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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 />INTER - OFFICE MEMORANDUM <br />Date: July 26, 2011 <br />To: Susan Burgmaier <br />From: Rob Zuber <br />Re: Photos and notes from 7/22/11 site visit to Seneca II -W <br />Drainage structures at the Seneca II -W mine have been failing due to extreme precipitation, including spring <br />snowmelt after heavy snowfall and summer thunderstorms. These structures include rip rap lining channels, <br />turf reinforcement materials (TRM) lining channels, and surge ponds. To view these problems, Rob Zuber, an <br />EPS with DRMS, inspected the site along with Susan Burgmaier, also of DRMS, and Jay (last name unknown), a <br />representative of Peabody Coal Company. <br />During the site inspection and afterwards, some potential solutions were discussed: <br />• Design for a larger event. This could entail one of the following or a combination. <br />o More ponds such as the "string of pearls" at Edna <br />o Larger ponds (Larger ponds could also reduce the short circuiting situation that exists now). <br />• Check dams. <br />• Drop structures. <br />• Discuss problem with the Nilex representative who sold Peabody the TRM. Perhaps he has ideas on <br />better installation methods (such as a way to get better surface contact between the ground and the <br />TRM) or other products (e.g., plastic check dams). <br />Most of these solutions would entail significant construction effort, time, and materials. Peabody must decide <br />if there is a way to avoid these costs and the impacts on the reclamation. Given the amount of energy in the <br />flow down these very steep drainages during extreme runoff events, construction of larger structures and /or <br />removal of rocks below the TRM may be the only solution. <br />The following photographs were taken by Rob Zuber during this inspection. <br />Office of Office of <br />Denver • Grand Junction • Durango Active and inactive Mines <br />Mined Land Reclamation <br />STATE OF COLORADO <br />COLORADO <br />D I V I S I O N O F <br />RECLAMATION <br />MINING <br />— &— <br />SAFETY <br />