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George Patterson <br />Page 4 <br />December 22, 2014 <br />• Nitrogen as Nitrate/Nitrite - 100 mg /L <br />• pH -6.5to 8.5 <br />• Total Dissolved Solids— 1,176 mg /L. <br />The TDS standard of 1,176 mg /L was calculated by multiplying the baseline data value of 941.5 <br />mg /L by 1.25 (per Table 4 in Reg. 41, which establishes a TDS standard from the baseline data). <br />The value of 941.5mg /L originates from page 2.04.7 -17 in the PAP; it is the average TDS value <br />found in baseline mine area groundwater. <br />The following observations have been made by the Division regarding the 2011 — 2013 data for <br />MW -65 and these standards: <br />• Dissolved Iron — none of the values in the 2011 — 2013 reporting period exceeded 0.03 <br />mg /L, which is well below the standard of 5 mg /L. <br />• Dissolved Manganese - none of the values in the 2011 — 2013 reporting period exceeded <br />0.142 mg /L, which is below the standard of 0.2 mg /L. <br />• Nitrogen as Nitrate/Nitrite - none of the values in the 2011 — 2013 reporting period <br />exceeded 0.35 mg /L, which is three orders of magnitude below the standard of 100 mg /L <br />• pH - all of the values in the 2011 — 2013 reporting period were within the range of the <br />groundwater standards. <br />• Total Dissolved Solids - none of the values in the 2011 — 2013 reporting period exceeded <br />1,160 mg /L, which is below the standard of 1,176 mg /L. <br />Analysis of Groundwater Level Data <br />The data for 2011 — 2013 include water levels measured in the wells. It is important to note that <br />these levels represent the potentiometric head at a single location, in the interval in which the <br />well is screened. This is the level to which water will rise in a tightly cased well; it is not the <br />depth to groundwater. The head values at individual wells represent points on a theoretical <br />potentiometric surface, which may be projected given sufficient data. Assuming that each well is <br />correctly constructed, in December 2013: <br />• At MW -23 the potentiometric surface of water confined in the Red Arrow coal seam, was <br />142.6 feet below the ground surface, which is approximately seven feet above the Red <br />Arrow coal seam. <br />• At MW -65 the potentiometric surface for water confined in the Jack O'Lantern coal seam <br />was 285.5 feet below the ground surface, which is over 500 feet above the Jack <br />O'Lantern coal seam. <br />