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4 <br />If this system is abandoned, it is likely that the siphon discharge will exceed the mine <br />inflow rate, thereby breaking the siphon. Once the siphon breaks, the mine water level <br />will likely rise above the backfilled portal floor elevation, and to an elevation at or neaz <br />the backfilled portal roof. [f this occurs, it is likely that the backfilled material will <br />saturate and fail in a catastrophic manner. If this failure occurs, large quantities of mud <br />and water may rush onto and across Interstate 70, posing a significant threat to the <br />Interstate 70 structure, and to persons travelling on Interstate 70. Refer to the expert <br />reports prepared by Dr. Jim Burnell and Byron Walker, P.E., which discuss this issue in <br />more detail. Installation of an approved alternate dewatering system will eliminate this <br />risk. <br />ii. Unreclaimed Coal Mine Refuse Piles - <br />There are a total of three unreclaimed Coal Mine Refuse Piles at the Roadside Mine. <br />These are known as the Roadside Refuse Pile, the Cameo Refuse Disposal Area No. I <br />(CRDA1) and the Cameo Refuse Disposal Area No. 2 (CRDA2). CRDAI and CRDA2 <br />aze located adjacent to the Coal Creek, which is tributary to the Colorado River. The <br />CRDA 1 and CRDA2 refuse piles include runoff diversion and containment ditches, and <br />sedimentation ponds. The CRDAI pile area covers approximately 25 acres, and the <br />CRDA2 pile covers approximately 6 acres. <br />