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<br /> <br />c~RUs <br />Empire Corporation <br />III IIIIIIIIIIIIIIII <br />P.O. Box 68 <br />Craig, Colorado 81626 <br />303-824~~8246 <br />~~~~I~~® <br />July 19, 1989 JUL 25 1989 <br />MINED LAND <br />RECLAMATION DIVISION <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. 7'he 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 pond: 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 <br />contact me at your convenience. <br />Sinycerely, <br />' ~~~ <br />Terrell K. son <br />Environmental Engineer <br />or information needed, please <br />TKJ/js <br />attachment <br />