GENERAL33175 - Laserfiche WebLink

Home Browse Search

Downdip monitoring well (83-03). The water level in the Middle Sandstone well farthest from mine workings has been gradually recovering since mining ceased in 1995. Its level had dropped 50 ft. from 1985 to 1997. Water quality has shown no impact from mining. The trends in water levels and the stable water quality indicate mining has not adversely impacted the Middle Sandstone aquifer outside the permit boundary. Ttivenryrnile Sandstone Water level monitoring data reported through the 1998 annual hydrology report show no change in the piezometric levels in the Twentymile Sandstone that could be attributable to mining activities. The water quality data for the two Twentymile Sandstone wells, No. 9 Mine Well and Well 259, show no adverse impact or trend. Willinms Fork Alluvium Ground water levels in the alluvium have remained fairly rel;ulaz, with normal seasonal fluctuations apparently related to changes in river Ir:vels. Ground water levels in the alluvium aze plotted in Figure 22 in Section 2.04.7 of the permit application package. Annual hydrology reports through 199£. indicate no depletion has occurred and mining appears to not have affected Williams Fork River alluvial water quality. Observed Surface Water Impacts Discharges from the 5 and 6 mines have not caused measurable depletion of stream flows in the mine vicinity. IF all of the mine inflows during active mining (approxi- mately 2 cfs) came from the Williams Fork and Yampa Rivers, it would be too small of a depletion to detect in those rivers' 7-day/10-yeaz low flows. Monitoring data in the mines' annual hydrology reports from 1981 through 1998 indicate the Eagle Mines have not impacted the water quality of the Williams Fork River. G. No surface water is proposed to be discharged or directed into underground mine workings. H. RAG Empire does not plan to convert any monitoring wells to water supply wells. I. Stream Buffer Zones -Rule 4.05.18 The Eagle Mine Complex includes several structures which are located within 100 feet of the perennial Williams Fork River. These structures are a coal storage silo, a 48-inch cross country conveyor, waste water ponds, No. 5 Mine dewatering wells and associated substation and access road, haul road bridge, well 259 and pond HR-P1, and rail road at tail [rack end. The conveyor is an e:aclosed structure as it crosses the river and the highway, therefore minimizing disturbance to the stream. The coal storage silo is a concrete structure utilized to load ;railroad cars. These vaziances from the I00-foot buffer zone for perennial streams have been granted by 25