U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2012–3129

November 2012

Prepared under the auspices of the U.S. Department of State

Summary of the Diamond Resource Potential and Production 

Capacity Assessment of Guinea

The Kimberley Process

In May of 2000, a meeting was convened 

in Kimberley, South Africa, by representatives 

of the diamond industry and leaders of 

African governments to develop a certification process intended to assure that export 

shipments of rough diamonds were free of 

conflict concerns. Outcomes of the meeting 

were formally supported later in December 

of 2000 by the United Nations in a resolution adopted by the General Assembly. By 

2002, the Kimberley Process Certification 

Scheme (KPCS) was ratified and signed by 

diamond-producing and diamond-importing 

countries. As of August 2012, the Kimberley 

Process (KP) had 51 participants representing 

77 countries.

Administrative Decision on Guinea

During the Seventh Annual Plenary 

Session of the KPCS held in Swakopmund, Namibia, in November 2009, an 

Administrative Decision (AD) on Guinea was 

adopted. The Swakopmund AD was the result 

of concerns relating to Guinea’s significant 

increase in diamond exports between the years 

2006 and 2008, in which production spiked 

from 473,862 carats in 2006 to 1,018,722 

carats in 2007 and 3,098,490 carats in 

2008 (Kimberley Process Rough Diamond 

Statistics, 2006, 2007, 2008). The AD 

requested that Guinean authorities relaunch a 

system of internal controls, including stopping 

any exports of rough diamonds of suspicious 

origin (KPCS Secretariat, 2009).

2010 Field Assessment

With the passing of the AD, the Plenary 

agreed that further efforts should be made to 

assess Guinea’s diamond production capacity 

(KPCS Secretariat, 2009). In support of 

this objective, the U.S. Geological Survey 

(USGS) partnered with the Kimberley Process 

Working Group of Diamond Experts (WGDE) 

and Guinea’s Ministry of Mines and Geology 

(MMG) to conduct a field campaign in Guinea 

from April 24 through May 2, 2010. The field 

team was composed of Mark Van Bockstael of 

the WGDE, Peter Chirico of the USGS, and 

several geologists from the MMG. 

The team visited diamond mining sites 

in western Guinea’s Kindia, Forécariah, 

Coyah, and Télimélé Prefectures, in which 

the Guinean government identified newly 

discovered deposits mined by artisans (fig. 1). 

Several mining sites within the Kissidougou 

Prefecture in southeastern Guinea were also 

visited as part of this study. Geologic and 

geomorphic information on the diamond 

deposits was collected at each site. The 

fieldwork conducted during this trip served 

as a means of acquiring critical data needed 

to conduct a full assessment of diamond 

resources and production capacity.

Figure 1. A bedrock fracture/paleoplacer 

deposit actively mined by artisans at 

Férékouré in the Kindia Prefecture of 

western Guinea.

2011 Training

A team from the USGS made a return 

trip to Guinea from May 31 through June 4, 

2011. The purpose of this trip was threefold. 

First, the results of the report drafted after 

the 2010 visit were presented to members of 

the MMG and representatives of civil society 

organizations such as the International Trade 

Centre for Development (CECIDE) and the 

Confédération Nationale des Diamantaires 

et Orpailleurs de Guinée (CONADOG), 

with the support from Partnership Africa 

Canada (PAC), the U.S. Embassy, and the 

U.S. Agency for International Development 

(USAID). Second, the methodology used by 

the USGS to conduct the diamond resource 

Figure 2.

Figure 2. A presentation given by the USGS 

for civil society organization representatives 

on the methodology used to conduct resource 

assessments, June 2011, Conakry, Guinea.

potential and production capacity assessments of Guinea was explained in detail to 

the MMG and civil society representatives 

(fig. 2). Third, the USGS demonstrated 

methods for conducting fieldwork and data 

gathering techniques to members of the MMG 

and civil society organizations during a trip to 

the Forécariah Prefecture. 

Multistakeholder Cooperation

To address the lack of necessary data, 

this effort represents a new direction in the 

KP’s monitoring and evaluation of diamond 

resources. Multiple stakeholders at several 

levels of government and civil society and 

industry cooperated to conduct fieldwork and 

gather data necessary to produce a countrywide diamond assessment. This cooperative 

agreement is conducted with international 

support from the KP and with support from 

the national government for the organizations 

CECIDE and CONADOG, which in turn 

represent artisanal mining interests, with the 

final partner being artisanal miners at the 

local level.

In March of 2012, further fieldwork was 

conducted by a team composed of Mamadou 

Diaby, Coordinator of the Programme 

Exploitation Artisanale de Diamant and the 

Kimberley Process at CECIDE; Thierno 

Amadou Diallo, Executive Director General 

of the Brigade Antifraude des Matières 

Précieuses; and Mahmoud Sano, Chef de 

Section Exploitation Artisanale Diamant at the 

MMG. The team visited five artisanal diamond 

mining sites in the Kindia and Télimélé 

Printed on recycled paper
Prefectures. Later that month, the USGS 

returned and conducted a joint fieldwork 

mission with geologists from CECIDE and 

the MMG and visited seven artisanal diamond 

mining sites in the Forécariah and Coyah 

Prefectures. The final fieldwork mission was 

conducted in May 2012 by the Guinean team. 

