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OOZlxt;j Mining, Conversion, and Processing Alternatives Coal mining, conversion, and processing aiternatives will be limited to technologies potentially appl icable to the Yampa River basin. It will be essential to determine the impacts of these alternatives' on the quantity and quality of the Yampa River and its tributaries, This will require an estimate of the types and amounts of residuals generated by coal mining and associated activities. Residualswill vary with the size and location of mining activi- ties. Models exist, or can be adapted, to estimate the impacts of different- sized processes (N, C, Matalas, written commun, , 1976). For the residuals- management analysis, the additional effort required to model all the many pro- posals does not seem justified, However, for the basin assessment, the use of site-specific information will be necessary, particularly for the mining pro- cess where projected coal-mining levels are documented (U,S. Bureau of Land Management and U.S. Geological Survey, written commun., 1976), For the residuals-management analysis, coal mining is assumed to occur from an even integer number of strip mines each producing 3,125x106 tons (2.84xI06 t) per year (N. C. Matalas, written cOmmun., 1976). This assumption is based on the estimated scale of coal mines in northwestern Colorado (U,S. Bureau of land Management and U,S. Geological Survey, written commun" 1976). Thus, two hypothetical mines, each supplying coal of the type found in the Williams Fork Mountains in the YampaRiver basin, will supply the 6.25xl06 tons (5.68xI06 t) per xear required for either a standard-sized coal-gasifi- cation plant of 250xl0 cubic feet (?lx106 m3) per day (Forney and McGee, 1972) or a standard 2,000-megawatt electric-power plant which will operate' under the highest levels of environmental control (N. C,' Matalas, written commun" 1976). Under less strict environmental controls, the excess coal will be assumed to ,be marketed for out-of-basin consumption. Each plant will be assumed to be suppl ied with one-half of the coal required from a mine lo- cated next to the plant with transportation of the other one-half of the re- quired coal from a neighboring mine, It is assumed that possible coal-gasification plants for the Yampa River basin will use the SYNTHANE conversion process (Forney and McGee, 1972) and be operated within the ranges of temperatures and pressures for which data col- lected under controlled laboratory conditions prior to construction of pilot~ scale plant facil ities have been obtained, It is assumed that the electric power-generating plants will use conversion processes and operating procedures the same as the p resen t state of techno logy. I tal so is assumed tha t the pow- er-generating capacities of the electric power-generating plants will be ap- proximately 1,200 megawatts. The validity of the last assumption is supported by electric-power plants at Craig and Hayden being expanded and under construc- tion, respectively, Sometime near 1982, proposed power-generating capacities at the Craig plant will be 1,070 megawatts; at the Hayden plant, 1,330 mega- watts (U,S. Bureau of Mines and U,S, Environmental Protection Agency, 1975), Although the power-generating capacities of the electric-power plants are fix- ed for the residuals-management analysis, computer programs that define the impact of plants of different power-generating capacities will have to be mod- i fied. II ..i!. :.<,tj;