2008-03-31_PERMIT FILE - C1980007A (34)

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West Elk Mine The minimum E Seam overburden for springs in the South of Divide and Dry Fork areas is 480 feet (Spring D-8), which occurs in the Deer Creek drainage above longwall panel E5. All other springs have at least 500 feet of overburden above the E Seam. Not all springs exhibit the same seasonal variation and many springs show wide annual fluctuation. The primary controlling factor is the water source of the spring. If the spring issues from alluvium or colluvium, the flows are likely to be seasonal with a peak during the late spring due to the alluvium/colluvium having high recharge/discharge rates. In contrast, water originating from bedrock sources will be attenuated in reaching the spring, and typically not exhibit a large seasonal fluctuation. Reservoirs and Stock Ponds The only reservoirs in the vicinity of the West Elk Mine are Minnesota and Beaver Reservoirs. Only Mineesota Reservoir is located within the permit area. However, a brief discussion of the volumetric capacity of each follows. Minnesota Reservoir has a storage capacity of approximately 467 acre-feet. The reservoir serves to capture spring runoff and water imported via Deep Creek Ditch for releases during late summer. Typically the reservoir will fill to its capacity by June/July and by September the reservoir will be almost dry. Similarly, Beaver Reservoir serves as storage of snowmelt for late summer irrigation. The reservoir has a decreed capacity of over 1600 acre-feet, however, under normal operating conditions, the reservoir yields about 680 acre-feet per year. There are approximately 37 stock ponds located within the existing permit area with an additional 14 stock ponds in the South of Divide permit area. There are 24 stock ponds in the WWE study area. Although the exact dimensions- of each pond are not known, a typical pond stores approximately 0.5 acre-feet. Therefore, the total storage capacity of the stock ponds within the' permit area is approximately 25.0 acre-feet. Surface Water Ouality The results of the water quality monitoring for, potentially affected surface waters are presented in an updated Exhibit 71, and in the latest Annual Hydrology Report. As a result, Table 17 was deleted. Regional surface waters sampled included downstream receiving waters such as Minnesota Creek and the North Fork. The water quality data have been compared to Colorado N?,ater quality standards (Colorado Water Quality Control Commission [WQCC]) for recreation, aquatic liic, agricultural, and water supply uses fog' segment 2 of the North Fork. A summary of the parameters which exceeded Colorado water quality standards for surface waters is shown, along will. the sampling date, in Table 18. As shown in this table, the parameter most frequently exceede-d -\x,-as total iron. The frequency with which this parameter was exceeded indicates the pre-vule:.ce of =.atPurally-occurring sources of iron in the area. Other parameters that exceeded standards include total manganese, dissolved iron, and pH. The causes for these standard exceedances are either natural or related to activities not associated with the West Elk Mine, since there are no current mining activities at the regional sites shown in Table 18. 1.04-106 Revised Alovember 2004 PRIG; Rev. April 2006 PRIG; Sep. 2007 PR12; Feb. 2008 PR11