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roli Applegate <br /> Group,inc. <br /> Water Resource Advisors for the West <br /> May 20, 2015 <br /> Ms. Ioana Comanichiu <br /> Division of Water Resources <br /> 1313 Sherman Street, Suite 818 <br /> Denver, Colorado 80203 <br /> RE: Request for 90-Day Test Approval of the SerFer Pit Liner <br /> Mine ID No. M-2008-006 <br /> Dear Ms. Comaniciu: <br /> The 90-day period for the liner leak test on the SerFer Pit has completed. During the initial 66 <br /> days of the test the reservoir had standing water in the bottom. On April 14, 2014 at your request <br /> the standing water was pumped out of the reservoir. The contractor scarified and recompacted <br /> the reservoir bottom and the reservoir bottom remained dry with the exception of precipitation <br /> for the remainder of the leak test period. Due to heavy rainfall and scheduling for the final survey <br /> the testing period was 91 rather than the required 90 days. Calculations were adjusted <br /> accordingly. <br /> Procedure <br /> A rain gage is located on-site and data collection was performed weekly and specifically after all <br /> precipitation events. Precipitation data was also gathered at nearby weather stations. As <br /> mentioned above, water was pumped out of the reservoir on April 14, 2014. The total volume <br /> pumped was 2.66 acre-feet. No other water entered or left the pit or repaired areas during the 91- <br /> day test except through precipitation and evaporation. A copy of the rain gage data is included as <br /> an attachment to this letter. <br /> Because there were two distinct periods of testing, calculations were performed in two parts: day <br /> 1 through day 66 with standing water on the bottom of the reservoir, and days 67 through 91 <br /> with little to no standing water. A water balance equation was applied to the data to determine <br /> the amount of water that seeped into the test area during the two phases of the testing period. <br /> Evaporation was considered in these calculations since standing water was present. The seepage <br /> calculation has been compared with the allowable seepage calculation derived from the equation <br /> provided by the State. <br /> Weather data was collected from two nearby weather stations, one located in southwest Windsor <br /> and one in Highpointe Estates. The Southwest Windsor weather station is located at Lat: N <br /> 7405 W.Highway 50,Suite 123 1490 W.1215}Avenue,Suite 100 118 W.6th Street.Suite 100 <br /> Salida,CO 81201 Denver,CO 80234 Glenwood Springs,CO 81601 <br /> 303-452-6611 <br /> www.applegategroup.com <br />