REP19780 - Laserfiche WebLink

Home Browse Search

• • • Hydrologic Dara Interpretation and Impact Assesnnnu for the Permit and Adjacent Arear manganese were similar with values of 9.9, 1.29 mmhos/cm, 5.9 percent, 305, 20 mg/1, and 0.18 mg/l, respectively. The amount of refuse material placed in the lower refuse pile is highly dependant on conditions encountered in the mine. Projected refuse produc- tion for 1991 from development in the "F' and "B" seams and rehabilitation of the "F' seam entries to the "B" seam slopes is approximately 48,500 tons. Assessment of Springs station on the North Fork near Somerset and the West Elk Coal Co. water quality monitoring station on the North Fork below the mine. Both stations were downstream of the surface facilities area and downstream of all discharge points. Baseline data and analysis of these data are provid- ed in the Mining and Reclamation Plan for the Mt. Gunnison No. 1 Mine and in the first annual hydrology report. Comparison of Baseline Wafer Quality with Operational Data A comparison of 1990 monitoring data with previous years shows no significant trends or changes which can be associated with mining activity. Most springs are responsive to spring runoff, but flow rates arc sporadic and many times do not correlate well with other seasonal parame- terssuch as snowpack, precipitaiion, or stream0ow. Assessment of Surface Water and AVF'S Efforts were made in previous annual reports to characterize baseline river water quality. The purpose was to evaluate potential changes in surface water quality due to mining activities at the Mt. Gunnison No. 1 Mine. Continuous monitoring of stream (lows and periodic monitoring o(spring discharge rates are performed to provide the long term data base from which possible impacts of mining can be assessed. Baseline Characterization of Water Quality and Streamflow A baseline characterization of North Fork water quality was performed in previous annual reports to evaluate the potential changes in North Fork water quality that could result from discharges at the Mt. Gunnison No. 1 Mine. Baseline character- ization was performed downstream of the mint before the start of construction in August 1981. Data sources were the USGS stream gauging 13 Of the ten parameters selected for baseline charac- terization, seasonal trends arc apparent for TDS, TSS, and total iron. The other parameters do not exhibit seasonal variation. Total dissolved solids are least concentrated in the North Fork during the period between about May and July. The likely reason for this pattern is during this period high- TDS groundwater is diluted by snow runoff. Total iron is most concentrated during this period. Total suspended solids are most concentrated from April to July. A comparison of baseline water quality data in the North Fork of the Gunnison River with 1990 monitoring data shows no significant changes in water quality in the North Fork. No apparent changes in the water quality of the North Fork oC the Gunnison River can be attributed to affects of mining during water year 1990. Mine Water Management and Impact Assessment The discussion of the mint water system and hydrologic impact assessment is organized by the four sources of water: • North Fork water • sanitary wastewater • mine water, and • runoff from disturbed areas. Use and discharge of water from these sources is studied for its potential to affect the North Fork.