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CTL/Thompson also performed a stability analysis of the <br />Lorencito Canyon Mine waste to be processed at the New Elk Mine and <br />stored in the RDA. Results of this study are also presented in <br />Exhibit 30, Geotechnical Study - Coal Processing Waste Bank. <br />Since mining has ceased at the New Elk Mine, no <br />underground development waste will be produced. The Development <br />Waste Pile will continue to be used for wastes such as pond <br />cleanings. Design and analysis of this pile is presented in <br />Exhibit 30 - Geotechnical Study - Coal Processing Waste Bank. <br />CTL/Thompson has conducted testing in the pile to confirm design <br />specifications are being met. <br />(9) Return of Coal Processing Waste to Abandoned Working <br />The New Elk Mine Preparation Plant receives mined coal <br />from the Lorencito Canyon Mine. As the coal is washed, refuse is <br />deposited in the thickener, dewatered by the belt press, and sent <br />by conveyor to the Refuse Disposal Area. Handling of these fines <br />has caused problems for the operating efficiency of the Prep Plant. <br />Basin is proposing to dispose of these fines by pumping a <br />refuse/water slurry into the abandoned New Elk Mine and recovering <br />clear water from gravity dewatering for returned use in the Prep <br />Plant. <br />Refuse fines will be recovered from the bottom of the <br />thickener and pumped in a four-inch poly-pipe line to the New Elk <br />Mine slope. This line will be buried from one-to-three feet below <br />the surface of the ground to prevent freezing and disturbance from <br />surface operations. Exposed portions of the pipe will be bermed to <br />prevent runoff should a spill occur. The refuse slurry will <br />consist of a maximum 34 percent solids by weight and water will be <br />used as the transport medium. The slurry will be allowed to <br />accumulate at the bottom of the slope with the overflow running to <br />other portions of the underground workings. Return water will be <br />recovered by pump located north of the Prep Plant and piped to the <br />Prep Plant for reuse. Slurry will be pumped at a maximum rate of <br />700 gallons per minute with Return water being pumped at the <br />comparable liquid percentage to allow for makeup water in the <br />plant. A second set of pipes will be installed to provide a backup <br />system should the pipes or pumps malfunction or be taken out of <br />service for maintenance. The existing belt press system will be <br />retained in the Prep Plant for additional backup in the event that <br />the system is out cf service. <br />Areas to be backfilled will be operated in phases. The <br />first phase will include the area in the vicinity of the East <br />Portal. Subsequent phases of the operation will include the West <br />Portal Area and the South Mains Area. It is anticipated that <br />approximately seventy percent of the mains will be filled with fine <br />refuse at the completion of the project. The New Elk Mine is <br />currently abandoned and these proposed disposal operations will not <br />affect underground mining operations at the Golden Eagle Mine <br />because that mine is in a different coal seam. Because the New Elk <br />~) ~ <br />3osaa.s3s 2.05-44 revised 10/23/97 r~/' <br />