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w • • <br />Mr. Gossett - 2 - December 2, 1987 <br />Mine Inflow <br />Records of the monthly totals for pumpage from the Animas/Helen, and "old" or <br />"Storage" mine were provided together with field determinations of iron <br />content, pH, temperature and conductances. As noted by the operator, there is <br />a general relationship apparent between monthly totals for mine pumpage <br />(inflow) and the amount of local precipitation. In the case of the Animas and <br />Helen Mines, the monthly totals are also influenced by the work schedules of <br />mine personnel. Pumping from the storage mine, however, has been reported <br />previously as being controlled by a float mechanism. There is little <br />correlation between the apparent monthly mine inflow data reported for the <br />1985-1986 year and the current year. Work schedules of the mine personnel <br />were apparently the major factor in timing the pumpage from the various mines <br />during the 1985-1986 monitoring year. <br />Summary <br />The quality of both the surface and ground water sampled from the area of the <br />Animas Mine during the 1986-1987 monitoring year is relatively unchanged from <br />previous years. Since the mine has been in temporary cessation since <br />mid-1984, little recent change would be expected. While there is no apparent <br />influence of the mine on the quality of ground water locally, some continued <br />surface water effects can be expected. There is a significant difference <br />between the quality of the water occurring in the Starkville Gulch permanent <br />diversion and that discharged from the mine's sediment pond. These discharges <br />are, however, allowed under the existing NPDES permit for the mine and limits <br />are set by the permit for certain dissolved and suspended constituents in the <br />water discharged. <br />As regards the permitted discharges, the Animas Mine has, until recently, had <br />a problem complying with the NPDES limits for settleable solids. Exceedances <br />of the permit level were fairly common and continued into the third quarter of <br />1986. Measures taken by both the previous and present operators, since that <br />time, to reduce the volume of these discharged solids to permitted levels have <br />apparently been adequate. There were no NPDES violations during the last <br />three quarters of the 1986-87 monitoring year. With the apparent resolution <br />of this problem, there are no significant current hydrologic concerns about <br />the Animas Mine. <br />Sincerely, <br />J~n~ C~~~ <br />James C. Stevens <br />Reclamation Specialist <br />JCS/vjr <br />3735E <br />