Laserfiche WebLink
The primary impact of Seneca II-W mining operations (including south <br />extension operations) on surface water quality will be an increase in total <br />dissolved solids (TDS) concentration resulting from the occurrence of spoit <br />springs after backfilled spoil in the mine pits has become saturated. The <br />projected impacts on each of the affected drainages near the permit area are <br />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 <br />676 mg/l to 1,787 mg/1. This prediction was calculated from mean discharges <br />and mean TDS concentrations for June -September data for the entire period <br />of record. This projection exceeds the Division's suspect level for material <br />damage for water used to imgate hay crops. SCC estimated production losses <br />resulting from the increase in salinity. Based on the information provided by <br />SCC, the Division fmds that no material damage will occur. See Section B.XII <br />of this document for additional details. <br />Dry Creek <br />SCC projects impacts from all spoil springs will increase TDS in Dry Creek <br />from 1,048 mg/1 to 2,451 mg/l. The TDS increase extends from Hubberson <br />Gulch to the Dry Creek reach monitored by Station WSDS (upstream of the <br />fields irrigated from Temple Reservoir /f 1). At this point, the baseline TDS <br />level in Dry Creek begins to increase downstream. At a downstream location in <br />Dry Creek, the TDS concentrations are elevated enough (TDS = 3,567 mg/l) <br />that the cumulative spoil discharge influences from both mining areas (Seneca <br />II-W and Seneca II-W South) will be minimal. The source of the salt loading to <br />Dry Creek is principally seepage from dry land farming that extends from the <br />hillslopes at the base of the mountains to Hayden. Dry Creek water is mixed <br />with water from the J.C. Temple Reservoir 1/1 for irrigation in fields below this <br />reservoir. The Division fmds that there will be no material damage to water in <br />Dry Creek since the background TDS levels are higher than the projected TDS <br />levels from Hubberson Gulch. <br />Seneca II-W Findings Document 4g June l2. 2006 <br />Permit Renewal No. 5 <br />