Atacama Minerals Corporation, Canada
Barton Mines Company LLC, USA
BHP Billiton, Australia
Caemi International, Brazil
Calcium Products of Arizona, USA
CalEnergy, Inc., USA
Caterpillar World Trading Corp., USA
Cleveland-Cliffs Iron Co., USA
Comalco Aluminum Limited, Australia
Dead Sea Works Ltd., Israel
FMC Corporation, USA
Franz L. Brümmer GmbH & Co., Hamburg, Germany
Gencor, South Africa
Government of Jamaica
Gwalia (USA) Inc., USA
Hecla Mining Co., USA
Hudson Resources, Australia
Kennecott Corporation, USA
Lafarge Canada, Inc., Canada
Luzenac America, Inc., USA
Metallurgica North America, USA
Minera Tayahua SA de CV, Mexico
Mitsubishi International Corp. USA
Nord Resources Corp., USA
Norsk Hydro, Norway
Petroleum Corporation of Jamaica, Jamaica
Phelps Dodge and Phelps Dodge Cobre Mining, USA
Placer Dome U.S.A. Corp.
Rana Gruber AS, Norway
Rotem Amfert Negev Ltd., Israel
Saudi Arabian Mining Company (Ma’aden), Saudi Arabia
Government of Sierra Leone
Sociedad Química y Minera de Chile S.A., Chile
SOQUEM, Quebec, Canada
Government of Sri Lanka
Statia Terminals Canada Ltd., Canada
Sumitomo Corporation, Japan
Technical Research Centre of Finland
Union Pacific Corporation, USA
United Nations, USA
UNIDO, Austria
Universal Minerals, Inc., USA
US Borax Inc., USA
Grupo Vitro, Mexico
Vulcan Materials, USA
WMC Resources, Ltd., Australia
World Bank, USA
Zemex Corporation/Feldspar Corp., USA