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March 1992 Kerr Coal Company Adequacy Responses ~ 2 <br />No. C-80-006 comment letter, flows aze in response to snowmelt and precipitation events. <br />Limited baseline data collected is Bush Draw, 12/79 Ihru 5/80, has been reviewed and indicates that <br />premining conditions had naturally elevated total dissolved solids (TDS) and sulfate values. Attached <br />are three graphs showing representative premising TDS and sulfate values; <br />• KERR COAL -MAY 21, 1980, Baseline Water Quality Da[a. <br />This graph presents TDS and sulfate values from two deep wells (79-27 and 79-61), two alluvial <br />wells (AH-1 and AI-1) and one surface site (314) in Bush Draw collected on May 21, 1980. As <br />shown, [he lowest TDS level was 744 mg/1 is web 79-61 ranging to a high of 5410 mg/I in alluvial <br />well AH-1. Sulfate ranged between 152 and 4200 mg/1. <br />• KERR COAL -SAMPLE SITE 79-27, Baseline Water Quality Da[a. <br />This graph depicts ground water quality trends from December, 1979 through May, 1980. I[ <br />demonstrates the difference in TDS and sulfate concentrations during runoff periods and low/no <br />Flow periods. This is similar [o the [read experienced in 1991. <br />• KERR COAL -SAMPLE SITE AH-1, Baseline Water Quality Data. <br />This graph presents alluvial water quality trends from February, 1980 through May, 1980. I[ <br />depicts [be difference in TDS and sulfate concentrations during runoff periods and low/no Bow <br />periods. This is similar [o the trend experienced in 1991. <br />(Note: Baseline sample locations are shows on attached map, Water Monitoring Sites, Map 23-2.) <br />I[ is Kerr's contention [hat [he high TDS and sulfate levels at Site 306 are due [o one or more of [he <br />following: <br />• Bush Draw is [he surface expression of a major fault. I[ is suspected that surface water percolates <br />into the fault zone and [hen resurfaces in [he vicinity of Site 306 as a surface flow. <br />• Sample Site 306 is located is an area [hat remains wet, but does not always experience surface <br />Flow. During [he dry summer months a white precipitate can be seen on the surface. I[ is <br />suspected that a re-dissolution of precipitated solids occurs during we[ periods. <br />• Samples are taken either during spring ssowmel[ or during very low Bow conditions. The quality <br />from snowmel[ samples are in line with quality from other monitoring samples. <br />• Discussions with Kerr persomel indicates that low flow samples are taken at a location where <br />water is ponded. This sampling probably represents stagnant conditions and is so[ true sur[ace <br />water flow. Although Si[e 306 may so[ be representative of surface water quality, no other viable <br />surface water sampling sites have been identified in the immediate area. <br />Site 314, located to take advantage of surface Flows, also experiences intermittent Bow and may not <br />represent [rue flow quantities, no other viable sample locations have been identified. <br />Kerr has intentionally designed and located Pit 1 to avoid [his fault zone. The pit does not experience <br />any inflow or outflow of surface or ground water. The only water encountered in the pi[ results from <br />precipitation runoff within [he pit. This water is collected in a sump and pumped into a water truck for <br />use on the haul roads or is discharged to a sediment pond. Water quality samples, Site 328, are collected <br />from this sump and do not indicate that this is a source of negative impacts [o water quality. <br />~\~h\P7\trrt\ 1991 ryt.np <br />OJ/1l /92 &m <br />