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<br />iii iiiiiiiiiiiiiiii <br />999 <br />COAL <br />COMPANY <br />5731 State Highway 13 <br />Meeker, Colorado 81641 <br />(303) 824-4451 <br />,~ fi~%~:11~F 0 <br />June 15, 1993 <br />SUN 16 ~g~~, <br />Mr. Mike Long, Director ~nM1,,, , <br />Colorado Division of Minerals and Geology - :.~:;;:,.,, <br />215 Centennial Building <br />1313 Sherman Street <br />Denver, Colorado 80203 <br />RE: PERMIT NO. C-81-019, COLOWYO COAL COMPANY <br />NOTICE OF VIOLATION C-93-077 <br />REQUEST FOR VACATION <br />ADDITIONAL INFORMATION <br />Dear Mr. Long: <br />As per the Friday afternoon, June 11th phone call from <br />Steve Renner, enclosed please find additional information to aid in <br />your evaluation of Colowyo's request to vacate the above mentioned <br />NOV. <br />Colowyo's Hydrology South Sheet is enclosed with polaroid <br />pictures attached to aid in visualizing the impacts of the severe <br />rain/hail storm of May 16, 1993. Additionally, using measured high <br />water flow dimensions taken above the Lower and Upper Breach Areas, <br />SEDCAD computer calculations were generated showing ditch flow and <br />velocity. To lend further credibility to this calculation of flow <br />and velocity, Ed Mighell, Executive Vice President of Tipton and <br />Kalmbach, Inc., (T&K) consulting engineers, Denver, Colorado, was <br />retained to perform a completely independent flow and velocity <br />calculation given only the ditch geometry. <br />Two separate locations on the South Collection Ditch <br />experienced breaching and are referred to as the Lower and Upper <br />Breaches. Prior to the breaches developing in the ditch, the ditch <br />was fully functional and carried water to the Prospect Pond raising <br />the pond water elevation by approximately 1.5 feet. As the water <br />quantity increased beyond the ditch's carrying capacity, the Lower <br />Breach occurred first. At some point shortly after the Lower <br />Breach, the Upper Breach occurred. The Upper Breach was actually <br />a series of numerous breaches. <br />Rock and debris was picked up and transported by the <br />water from the ditch breaches, as well as additional water added <br />from the natural topography. The storm was of such unusual <br />intensity that even small undisturbed, natural watersheds which <br />normally have no flow, experienced great water flow, erosion, and <br />