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high cost of deep drill holes. What variability hypothesis does Dr. Posey want disproved with more drill holes? It is CC&V's position that these two drill holes and cores are representative of the mineralogy at depth. Role of Jarosite. Dr. Posey continues, on page 2, to observe "This section also states that jazosite will encapsulate the pyrite crystals and inhibit weathering. This is highly unlikely as jazosite is extremely soluble. Jazosite will release ferric iron and actually promote pyrite solution and acid generation." CC&V disagrees. In Secondary Minerals and Acid-Water Chemistry, Alpers, C.N., Blowes, D.W., Nordstrom, D.K, and Jambor, J.L. list jarosite in the category of "less soluble sulfates" (pages 247-270). An actual solubility constant for jarosite is not, as yet, available. Jarosite is more soluble than pyrite. Jazosite is a common mineral in acidic and high sulfate environments. Acid Generation From Oxide Material. On page 2 of the Memorandum, Dr. Posey states "Section 5.2 states that there is very little potential to generate acid from rocks in the oxidation zone. This is not correct. CC&V's classification of rocks into "oxide," "transitional" and "sulfide" zone reflect an empirical average of pyrite and other mineralogy. However, it is recognized that the mineralogy of these zones is not unique or homogeneous. Pyrite is found in the oxide zone and, if exposed to weathering, will produce acid. The degree to which it will produce acid depends on the degree of crushing (amount of surface exposure) and the amount of pyrite in discrete segments of the rock mass. Because some parts of the so~alled oxide zone have higher pyrite concentrations than others, the degree to which those parts can produce acid and metals depends on their mineralogy, not on CC&V's classification." CC&V's "classification" is based on logical grouping of the samples not only by mineralogy but also by sulfur analyses and the results of the humidity cell tests. Dr. Posey, we presume, recognizes the weathering process that the in-situ rocks have already experienced. In this context, the oxide zone, which all who have investigated agree exists, has already generated acid, some of which has been neutralized by carbonates. A relatively minor amount of additional acid was generated by the humidity cell rests. No pre-historic of historic adverse affects on downstream or downgradient waters as a result of this weathering have been postulated. Thus substantial portions of pyrite have already been removed and neutralized without reported adverse affects on water quality. The Arequa Gulch watershed is, of course, plated with this oxide rock -millions of tons of it. Arequa Gulch is slightly acidic from the spring system fed by ground water, but surface runoff reaching the Gulch channel is generally not particulazly acidic. The humidity cell, as well as the static, tests use material ground to pass a #10 mesh. In fact, the overburden will likely range in size from about 4 feet to about a 40 mesh (estimated) screen. The median size may be on the order of 8 inches. Thus the test procedures would appear to expose much more pyrite than would the mining and reclamation procedures. 16