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-6- recharge of the reclaimed spoils material will enable rapid recovery of the original storage volume of the undisturbed overburden aquifer from the temporary dewatering due to mining. These conflicting statements should be revised to clarify this situation with regard to dewatering of the overburden aquifer. 2. Recharge Capacity The post-mining recharge rate of the overburden aquifer 1n the Mine No. 3 area was estimated by the applicant to be 140 acre-feet/year as compared to the recharge rate of 9.0 acre-feet/year for the overburden aquifer in the pre-mining condition (page 2.05-167). This raises the question of water balance. The applicant states that water•lnfiltrating into the backfilled mine pits will flow downslope to the highwall where it will provide recharge to the undisturbed overburden aquifer. Supporting calculations are needed to verify that the undisturbed overburden aquifer is capable of transmitting this increased volume of recharge water, so that spoils water from the reclaimed pits does not eventually discharge from the toe of the pits to the surface water or shallow alluvial aquifer systems. 3. Solute Leaching In an attempt to quantify the amount of solute leaching from backfilled mine pits, the applicant performed a leaching study on overburden material collected from the Eckman Park Mine. One of the most important results of a leaching study such as this is to estimate an anticipated "worst case" value for total dissolved solids concentration of leachate percolating through the reclaimed spoils pits. An anticipated "worst case" TDS value for spoils leachate should be included in this section. Also, the raw data compiled from the leaching experiment should be included in the permit application. 4. Solute Transport The applicant has qualitatively discussed the mechanism of increased dissolved solids transport from the backfilled mine pits to the undisturbed overburden aquifer system. However, a quantitative interpretation of effects has not been presented. A numeric projection of anticipated Impacts of spoils water discharge on the ambient hydrologic system should be produced and supporting data and calculations should be included in the permit application. SURFACE WATER EFFECTS 1. Runoff and Erosion A quantitative evaluation of the anticipated increase in runoff and erosion rates for all disturbed areas should be presented along with supporting data and calculations. 2. Sediment and Dissolved Salt Load The applicant should include a numeric estimation of the change 1n sediment and dissolved salt load on receiving streams due to existing and proposed mining activities both during mining and post-reclamation.