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III IIIIIIIIIIIIIIII <br />999 <br />STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Depanmenl of Natural Resources <br />1313 Sherman Si.. Room 2I5 <br />Denver, Colorado 80203 <br />Phone. U03) 866-3567 <br />FA%: (3031 832-8106 <br />DATE: <br />TO: <br />FROM: <br />RE: <br />January 3, 1996 <br />Barbara Pavlik <br />Erica Crosby~~ <br />Eastside Mine (C-84-063) <br />TR-13; Drainage to Harvey Gap Creek <br />I~~~~ <br />DEPARTMENT OF <br />NATURAL <br />RESOURCES <br />Roy Romer <br />Governor <br />lames 5. Lochhead <br />Executive Dnecmr <br />Michael 8. Long <br />Drvismn Director <br />Barb, per your request I reviewed the designs submitted by Eastside Coal Company for the <br />drainage in the reclaimed area to Harvey Gap Creek. It appears that the runoff volume <br />from the 10-year, 24-hour precipitation event was addressed recently under TR-10. <br />Therefore, I only reviewed the design for the rip rap channel held in place with wire mesh <br />and roofbolts using the runoff approved under TR-10. I do have a few concerns that should <br />be directed to the operator; <br />1. Eastside prepared a typical drainage ditch design. This figure needs to be certified <br />by professional engineer as required under Rule 2.10.3(2). Please have the design <br />certified by a professional engineer. <br />2. On revised page 109, the second paragraph states that drainage calculations indicate <br />the peak flow event in the drainage would be 10.1 cfs based on the 10-year, 24-hour <br />event. The fifth paragraph on page 109 states that the 10-year event is 11.4 cfs. <br />Please clarify this discrepancy with the Division. <br />c:\wp51\misc\960103 <br />