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TCC projects that impacts to the Fish Creek AVF will not significantly impact the <br />cattle operation. <br />Technical Revision No. 14 (TR14) approved the undermining and subsidence of a <br />small portion of Fish Creek due to longwall extraction in panels 5, 6 and 7 in the <br />Southwest Mining District. No farming activities are currently undertaken along <br />Fish Creek in this area. Subsidence did not preclude the farming of this area. <br />The Fish Creek AVF was the only AVF approved to be undermined as a result of <br />Permit Revision No. 6 (PR6). No stream pirating or loss of flow was experienced <br />during the mining approved by PR6. <br />2. The proposed mining operations will not cause material damage to the quantity <br />and quality of surface and ground water that supply the alluvial valley floor. <br />The only significant degradation of the stream water from TC's mining operations <br />has been caused by pumping of underground mine water into Fish Creek and <br />Foidel Creek. Data in TC's annual hydrology reports document this degradation. <br />Pumping occurs at two sites 115 (Fish Creek borehole) and 109 (portal area). The <br />pumping loads the streams with dissolved solids, mainly sulfate. The operator has <br />maintained stream water quality below the material damage threshold by limiting <br />the pumping rates at both sites and treating the pumped water at one of the sites, <br />115. The operator will continue to limit pumping rates and treating water as in the <br />past; therefore, mine pumping can be expected to not cause material damage to the <br />quality of surface or alluvial water. <br />Water in Fish Creek could see a slight increase in sediment load as subsidence <br />creates slight changes to the stream channel gradient and minor erosion occurs at <br />the head cuts in the stream. This increase in sediment load is anticipated to be no <br />more than the sediment increase observed during spring runoff and after large <br />rainstorms. An increased sediment load was not detected during past subsidence <br />of Fish Creek, Foidel Creek, or Middle Creek. <br />No impact to groundwater quality is predicted. Ground water could flow between <br />aquifers through subsidence fractures. The Fish Creek alluvium and the <br />Twentymile Sandstone have the greatest potential for such interstitial flow, but the <br />stratigraphic separation of several hundred feet between the two units would <br />prevent any significant amount of flow between them. <br />Water quality impacts to the stream/alluvial aquifer system of Fish Creek could <br />result from two additional processes: mine water discharge through the Fish Creek <br />borehole or Fish Creek Vent Shaft during mining and contamination of tributary <br />ground water through seepage from the underground workings after mining has <br />ceased and the workings have flooded. Impacts from mine water discharge during <br />operation will be discussed first. <br />Foidel Creek Mine 41 August 10, 2018 <br />