This Bureau of Mines study estimates capital investment, operating costs, and selling prices for three underground bituminous mines producing coal with annual production ranging from 1.03 to 3.09 million tons. It is assumed that the mines have a 20-year life. Wages and union welfare payments are considered as of November 12, 1973, under the bituminous wage agreement of 1971, and costs for material and equipment are based on 1973 indexes. Initial capital investment ranges from $12,938,200 for the 1.03-million-ton-per-year (mm tpy) mine to $31,435,500 for the 3.09 Mm tpy mine. Total capital investment ranges from $21,607,200 to $51,982,000 for the same mines. Corresponding selling prices for the coal range from $9.11 to $8.06 Per ton, assuming a 12-percent discounted cash flow rate of return after federal income taxes.