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1 INTRODUCTION Wyoming Fuel Company's (WFC) Canadian Strip Mine is located in Jackson County, Colorado (T8N, R78W). The mine was projected to utilize a phased open pit mining technique with two genera] areas of production. Pit #1 lies in Section 2 (T8N, R78W) and has been mined out with reclamation activities completed in 1987. The proposed Pit #2 lies in Section 10 (T8N, R78W) with no development occurring. 1 WFC discontinued all mining operations at tfie mine site in mid 1982 because of coal marketing difficulties. To comply with Stipulation 1 of the permit issued by CMLRB, an annual report of water resources ' monitoring must be submitted. The intent of this report is to comply with this requirement by presenting the data collected to date for groundwater investigations. The following sections contain the materials, methods and results of the groundwater and NPDES monitoring program in the Pit #i area during the 1989 water year. GROUNDWATER ' The Canadian Strip Minc lies in the northeast corner of North Park, a large basin underlain by thick sequence of sediments. These sediments Cill the large synclinal depression between the surrounding mountain ranges. Within this synclinal depression lie numerous smaller structural features. Onc such ' feature is the McCallum anticline with the mine site being located on its southern terminus. At this location, the anticline is breached such that the older rocks of the Pierre Formation arc exposed in the center of the younger strata of the Coalmont Formation. As a result, this area acts as a groundwater recharge zone Cor the Coalmont Formation. However, being at a high topographic elevation with no ' perennial streams, the recharge potential is limited to snow melt and major precipitation events. Fifteen groundwater monitoring wells were installed within the vicinity of the Canadian Strip Mine ' (Exhibit C-2) all o(which are completed in the Coalmont Formation. Four wells were initially installed for monitoring the Pit #1 area. Wells 1 and 1C are completed below the Sudduth Coal Scam, Wcll lA is completed in the seam and Well 1B is above the seam. The rationale (or locating the wells where they are was to monitor the down dip and down gradient effects on the groundwater system before, during and after ' mining. In addition to those four wells, ten wells were installed in the proposed Pit #2 area. Wells 4A, SA and ' 6A arc completed in the undcrburden below the coal; Wells 4B, SB and 6B arc completed in the coal; Wells 4C, SC and 6C are completed in the overburden immediately overlying the coal; and Wcll 2 is located in unconsolidated surface material adjacent to Weir #1. All of these wells (except Wcll 2) were reclaimed in ' September, 1989. Well 7 was installed in late 1980. It is located in the reclaimed area of Pit #1 to monitor groundwater beneath the backfill. Additional information and lithology logs for each well have been provided in the ' permit document. Water levels in each of the wells have been monitored monthly during 1981 and ]982 and annually from ' 1984 through 1989. Water levels were measured with a Soiltest, Inc. Model DR-762A electric lint to the nearest hundredth of a foot from the top of the well casing. Water samples were collected with a hand bailer. Prior to sample collection, a minimum of three columns of water were evacuated to obtain a ' representative sample. All samples were filtered with glass fiber Cilters, preserved and stored in bottles, and analyzed at Core Laboratories utilizing the methodologies as specified in Appendix 2. Those parameters which were analyzed are listed in Table 1. ' The physical characteristics of each well are listed in Table 2. Water levels in each of the wells (Appendix 1, Figure ]) have exhibited a relative increase in water Icvcl over the monitoring period. These water levels may be affected by the artesian head which exists because oC the down dip locations of the 1