2015-03-18_REPORT - C1982056 (4)

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WMD are still on the order of 50 to 60 gpm. Freeboard in the old WMD in the fall of 2014 was on the order of 36 feet. 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 2014 was on the order of 45 feet. NMD: 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 Submains, although there appears to be a continued decrease in ceiling dripping. The highest inflows were about 20 gpm 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 Western Mining District (new WMD): The most recent inspection along the new gate roads indicated estimated inflows of less than 10 — 12 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, had dried up by 2014. 3.9 Water Balance In early 2009, TC conducted a water balance study to better access water use and allocations for mine operations, as well as mine dewatering. A flow chart was provided in the 2009 AHR, illustrating water movement for the mine in early 2009. Note that there have been some changes in flow patterns since this study. Another mine water balance may be performed in 2015, which would require expenditures for flow meters at key locations. 4.0 SUBSIDENCE IMPACTS Fish Creek: Historically, hydrologic monitoring of potential subsidence impacts from the earlier 17 and 18 - Right Panels utilizes four alluvial wells and four nearby surface sites. These sites are shown on the attached First Half 2008 Subsidence Map. These include alluvial well AVF -14 and associated surface site SW -14 (upstream of 17 -Right subsidence zone). Also utilized are alluvial well 008 -AU3 and associated surface Site 305 (downstream of 17 -Right subsidence zone). Note that sites 305 and 008 -AU3, were designated under TR03 -42 as downstream subsidence monitoring sites. 16