellaneous assay processes None Coeur d'Alene Coeur Rochester, Inc. NV 12,435,346 Miscellaneous assay processes None Coeur d'Alene Coeur Rochester, Inc. NV 12,435,346 Miscellaneous assay processes None Coeur d'Alene Coeur Rochester, Inc. NV 12,435,346 Miscellaneous assay processes None Coeur d'Alene Coeur Rochester, Inc. NV 12,435,346 Miscellaneous assay processes None Coeur d'Alene Coeur Rochester, Inc. NV 12,435,346 Miscellaneous assay processes None Florida Canyon/ Jipangu Florida Canyon Mine NV 6,256,953 Pregnant/barren solution tank None Florida Canyon/ Jipangu Florida Canyon Mine NV 6,256,953 Pregnant/barren solution tank None Florida Canyon/ Jipangu Florida Canyon Mine NV 6,256,953 Drying oven None 
. 

B-12 

Table B-6. Summary of Gold Mining Facilities Using Other Thermal Processes in the United States (ConParent company Facility name State Total ore processed by facility (tons) Process Control technologieFlorida Canyon/ Jipangu Florida Canyon Mine NV 6,256,953 Drying oven None Florida Canyon/ Jipangu Florida Canyon Mine NV 6,256,953 Drying oven None Florida Canyon/ Jipangu Florida Canyon Mine NV 6,256,953 Drying oven None Florida Canyon/ Jipangu Florida Canyon Mine NV 6,256,953 Fire assay furnace None Florida Canyon/ Jipangu Florida Canyon Mine NV 6,256,953 Fire assay furnace None Florida Canyon/ Jipangu Florida Canyon Mine NV 6,256,953 Fire assay furnace None Florida Canyon/ Jipangu Florida Canyon Mine NV 6,256,953 Miscellaneous assay processes None Florida Canyon/ Jipangu Florida Canyon Mine NV 6,256,953 Miscellaneous assay processes None Florida Canyon/ Jipangu Florida Canyon Mine NV 6,256,953 Miscellaneous assay processes None Florida Canyon/ Jipangu Florida Canyon Mine NV 6,256,953 Miscellaneous assay processes None Glamis Glamis Marigold Mine NV 9,858,024 Miscellaneous assay processes None Barrick Placer Turquoise Ridge Inc. NV 0 Fire assay furnace Fabric filter Barrick Placer Turquoise Ridge Inc. NV 0 Fire assay furnace Fabric filter Barrick Placer Turquoise Ridge Inc. NV 0 Fire assay furnace Fabric filter Barrick Placer Turquoise Ridge Inc. NV 0 Fire assay furnace Fabric filter Kinross/ Barrick Round Mountain Gold - Smoky Valley Common Operation NV 55,352,143 Drying oven None Kinross/ Barrick Round Mountain Gold - Smoky Valley Common Operation NV 55,352,143 Drying oven None Kinross/ Barrick Round Mountain Gold - Smoky Valley Common Operation NV 55,352,143 Drying oven None Kinross/ Barrick Round Mountain Gold - Smoky Valley Common Operation NV 55,352,143 Drying oven None Kinross/ Barrick Round Mountain Gold - Smoky Valley Common Operation NV 55,352,143 Drying oven None Kinross/ Barrick Round Mountain Gold - Smoky Valley Common Operation NV 55,352,143 Drying oven None Kinross/ Barrick Round Mountain Gold - Smoky Valley Common Operation NV 55,352,143 Drying oven None Kinross/ Barrick Round Mountain Gold - Smoky Valley Common Operation NV 55,352,143 Induction furnace Wet scrubber Kinross/ Barrick Round Mountain Gold - Smoky Valley Common Operation NV 55,352,143 Fusion furnace Wet scrubber 
. 

