678 



UNITED STATES MINERAL RESOURCES 



is available, however, through the more imaginative 

 use of known techniques especially for the identifi- 

 cation of favorable environments in covered areas. 

 Intensive application of various geophysical methods 

 to locate contact zones or buried stocks and cupolas, 

 with which many tungsten deposits are associated, 

 is an approach that should prove fruitful. 



Technological problems in recovery of tungsten 

 from ore have been as varied as the modes of 

 occurrence. Where ore minerals are coarse grained 

 and the gangue has low specific gravity, the problem 

 is minimal; in tactites where the gangue minerals 

 are nearly as heavy as the ore minerals, recovery 

 is more difficult and still inefficient; in special oc- 

 currences, as at Golconda, expensive chemical proc- 

 esses must be used that can recover only a part of 

 the contained metal; and for some occurrences, as 

 at Searles Lake, no economic process has yet been 

 devised for recovery. Most of the scheelite recovered 

 from tactite deposits contains several percent cal- 

 cium molybdate (powellite) in its molecular struc- 

 ture, and for many uses, the scheelite must be puri- 

 fied by chemical treatment to remove the molyb- 

 denum. Byproduct recovery from very low grade 

 material is usually extremely inefficient, and new 

 techniques to improve such recovery may also be 

 applicable to the recovery of much of the tungsten 

 that has been lost or is still being lost in the tailings 

 piles of tungsten mills. 



REFERENCES CITED 



Barabanov, V. F., 1971, Geochemistry of tungsten: Internat. 



Geology Rev., v. 13, p. 332-344. 

 Bateman, P. C, 1965, Geology and tungsten mineralization 



of the Bishop district, California: U.S. Geol. Survey 



Prof. Paper 470, 208 p. 

 Carpenter, L. G., and Garrett, D. E., 1959, Tungsten in 



Searles Lake: Mining Eng., v. 11, no. 3, p. 301-303. 

 Cooper, J. R., 1951, Geology of the tungsten, antimony, and 



gold deposits near Stibnite, Idaho: U.S. Geol. Survey 



Bull. 969-F, p. 151-197. 



Gray, R. F., Hoffman, V. J., Bagan, R. 'J., and McKinley, H. 

 L., 1968, Bishop tungsten district, California, in Ore de- 

 posits of the United States, 1933-1967 (Graton-Sales 

 Volume) , V. 2 : New York, Am. Inst. Mining, Metall. 

 and Petroleum Engineers, p. 1531-1554. 



Griffith, R. F., 1970, Tungsten, in Mineral facts and prob- ' 

 lems: U.S. Bur. Mines Bull. 650, p. 399^15. 



Hess, F. L., 1919, Tactite, the product of contact metamor- 

 phism: Am. Jour. Sci., 4th ser., v. 48, p. 377-378. 



Hobbs, S. W., and Clabaugh, S. E., 1946, Tungsten deposits 

 of the Osgood Range, Humboldt County, Nevada: Nevada 

 Bur. Mines Bull., v. 40, no. 5, Geology and Mining Ser. 

 44, 32 p. 



Hotz, P. E., and Willden, Ronald, 1964, Geology and mineral 

 deposits of the Osgood Mountains quadrangle, Hum- 

 boldt County, Nevada : U.S. Geol. Survey Prof. Paper 

 431, 128 p. 



Kerr, P. F., 1940, Tungsten-bearing manganese deposit at 

 Golconda, Nevada: Geol. Soc. America Bull., v. 51, no. 9, 

 p. 1359-1389. 



Krauskopf, K. B., 1970, Tungsten (wolfram) , section in 

 Wedepohl, K. H., ed.. Handbook of geochemistry, V. 11/ 

 2: Berlin, Heidelberg, New York, Springer- Verlag, p. 

 74-B to 74-0. 



Larson, L. P., and others, 1971, Availability of tungsten at 

 various prices from resources in the United States: 

 U.S. Bur. Mines Inf. Circ. 8500, 65 p. 



Runner, J. J., and Hartmann, M. L., 1918, The occurrence, 

 chemistry, metallurgy and uses of tungsten: South 

 Dakota School Mines Bull. 12, 264 p. 



Wallace, S. R., Muncaster, N. K., Jonson, D. C, Mackenzie, 

 W. B., Bookstrom, A. A., and Surface, V. E., 1968, Mul- 

 tiple intrusion and mineralization at Climax, Colorado, 

 in Ore deposits of the United States, 1933-1967 (Graton- 

 Sales Volume), V. 1: New York, Am. Inst. Mining, 

 Metall. and Petroleum Engineers, p. 605-640. 



GENERAL REFERENCES 



Kerr, P. F., 1946, Tungsten mineralization in the United 

 States: Geol. Soc. America Mem. 15, 241 p. 



Li, K. C, and Wang, C. Y., 1955, Tungsten— its history, 

 geology, ore-dressing, metallurgy, chemistry, analysis, 

 applications, and economics [3d ed.] : Am. Chem. Soc. 

 Mon. 94, 506 p. 



Lemmon, D. M., and Tweto, 0. L., compilers, 1962, Tungsten 

 in the United States, exclusive of Alaska and Hawaii : 

 U.S. Geol. Survey Mineral Inv. Resource Map MR-25. 



