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r <br /> f l <br /> r � J J/ <br /> of � STATE, OF COLOFADO <br /> Roy Romer, Governor <br /> 1876 <br /> DEPARTMENT OF NATURAL RESOURCES <br /> MINED LAND RECLAMATION DIVISION <br /> FRED R. BANTA, Director <br /> March 29, 1989 <br /> Mr. Scott Jones <br /> Mid-Continent Resources, Inc. <br /> Box 500 <br /> Carbondale, CO 81623 <br /> Re: Coal Basin Mines (Permit No. C-81-017) MR15, Pipe Diversion System <br /> Dear Mr. Jones: <br /> The Division is in receipt of the above referenced request for minor revision, <br /> but the following issue has been identified. <br /> The ponds were reported to be designed to handle a 10 year/24 hour <br /> precipitation event plus 1500 gpm of mine water inflow. This same estimate of <br /> maximum inflow from the mine was used in the calculations submitted in support <br /> of TR05 which was approved in 1986 to allow construction of two additional <br /> ponds for treatment of the mine water. The calculations submitted in support <br /> of the proposed diversion, however, utilize recent average flow from the mine <br /> of 500 gpm and indicate inability to accommodate even this inflow, for the <br /> required period of time plus a 10 year/24 hour event, unless all 3 ponds are <br /> functional . Clearly, additional capacity is needed, if any pond from the <br /> present series is isolated for cleaning. The addition of Pond D, as recently <br /> proposed in TR 11 to be constructed in the fall of 1989 and to be included in <br /> the diversion system, would appear to provide this. Until that pond is built, <br /> however, the Division requires a commitment by Mid Continent not to clean the <br /> present series of ponds and to keep all connections between the ponds open <br /> during a precipitation event. Upon receipt of this commitment the Division <br /> can consider proposed MR15 complete and begin the approval process. <br /> By requiring this commitment, the Division does not intend to release Mid <br /> Continent Resources of any responsibility to properly maintain these ponds so <br /> as to meet effluent limits at Discharge Point 016. Cleaning should be <br /> scheduled and completed well enough in advance of absolute necessity, so that <br /> any delay in cleaning caused by a precipitation event or events will not <br /> result in the ponds being unable to accommodate mine inflow and the required <br /> 10 year/24 hr precipitation event. <br /> 215 Centennial Building, 1313 Sherman Street Denver, Colorado 80203-2273 Tel.(303) 866-3567 <br />