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id <br />thi <br />AHR <br />7 <br />d i <br />T <br />bl <br />Th <br />l <br />d <br />f th <br />t <br />d <br />d <br /> prov <br />. <br />e <br />n <br />s <br />on <br />a <br />e <br />e on <br />y excee <br />ance o <br />ese s <br />an <br />ar <br />s <br /> this year was iron. The standard is 8.06 mg/1, while values of 9.64 and <br /> 10.4 mg/1 were observed this year. The iron standard established for <br /> this alluvium was the highest of the pre-1994 value's noted in the Dry <br /> Creek alluvium. This particular well was drilled in 1998 for Peabody's <br /> Big Elk Project, therefore no pre-1994 data exists at this well. It is <br /> unlikely that the elevated values of iron are attributed to mining <br /> since, 1) the iron value this year at the next alluvial well upstream, <br /> WHAL7-2, was 3.95 mg/l, 2) the high NPDES pond iron value this year was <br /> 1.63 mg/l, 3) the highest spoil spring iron value this year was 1.84 <br /> mg/1 and 4) this well displayed high iron values (6.96) and 11.1 mg/1) as <br /> soon as it was drilled. High levels of iron may be the result of organic <br /> matter and plant debris present in the alluvium (Hem, 1989, pg. 77). <br />Ground Water Quality Summary. Increasing TDS trends were observed at <br />twelve wells downgradient of mining. Six downgradient wells exhibit <br />stable or decreasing TDS trends. One well did not have enough water to <br />sample this year. TDS values this year were below PHC predicted values <br />for all wells except for WHAL7-2, WOV14, WOV17 and WW14. <br />Agricultural ground water standards were exceeded this year at certain <br />monitoring wells. Tab 7 of the Seneca II-W PAP contains a section that <br />discusses the suitability of using water from the various aquifers <br />monitored at the Seneca II-W Mine for irrigation or livestock watering. <br />The discussion mentions that all aquifers prior to miming at the Seneca <br />II-W Mine have exhibited several parameter concentrations in excess of <br />both irrigation and livestock standards compared, rendering them <br />questionable regarding their suitability for either irrigation or <br />livestock. All bedrock aquifers affected by mining have been determined <br />to have transmissivities less than 100 ft2/day, which would also <br />preclude their use for yielding sufficient water for irrigation, or even <br />livestock. <br />• Surface Water <br />I1