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.- <br /> <br />operators to prevent the release of acid or toxic substances. Molybdenum, in elevated <br />concentrations, can be toxic, so its release in toxic quantities should be minimized. <br />The Division suggested that CMC might sample raw mine water to screen for appropriate <br />monitoring constituents. It was assumed that the mine water, that is, water flowing from <br />underground to the surface, would contain a representative sample of dissolved constituents that <br />resulted from the underground disturbance, and thereby would mimic the composition of waters <br />that flow through the surface mine waste and into groundwater. CMC certainly may elect not to <br />sample the drainage in this potentially simpler way, but this does not abrogate their responsibility <br />for evaluating groundwater. <br />With regard to the notion that the rocks do not contain regulated constituents in quantities <br />sufficient to cause water quality problems, the operator should recognize that it is not the quantity <br />of regulated constituents in the rock that matters but rather the quantity that may leave the rock <br />due to activities at the mine or due to weathering of the waste rock. For instance, Al in present in <br />many of the most common rocks but rarely presents a surface water quality problem uriless the <br />rock weathers quickly in the presence of acid such as sulfuric acid from the weathering of pyrite. <br />Such circumstances may liberate other metals as well unless the rock is protected. <br />As we discussed, gold should not be analyzed. Ag was a typographical error in an earlier <br />communication, and should have read "Ag." Silver should be monitored during the baseline <br />characterization phase of groundwater monitoring. <br />cc: Bruce Humphries <br />Carl Mount <br />Jim Pendleton <br />2 <br />