B-13 

Table B-6. Summary of Gold Mining Facilities Using Other Thermal Processes in the United States (ConParent company Facility name State 

Total ore processed by facility (tons) Process Control technologie

Kinross/ Barrick Round Mountain Gold - Smoky 

Valley Common Operation 

NV 55,352,143 Fusion furnace Wet scrubber 

Kinross/ Barrick Round Mountain Gold - Smoky 

Valley Common Operation 

NV 55,352,143 Fusion furnace Wet scrubber 

Kinross/ Barrick Round Mountain Gold - Smoky 

Valley Common Operation 

NV 55,352,143 Fusion furnace Wet scrubber 

Kinross/ Barrick Round Mountain Gold - Smoky 

Valley Common Operation 

NV 55,352,143 Fusion furnace Wet scrubber 

Kinross/ Barrick Round Mountain Gold - Smoky 

Valley Common Operation 

NV 55,352,143 Fusion furnace Wet scrubber 

Kinross/ Barrick Round Mountain Gold - Smoky 

Valley Common Operation 

NV 55,352,143 Fusion furnace Wet scrubber 

Kinross/ Barrick Round Mountain Gold - Smoky 

Valley Common Operation 

NV 55,352,143 Fusion furnace Wet scrubber 

Kinross/ Barrick Round Mountain Gold - Smoky 

Valley Common Operation 

NV 55,352,143 Fusion furnace Wet scrubber 

Kinross/ Barrick Round Mountain Gold - Smoky 

Valley Common Operation 

NV 55,352,143 Fusion furnace Wet scrubber 

Barrick/ Kennecott Cortez Gold Mines Mill #2 

(Pipeline Mill) 

NV 41,603,701 Drying oven Fabric filter 

Barrick/ Kennecott Cortez Gold Mines Mill #2 

(Pipeline Mill) 

NV 41,603,701 Drying oven Fabric filter 

Barrick/ Kennecott Cortez Gold Mines Mill #2 

(Pipeline Mill) 

NV 41,603,701 Drying oven Fabric filter 

Barrick/ Kennecott Cortez Gold Mines Mill #2 

(Pipeline Mill) 

NV 41,603,701 Drying oven Fabric filter 

Golden Phoenix Mineral Ridge Mine NV 280,000 Drying oven None Newmont Twin Creeks Mine NV 7,123,665 Pregnant/barren solution tank Wet scrubber Newmont Twin Creeks Mine NV 7,123,665 Pregnant/barren solution tank None Newmont Twin Creeks Mine NV 7,123,665 Drying oven Fabric filter Newmont Twin Creeks Mine NV 7,123,665 Fire assay furnace Fabric filter Newmont Twin Creeks Mine NV 7,123,665 Fire assay furnace Fabric filter Newmont Twin Creeks Mine NV 7,123,665 Fire assay furnace Fabric filter Newmont Twin Creeks Mine NV 7,123,665 Fire assay furnace Fabric filter Newmont Twin Creeks Mine NV 7,123,665 Lime slaker Wet scrubber Newmont Twin Creeks Mine NV 7,123,665 Lime slaker Wet scrubber 
. 

B-14 

Table B-6. Summary of Gold Mining Facilities Using Other Thermal Processes in the United States (ConParent company Facility name State 

