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Elevated levels of iron (i.e., greater than 5 mg /1) may be attributed to <br />natural (i.e., not mining related) conditions, since the highest level <br />of iron found in spoil springs at this mine is 0.17 mg /l. The one <br />bedrock well (WW14) that often exhibit high levels may have higher than <br />usual concentrations of iron pyrite in the rock. The high levels of iron <br />displayed in the one alluvial well this year may be the result of <br />organic matter and plant debris present in the alluvium (Hem, 1989, pg. <br />77). <br />High manganese values may, in part, be due to recharge from the spoil <br />aquifer, although high values are often common, especially in alluvial <br />material (Hem, 1989, pgs. 86 -89). This standard is used to protect crops <br />grown in soils with a pH value lower than 6.0. In January 2008, CDPHE <br />revised their ground water agricultural standard to reflect this pH <br />qualifier. In soils with a higher pH (as are found in the Seneca II -W <br />region), a more appropriate standard would be 10 mg /1 (EPA, 1976). This <br />year, none of the Seneca II -W wells displayed a value higher than 1.72 <br />mg /l. <br />At the Seneca II -W shop well, Well 201TC, CDPHE drinking water standards <br />were used to determine its suitability. No human health standards were <br />exceeded. The secondary standard for sulfates (250 mg /1) was exceeded <br />with a value of 260 mg /l. However, bottled water is consumed at Seneca <br />II -W. Also, since the aquifer for the shop well (Trout Creek Sandstone) <br />starts at 280 feet below the Wadge Coal and is separated by confining <br />shale layers, water from this well should not be affected by mining and, <br />therefore, reflects the natural characteristics of the aquifer. <br />Ground Water Points of Compliance <br />A GWPOC have been established in the Dry Creek alluvium for the Seneca <br />II -W Mine. Appendix 15--33 of the Seneca II -W PAP provides the details. <br />The ground water standards for Dry Creek Alluvial Well DCAL -02 are <br />provided in this AHR on Table 7. No exceedances of these standards <br />occurred this year. <br />7 <br />