U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2015–3075

Version 1.1, December 2015

Conflict Minerals From the Democratic Republic of the Congo—

Gold Supply Chain

The U.S. Geological Survey (USGS) analyzes mineral and 

metal supply chains to identify and describe major components 

of material flows from ore extraction, through intermediate 

forms, to a final product. Supply chain analyses may be used 

to identify risks to the United States associated with the supply 

of critical and strategic minerals and metals and to provide 

greater supply chain transparency so that policymakers have the 

fact-based information needed to formulate public policy. 

The USGS National Minerals Information Center (NMIC) 

has been asked by governmental and nongovernmental organizations to provide information about tantalum, tin, tungsten, 

and gold (collectively known as “3TG minerals”) processing 

facilities worldwide in response to U.S. legislation aimed at 

identifying and removing the supply chain links associated with 

the trade of these metals and minerals among armed groups 

in the Democratic Republic of the Congo (DRC) and adjacent 

countries. Post-beneficiation processing plants (generally called 

smelters and refineries) for tantalum, tin, and tungsten (3T) 

mineral ores and concentrates were identified by company and 

industry association representatives as being the link in the 3T

mineral supply chain through which these minerals can be traced 

to their source of origin (mine). Tungsten processing plants were 

the subject of the first fact sheet in a series of USGS reports 

about 3TG minerals, which was published by the NMIC in 

August 2014 (Bermúdez-Lugo, 2014). Background information 

about historical conditions and the voluntary due diligence of 

multinational stakeholders for minerals from conflict-affected 

and high-risk areas is presented in the tungsten fact sheet. The 

current fact sheet, the fourth and last in the series about 3TG 

minerals, focuses on the gold supply chain.

Processing of the 3T mineral concentrates requires 

substantial infrastructure and capital and generally is done at 

relatively few specialized facilities that are not located at the 

mine site; primary and secondary processors typically are at 

separate locations. Gold, however, can easily be processed into 

semi-refined products at or near the mine site and has a high 

unit value in any form, which allows it to be readily exported 

through undocumented channels, making it more difficult to 

track to the mine or region of origin. To put this in perspective, 

30 kilograms (66 pounds) of 83-percent-pure (20-carat) gold 

would form a cube measuring 12 centimeters per side (about the 

size of a small tissue box) and, at a price of $1,200 per ounce, 

would be worth nearly $1 million. By contrast, the equivalent 

value of tungsten concentrates would weigh about 45 metric 

tons (t) (100,000 pounds). Once conflict-sourced gold has been 

combined with gold from other mines and scrap at a refinery, 

Average world gold mine production by country, 2009–13.

180° 140° 100° 60° 20° 0° 20° 60° 100° 140° 180°

40°

20°

0°

20°

40°

60°

80°

80°

60°

Average percentage of gold mine

 production by country, 2009–13

EXPLANATION

>5 (6 countries, 53%)

1 to 5 (20 countries, 38%)

<1 (73 countries, 9%; 

 unlabeled)

RUSSIA

CHINA

AUSTRALIA

SOUTH AFRICA

PERU

BRAZIL

MALI

GUINEA

GHANA

KAZAKHSTAN

KYRGYZSTAN

UZBEKISTAN

INDONESIA

ARGENTINA

CHILE

BURKINA

FASO

TOGO TANZANIA

PHILIPPINES

PAPUA

NEW GUINEA

TURKEY

MEXICO

COLOMBIA

CANADA

UNITED STATES

OF AMERICA

SUDAN
there is no feasible way to distinguish the source of the gold. 

Thus, once the gold leaves the immediate area of production, 

it is nearly indistinguishable from gold products mined in 

other areas.

Background

Gold occurs naturally as native metal. It may be mined as 

a primary product from hard rock and alluvial placer deposits 

or recovered as a byproduct from copper, lead, platinum-group 

metals, silver, and zinc ores processing. Gold is chemically quite 

unreactive, although it will dissolve in aqua regia (a mix of nitric 

acid and hydrochloric acid). It is also malleable, ductile, and an 

excellent conductor of electricity and heat. Gold production was 

reported in almost 100 countries from 2009 to 2013; however, 

the six leading gold producers (in descending order of production)—China, Australia, Russia, the United States, South Africa, 

and Peru—accounted for 53 percent of global production. 

Gold has been treasured since ancient times for its beauty and 

permanence and remains the decorative metal par excellence. 

Gold is used as a store of value, because it does not degrade 

over time, can be easily recycled, and has a high intrinsic value. 

Throughout time, people have used gold as a form of wealth, 

whether it was in the form of bars, coins, jewelry, or artwork. 

About 7 percent of refined gold is used in nonmonetary applications such as electronic contacts, restorative dentistry, medical 

devices, and electromagnetic and infrared shielding, particularly 

in satellites.

Global Gold Supply Chain

Global gold supply, which begins at the mine, may involve 

large-scale industrial gold producers, byproduct gold recovery 

operations, placer mining operations, or artisanal and smallscale gold mines (ASGM). Small-scale mines may include 

semi-mechanized operations, while artisanal mines are dug by 

hand, using only rudimentary tools, such as shovels and sifters. 

