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<br />• <br />• <br />2.0 Hydrologic Data Interpretation and lmpaR Assersmem for the Prrmit and Adjacem Areas <br />than the secondary drinking water standard <br />for groundwater of 0.3 mg/1 for all WY 95 <br />sampling events. <br />JMB-12 monitors an alkaline, saline (TDS is <br />approximately 1300 mg/I) sodium <br />bicarbonate water of low hardness (34 <br />mg/l). Iron and manganese concentrations <br />regularly exceed the secondary drinking <br />water groundwater standards. <br />The salinity, high concentrations of sodium, <br />and periodic exceedances of groundwater <br />standards would preclude the B seam from <br />use as an untreated drinking water source. <br />Its depth in the mine's locale and the <br />availability of better quality, more easily <br />accessed water also would limit its use <br />within the foreseeable future. <br />2.3.6 Rollins Sandstone <br />Well SOM 128-H was established in late <br />1990 to monitor water levels in the Rollins <br />Sandstone, a formation below the "B" <br />Seam. The water levels measured in SOM- <br />128-H appear to represent the piezometric <br />surface established in WYs 1992 and 1993. <br />No sustained floor flows have been encoun- <br />tered during mining of the "F" or the "B" <br />seams. Mining activities, in both the "F" <br />and the "B" seams, are thought to have had <br />no impact on groundwater in the Rollins <br />Sandstone to date. The water is an alkaline, <br />saline (TDS of 8300 mg/I) sodium chloride <br />water of low hardness. <br />LP-1 was installed at the ventilation <br />facilities in Lone Pine Gulch after the end of <br />WY 1994. The well was dry for five <br />months and then increased eighteen feet over <br />the summer. The water is a very alkaline <br />(pH is 11.9), saline (TDS of 2500 mg/I) <br />calcium sulfate water of high hardness. <br />AFIR-95.210/06/PS/96(I:JSpm) <br />19 <br />2.4 ASSESSMENT OF <br />SURFACE WATER <br />The purpose of monitoring the river waters <br />is to evaluate potential changes in surface <br />water quality due to mining activities at the <br />West Elk Mine. In addition, continuous <br />monitoring of stream flows and periodic <br />monitoring of spring discharge rates are <br />performed to provide the long term data <br />base from which possible impacts of mining <br />can be assessed. <br />High flows were seen between May and <br />mid-July. Smaller drainages exhibited peak <br />flows from mid-May though mid-June. <br />Flows on the North Fork of the Gunnison, <br />on the Lower Dry Fork and on the East <br />Fork of Minnesota Creek are influenced by <br />reservoirs upstream of the sites. Sylvester <br />Gulch was dry from October 1, 1994 <br />through November 27, 1994. <br />2.4.1 Comparison of <br />Baseline Water Quality <br />with Operational Data <br />Seasonal variation occurs for Total <br />Dissolved Solids (TDS), Total Suspended <br />Solids (TSS), and total iron. Total dissolved <br />solids are least concentrated in the North <br />Fork during the period between about May <br />and July. The likely reason for this pattern <br />is during this period the water salinity is <br />diluted by snow runoff. Total suspended <br />solids are most concentrated from April to <br />July. Total iron is most concentrated during <br />this period probably reflecting associated <br />higher levels of TSS. <br />A comparison of baseline water quality data <br />in the North Fork of the Gunnison River <br />with WY 1994 monitoring data shows no <br />significant changes in water quality in the <br />