The platinum group comprises six closely related metals: platinum , palladium, rhodium, ruthenium, iridium, and osmium, which commonly occur together in nature and are among the scarcest of the metallic elements. Together, with gold and silver, they are known as precious or noble metals. They occur as native alloys or mineral compounds in placer deposits, sometimes associated with gold, and in lode deposits where they are commonly associated with nickel and copper. Nearly all of the world's supply of these metals currently is extracted from lode deposits in three countries--the Republic of South Africa, the U.S.S.R., and Canada. This Bureau of Mines report presents comprehensive data on the plantinum-group metals including strategic considerations; problems; technology trends and developments; reserves, resources, and reserve base; supply-demand relationships; economic factors and problems; operating factors and problems; and outlook to 2000.