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Scientific Investigations Report 2010–5045

Prepared in cooperation with the Geological Survey Department,
Minerals Commission,
and Precious Minerals Marketing Company of Ghana
under the auspices of the U.S. Department of State

Alluvial Diamond Resource Potential and Production Capacity Assessment of Ghana

By Peter G. Chirico, Katherine C. Malpeli, Solomon Anum, and Emily C. Phillips

Thumbnail image of report cover


In May of 2000, a meeting was convened in Kimberley, South Africa, and attended by representatives of the diamond industry and leaders of African governments to develop a certification process intended to assure that rough, exported diamonds were free of conflictual concerns. This meeting was supported later in 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 both diamond-producing and diamond-importing countries. Over 70 countries were included as members at the end of 2007.

To prevent trade in "conflict" diamonds while protecting legitimate trade, the KPCS requires that each country set up an internal system of controls to prevent conflict diamonds from entering any imported or exported shipments of rough diamonds. Every diamond or diamond shipment must be accompanied by a Kimberley Process (KP) certificate and be contained in tamper-proof packaging.

The objective of this study was to assess the alluvial diamond resource endowment and current production capacity of the alluvial diamond-mining sector in Ghana. A modified volume and grade methodology was used to estimate the remaining diamond reserves within the Birim and Bonsa diamond fields. The production capacity of the sector was estimated using a formulaic expression of the number of workers reported in the sector, their productivity, and the average grade of deposits mined. This study estimates that there are approximately 91,600,000 carats of alluvial diamonds remaining in both the Birim and Bonsa diamond fields: 89,000,000 carats in the Birim and 2,600,000 carats in the Bonsa.

Production capacity is calculated to be 765,000 carats per year, based on the formula used and available data on the number of workers and worker productivity. Annual production is highly dependent on the international diamond market and prices, the numbers of seasonal workers actively mining in the sector, and environmental conditions, which influence seasonal farming.

First posted June 8, 2010

For additional information contact:
Peter G. Chirico
USGS National Center
Mail Stop 926A
12201 Sunrise Valley Dr.
Reston, VA 20192

Alluvial Mining Diamond Project

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Suggested citation:

Chirico, P.G., Malpeli, K.C., Anum, Solomon, Phillips, E.C., 2010, Alluvial diamond resource potential and production capacity assessment of Ghana: U.S. Geological Survey Scientific Investigations Report 2010–5045, 25 p.
(available only online at




Ghana Diamond History

Introduction to the Geology of Ghana

Alluvial Diamond Deposits

Methodology of the Study of Ghanaian Diamond Resources

Methodology to Estimate the Diamond Potential of Ghana

Methodology to Estimate the Diamond Production Capacity of Ghana

Results of the Modified Volume and Grade Approach

Results of the Diamond Production Capacity


References Cited

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