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Scientific Investigations Report 2012–5256

Prepared in cooperation with the Ministère des Mines et de la Géologie of Guinea under the auspices of the U.S. Department of State

Alluvial Diamond Resource Potential and Production Capacity Assessment of Guinea

By Peter G. Chirico, Katherine C. Malpeli, Mark Van Bockstael, Mamadou Diaby, Kabinet Cissé, Thierno Amadou Diallo, and Mahmoud Sano

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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.

The goal of this study was to estimate the alluvial diamond resource endowment and the current production capacity of the alluvial diamond mining sector of Guinea. A modified volume and grade methodology was used to estimate the remaining diamond reserves within Guinea’s diamondiferous regions, while the diamond-production capacity of these zones was estimated by inputting the number of artisanal miners, the number of days artisans work per year, and the average grade of the deposits into a formulaic expression.

Guinea’s resource potential was estimated to be approximately 40 million carats, while the production capacity was estimated to lie within a range of 480,000 to 720,000 carats per year. While preliminary results have been produced by integrating historical documents, five fieldwork campaigns, and remote sensing and GIS analysis, significant data gaps remain. The artisanal mining sector is dynamic and is affected by a variety of internal and external factors. Estimates of the number of artisans and deposit variables, such as grade, vary from site to site and from zone to zone. This report has been developed on the basis of the most detailed information available at this time. However, continued fieldwork and evaluation of artisanally mined deposits would increase the accuracy of the results.

First posted November 26, 2012

Revised April 30, 2014

For additional information contact:
Peter G. Chirico
U.S. Geological Survey
MS 926A National Center
12201 Sunrise Valley Drive
Reston, VA 20192

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Suggested citation:

Chirico, P.G., Malpeli, K.C., Van Bockstael, Mark, Diaby, Mamadou, Cissé, Kabinet, Diallo, T.A., and Sano, Mahmoud, 2014, Alluvial diamond resource potential and production capacity assessment of Guinea (ver. 1.1, April 2014): U.S. Geological Survey Scientific Investigations Report 2012–5256, 49 p. Also available at (Supersedes ver. 1.0 released November 26, 2012.)




Historical Setting

Geologic Setting

Study Areas


GIS Modeling Results


References Cited

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