GENERAL47069 - Laserfiche WebLink

Home Browse Search

impact area is divided into two basins by the Tow Creek Anticline: the Twentymile Park Basin to the east of the Seneca II Mine, and, the regional Sand Wash Basin to the west. The mines which are included in the Twentymile Park ground water basin, for purposes of this assessment, are the Colorado Yampa Coal Company's Mine No. 1, Mine No. 2, Mine No. 3, and Eckman Park Mine; Twentymile Coal Company's Foidel Creek Mine, Fish Creek Tipple, and Middle Creek Mine; Sunland Mining Company's Apex No. 2 Mine; Pittsburgh and tdidway's Edna Mine; and, a portion of Peabody Coal Company's Seneca II Mine. The mines which are included in the Sand Wash ground water basin area include a portion of the Peabody Coal Company's Seneca II Mine and Seneca II-W tAine; Sun Coal Company's Meadows No. 1 Mine; and, Rockcastle Company's Grassy Gap Mine No. 1. The surface water study area is the Yampa River basin above Hayden, Colorado. The mines which are included in this analysis are the same as those listed above. The mines, however, are all considered to be in the same drainage basin: the Upper Yampa River drainage basin. 2. Surface Water An assessment of the cumulative impacts of coal mining within the Yampa River Basin on surface water resources is discussed in this section. The basin area as defined for the purposes of this surface water assessment is the Yampa River drainage above Hayden, Colorado. Cumulative surface water impacts within the Yampa River basin due to coal mining activities are limited to the loading of total dissolved solids into local streams. This result of coal mining activities in the basin is discussed in the Probable Hydrologic Consequences section of this document. An assessment of cumulative impacts was undertaken for both the Fish Creek and Grassy Creek basins in relation to coal mining at the Seneca II Mine site. The method employed was a mass-balance loading of the Seneca II Mine effluent into the affected receiving streams, Fish and Grassy Creeks. Flow and TDS conditions used in the mass-balance calculations were those described in the Probable Hydrologic Consequences section of this document, and as reported by Peabody Coal Company. Flow conditions and TDS concentrations used for the two receiving streams were the June to September mean daily flow during years of record which exhibited low flow conditions. The water year 1977 for the Yampa River at Hayden, Colorado and 1980 for Fish Creek above Cow Camp Creek were used. TDS concentrations used for the receiving stream locations were the mean value obtained during the same period of record as the stream flow record. -26-