2017-05-08_REPORT - C1982056 (3)

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HistoriI cally, when pumping mime water from the Fish Creek Borehole (mine discharge site 1115) the flow becomes a contributor to sulfate levels in Fish Creek. Fish Creek in tunsI contributes to the sulfate levels in Trout Creek. Trout Creek currently had a secondary drinking water standard Illimiting sulfate concentrations above 250 mg/l. Table 53a provides historical water quality data. 3.8 2016 Inflow Survey An inflow study was conducted underground in the fall and winter. Flow rates and field parameters were recorded for measurable inflows from the accessible areas of the underground mine. Results of this survey are presented on Figure 117, 2016 Inflow Study Mined Area (in map pouch at back of report). Note that this map also includes historic data for older underground areas, the majority of which have subsequently dried up. Background WMD: The old WMD was closed in 1996. At that time inflows were 52 gpm. Note that water elevations for the old WMD were monitored periodically at the Fish Creek Borehole. Our best estimate is that inflows for the old WMD are still on the order of 50 to 60 gpm. Freeboard in the old WMD in the fall of 2016 was on the order of 36 feet. EMD: Longwall mining was completed in the EMD by early -January 2001. Production from the NMD, 12 Rt Longwall Panel, was underway by late January 2001. The EMD was permanently sealed in October 2001 removing all access to the 6 Rt and 7 Rt gate roads. Thus, no measurements are available in this area for 2006. Historical data is available in previous AHRs. The last flows measured for 2000 showed seasonal variations, with an average annual flow of approximately 65 gpm. Water levels for the EMD are monitored on a periodic basis at the l ORT well shaft. Freeboard in the EMD in the fall of 2016 was on the order of 45 feet. NNW: At the time of the 2010 inflow study, the mine operation had completed the 23 Rt panel. The primary sources of water came from the two most recent shafts in the 6MN area, and two fault crossings. Total inflow was estimated to be on the order of 80 gpm. Inflows continued in the Northeast Submair s, although there appears to be a continued decr ase in ceiling dripping. The highest inflows were about 20 gprn for the new 6MN shaft, and about 15 gpm from a floor sump at inflow site 8 (IF8) with a conductivity of 2270 (Trout Creek Water). This may have been impacted by the addition of roof drip collection to the sump system. The next highest inflow was at raise bore area (IF 38 and IF 37), which was on the order of 10-gpm (down from an estimated 20 gpm in 2005), Field conductivity measurements :were about 1500 umhos/cm. This site is a blend of Wadge and Twentymile Sandstone water. Inflow at the remaining sites (primarily roof drippers) were either dry or significantly lower, often less than a gallon per minute. New Rlestern Mining District ew WMD): The most recent inspection along the new gate r ads indicated estimated inflows of less than 10 gpm. The majority of sites were (modest roof drippers. Sites 70 and 72 exhibiting the highest flow in 2013, are almost dry. The majority of the drippers seen in 2013 and 2014,had dried up by 2015. 16