Many ASGMs are in remote areas without adequate government 

oversight, further allowing for undocumented gold production 

and transport. The gold recovered is concentrated and at least 

partially processed at or near the mine. The larger scale mines 

typically produce doré bars that are mostly gold and silver. The 

ASGMs sell a concentrate (such as gold-bearing sand, gold 

flakes, gold nuggets, or gold amalgamate) to a local buyer. The 

local buyer collects the gold and then arranges to have the gold 

further processed. 

Although large-scale refineries exist, numerous small 

refineries process doré bars, low-grade material, and scrap 

for use in jewelry fabrication or sale to other fabricators, thus 

bypassing bullion certification. Refineries may process gold from 

mines, old scrap, intermediate refineries, and other gold-bearing 

material to produce gold products (such as bullion, coin, foil, 

jewelry stock, powder, and wire). Unlike other metals, after the 

gold is recovered, it is considered as above-ground stockpile 

because it can easily be returned to the refineries to be recycled 

or transferred to other customers with little or no further 

processing. An estimated 7,500 to 8,000 metric tons (t) of gold 

Estimated global above-ground stocks of gold as of 

yearend 2014. (Source: Thomson Reuters Ltd., 2015)

was refined in 2013, of which 2,800 t was from mine production, 

1,600 t was from old scrap, and the rest was from re-melting 

of semi-manufactured goods or bullion bars (London Bullion 

Market Association, 2015). 

A major source of gold supply is the available aboveground stockpiles. Because gold is chemically unreactive 

and easily recycled, almost all the gold ever produced is still 

available for use. The estimated cumulative historical global 

gold mine production as of yearend 2014 was 184,000 t. At that 

time, about 31,000 t was held by central banks as official stocks, 

about 37,000 t was held privately as investments, about 87,000 t 

was held privately as jewelry, 25,000 t was in other fabricated 

products, and about 4,000 t was unaccounted for (pie chart, 

above) (Thomson Reuters Ltd., 2015, p. 52).

Certified Gold Bullion 

To sell gold bullion, a refinery must be certified to 

produce certified pure gold. Table 1 lists the 10 gold bullion 

markets and the number of refineries certified to deliver gold 

bullion. Although the gold bullion markets listed contain only 

approximately 140 nonduplicate refiners of gold, the number 

of global refineries may exceed 500, and many of the refineries 

are listed on more than one bullion market. Most gold that is 

purchased by manufacturers and fabricators comes through 

one of these 10 markets; however, some manufacturers and 

fabricators purchase gold directly from refiners or purchase 

gold scrap for direct use. In 2013, the 72 refineries listed on the 

Good Delivery List, of the London Bullion Market Association 

(LBMA), the oldest and leading gold exchange, produced about 

85 to 90 percent of globally refined gold (London Bullion 

Jewelry

87,000 t

Official

holdings

31,000 t

Private

investment

37,000 t

Other

fabrication

25,000 t

Unaccounted for 

4,000 t

Total=184,000 metric tons (t)
Table 1. Gold bullion accreditors.

[NA, not available. Sources: Markets listed in the first column]

Market Country Number of 

refineries1

BM&Fbovespa (BM&F)2 Brazil 5

Shanghai Gold Exchange (SGE)2 China 30

The Chinese Gold & Silver Exchange Society, Hong Kong (CGSE)2 China 12

Multi Commodity Exchange of India Ltd. (MCX)2 India NA

Indian Bullion Market Association (IBMA) India 8

Tokyo Commodity Exchange (TOCOM) Japan 44

Istanbul Gold Exchange (IGE)2 Turkey 3

Dubai Multi Commodities Center (DMCC) United Arab Emirates 14

London Bullion Market Association (LBMA) United Kingdom 72

CME Group - Market Contract (COMEX) United States 27

1

Some refineries are listed by multiple markets. The total number of distinct refineries listed on these exchanges is 140.

2

LBMA-accredited refiners are also accredited on these exchanges.

Table 2. Gold production from the Democratic 

Republic of the Congo (DRC) region, Africa, 2009–13.

[NA, not available. Source: George, 2015]

Country 2009–13 average 

(kilograms per year)

Angola NA 

Burundi 380e

Central African Republic 56e

Congo (Brazzaville) 140e

Congo (Kinshasa) (DRC) 11,500e

Kenya 2,450 

Rwanda 8e

Sudan and South Sudan 27,100e

Tanzania 41,000 

Uganda 260 

Zambia 4,120e

Total 86,800 

World total 2,650,000 

e

Estimated.

Market Association, 2015). Although these markets exist to 

certify that the gold bullion is pure gold, other organizations 

have initiated programs to certify that the source of the gold 

was not from a conflict region. Currently the LBMA, the Dubai 

Multi Commodities Center, and the World Gold Council have 

programs to document the source of the gold. More information 

can be found at the respective Web sites. 

