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STATE OF COLORADO <br />DIVISION OF RECLAMATION, MINING AND SAFETY <br />Department of Natural Resources <br />1313 Sherman St., Room 215 <br />Denver, Colorado 80203 <br />Phone: (303) 866 -3567 <br />FAX: (303) 832 -8106 <br />COLORADO <br />Q I V I S I O N O F <br />RECLAMATION <br />MINING <br />SAFETY <br />John W. Hickenlooper <br />Governor <br />April 5 2012 Mike King <br />A <br />P Executive Director <br />KurtIS Blunt Loretta E. Pineda <br />Director <br />Colowyo Coal Company <br />5731 State Highway 13 <br />Meeker, CO 81641 <br />RE: Colowyo Mine, Permit C- 1981 -019 <br />Fourth Quarter 2011 Sediment Pond Inspections <br />Dear Mr. Blunt: <br />The Colorado Division of Reclamation, Mining, and Safety (Division) has reviewed and found the above <br />referenced report to be in compliance with the following regulations: <br />4.05.9(14) - The impoundments have been maintained as designed, in accordance with the approved <br />plan and the applicable regulations. <br />4.05.9(15) - Certified inspection reports shall include: any appearance of erosion, instability, <br />structural weakness or other hazardous conditions. <br />4.05.9(17) - All impoundments shall be examined at least quarterly by a qualified person designated <br />by the operator for appearance of structural weakness and other hazardous conditions. <br />4.05.9(17) - A copy of the report shall be submitted to the Division on a quarterly basis. <br />The fourth quarter sediment pond inspection report and the pond capacity data were received by the <br />Division on December 29, 2011. Sediment pond inspections were conducted by CCC between <br />November 8 and November 30, 2011. <br />The values in the Existing Storage Capacity row in the table provided with the Pond Outfall <br />Inspection report indicate the possible need for cleaning of several ponds. When these values <br />are used in conjunction with the information in Table 6 of Exhibit 7, it appears that several <br />ponds have too much sediment for them to function properly. <br />Streeter Pond may be used as an example. According to Table 6 (as well as the As Built <br />drawing) the capacity of the pond is 2.63 acre feet at the lowest spillway perforation. The <br />available sediment storage volume for this pond is 0.84 acre feet. If 0.84 is subtracted from <br />2.63 the result is 1.79. However, the inspection report indicates that the capacity of the pond <br />is only 1.43 acre feet. Thus, it appears that this pond needs to be cleaned. (This calculation <br />does not account for the fact that ponds should be cleaned when the available sediment <br />storage is reduced by 60 percent per Colowyo's PAP; it allows sediment accumulation up to <br />the maximum volume.) <br />Office of Office of <br />Mined Land Reclamation Denver • Grand Junction • Durango Active and Inactive Mines <br />