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and directly to surface water. Can the model be run to better represent the actual path of <br />contaminants for each mine setting? <br />We also question the effects of the less-permeable strata in the stratigraphic succession on the <br />transport of potential contaminants. Intuitively it seems that the siltier and shaleier units would <br />slow the rate of vertical transport, and spread out the contaminant plume. Accepting that <br />assumption, we wonder whether the contaminant plume would spread to, say, a cliff face where <br />it would flow more directly and quickly to the adjacent stream. (We recognize that at least some <br />of the mineralized strata dip away from the adjacent streams, but do they all do so?) The model <br />simulations appear not to account for the effects of what we would presume are the variable <br />transmissivities of each stratigraphic unit. <br />JD-9 Mine. The mining horizon at the JD-9 mine lies apparently in saturated rock, as <br />groundwater is pumped to the surface, treated, and discharged under a CDPH (NPDES) permit. <br />That water treatment and discharge under an NPDES permit are required is, by Division <br />practice, sufficient indication to warrant DMO status, even though the mine taps a perched <br />aquifer. Unless the operator has better information showing why this mine should not qualify as <br />a DMO, the division wilt so designate. <br />If the operator or consultants have any questions, they should please feel free to contact me at <br />303-866-3927 or Kate at 970-259-5861. <br />Cc: Bruce Humphries (via a-mail) <br />Carl Mount (via a-mail) <br />Steve Shuey <br />