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the bedrock in the footprint of OSA, flows through the diatremal rockmass, and exits with the <br /> natural groundwater via Carlton Tunnel. <br /> To provide assurance that there will be no impact from surface excursion of OSA seepage water, any <br /> observed occurrence will be mitigated as follows: <br /> 1. Seepage will be collected in a small reservoir constructed at the location of the seepage. <br /> 2. Collected water will be directed to the diatreme either by gravity drainage through a drilled <br /> borehole to underground workings in the diatreme, or by pumping to the nearest backfilled or <br /> open surface mine. <br /> 3. Any collected seepage water will pass through the diatreme, be neutralized, and will emerge <br /> through Carlton Tunnel with the rest of the natural groundwater flow, and will not affect the <br /> chemistry of that flow. <br /> Adequacy Issue#5: OSA Leachate Quality <br /> DRMS Adequacy Comment <br /> Additional and ongoing geochemical testing will provide data to help minimize future concerns[about <br /> geochemical interactions between the OSA leachate and the material underlying the pile]. <br /> a. Therefore, the Division requires the operator conduct sequential batch leach tests continually, <br /> using ASTM approved methods to document results of such tests. The results must be submitted <br /> on a quarterly basis or when enough representative sample data is collected. The tests must be <br /> an ongoing process throughout the life of the operation. <br /> b. Please provide the type(s) of ongoing sequential batch leach tests the operator plans to <br /> implement throughout the life of the operation. <br /> c. For post closure, CC&V must provide a worst case scenario of the quantity and quality of release <br /> from the overburden pile based on the results of these tests. Long term worst case scenario with <br /> ranges between maximum and minimum releases must be submitted to the Division. <br /> CC&V Response <br /> a. Sequential Batch Leach Tests.Long term ASTM sequential batch testing has been conducted for <br /> all the materials that will be surface mined from the Cripple Creek district12.This testing <br /> comprised a total of 42 tests of weathering of overburden materials from Tertiary volcanic rocks <br /> (23 tests), Precambrian granitic rocks (17 tests), and mixtures of mined rock with Cripple Creek <br /> district calcitic rock (2 tests). The tests were conducted under ASTM D574413. These tests <br /> comprised rock selected to reflect the full range of geologies, sulfide content in the district, and <br /> the full range of overburden particle size capable of being tested by the ASTM <br /> 12Cresson Project Hydrogeochemical Evaluation,Adrian Brown Consultants, Inc.,April 2008("MLE1 <br /> Hydrogeochemistry Report"),Appendix 1 of Cresson Project Mine Life Extension Permit M-1980-244, dated April <br /> 2008. <br /> 13ASTM D5744:Standard Test Method for Laboratory Weathering of Solid Materials Using a Humidity Cell, <br /> American Society for Testing Materials. http://www.astm.org/Standards/D5744.htm. <br /> Adrian Brown Consultants, Inc. Page 7 of 8 <br />