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'- _. <br /> <br />millimeters of "holes." Obviously this azea infinitesimal in comparison to the :en percent. Thus <br />the ten percent used in the calculations is very conservative in comparison to the EPA-designated <br />"acceptable" leak rate. <br />The Meteoric Water Mobility Procedure involves bottle-rolling a specimen cf the material for <br />24 hours. This procedure results in contact of essentially all surface areas o1' the specimen for <br />the full 24 hours. In the case of saturated seepage, it is improbable that the total surface area <br />of the particles will be contacted during the tortuous flow of a specific molecule of water. <br />Along the tortuous flow path followed by the molecule of water, it is more probable that only <br />25 percent of the surface area of particles may be contacted. If it is assumed that this molecule <br />of water will dissolve the chemical constituents on the particle surface in a nanner similar to <br />that occurring in a MWMP test, then it is reasonable to assume that the water quality of this <br />molecule will be equivalent to 25 percent of that measured by the MWMP [c:st procedure. <br />The earlier submission made for the Ironclad material was submitted in May 1994. Those data <br />included MWMP water-quality data that were subsequently incorporated into the revised <br />assessment submitted at the conclusion the meeting held with you and Office staff (submitted <br />July 8, 1994). The remaining chemical and related data submitted in May remain directly <br />applicable to the materials for which approval has been requested. <br />The additional cell test will be performed as stated in our July 8 letter. "he water quality <br />standards used for comparison with leachate quality are those for the nearest tributary, Cripple <br />Creek (Segment 22 of the Upper Arkansas River), into which Arequa Gulch flews. The streams <br />in this particular headwaters region of the Cripple Creek Mining District are not classified for <br />domestic water supply. That makes sense when one reviews the natural pH (moderately low) <br />and sulfate content (moderately high). There are no known ground-water uses in the area. <br />Ground water draining from the Carlton Tunnel (which drains to Fourmile i.reek) must meet <br />the surface-water quality standards adopted for Fourmile Creek. Naturally-occurring ground <br />water in the vicinity of the spring(s) that feed Arequa Gulch are of poorer quality than the <br />surface water. Until more information is examined, it makes sense, we believe, to compare test <br />data with surface-water quality criteria based on Class I, cold-water, aquatic life protection, as <br />adapted to ambient conditions by the Water Quality Control Commission of the Department of <br />Health Services and Environment. <br />We hope that this information allows the Office to accept the prior submissions relevant to the <br />Ironclad materials and water quality. <br />;er Environmental Affairs <br />CC& VSTIP.002 <br />2 <br />