2013-03-14_REPORT - C1982056 (3)

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There has been no flow from site 109 to Foidel Creek for several years, and none in 2012. Site 115 had not discharged to Fish Creek since early 2005, but was reactivated in 2008 and 2009, both for a limited times (i.e. approx. one to three months) with low flows (25 — 500 gpm). In 2010, site 115 did not discharge. In January 2011, the site discharged for about two days due to a crack in a pipeline valve where treated water flows underground. The crack was repaired and there were no subsequent discharges in 2011. Site 115 did not discharge in 2012. Note that mine water is pumped from underground to the surface (from the old WMD), and is treated via an electro- coagulation process at the surface, where water enters the 3 former treatment ponds that can be directed through site 115. However, the majority of this treated water is pumped directly back into the mine for underground dust suppression. Additional overflow piping was added (which was where the valve crack occurred), so the treatments ponds cannot overflow. Overflow water is directed back into the mine via a former pump well. Historically, when pumping mine water from the Fish Creek Borehole (mine discharge site 115) the flow becomes a contributor to sulfate levels in Fish Creek. Fish Creek in turn contributes to the sulfate levels in Trout Creek. Trout Creek currently had a secondary drinking water standard limiting sulfate concentrations above 250 mg /l. The 2012 Water Year data for mine water discharge site 115 is presented on Table 53. Table 53a provides historical water quality data. 3.8 2012 Inflow Survey During the fall of 2012, an inflow study was conducted underground by Brian Watterson and Rocky Thompson. Flow rates and field parameters were recorded for measurable inflows from the accessible areas of the underground mine. Results of the 2012 survey are presented on Figure 115, 2012 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. 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 2012 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 TORT well shaft. Freeboard in the EMD in the fall of 2012 was on the order of 45 feet. 15