The Bureau of Mines evaluated the potential supply of cobalt from known domestic resources, both as a primary product from some deposits and as a byproduct from others, and found that U.S. production could play an important role in meeting U.S. cobalt needs by the mid-1980's. This production would be of a relatively short duration, however, with production declining significantly before the year 2000. A tonnage-price relationship was developed indicating the quantity of cobalt that could be produced from known cobalt-bearing deposits at various primary commodity prices and at a 15-percent rate of return on the required capital investment. All capital and operating costs are calculated in August 1980 dollars, and commodity prices are based on August 1980 prices. Known U.S. cobalt-bearing deposits which represent the current U.S. cobalt reserve base contain about 310,800 metric tons of cobalt in slightly over 1 billion metric tons of demonstrated mineralized material. Approximately 37 percent of the cobalt contained in the reserve base is considered recoverable using existing technology. Of this quantity, about 87,000 metric tons of cobalt is economically recoverable assuming a cobalt price of $25 per pound, a copper price of $1 per pound, and a lead price of $0.40 Per pound. Assuming that the cobalt price decreases to $15 per pound, keeping copper and lead prices constant, the quantity that is considered economically recoverable declines to about 45,700 metric tons. No primary cobalt has been produced from domestic resources since 1971.