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CYPRUS Box t68 <br /> o <br /> � CraiCrai g, Colorado 81626 <br /> " Empire Corporation 303-824-8246 <br /> July 19, 1989 <br /> Mr. James C. Stevens <br /> Colorado Mined Land Reclamation Division <br /> 215 Centennial Building <br /> 1313 Sherman Street <br /> Denver, Colorado 80203 <br /> RE: Ponds 9-P2 & 9-P3, Permit C-81-044 <br /> Dear Mr. Stevens: <br /> Ponds 9-P1, 9-P2 and 9-P3 are structures which were originally part <br /> of the #9 Mine dewatering system. These ponds were evaluated by <br /> Leonard Rice Consulting Water Engineers back in 1981 and approved <br /> by CMLRD (see exhibit 18 pages 21-23 of permit) . There are no <br /> dewatering devises in the bottom of these ponds. The statement on <br /> page 2 . 05. 3-37R is referring to the three treatment ponds which are <br /> part of the 5 Mine dewatering well system (Ponds 5-P5, 5-P6 and 5- <br /> P7 Map 26) . As you are aware, the #9 Mine has been closed and <br /> ponds 9-P2 and 9-P3 currently are serving as a treatment facility <br /> for water being discharged from the #5 Mine via the 7 N Angle Well. <br /> As can be seen in the exhibit 18 evaluation, page 23 , the runoff <br /> from undisturbed tributary area for a 10-year rainfall event is <br /> small compared to 400 gpm from the 7 N Angle Well. Calculations <br /> attached show that the ponds are able to meet a retention time of <br /> 25. 1 hours with an inflow of 1,400 gpm when ponds are full. It <br /> should also be noted that the discharge from the 7 N Angle Well is <br /> currently meeting CDPS permit effluent limits before it goes <br /> through the ponds. <br /> If there are further questions or information needed, please <br /> contact me at your convenience. <br /> Si cerely, <br /> Terrell K. son <br /> Environmental Engineer <br /> TKJ/js <br /> attachment <br />