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• <br />• <br />C , <br />J <br />Hydrologic Moni~oringAUivifiv <br />GROUNDWATER <br />MONITORING <br />Twenty-one wells were monitored during the 1989 <br />water year (Table 4). Their locations are shown on <br />Exhibit 1. Sampling frequency for water levels and <br />water quality was 3 times per year for all except <br />the "B" seam wells. These wells were sampled <br />monthly to establish a baseline for "B" seam <br />mining. <br />Monitored parameters included water level, pH, <br />conductivity, temperature, total dissolved solids, <br />total suspended solids, total iron, and total manga- <br />nese. Results of the sampling efforts are summa- <br />rized in Appendix H. Hydrographs depicting water <br />levels from 1978 to the present have been included <br />as Appendix I. Minimum and maximum informa- <br />tion for the entire monitoring period is presented <br />in Appendix E. <br />Water level and sampling records for water year <br />1989 were complete for seven wells. Water in ten <br />wells was either nonexistent or insufficient for <br />sampling. Neither water level or quality samples <br />were acquired from wells SOM-38-H2 and SOM- <br />38-H3. Casings of these wells were damaged before <br />the 1989 water year (probably by local subsidence). <br />in addition, both wells are apparently in contact <br />with the mine ventilation system. <br />The "B" seam wells were monitored monthly <br />during 1989 to establish a baseline For impact <br />assessment. Monitored parameters included water <br />Icvel, temperature, and chemistry. The results are <br />presented in Appendix J. Hydrographs depicting <br />water levels for the monitoring period are included <br />as Appendix IC <br />Average Oows were estimated for the spring runoff <br />season and the low-[low time of year (Exhibit 11). <br />Inflows into previously mined areas along Sylvester <br />Gulch and near the main portals continued to be <br />responsive to the spring runoff season. However, <br />the duration and amount of inflow were less than <br />in previous years because of low precipitation and <br />runoff. Areas along the Sylvester Gulch Main Minc <br />Fan entries produced measured Oows ranging from <br />0.25 to 0.5 gpm during low flow conditions. Spring <br />runoff Oows ranged from 3 to 5 gpm. T'he old <br />Sylvester Gulch area (entries 14 through 21, main <br />intakes) produced estimated flows ranging from <br />0 gpm during low flow conditions to 1 gpm during <br />spring runoff conditions. <br />Flows in the main portal arcs (entries 1 through 5) <br />were Icss similar to those of the 1988 water year. <br />Estimated flows ranged from 0 to 0.25 gpm during <br />low flow conditions. Spring runoff conditions <br />produced Oows of 1 to 3 gpm. Entry 1 on the east <br />side of the main intake from crosscut 1 to crosscut <br />7 had standing water year-round. Flows in this area <br />were estimated at 0.0 to 0.5 gpm during low Oow <br />conditions and 2 to 5 gpm during the spring <br />runoff. Entry 9 on the west side of the southwest <br />main intakes from portal entry 5 to crosscut 7 <br />produced (lows estimated at 0 to 0.25 gpm during <br />law flow conditions and 0.5 to l.0 gpm during <br />spring runoff conditions. <br />The flow from panel 1W2S dried up completely <br />during 1989. This water appeared near the panel <br />seals during November and December 1987. Flow <br />peaked at approximately 9.8 gpm during the 2nd <br />quarter of 1988 and declined steadily thereafter. <br />T'he 1 East Submains were retreat mined during <br />1989. No significant water was encountered during <br />retreat mining. <br />MINE WATER <br />MONITORING <br />Mine water inflows in areas being actively mined <br />were mapped during water year 1989. Areas of <br />previous mint inflows were monitored by occasion- <br />al visits. Exhibit 1[ shows locations of inflows and <br />estimated amounts of mine inflows. Areas of <br />standing water are also shown. <br />New areas mined in 1989 produced minor damp <br />and wet areas with no associated measurable flows. <br />T'he wet areas consisted of damp and wet roofs in <br />Panel 1 WSS and wet Moors near Panel 1 W4S. Roof <br />fractures and nearby sandstone channel margins <br />are probably the sources of the water. <br />During 1989, samples of mine discharges were <br />taken from the MB-1 and MB-2 sediment ponds. <br />5 <br />