Laserfiche WebLink
0 ~II ~I~~I~II~~I~~III <br />999 <br />MINED LAND RECLAMATION DIVISION <br />Oepariment of Natural Resources <br />1313 Sherman St., Room 215 <br />Denver. CO 80203 <br />303 6663567 <br />Fn X: 303 832-6106 <br />October 16, 1991 <br />Mr. Karl Koehler <br />Cyprus Orchard Valley Coal Company <br />P. 0. BoX E <br />Paonia, CO 81428 <br />RE: Adequacy Letter, TR-14, Orchard Valley Mine, C-81-038 <br />Dear Mr. Koehler: <br />pF COQ <br />~~ ,~ <br />N~ <br />.+~ <br />~ re 76 ~ <br />Roy Romer, <br />Governor <br />Fred R. Banta. <br />Division Dveotor <br />1> Could you put together a table of contents for the culvert, ditch and <br />peak flow packets? <br />2> Please revise the rainfall on the peak flow events to 2.7 inches for the <br />100-year and 1.9 inches for the 10-year event. <br />3> Confirm, in the culvert summary, that Culvert L' can handle flow from <br />Culvert L and the L' drainage area. <br />4) Please provide calculations to verify that the two 30-inch clean water <br />culverts and the 60-inch culvert for the Farmer's Ditch, located at the <br />loadcut, are adequate to handle the 10-year, 24-hour event per Rule <br />4.06.4(1)and 4.05.4(2)(b). If this information currently exists in the <br />permit, please reference it. <br />6> Channel designs suggest erosive velocities for the 100-year event at <br />cross-sections A, D, E and H. Please modify designs to afford 100-year, <br />24-hour event protection for the waste pile, either by modifying the road <br />ditch or installing a larger ditch at EE per Rules 4.10.3(2) and <br />4.09.2(7). <br />6) Modify Map 8-lA's labeling of the Channel "L" area, the Culvert "L"' area <br />and the Culvert "G "' area. <br />7) Please label the 221 Drainage on the Timber Storage Area Map, No. 8-2. <br />Sincerely, <br />(1 C~~i~~ ~~ ~~~ ,~ <br />Catherine W. Begej ~~~~~ <br />Reclamation Specialist <br />CWB/gaw <br />cc: Randy Price <br /> <br />STATE OF COLORADO <br />8739E <br />