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• Hydrologic Monitoring Acrividi GROUNDWATER Average flows were estimated for the spring runoff season and the low-flow time of year (Exhibit 11). MONITORING Inflows into previously mined areas along Sylvester Gulch and near the main portals continued to be Twenty-one wells were monitored during the 1989 responsive to the spring runoff season. However, water year (Table 4).Their locations are shown on the duration and amount of inflow were less than Exhibit I. Sampling frequency for water levels and in previous years because of low precipitation and water quality was 3 times per year for all except runoff.Areas along the Sylvester Gulch Main Mine the "B" seam wells. These wells were sampled Fan entries produced measured flours ranging from monthly to establish a baseline for "B" seam 0.25 to 0.5 gpm during low flow conditions. Spring mining. runoff flows ranged from 3 to 5 gpm. The old Sylvester Gulch area (entries 14 through 21, main Monitored parameters included water level, pH, intakes) produced estimated flows ranging from conductivity, temperature, total dissolved solids, 0 gpm during low flow conditions to 1 gpm during total suspended solids, total iron,and total manga- spring runoff conditions. nese. Results of the sampling efforts are summa- rized in Appendix H. Hydrographs depicting water Flows in the main portal area (entries 1 through 5) levels from 1978 to the present have been included were less similar to those of the 1988 water year. as Appendix 1. Minimum and maximum informa- Estimated flows ranged from 0 to 0.25 gpm during tion for the entire monitoring period is presented low flow conditions. Spring runoff conditions in Appendix E. produced flows of 1 to 3 gpm. Entry 1 on the east side of the main intake from crosscut I to crosscut Water level and sampling records for water year 7 had standingwater year-round. Flows in this area 1989 were complete for seven wells. Water in ten were estimated at 0.0 to 0.5 gpm during low flow • wells was either nonexistent or insufficient for conditions and 2 to 5 gpm during the spring sampling. Neither water level or quality samples runoff. Entry 9 on the west side of the southwest were acquired from wells SOM38-1-12 and SOM- main intakes from portal entry 5 to crosscut 7 38-H3. Casings of these wells were damaged before produced flows estimated at 0 to 0.25 gpm during the 1989 water year (probably by local subsidence). low flow conditions and 0.5 to 1.0 gpm during In addition, both wells are apparently in contact spring runoff conditions. with the mine ventilation system. The flow from panel 1W2S dried up completely The "B" seam wells were monitored monthly during 1989. This water appeared near the panel during 1989 to establish a baseline for impact seals during November and December 1987. Flow assessment. Monitored parameters included water peaked at approximately 9.8 gpm during the 2nd level, temperature, and chemistry. The results are quarter of 1988 and declined steadily thereafter. presented in Appendix J. Hydrographs depicting water levels for the monitoring period are included The 1 East Submains were retreat mined during as Appendix K. 1989. No significant water was encountered during retreat mining. MINE WATER New areas mined in 1989 produced minor damp MONITORING and wet areas with no associated measurable flows. The wet areas consisted of damp and wet roofs in Mine water inflows in areas being actively mined Panel 1W5S and wet floors near Panel 1W4S. Roof were mapped during water year 1989. Areas of fractures and nearby sandstone channel margins previous mine inflows were monitored by occasion- are probably the sources of the water. al visits. Exhibit 11 shows locations of inflows and estimated amounts of mine inflows. Areas of During 1989, samples of mine discharges were . standing water are also shown. taken from the MB-1 and MB-2 sediment ponds. 5