Total ore processed by facility (tons) Process Control technologie

Newmont Twin Creeks Mine NV 7,123,665 LECO furnace Fabric filter Barrick Goldstrike Mines NV 12,809,234 Drying oven None Barrick Goldstrike Mines NV 12,809,234 Drying oven None Barrick Goldstrike Mines NV 12,809,234 Drying oven None Barrick Goldstrike Mines NV 12,809,234 Drying oven None Barrick Goldstrike Mines NV 12,809,234 Drying oven None Barrick Goldstrike Mines NV 12,809,234 Fire assay furnace Fabric filter Barrick Goldstrike Mines NV 12,809,234 Fire assay furnace Fabric filter Barrick Goldstrike Mines NV 12,809,234 Fire assay furnace Fabric filter Barrick Goldstrike Mines NV 12,809,234 Fire assay furnace Fabric filter Barrick Goldstrike Mines NV 12,809,234 Fire assay furnace Fabric filter Barrick Goldstrike Mines NV 12,809,234 Fire assay furnace Fabric filter Barrick Goldstrike Mines NV 12,809,234 Fire assay furnace Fabric filter Barrick Goldstrike Mines NV 12,809,234 Miscellaneous assay processes Fabric filter Barrick Goldstrike Mines NV 12,809,234 Miscellaneous assay processes Fabric filter Queenstake Jerritt Canyon NV 1,305,833 Drying oven None Queenstake Jerritt Canyon NV 1,305,833 Drying oven None Queenstake Jerritt Canyon NV 1,305,833 Drying oven None Queenstake Jerritt Canyon NV 1,305,833 Drying oven None Queenstake Jerritt Canyon NV 1,305,833 Drying oven None Queenstake Jerritt Canyon NV 1,305,833 Drying oven None Queenstake Jerritt Canyon NV 1,305,833 Miscellaneous assay processes None Queenstake Jerritt Canyon NV 1,305,833 Miscellaneous assay processes None Queenstake Jerritt Canyon NV 1,305,833 Miscellaneous assay processes None Queenstake Jerritt Canyon NV 1,305,833 Miscellaneous assay processes None Queenstake Jerritt Canyon NV 1,305,833 Miscellaneous assay processes None Queenstake Jerritt Canyon NV 1,305,833 Miscellaneous assay processes None Queenstake Jerritt Canyon NV 1,305,833 Miscellaneous assay processes None Queenstake Jerritt Canyon NV 1,305,833 Miscellaneous assay processes None Queenstake Jerritt Canyon NV 1,305,833 Miscellaneous assay processes None Queenstake Jerritt Canyon NV 1,305,833 Miscellaneous assay processes None 
. 

B-15 

Table B-6. Summary of Gold Mining Facilities Using Other Thermal Processes in the United States (ConParent company Facility name State 

Total ore processed by facility (tons) Process Control technologie

Queenstake Jerritt Canyon NV 1,305,833 Miscellaneous assay processes None Newmont Gold Quarry Operations NV 22,090,847 Drying oven None Newmont Gold Quarry Operations NV 22,090,847 Drying oven None Newmont Gold Quarry Operations NV 22,090,847 Drying oven None Newmont Gold Quarry Operations NV 22,090,847 Fire assay furnace Fabric filter Newmont Gold Quarry Operations NV 22,090,847 Fire assay furnace Fabric filter Newmont Gold Quarry Operations NV 22,090,847 Fire assay furnace None Newmont Gold Quarry Operations NV 22,090,847 Fire assay furnace None Newmont Gold Quarry Operations NV 22,090,847 Fire assay furnace None Newmont Gold Quarry Operations NV 22,090,847 Fire assay furnace None Newmont Gold Quarry Operations NV 22,090,847 Fusion furnace None Newmont Gold Quarry Operations NV 22,090,847 Fusion furnace None Newmont Gold Quarry Operations NV 22,090,847 Electrolyte tank Carbon adsorption unBarrick/ Placer Dome Bald Mountain Mine (including 

Mooney Basin) 

NV 2,225,405 Drying oven None 

Barrick/ Placer Dome Bald Mountain Mine (including 

Mooney Basin) 

NV 2,225,405 Drying oven None 

Barrick/ Placer Dome Bald Mountain Mine (including 

Mooney Basin) 

NV 2,225,405 Drying oven None 

Barrick/ Placer Dome Bald Mountain Mine (including 

Mooney Basin) 

NV 2,225,405 Drying oven None 

Barrick/ Placer Dome Bald Mountain Mine (including 

Mooney Basin) 

NV 2,225,405 Fire assay furnace None 

Barrick/ Placer Dome Bald Mountain Mine (including 

Mooney Basin) 

NV 2,225,405 Fire assay furnace None 

Kennecott/ Hecla Kennecott Greens Creek Mining 

Company 

AK 717,564 Dore furnace None 

Kinross Echo Bay Minerals Co., Kettle 

River Operations 

WA 278,248 Induction furnace Fabric filter 

Total