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Eventually, water at Seneca II -W Mine will begin to discharge to the surface as the <br />water elevation exceeds the ground level or when sufficient head is developed. <br />The primary impact of Seneca II -W mining operations (including south extension <br />operations) on surface water quality will be an increase in total dissolved solids <br />(TDS) concentration resulting from the occurrence of spoil springs after backfilled <br />spoil in the mine pits has become saturated. The projected impacts on each of the <br />affected drainages near the permit area are summarized below. <br />Hubberson Gulch <br />Seneca Coal Company projects spoil springs in the Seneca II -W South Area will <br />increase TDS in Hubberson Gulch upstream from the Pond 006 drainage from 676 <br />mg /l to 1,787 mg /1. This prediction was calculated from mean discharges and mean <br />TDS concentrations for June - September data for the entire period of record. This <br />projection exceeds the Division's suspect level for material damage for water used <br />to irrigate hay crops. SCC estimated production losses resulting from the increase <br />in salinity. Based on the information provided by SCC, the Division finds that no <br />material damage will occur. See Section B.XII of this document for additional <br />details. <br />Dry <br />SCC projects impacts from all spoil springs will increase TDS in Dry Creek from <br />1,048 mg /l to 2,451 mg /1. The TDS increase extends from Hubberson Gulch to the <br />Dry Creek reach monitored by Station WSD5 (upstream of the fields irrigated from <br />Temple Reservoir #1). At this point, the baseline TDS level in Dry Creek begins to <br />increase downstream. At a downstream location in Dry Creek, the TDS <br />concentrations are elevated enough (TDS = 3,567 mg /1) that the cumulative spoil <br />discharge influences from both mining areas (Seneca II -W and Seneca II -W South) <br />will be minimal. The source of the salt loading to Dry Creek is principally seepage <br />from dry land farming that extends from the hillslopes at the base of the mountains <br />to Hayden. Dry Creek water is mixed with water from the J.C. Temple Reservoir <br /># 1 for irrigation in fields below this reservoir. The Division finds that there will be <br />no material damage to water in Dry Creek since the background TDS levels are <br />higher than the projected TDS levels from Hubberson Gulch. <br />Seneca II -W Findings Document 41 C -1982 -057 <br />Permit Revision No. 6 January 6, 2012 <br />