_REPORT - C1980007 - Laserfiche WebLink

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EXECUTIVE SUMMARY This annual hydrologic report is the eighth annual discharged from the underground workings in 1989 report submitted for the Mt. Gunnison No. I Mine was about 13.2 acre feet versus an estimated and covers the period from 1 October 1988 16.8 acre feet in 1988. Areas being mined during through 30 September 1989(water year 1989).The water year 1989 were drier than during 1988. report describes and interprets hydrologic monitor- ing data collected at the Mt. Gunnison No. 1 Mine Precipitation was slightly less in 1989 than in 1988. during water year 1989 and assesses hydrologic Spring runoff and stream flow rates reflected this impacts. difference. The report is divided into two sections. The first The quality of mine water sampled in 1989 was section describes monitoring activities for water good and all discharges were well within NPDES year 1989. The second section interprets the effluent limitations without treatment. hydrologic data collected during the year and relates this information to mining and reclamation Mine water discharge in 1989 was from Portals activities at Mt. Gunnison to assess the impacts, if No. 2 and No. 5 into pond MB-1. No water was any, on the hydrologic balance. This section also discharged from the Sylvester Gulch underground addresses hydrologic impacts that might be expect- sump. Discharged water had no measurable effect ed to occur during water year 1990. on the quality of the North Fork of the Gunnison River. An extensive baseline monitoring data base has been developed for the Mt. Gunnison No. 1 Mine. Activities at the Lower Refuse Pile also had no Operational monitoring started in August 1981 measurable effects on surface or groundwater • with commencement of construction activities at quality during water year 1989. Mt. Gunnison. Underground mining activities did not produce a Monitoring data for the period I October 1988, significant effect on any springs,groundwater wells, through 30 September 1989 show no significant or surface water monitoring stations during water adverse impacts to the hydrologic balance from year 1989. mining activities at the Mi. Gunnison No. I Mine. Water year 1990 is expected to be similar to 1989 Mine inflows duringwater year 1989were less than relative to hydrology at the mine. No significant during water year 1988. The volume of water impacts are expected.