Minerals Yearbook, 1991: Rare Earths. The Lanthanides, Yttrium, and Scandium

摘要

Mr. Hedrick is a physical scientist in the Branch of Industrial Minerals. He hasbeen the commodity specialist for rare earths since 1981. Domestic survey data were prepared by Kevin Bacon, statistical assistant; and international data were prepared by Harold Willis, international data coordinator. Domestic mine production data for rare earths are developed by the U.S. Bureau of Mines from the voluntary survey, Rare Earths, Thorium, and Scandium. The two mines to which a survey form was sent responded, representing 100% of known production. Production data are withheld to avoid disclosing company proprietary data.