2014-07-11_REPORT - C1980007 - Laserfiche WebLink

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West Elk Mine 2013 Annual Hydrology Report 41 4.2 Water Rights MCC diverts water from the NFGR via the Mt. Gunnison Pipeline water right for surface and in -mine processes and potable uses. Approximately 314.2 ac -ft of water was diverted using this water right during WY 2013 (MCC, 2014). Because the Mt. Gunnison Pipeline (Structure ID: 1882) is a relatively junior water right, it may be called out of priority during the late summer and early fall. In WY 2013, a senior water right placed a call on the NFGR from July 2, 2013 to September 22, 2013, causing the Mt. Gunnison Pipeline water right and all other junior rights to augment their uses from the NFGR (MCC, 2014). MCC's out -of- priority diversions from the NFGR are augmented using releases from MCC's mine water right to Sylvester Gulch and /or leased water released from East Beckwith Reservoir (a.k.a. Lost Lake Slough). 4.3 Sedimentation Ponds The sedimentation and treatment ponds (Figure 9) at the mine site are utilized to manage groundwater collected in the mine, stormwater runoff, and wastewater treatment effluent. All of the ponds are lined with HDPE materials, except ponds MB -5E and MB -3 that are clay -lined and pond MB -4 that is a concrete basin. There are now two "freshwater" ponds (FW -1 and FW -2) that are used to equalize diversions from the NFGR and provide water storage. These ponds serve as the raw fresh water supply for the mine's domestic water use and surface and in -mine water needs. 4.3.1 Pond MB -5E Pond MB -5E (that replaced ponds MB -1 and MB -2R) collects stormwater runoff and effluent from the WWTP. Until MCC's renewed CDPS permit is approved, any discharges from pond MB -5E are routed to and through the approved discharge point (004) for former pond MB -2R. Water may be stored in pond MB -5E or transferred to ponds FW -1 and FW -2 per MCC's water storage rights. Pond MB -1 is now freshwater pond FW -2 and pond MB -2R has been filled -in and is the location of the Stacktube 5 coal stockpile. MCC's sediment ponds are designed to retain water over a period of time so settling of sediment occurs prior to discharge (batch mode). In WY 2013, pond MB -5E did not discharge to the NFGR (Figure 9) (MCC, 2014). 4.3.2 Ponds MB -3 and MB -4 In addition to pond MB -5E, ponds MB -3 and MB -4 also receive stormwater runoff. In WY 2013, no water was discharged from ponds MB -3 or MB -4 in WY 2013 (Figure 9) (MCC, 2014). 4.3.3 Ponds FW -1 and FW -2 Freshwater ponds FW -1 and FW -2 store raw fresh water from the NFGR diversion intake gallery. Water from these ponds is pumped to the mine water storage tank and the Water Treatment Plant and potable water storage system. If the ponds overfill, excess water is discharged back to the NFGR. June 2014