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-= <br />Mancos shale outcrop can be postulated due to precipitation <br />patterns of late in this area. The McClane Mine has seen two 100 <br />year 24 hour events in the last two years, and it is likely that <br />new erosional degradation has occurred upstream as well. The last <br />precipitation 100 year, 24 hour event occurred on July 12, 1992 <br />with 2.5 inches measured to have fallen within a 30 minute period. <br />The second justification could be a change in lab procedure, lab <br />company or techniques. A phone call to John Walters was made to <br />verify if this was the case. <br />According to John Walters, there has been no lab change in company <br />or technique to his knowledge. He could offer no plausible <br />explanation for this phenomena but said he would contact me later <br />this week with this spring's sample results which may indicate if <br />this effect has decreased or continues to rise. <br />Ground Aater MonitorinC <br />Ground water wells GW-1 and GW-4 continue to be monitored quarterly <br />for partial analysis of Temperature, EC, Static Water Level (SWL) <br />and pH as per permit commitments. All parameters monitored were <br />within compliance. <br />Conclusion <br />Except for the accelerated levels of manganese in the mine area, <br />there appear to be no problems oa the mining sites of McClane and <br />Munger Mines. Siace the manganese problem exists both upstream and <br />downstream from the McClane Mine, this problem is background and <br />not the direct result of mining in the valley. <br />This concludes my Annual Hydrology Review for 1992 water year. <br />Addendum March 23, 1993 <br />After receiving a return call from John Walters, the manganese <br />issue seems to be resolved. Mr. Walters stated that his sampling <br />methodology has changed since the mine office moved from Grand <br />Junction to the mine site in 1991. Now he "catches" the first flow <br />rather than the peak flow, which would be higher in salt contents. <br />Also, evidence in the permit indicates that the manganese level in <br />the Colorado River, 18 miles away is 1.0 mg/1, allowing for a <br />dilution factor from upstream waters that are manganese rich. <br />