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• Since mid-1987 hydrologic monitoring has been conducted primarily by Cyprus personnel with water quality <br />analyses primarily performed by ACZ Laboratories (formerly Bookcliffs) of Steamboat Springs, Colorado. Prior <br />to June, 1986 some water quality analyses were performed by [he CYCC laboratory. In May of 199, a private <br />firm (Miller Water Monitoring Service) was contracted to assist with hydrology monitoring at the Foidel Creek <br />Mine. Three surface water sites addressed in this report (USGS 09243700, USGS 09243800 and USGS <br />09243900) are monitored for flow by [he US Geologic Survey (USGS). Prior to the 1989 Water Year, the USGS <br />also collected and analyzed water quality samples from these sites. Since [he 1989 Water Year, Cyprus collects <br />water quality samples for subsequent analysis by ACZ laboratories. Unless otherwise indicated, all references to <br />"1999" in this report to refer to the 1999 Water Year. <br />BEDROCK GROUNDWATER MONITORING <br />The Wadge Overburden formation (including the Wadge coal seam) overlies the Trout Creek Sandstone and <br />underlies the Twentymile Sandstone. All three geologic units are monitored within [he Foidel Creek Mine permit <br />area. <br />Wade Overburden: During 1999, seven Wadge Overburden wells (009-79-4, FBR-1 1-A, 006-82-74C, 91 M006, <br />008-77-58, 93M001, and 93M003) required monitoring for water levels, field parameters, and water quality <br />parameters on asemi-annual basis. All monitoring requiremems were completed at these sites with field <br />measurements obtained and water quality samples collected during April, May, and September. Tables I through <br />7 provide summaries of the 1999 Water Year data collected at each site. Tables I a through 7a provide period of <br />record statistical summaries of collected data at each site. Tables 1 b through 7b provide period of record water <br />level sunttttaries for each site. Figures 3 through 16 provide graphical representations of+vater levels and selected <br />water quality parameters recorded at each site. <br />The potentiome[ric surface in [he Wadge Overburden is generally observed to slope from south to north in <br />monitored wells in the vicinity of the TCC facilities as shown by water levels in wells 009-79-4, 006-82-74C, and <br />91M006. During 1999, the water levels in wells 009-79-4 (Figure 3) returned values comparable to those of <br />recent }'ears. 006-82-74C (Figure 7) sho+as a steady increase in the water level, while Well 91 M006 (Figure 9) <br />continued to show a steady decline in water level. The potentiometric surface reflected by wells 93M001, <br />93M003, and FBR-I I-A is generally observed to slope from southwzst to northeast. Wells FBR-I I-A (Figure 5), <br />93M001 (Figure 13), and 93M003 (Figurz IS) all showed declines relative to last fall. These declines are <br />associated with mining of the Eastern Mining District (EMD). Well 008-77->8 (Figure I I) has been unaffected <br />by mining and exhibits seasonal water level fluctuations. During 1998, this well experienced an unusually long <br />seasonal decline, but in 1999 the previously established recovering water level trend resumed. <br />No anomalous water quality impacts attributable to mining were evident in data collected from Wadge <br />Overburden wells during 1999. At well FBR-I I-A (Table 2), new maxinuun values for cadmium and lab <br />. conductivity were recorded. At well 006-82-74C (Table 3), a new minimum value for lab pH was recorded. At <br />well 91M006 (Table 4) elevated pH values continued to remain evident during 1999. New minimum values were <br />_~ <br />