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u Hydrologic Monitoring Activities The hydrologic monitoring program (or the West Elk Mine began in 1971 with the completion of several groundwater observation wells. This prelim- inary monitoring network was expanded consider- ably and in 1981, with the approval of the West Elk Mine Mining and Reclamation plan (M and R Plan), became the "approved" hydrology monitor- ing program. Data from seasonal water level and water quality measurements at 21 wells (2 wells of the original 23, SOM-38-H2 and SOM 38-H3. were lost. Casings of these wells were dam- aged before the 1991 water year, probably by local subsidence. In addition, both wells are apparently in contact with the mine ventila- tion system.); and In 1984, 1987, and 1989 the program was revised. The 1981 and 1987 revisions were made to more efficiently monitor possible effects from mining and provide data for future permitting. The sampling seaons or "windows' arc established as presented on Table 16 of the NI and R Plan. These windows include collection of samples on the rising limb of the hydrograph (April 3 to May l3), hydrograph peak (April 21 to Junc 26), and full low flow (July 10 to October 8). The 19139 revi- sion incorporated provisions for collecting "B" seam baseline data and monitoring for potential mining impacts in anticipation of the 1990 opening of the "B" Seam. All revisions were approved by the Colorado Mined Land Reclamation Division (CMLRD). No changes in surface water, spring, mine water, or groundwater monitoring procedures occurred during 1992. The 1992 Annual Hydrolo~ry Report contains the following: • Data from live continuous Ilow monitoring stations; • Data from two U.S. Geological Survey (USGS) continuous flow monitoring stations; • Data from seasonal water quality sampling at two surface water quality monitoring stations; • Data from seasonal measuremenu of pH, temperature, dissolved o~ygcn, turbidity, and COndUCllvl[y al Lhe SLx Slream gauging Sl3lIOn5 in the Minnesota Creek Basin and Sylvester Gulch; • Data Gom seasonal measurements of dis- charge and water quality sampling at seven springs issuing from or below the "P' seam coal; Data from measurements of mine water discharges and mapping of inflow locations. Surface Water Monitoring Mountain Coal Company's (MCC) surface water monitoring program includes nine monitoring locations (Table I). The locations of these moni- toring stations are shown on Exhibit I. Daily flow estimates (including mean, maximum, and mini- mum flows) for the five MCC gauges arc summa- rized in Appendix A. F•wapr for three stations with a few mechanical problems, the records are com- plete. Table L Summary of Surface Water A7oni- toring Program tit the West Glk Mine Smtion Flow Wafer Qualify Sylvester Gulch Continuous 3 times per year USGS/MCC Gaging Station Continuous 3 limes per year East Fork Minnesota Creek Flume Cominuous 3 Times per year Lower Dry Fork Flume Cominuom 7 times per year Upper Dry Fork Flume Continuous i fim~s per near Lick Creek Flume Cominuaus 3 limes per near North Fork Upper ~- i limn per year North Fork Lower -- ? limes per tear USGS Noah Fork ga~ing slallOn near SOmCfSCI Comin uuux ~~ One stilling well froze in Ocwber, the other four froze in December. Thawing began in late Febru- •