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i • The effects on ground eater attributable to the disposal of coal processing waste in abandoned underground workings is considered negligible. The water used in the disposal process will be reused and what ground water that ccmes in contact with the waste should not be significantly a?fected since this ground water is in contact with the same material under natural condition. The workings in the Cameo ?line will be flooded creating anaerobic conditions, causing sloe dissolution of exposed minerals. The Cameo Coal Pine processing waste pile is underlain bq a series of rock drains causing leachate to enter the sediment control ponds. The Roadside Hine waste pile overlies Colorado River alluvium, therefore, leachate from it will have some effect on the Colorado River water quality. These effects oa eater quantity and quality is considered negligible since the worst case conditions shoe only an average increase of 0.01 cfs in the Colorado River volume. This would have average total dissolved solid level of 875 mg/1, raising the TDS level for the river by leas than O.OLZ, All surface runoff from disturbed areas will be contained by sediment ponds and released after a 24-hour settling time if effluent standards are considered acceptable. Surface water monitoring will be done on these ponds on a periodic basis. The amount of runoff eater reaching the Colorado River will be slightly less than pre-mining conditions because of dead storage below the maximum sediment storage level in the sediment ponds. This effect should be negligible, since the amount lose would be, at worst case, 0.075 of the dally average floe of the Colorado River. With removal and reclamation of the __ sediment control 'system, runof: should return to normal conditions. A technical assessment of the effects of undermining Rapid and Cottonwood Creeks vas completed by CMLBD. The analysis shoes that in the absence of subsidence ar vaterflovs through natural fractures, changes 1n eater floes should be insignificant, and there would be no material damage to downstream users. The company will be mining beneath the stream valleys following an approved extraction plan. Consequently subsidence effects should be reduced . or eliminated. The possibility of eater floes through natural fractures is difficult to predict. Major fractures such as a fault would normally be Sdentified during zesource evaluation, and none has been identified by the company. It is recognized that the abandoned Blue Flame Mine located about 200 feet away is flooded in its northers most workings, some of the workings underlie Rapid Creek, but this mine vas never designed for subsidence control and has been abandoned since about 1968. It Ss, therefore, appropriate to monitor the stream-alluvial aquifer system during mining sad reclamation, sad to identify appropriate mitigations that could be undertaken should monitoring identify an undesired effect. Presently, there Ss only one surf ace'vater monitoring station on Papid Creek located near the lover portion of the permit area. Hors station are needed is order to monitor the effects on Rapid and Cottonwood Creeks (please see state stipulations). Ia the absence of subsidence, there should be no significant effect on the water floes in Rapid and Cottonwood Creeks. However, in the event that sur'_ace flows were depleted or reduced through natural or subsidence related •~ fracture s, the Cameo Pine will be required to mitigate the effects from mining - and this so stipulated. -11-