Laserfiche WebLink
1 <br />January 1996 Ken Coal Company * 1995 Annual Hydrology Repon * CO Permtt No. G80-006 ~ 3 <br />3.0 MINE AREA CONFINED GROUND WATER <br />Confined ground water occtirs in two water-bearing zones at the mine site: Mine Area Coal <br />Aquifer and Mine Area Overburden. The Mine Area Coal Aquifer is monitored ar well 79-61. <br />This well is located just north of the historic Pit 1, along Bush Draw, in the undisturbed coal <br />seam. The Mine Area Overburden wells are designated 79-1 and 79-2. These wells are located <br />at the north and south ends of the historic 720 Pit, adjacent to what was historially the east <br />crest of the pit. See Map 1, Mine Area Monitoring Sites, for general locations. <br />Ground water levels were measured and samples taken from these wells during October 1994 <br />J and April 1995, as designated in the Monitoring Plan. The field data from the Confined Ground <br />J Water Wells are contained in Exhibit A, 1995 Field Data. The individual analyses of samples <br />collected are presented in Exhibit B, 1995 Coal Aquifer Water Quality Analyses and Exhibit C, <br />1995 Overburden Water Quality Analyses. The water quality data are summarized on Table <br />1, 1995 Ground Water Quality Statistics. Figure 1, Mine Area Aquifer Water Level, shows the <br />relative ground water levels for the coal and overburden aquifers over the past five years. <br />3.1 MINE AREA COAL AQUIFER <br />The mine area coal aquifer well (79-61) was monitored and sampled in October 1994 and April <br />1995. Table 1, 1995 Ground Water Quality Statistic, presents the water quality summary for <br />the year. In general, the coal aquifer, remains lower in total dissolved solids (TDS) than the <br />overburden aquifer, suggesting little interaction between the aquifer systems. For comparison <br />purposes, the mean field and laboratory parameter values for Well 79-61 over the last five years <br />are presented in Table 2, Historic Mine Area Coal Aquifer Water Quality Data. Note that the <br />1 mean annual sulfate values in the coal aquifer have decreased substantially over the past five <br />years, 126 mg/I in 1991 to 22 mg/1 in 1995. <br />Figure 2, EC vs TDS, Well 79-61; presents a comparison of elettripl conductance (EC) to TDS <br />concentrations over the last five years. The values plotted represent actual levels measured <br />rather than a mean value. As seen in Figure 2, EC vs TDS -Well 79-61, the quality of ground <br />water in the coal aquifer exhibits strong seasonal variability, probably related to infiltration of <br />snow melt. <br />3.2 MINE AREA OVERBURDEN <br />Table 1, 1995 Ground Water Quality Statistics, also includes a summary of the field and lab <br />results for the yeaz from wells 79-1 and 79-2. <br />For comparison purposes, the mean field and laboratory parameter values for the last five years <br />are presented in Tables 3 and 4, Historic Mine Area Overburden Water Quality Data. As <br />shown, there have been minor fluctuations in concentration values, but there have no[ been <br />identifiable trends on a yearly basis. Figure 3, EC vs TDS, We11 79-1, and Figure 4, EC vs TDS, <br />Well 79-2, show comparisons and trends over the past five years. <br />H:\951\95ANN UAL.RPT\t[YDRO.FNL <br />01/IB/964:p1pm mps v~m~ TenaMatnx Inc. * P.O. Box 774018 * Steamboat Springs, Colorado 80477 * (970J 8796260 <br />