622 



UNITED STATES MINERAL RESOURCES 



similar to talc, has many of the same uses as talc 

 and is in fact generally included with talc in re- 

 source studies. In the United States it is produced 

 in North Carolina and California (Espenshade, 

 1962), and in the past 10 years pyrophyllite con- 

 sumption averaged about 13 percent of talc con- 

 sumption. Resources of pyrophyllite are much less 

 extensive than those of talc, so although its sub- 

 stitutability for talc is high, its percentage of the 

 industrial talc market probably will not increase 

 significantly. 



EXPLOITATION 



Talc was used by the Indians and early settlers 

 for cooking utensils carved from soapstone that 

 occurred mainly in altered ultramafic bodies. Mining 

 of talc and soapstone deposits for other uses began 

 in some districts in the early 1800's, but because 

 industrial talc is tied closely to the demands of a 

 modern industrial society, extensive mining has 

 occurred only in about the past 50 years. Figure 70 



CO 400 



5 Data not 



g available 



Figure 70. — United States consumption of talc, soapstone, 

 and pyrophyllite, 1910-70. 



shows the consumption curve for talc, soapstone, 

 and pyrophyllite during 1910-70. The figures are 

 from the Bureau of Mines yearbooks, and the in- 

 cluded pyrophyllite ranges from 10 to 15 percent 

 of the total. The graph shows increases during na- 

 tional emergencies and other fiuctuations owing to 

 changing economic conditions of industry during 

 more normal periods. The overall slope of the curve 

 is straight and steep. 



Because of the diversity of uses for industrial 

 talc, total consumption increases steadily, even when 

 demand for individual consumer products fluctuates 

 drastically. As technology develops new products, 

 such as the widespread use of plastic insulation in 

 place of rubber, the demand for talc as a filler may 

 continue because both plastic and rubber require an 

 inert mineral filler. Likewise, increasing use of talc 

 as a base by the ceramic industry since about 1955 

 has offset decreased consumption by the rubber and 

 insecticide industries (fig. 69), and the booming 

 use of white plastic by our society has apparently 

 caused an increase in talc consumption as a white 

 filler. Other, more sophisticated uses are being de- 

 veloped; for example talc reduced to minus 50- 

 millimicron particle size was used in a patented 

 method by which an electrically insulating surface 

 layer can be induced by electrophoresis on the ex- 

 terior of an article that in itself is electrically con- 

 ducting (Wells, 1970, p. 7) . 



BYPRODUCTS AND COPRODUCTS 



Talc mining generally produces no byproducts. 

 Because of the great variety of talc grades required 

 by different consumers, selective mining, milling, 

 and laboratory control results in high recovery of 

 numerous marketable grades from most deposits. 

 In effect, the many grades of industrial talc are 

 coproducts. Bilbrey (1962, p. 22) reported that a 

 cobalt-nickel concentrate was a byproduct of talc 

 flotation in Vermont for a few years in the 1940's. 

 The U.S. Bureau of Mines "Minerals Yearbooks, 

 1940-43" indicate a total sale of 109 tons of concen- 

 trate containing 1.16 percent cobalt and 12.7 per- 

 cent nickel. Other potential byproducts are antho- 

 phyllite asbestos at Dadeville, Ala. (Neathery and 

 others, 1967), and magnesite from Johnson, Vt. 

 (Cooper and Hartwell, 1970). 



The recent discovery of scheelite in soapstone 

 deposits in Madison County, N.C., raises the possi- 

 bility of coproduction from these deposits. (See 

 "Tungsten.") 



ENVIRONMENTAL PROBLEMS 



Mining of industrial talc is from both under- 

 ground and opencut mines. Inasmuch as recovery is 

 higher than that in mining for vein minerals, far 

 less of the landscape is disrupted by the operation, 

 and waste piles are relatively small. Only a few 

 operations, such as at Johnson, Vt., use flotation 

 methods for mineral separation; therefore, most 

 talc mining does not have tailings ponds. 



One environmental problem does confront the 

 industry, however; research mainly by a group in 