Seventeen artisanal diamond mining sites in 

the intensively mined Macenta and Kérouané 

Prefectures of southeastern Guinea were 

visited during this mission (fig. 3). 

Diamond Resource Potential

To conduct the assessment, Guinea’s 

diamond deposits were first separated into 

five “diamondiferous regions,” in order to 

more accurately reflect the geomorphological 

parameters of each deposit. Hydrologic and 

geomorphic models were then developed for 

each of the regions. The resource potential 

was first calculated for the individual regions 

using the following variables: estimated 

grades, gravel thicknesses, and surface areas 

of the alluvial flats and terraces. The volume 

of the diamondiferous gravel was calculated 

by multiplying the average gravel thickness 

by the surface area of the alluvial flats and terraces. Three-quarters of the volume of gravel 

was multiplied by the “basic” grade, while the 

remaining quarter of the volume was multiplied by the higher “concentration” grade.

The results for each region were then 

totaled, amounting to 60 million carats. 

The next step was to subtract the number of 

carats that had already been mined, which 

was estimated to be 20 million carats. Once 

subtracted from the total estimated reserves, 

the revised total diamond resource came to 

approximately 40 million carats.

Production Capacity Assessment

The diamond production capacity was 

then estimated by a mathematical formula, 

using the following variables: the volume of 

gravel mined per person per day, estimated to 

be 0.14 cubic meter; the average gravel grade 

of the deposits, estimated to vary regionally 

from 0.08 to 0.2 carats per cubic meter; the 

number of days worked per year, estimated 

to be 216; the total number of active artisanal 

miners, estimated to be 100,000; and the total 

industrial production, estimated to be 100,000 

carats. Applying these variables to the equation 

resulted in a production capacity of 600,000 

carats per year. 

Multiple variables, the values of which 

were calculated from historical records and 

field data, were utilized to arrive at the production capacity estimates. It is possible that the 

values of one or more of the variables used 

in the equation may overestimate or underestimate the situation on the ground. However, 

due to the significant amount of data collected 

during the multiple fieldwork missions and the 

exhaustive background literature review, the 

total production capacity likely does not fall 

below or above 20 percent of the estimated 

600,000 carats. A realistic range of production 

for Guinea therefore is 480,000 to 720,000 

carats per year.

Conclusion

Although preliminary results have been 

obtained, it is important to note that artisanal 

diamond mining is a highly dynamic sector, 

and therefore it is challenging to make firm 

production calculations. The results estimated 

in this study, however, were developed through 

an examination of all available information 

concerning Guinea’s diamond deposits 

and therefore is the best available guide to 

assessing Guinea’s diamond deposits. While 

data gaps remain, this assessment provides a 

reliable baseline from which other studies may 

be conducted. The summary of the information 

here is also a step toward greater information transparency with respect to alluvial 

diamond resources. 

References Cited

Kimberley Process Rough Diamond Statistics, 

2006, Annual global summary—2006 production, imports, exports and KPC counts: 

Kimberley Process Rough Diamond Statistics Web site, accessed October 15, 2012, at 

https://kimberleyprocessstatistics.org/static/

pdfs/public_statistics/2006/2006Global

Summary.pdf.

Kimberley Process Rough Diamond Statistics, 

2007, Annual global summary—2007 production, imports, exports and KPC counts: 

Kimberley Process Rough Diamond Statistics Web site, accessed October 15, 2012, at 

https://kimberleyprocessstatistics.org/static/

pdfs/public_statistics/2007/2007Global

Summary.pdf.

Kimberley Process Rough Diamond Statistics, 

2008, Annual global summary—2008 production, imports, exports and KPC counts: 

Kimberley Process Rough Diamond Statistics Web site, accessed October 15, 2012, at 

https://kimberleyprocessstatistics.org/static/

pdfs/public_statistics/2008/2008Global

Summary.pdf.

Kimberley Process Certification Scheme 

(KPCS) Secretariat, 2009, Administrative 

Decision: Kimberley Process Plenary 

Session, November 5, 2009, Swakopmund, 

Namibia, 3 p., accessed October 15, 2012, 

at http://kimberleyprocess.com/web/

kimberley-process/administrative-decisions.

Kissidougou

Boké

Kindia

Kindia

Conakry

Conakry

Forécariah

Labé Siguiri

Kankan

Kissidougou

Macenta

Kérouané

Nzérékoré

SIERRA LEONE

LIBERIA

GUINEABISSAU

SENEGAL

MALI

CÔTE D’IVOIRE

GUINEA

ATLANTIC OCEAN

Milo R

Diani R

Kolenté R

Niger R

Niger R

Konkoure R

Télimelé

Macenta

Kérouané Forécariah

15°W 12°W 9°W

12°

 N

9°

N

0 100 KILOMETERS 50

0 50 MILES 25

Base modified from the Ministère des Mines et de la Géologie-Division des Mines

Shaded relief modified from Shuttle Radar Topography Mission

Field site

USGS track

Prefecture visited

EXPLANATION

April 2010 mission

June 2011 mission

March 2012 mission

May 2012 mission

Figure 3. Guinean sites visited during each of the fieldwork missions.

Additional Information

Peter G. Chirico, pchirico@usgs.gov

Katherine C. Malpeli, kmalpeli@usgs.gov

12201 Sunrise Valley Drive

National Center, MS 926A

Reston, VA 20192