Talc resources of the United States

摘要: The United States is self sufficient in most varieties of talc and depends upon imports only for small tonnages critical block steatite some varieties, such as cosmetic grades, where demand based consumer preference. yields about one-third the world's total production principal talc-producing nation. World was 1.5 million tons 1956. Quantitative appraisal domestic resources terms various types grades complicated by wide variations properties, complex geologic features deposits, industrial factors that preclude precise specifications many particularly higher ones. uses are varied. Relatively quantities lump required special crayons steatite. Ground used a range applications. Classified sense materials composition from virtually pure mineral to gross admixtures talc, carbonate, tremolite, serpentine, other minerals. Deposits associated principally with sedimentary rocks ultramafic mafic igneous rocks. Most these deposits confined regions which have been folded metamorphosed. Carbonate rock, chiefly dolomite, common parent rock rocks; serpentinite show genetic relations. Some were formed contact metamorphism, others regional metamorphism. Relationships stratigraphy structural vary widely nature relative importance. carbonate quartzite commonly consist relatively talc. Steatite, an especially variety commercial almost exclusively rock. argillaceous generally contain minerals limit either value or use Block has produced, though sporadically quantities, Montana and, probably, California; none currently produced States. Steatite California. chief producers California, New York, Vermont, Maryland, North Carolina, Georgia, Texas, Nevada. Washington, Mexico, Arkansas are, been, minor sporadic producers. no known reserves steatite, but potential Reserves more than 2 tons, probably several times TALC RESOURCES OF THE UNITED STATES that. Crayon-talc resources, poorly known, ample decades. adequate any foreseeable requirements. INTRODUCTION PURPOSE AND SCOPE REPORT This report summary available information on It concerns all talc,1 main emphasis essential our needs likely be strategic critical. These composed essentially include (ground), crayon Less may eventually serve when advances technology permit upgrading impure material forming ground into blocks substitutes natural massive varieties. Geologic stressed because determine large extent physical chemical characteristics However, discussion limited evaluation resources. For details theory descriptions individual districts, reader referred publications cited bibliography. SOURCES INFORMATION kinds information. Three talc-bearing regions, whole part, studied detail authors Engel, Gouverneur district, York ; Chidester, Vermont; Wright, Engel Chidester visited Inyo Eange-Northern Panamint Kange district Dillon-Ennis Montana, Murphy Carolina 1950; Chatsworth Georgia examined Southern Death Valley-Kingston Range California 1952; Wright Hembrillo Canyon-San Andres Mountains Mexico Palmetto-Oasis Nevada 1942; reexamined 1957. literature thoroughly searched. statistical data obtained U.S. Bureau Mines, Minerals Yearbook annual Mineral Market Reports "Talc, Soapstone, Pyrophyllite." Because time interval between visits mines inherent project this kind, 1 Pyrophyllite, lumped those compilations, not included report.