576 



UNITED STATES MINERAL RESOURCES 



and the world lead reserves are 140 million tons 

 (see "Lead" chapter), there is a resource of seleni- 

 um of 3.2 million pounds in lead ores. 



Selenium production from the burning of pyrite 

 for sulfur is at present small. The world supply of 

 sulfur in the form of pyrite is estimated to be 375 

 million long tons (Lewis, 1970). Assuming an aver- 

 age value of 10 ppm selenium in pyrite, there is a 

 reserve of 8.4 million pounds of selenium contained 

 in pyrite. 



The average content of selenium in coal is at least 

 1.5 ppm. Coal resources in the United States are 

 estimated to be 1,580,000 million tons (rounded) and 

 their estimated selenium resource should be 2.37 

 million tons. Thus, coal contains the major resource 

 for selenium if it can be recovered. 



The average selenium content of 86 samples of 

 United States coal from 20 States as given by Pillay, 

 Thomas, and Kaminski (1969) was 3.36 ppm. East- 

 ern coals were higher in selenium content than coals 

 from west of the Mississippi River. Table 119 gives 



Table 119. — Selenium content of annual coal consumption 

 at five operating and five proposed powerplants in Western 

 United States 



[Data from Swanson, 1972] 



the average selenium content of coal used in five 

 existing powerplants and of the coals proposed for 

 use in five powerplants planned or under construc- 

 tion, together with the tonnages used or projected. 

 The average selenium content of these coals is 1.65 

 ppm. The total selenium in the 54.5 million tons of 

 coal that will be burned in 1 year in these ten power- 

 plants is 177,600 pounds, which amounts to one- 

 sixth of the selenium used in the United States in 

 1968. The estimated annual release of selenium from 

 the combustion of coal in the United States is about 



8 million pounds. The portion of this selenium that 

 escapes into the atmosphere is in, or is rapidly con- 

 verted to, the form of elemental selenium and is not 

 available to plants or biosystems. 



Selenium is enriched in sandstone-type uranium 

 ores and in phosphate rocks mined for their phos- 

 phate content. Although some of these ores are rela- 

 tively high in selenium, they constitute a small 

 source of selenium and have not been exploited for 

 selenium. 



SELECTED REFERENCES 



Ageton, R. W., 1970, Selenium, in Mineral facts and Prob- 

 lems: U.S. Bur. Mines Bull. 650, p. 713-721. 

 Brunfelt, A. 0., and Steinnes, E., 1967, Determination of 

 selenium in standard rocks by neutron activation analy- 

 sis: Geochim. et Cosmochim. Acta, v. 31, p. 283-285. 

 Fleischer, Michael, 1955, Minor elements in some sulfide 

 minerals, in pt. 2 of Bateman, A. M., ed.. Economic 

 geology, 50th anniversary volume: Urbana, 111., Eco- 

 nomic G«ology Pub. Co., p. 970-1024. 

 Goldschmidt, V. M., and Strock, L. W., 1935, Zur G«ochemie 

 des Selens II: Nachr. Gesell. Wiss. Gottingen, Abh., 

 Math.-Phys. Kl IV, v. 1, p. 123-143. 

 Lakin, H. W., 1972, Selenium accumulation in soils and its 

 absorption by plants and animals: Geol. Soc. America 

 Bull., V. 83, no. 1, p. 181-190. 



1973, Selenium in our environment, in Symposium on 



trace elements in the environment: Am. Chem. Soc, 

 Advances in Chemistry Ser. (in press). 

 Lakin, H. W., and Davidson, D. F., 1967, The relation of the 

 geochemistry of selenium to its occurrence in soils, 

 chap. 3 of Selenium in biomedicine — Internat. Sympo- 

 sium, 1st, Oregon State Univ., 1966: Westport, Conn., 

 The AVI Pub Co., Inc., p. 27-56. 

 Lansche, A. M., 1967, Selenium and tellurium, a materials 

 survey, with a chapter on Resources by David F. David- 

 son: U.S. Bur. Mines Inf. Circ. 8340, 56 p. 

 Lewis, R. W., 1970, Sulfur, in Mineral facts and problems: 



U.S. Bur. Mines Bull. 650, p. 1247-1265. 

 Oldfield, J. E., chm., 1971 Selenium in nutrition: Natl. Acad. 



Sci., 79 p. 

 Pillay, K. K. S., Thomas, C. C, Jr., and Kaminski, J. W., 

 1969, Neutron activation analysis of the selenium con- 

 tent of fossil fuels: Nuclear Applications and Tech- 

 nology, v. 7, no. 5, p. 478-483. 

 Sindeeva, N. D., 1964, Mineralogy and types of deposits of 

 selenium and tellurium [translation from Russian] : 

 New York, Interscience Publishers, 363 p. 

 Swanson, V .E., 1972, Composition and trace-element con- 

 tent of coal and power plant ash, pt. 2 in Appendix J 

 of Southwest Energy Study: U.S. Geol. Survey open-file 

 report, 61 p. 

 Turekian, K. K., and Wedepohl, K. H., 1961, Distribution of 

 the elements in some major units of the Earth's crust: 

 Geol. Soc. America Bull., v. 72, no. 2, p. 175-192. 

 Wells, N., 1967, Selenium content of soil-forming rocks: 

 New Zealand Jour. Geology and Geophysics, v. 10, no. 

 1, p. 198-208. 



