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i <br />Mr. Scott Jones -2- April 17, 1984 <br />You have provided two maps and tables which present the results of 1983's mine <br />inflow study completed in November. The maps and inflow depictions were clear <br />and easy to compare. I only have two required changes. In order to identify <br />mine inflows from all sources (including intermittent and ephemeral streams) <br />it is ideal if the survey is done during the peak runoff season. We are <br />therefore asking that the mine inflow study be done during June of each year. <br />This will also facilitate comparison with the baseline study done by Dravo in <br />June 1981. It also eliminates the problem of frozen conditions which may <br />affect inflow rates. The only other concern we had was that mine discharge <br />and consumption data was not supplied with the inflow study. This information <br />is important in calculating a mine waterbalance that verifies the accuracy of <br />the inflow estimates. This information should be provided in the next inflow <br />study. <br />As we discussed in our April 12, 1984 telephone conversation, if Snowmass <br />agrees to do the inflow study in June we would agree to extend the time frame <br />for the annual hydrologic report to January of each year. Extension of the <br />annual hydrologic report from August to January makes sense for many reasons. <br />In the past year Snowmass has mined very little which minimizes any changes in <br />predicted impacts. In addition. little new hydrologic monitoring has been <br />initiated since the permit was issued. Finally, this deadline would allow you <br />to evaluate your mines hydrology yearly using the standard USGS water year <br />which is October to September. <br />As built designs with modifications made to the surface drainage system have <br />been reviewed. Final designs were in order. I will incorporate the as built <br />designs in Volume V of your application. <br />Mike Long of our staff reviewed your plan to control Canadian Thistle at the <br />mine. The plan is an effective, environmentally sound approach to controlling <br />this problem. Your plan is therefore approved. <br />Only one concern was raised with the quarterly hydrology submittal. It was <br />noted that well depths were reported as distance from top of casing. Since <br />some wells are underground and since casing elevations are not known I am <br />asking that Snowmass report all water levels as elevations or supply elevation <br />data from the top of casing that would make elevation conversion possible. <br />Snowmass has committed to filing for appropriate water augmentation plans by <br />April 1, 1984. To date the Division has not received any response from <br />Snowmass on this item. In order to remain in compliance with your permit you <br />will need to respond on what the status of the augmentation plan is. If more <br />time is needed a request to the Division should be made along with a schedule <br />of when and how this issue is to be resolved. This year, as in 1983, is not <br />expected to result in calls being placed on your water, however, any time <br />extension granted by this office does not relieve you of compliance with <br />Colorado Water Laws. Snowmass is directed to respond to this issue by <br />May 15, 1984. <br />