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• Page 2 • The remainder of the surface water and AVF sections of Rules 2 and 9, that I reviewed, have included sufficient information to be designated complete. Additional concerns will probably be raised during the adequacy review. The applicant's discussion of probable hydrologic consequences although complete should be expanded to be considered adequate. The assessment needs to be more quantititative and several additional concerns need to be analyzed. 1) Mine water will be discharged to the Foidel Creek stream/alluvial aquifer system. The applicant should provide a worst case estimate of the quantity and quality of this discharge, and predict the effects upon surface flow regieme, surface water quality, alluvial water levels, and alluvial water quality. Possible effects to downstream users of surface flow or alluvial water should be considered, and mitigations proposed if appropriate. 2) The underground mine would intercept ground water currently flowing toward 7Wentymile Park, and discharging to the Fish Creek stream/ alluvial aquifer system. The applicant should examine the possibility of decreased flow in the Fish Creek system. This could be approached by first assessing the relative significance of the flow passing through the mine site to the Fish Creek system, and then predicting the effects of mining. Possible effects to downstream users of the surface flow and alluvial ground water should be considered, and mitigation proposed if appropriate. 3) Reestablishment of normal ground water movement post-mining, will cause a plume of degraded ground water to migrate towards Twentymile Park and discharge to the Fish Creek stream/alluvial aquifer system. As a result, water quality in the Fish Creek system could be altered. The permit application contains a qualitative assessment of this possible effect, but it needs to be quantified to verify their condlusions. If an effect be predicted in the quantitate ve assessment, it should he evaluated relative to downstream water use, and mite gations proposed if appropriate. 9) The applicant should predict flow from the Foidel Creek stream/ alluvial aquifer system. This flow results from the artificial gradients created by mining, and is not eliminated because of the non-tributary nature of the overburden aquifer. In the absence of natural fractures or subsidence caused fractures, this flow is governed by the verb cal permeability of the intervening strata. I have not reviewed the AVF information for adequacy. It's adequacy will depend upon completing the AVF designation and further analysis of the probable hydrologic consequences of mining. The Division should therefore make its AVF designation prior to completing the preliminary adequacy review. If you have any questions about this memo, we can discuss them during todays meeting. /ep cc: Jim Pendleton Ed Bischoff Ei