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Recoverable Iron had also dropped considerably to 2.25 mg/L. Colowyo Coal Company <br />uses Inter-Mountain Labs (IML), based in Sheridan, Wyoming for lab analysis. Colowyo <br />Coal Company has a 30 day average of Total Recoverable Iron of 1 mg/L, whereas IML <br />had in their system to "flag" Total Recoverable Iron at 3.50 mg/L. Because of this <br />discrepancy, Colowyo was unaware of elevated levels of Total Recoverable Iron from the <br />sample taken on April 4, 2011. As a result, Colowyo did not sample Outfall 007A on April <br />11, 2011. Colowyo continued to do field measurements for the rest of the month, but did <br />not sample due to precipitation the week of April 18 and April 25, 2011. <br />Even though sampling was suspended after the week of April 11, results show a dramatic <br />downward trend from samples taken on April 4th to April 11th. For Outfall 001A, the level for <br />Total Suspended Solids dropped from 76 mg/L to 26 mg/L and the level for Total <br />Recoverable Iron dropped from 2.78 mg/L to 0.63 mg/L. For Outfall 004A, the level for <br />Total Suspended Solids Dropped from 68 mg/L to 12 mg/L and the level for Total <br />Recoverable Iron dropped from 5.03 mg/L to 2.25 mg/L. Colowyo firmly believes that <br />elevated levels of Total Recoverable Iron at Outfall 004A on April 11 is a direct result of <br />warm temperatures and continued runoff of snow pack in close ?roximity to the outfall. <br />Daily high temperatures have been above freezing from April 1S to April 11th, and the 24 <br />hour average temperatures have also been above freezing on many occurrences during <br />the same time frame. Please see attached climatological data for additional information, <br />and the attached picture taken of Outfall 004A on April 11, 2011. <br />Further more, Colowyo's historical laboratory analysis data does not show a trend toward <br />any type of elevated levels at these outfalls. The elevated levels Colowyo does experience <br />are associated with either a precipitation or runoff event. Colowyo does not believe that the <br />elevated level is related in any way to a lack of proper pond function as routine inspections <br />of the pond show that it is functioning as designed. Colowyo will continue to closely <br />monitor this and all other outfalls for indications of improper impoundment function but is <br />confident that no such indications or problems exist or will manifest themselves in the <br />future. <br />Colowyo is respectfully requesting a waiver be granted for the elevated levels reported at <br />Outfall 001A, Outfall 004A, and Outfall 007A. Colowyo thanks you in advance for your <br />consideration on this matter. If you should have any additional questions or concerns <br />please feel free to contact me at your convenience at (970) 824-1573. <br />Sincerely, <br />?r <br />Chip Brown <br />Environmental Engineer <br />CC: CDRMS/Janet H. Binns <br />NPDES Reports Binder Wencl. <br />C.F. 21.1.2