DRC Gold Supply Chain

The 2009–13 annual average gold production from the 

DRC and adjacent countries was about 87 t, which represents 

about 3 percent of the average global gold production during 

that period (table 2). The annual average worldwide gold mine 

production for 2009–13 was 2,650 t. Unlike the 3T minerals, the 

DRC has three large-scale industrial gold mines that produce 

gold for legal export: Kibali (Orientale Province), Namoya 

(Maniema Province), and Twangiza (South Kivu Province). 

These mines began production in 2012 or 2013 and produced 

2 t in 2012 and 5 t in 2013. An estimated 11 to 14 metric tons 

per year were produced from ASGM operations in the eastern 

North Kivu and South Kivu Provinces and Ituri region (Yager, 

2014). ASGM gold in the DRC and adjacent countries typically 

is recovered by panning or sluicing methods (gravity separation) that take advantage of the relatively high density of gold 

compared to other alluvial sediments. To further concentrate 

gold, ASGMs may use mercury in a process known as amalgamation. Following gravity separation, miners pour mercury 

into the gold-bearing sands and stir the mixture, often with their 

bare hands. The mercury and gold and (or) silver combine into 

a gray amalgam. The amalgam is then heated to boil off the 

mercury leaving behind very high concentrations of gold and 

(or) silver. A retort can be used to heat treat the amalgam so that 

the mercury can be captured and recycled. However, retorts are 

not used in most ASGM operations, and the mercury vapors can 

be released into the atmosphere with substantial human exposure 

and environmental health implications.
After the ASGM gold from the DRC and adjacent countries 

is recovered through gravity separation and amalgamation, it is 

sold to comptoirs (local gold buyers) who may further increase 

the purity before it is exported to a refinery. The gold collected 

by the comptoirs is generally more than 50 percent pure gold; 

the remainder is mostly silver. According to a United Nations 

report, about 98 percent of ASGM gold production in the DRC 

is exported illegally. One reported method of undocumented 

gold export is to transport the gold by boat across the Ruzizi 

River or Lake Tanganyika to Burundi, where it may be exported 

to a refinery (United Nations Security Council, 2015, p. 3). The 

same report surmised that approximately two-thirds of the gold 

illegally exported from the DRC passes through Uganda with 

smaller amounts shipped through Burundi and Tanzania. 

After ASGM gold leaves the DRC region and arrives at 

a refinery, gold from other mines or scrap material may be 

blended, and the ability to identify gold sourced from a conflict 

region is almost impossible. Unlike the 3T minerals, which are 

chemically heterogeneous, gold is often found in its elemental 

form and shows little or no chemical variation. Thus, it is 

unlikely that gold from a conflict region could be tagged as such 

through chemical analysis of the product.

References Cited

Bermúdez-Lugo, Omayra, 2014, Conflict minerals from the 

Democratic Republic of the Congo—Global tungsten processing plants, a critical part of the tungsten supply chain (ver. 1.1, 

August 2014): U.S. Geological Survey Fact Sheet 2014–3069, 

4 p., accessed October 1, 2014, at http://dx.doi.org/10.3133/

fs20143069.

George, M.W., 2015, Gold [advance release], in Metals and 

minerals: U.S. Geological Survey Minerals Yearbook 2013, 

v. I, p. 31.1–31.18. (Also available at http://minerals.usgs.gov/

minerals/pubs/commodity/gold/myb1-2013-gold.pdf.)

London Bullion Market Association, 2015, A guide to the 

London Bullion Market Association: London, United Kingdom, London Bullion Market Association, 4 p., accessed 

June 12, 2015, at http://www.lbma.org.uk/assets/market/gdl/

LBMA Brochure Final 20150501.pdf.

Thomson Reuters Ltd., 2015, Gold survey 2014: London, 

United Kingdom, Thomson Reuters Ltd., April, 116 p.

United Nations Security Council, 2015, Final report of 

the group of experts on the Democratic Republic of the 

Congo: United Nations Security Council, S/2015/19, 

January 12, 2015, 277 p., accessed May 12, 2015, at 

http://www.securitycouncilreport.org/atf/cf/%7B65BFCF9B6D27-4E9C-8CD3-CF6E4FF96FF9%7D/s_2015_19.pdf.

Yager, T.R., 2014, The mineral industry of Congo (Kinshasa) 

[advance release], in Area reports—International—Africa and 

the Middle East: U.S. Geological Survey Minerals Yearbook 

2012, v. III, p. 11.1–11.10. (Also available at http://minerals.

usgs.gov/minerals/pubs/country/2012/myb3-2012-cg.pdf.)

By Micheal W. George, with contributions by Omayra Bermúdez-Lugo

 and Thomas R. Yager

For more information, contact

Director, National Minerals 

 Information Center

U.S. Geological Survey

12201 Sunrise Valley Drive

988 National Center

Reston, VA 20192

Email: nmicrecordsmgt@usgs.gov

Or visit the USGS Minerals Information Web site 

 at http://minerals.usgs.gov/minerals/

An artisanal miner pans for gold in the Democratic Republic of the 

Congo. (Photograph by Guillem Valle/Corbis)

ISSN 2327-6916 (print)

ISSN 2327-6932 (online)

http://dx.doi.org/10.3133/fs20153075

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