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• Earlier work done with the Colorado Dept. of Public Health and Environment concluded the disposal cell is a Class <br />III Impoundment, pursuant to 9.2.4(A) and (B) of CDPHE Hazardous Materials and Waste Management Division's <br />REGULATIONS PERTAINING TO SOLID WASTE SITES AND FACILITIES, 6 CCR 1007-2, PART 1: <br />9.2.4 An impoundment shall be in Class III (unrestricted seepage) if it. <br />(A) Is located outside a recharge area for an underground source of drinking water or in an area <br />where no saturated zone exists between the surface and continuous strata of competent <br />bedrockwith an in-situ permeability of 1 x 10 cm/sec or less and minimum thickness of fifty feet <br />(50'); or <br />(B) Is located above an aquifer where impairment of existing or future use of ground water will <br />not occur due to unrestricted seepage of the waste or constituents intended for storage or disposal <br />in the impoundment. <br />The impoundment (a Class III Impoundment) is to be constructed on crystalline metamorphic and igneous rocks <br />with essentially zero hydraulic conductivity. A concrete barrier will be installed upon the up gradient face of the <br />first earth-fill terrace to minimize leachate through the structure (see Exhibit E). The natural slope, upon which the <br />fill will reside, is slightly less then 3h:ly. The clay contained in the waste stream (approximately 30% by weight) is <br />sufficient to seal any joints or fractures in the impervious bedrock. Leachate and solid waste qualities are given in <br />the laboratory analysis at the end of this Exhibit C. Both leachate and solids meet or exceed existing water quality. <br />Leachate quality actually exceeds existing groundwater quality by 2-3 orders of magnitude in many cases. <br />Metallurgical and corrosion controls require that the pH of the process water be in the range of 7.5-9. <br />Existing ground water quality is indicated in Wildeman's Water Handbook for Metal Mining, page 10, Table H, <br />column entitled "Central Zone". On page 13 (of the same), Figure 1 shows the effect of raising the pH of this <br />effluent water to 7-8. The method employed in Venture Resources' processing plant has the identical beneficial <br />• effect as shown in this Figure 1. This has also been verified by the Company and is evidenced by the waste stream <br />lab sample results. <br />100 <br />0 <br />W <br />75 <br />N <br />V) <br />0 <br />F- 50 <br />Z <br />W <br />U <br />ir_ <br />aW. 25 <br />.............................. <br />1 <br />1 ? <br />1 ? <br />1 ? •s <br />1 \\C d <br />j Zn\ <br />Cu <br />Fe <br />pH <br />FIGURE 1. HEAVY METAL BEHAVIOR AS A FUNCTION OF PH IN ARGO WATER. <br />12