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<br />.T <br />III IIIIIIIIIIIIIIII <br />999 <br /> STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Department of Natural Resources <br />1313 Sherman 51., Room 215 r <br /> <br />Denver, Colorado 80203 I <br />~~ <br /> <br />Phone: 1303) 866-3567 I <br />FAX'. (30 31 83 2-8106 <br /> DFPAFtTME[VT OF <br /> NATURAL <br /> RESOURCES <br />DATE: March 21, 1997 <br /> Roy Romer <br /> <br />TO: 'Bill Carter Governor <br /> lames S. Loc hhead <br /> Executive Dueaor <br />FROM: Susau Burgmaier Michael 8. Long <br /> Division Direuor <br />RE: Sanborn Creek Mine (C-81-022) <br />1996 Annual Hydrology Report <br />I have completed a review of the 1996 Annual Hydrology Report (AHR) for the Sanborn Creek Mine. <br />I reviewed the report itself, previous AHR's back through 1990, and the permit application as it <br />pertains to baseline hydrology and the prediction of probable hydrologic consequences (PHC). <br />Following aze my resulting comments and questions for the operator. <br />With a few exceptions, all required monitoring was completed. Exceptions noted were <br />a. The text of the AHR notes that Site WSC DH12 was not monitored in 1996 because <br />the low water level and well depth prohibit bailing and sampling. OCM notes that a <br />power bailer will be built to make sampling of the well easier. OCM should make <br />sure that whatever necessary equipment for monitoring is on line for the required June <br />sampling this yeaz. <br />b. Full suite analyses were not done during the second quarter at sites S-1, S-2, C-1, and <br />HN-1. OCM notes that the full suite analyses were scheduled for June, during which <br />no flows were observed. The monitoring plan requires quarterly full suite analyses, <br />and has not been approved for a specific month only. Because there was flow during <br />the second quarter, OCM should have obtained samples to be analyzed for the full <br />parameter suite. Please make an effort to ensure that all involved staff are aware of <br />this requirement so that samples will not be missed in the future. <br />c. The third quarter full suite was missed at Site T-1 for the same reason noted in Item <br />b., above. This information would have been especially important for this site, since <br />1996 data constitutes baseline data. <br />2. Field conductivity values rise significantly between Site S-1 and S-2 for the April and May <br />data (80 umhos/cm to 480 umhos/cm in April, 90 to 800 in May). No mention of these results <br />is made in the report text. How does OCM explain this increase? <br />3. Since 1990, total dissolved solids (TDS) values have risen steadily at Site SC-l. No mention <br />or explanation is made in the AHR text. Does OCM have any explanation for this increase? <br />4. Monitoring data for 1996 shows TDS values increasing between NF- I and NF-2, the upstream <br />and downstream monitoring sites on the North Fork of the Gunnison River. No discussion <br />is made as to what might be causing this increase. It is possible that the Bumping of water in <br />the mine to decrease total suspended solids is contributing to increased TDS in the minewater <br />discharge, which would elevate TDS in the North Fork. Has OCM looked into the TDS <br />increase? <br />