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3.8 2015 Inflow Survey <br />An inflow study was conducted underground in the winter. Flow rates and field parameters were recorded for <br />measurable inflows from the accessible areas of the underground mine. Results of this survey are presented on <br />Figure 117, 2015 Inflow Study Mined Area (in map pouch at back of report). Note that this map also includes <br />historic data for older underground areas, the majority of which have subsequently dried up. <br />Background <br />The old WMD was closed in 1996. At that time inflows were 52 gpm. Note that water elevations for the old <br />WMD were monitored periodically at the Fish Creek Borehole. Our best estimate is that inflows for the old <br />WMD are still on the order of 50 to 60 gpm. Freeboard in the old WMD in the fall of 2015 was on the order of <br />36 feet. <br />Longwall mining was completed in the EMD by early -January 2001. Production from the NMD, 12 Rt Longwall <br />Panel, was underway by late January 2001. The EMD was permanently sealed in October 2001 removing all <br />access to the 6 Rt and 7 Rt gate roads. Thus, no measurements are available in this area for 2006. Historical data <br />is available in previous AHRs. The last flows measured for 2000 showed seasonal variations, with an average <br />annual flow of approximately 65 gpm. Water levels for the EMD are monitored on a periodic basis at the TORT <br />well shaft. Freeboard in the EMD in the fall of 2015 was on the order of 45 feet. <br />NMD: At the time of the 2010 inflow study, the mine operation had completed the 23 Rt panel. The primary <br />sources of water came from the two most recent shafts in the 6MN area, and two fault crossings. Total inflow <br />was estimated to be on the order of 80 gpm. Inflows continued in the Northeast Submains, although there appears <br />to be a continued decrease in ceiling dripping. The highest inflows were about 20 gpm for the new 6MN shaft, <br />and about 15 gpm from a floor sump at inflow site 8 (IF8) with a conductivity of 2270 (Trout Creek Water). This <br />may have been impacted by the addition of roof drip collection to the sump system. The next highest inflow was <br />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), <br />Field conductivity measurements were about 1500 umhos/cm. This site is a blend of Wadge and Twentymile <br />Sandstone water. Inflow at the remaining sites (primarily roof drippers) were either dry or significantly lower, <br />often less than a gallon per minute. <br />New Western Mining District (new WMD): The most recent inspection along the new gate roads indicated <br />estimated inflows of less than 10 gpm. The majority of sites were modest roof drippers. Sites 70 and 72 <br />exhibiting the highest flow in 2013, are almost dry. The majority of the drippers seen in 2013 and 2014,had dried <br />up by 2015. <br />3.9 Water Balance <br />In early 2009, TC conducted a water balance study to better access water use and allocations for mine operations, <br />as well as mine dewatering. A flow chart was provided in the 2009 AHR, illustrating water movement for the <br />[C <br />