Document YDX2E7k42Jo9gqjxy2oxDO6x8

mmttttia * 26 3. SOURCES 3.1 Natural Occurrence Asbestos is a broad term embracing several fibrous minerals. The minerals are divided into two groups* (1) ' Pyroxenes--chrysotile; (2) Amphiboles--crocidolite, amosite, tremolite, actinolite, and anthophyllite. Properties of these minerals are listed in Table 7 of the Appendix. Asbestos probably occurs in nearly every country in the world, but only a few of the deposits are commercially valuable. Over 90 percent of the world asbestos production is Chrysotile, and Canada is the major source of this mineral for ( the United States. 93 Table 8 in the Appendix lists the world production. Prom these figures an estimate of known freeworld deposits is possible. It is noteworthy that some soils near asbestos mines contain considerable quantities of asbestos. In Finland, farmers working these high-asbestos-content soils have been * observed to suffer from asbestosis. 120 3.1.1 Mines The mining of asbestos in the United StateB has in creased 180 percent in the last 10 years. (Sec Table 9 in the Appendix.) This mining may constitute a source of air pollution. A high percentage of the increase in domestic production has been credited to California producers, who accounted for 65 percent of the total output in 1966. Four 8000 i<*39 PRODUCED BY FORD