_GENERAL DOCUMENTS - C1981017 (217)

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- 2 - has been adequately completed and the division proposes to approve the Coal Basin Mines Permit Revision Application. Findings The Findings of Compliance for Permit Revision No. 1 , dated August 1984 were written to account for the life-of-mine impacts. Sections applicable to the enlarged permit boundary include subsidence, ground water, geology, and the Probable Hydrologic Consequences of Mining". This revision entails no change to the Operation Description and includes no new surface disturbance. The revision was reviewed for possible environmental impacts by subsidence. A subsidence monitoring program was initiated in 1981 by Mid-Continent Resources. To date, maximum subsidence detected in 2.1 feet. Based on conjections by Division and Mid-Continent personnel , there are no visible surface effects of subsidence such as cracks, hammocked profiles or subsidence-induced slumps or landslides. As no change to the mining plan is proposed in this permit revision, no further effects to the surface by subsidence is projected. Therefore, no change to the original findings is required in respect to surface water, renewable resource lands or water rights. The findings for ground water were written for the life-of-mine and projected no significant ground water impact. Dewatering of the mines will lower the potentiometric head on the coal seams and associated sandstones, however, the affected strata dip steeply into the axis of the Piceance Basin and any affected aquifers are too deep to feasibly explore it for water supply. No new surface disturbance is approved in this permit revision. Therefore, no vegetation surveys were required. Also, the affected bedrock aquifers are not in hydraulic connection with any alluvial aquifers or stream systems. PHC is valid for the proposed operation. No increase to the surface in ground water monitoring porgram is required for this permit revision. srs 8536F