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=' LAWRENCE G. WHITE P.E. <br />1650 M. STREET PENROSE, COLORADO 81240 <br />August 4, 1993 <br />Ms. Shawn Smith <br />Reclamation Specialist <br />Division of Minerals 8 Geology <br />1313 Sherman Street, Roam 215 <br />Denver, Colorado 80203 <br />719-372-6461 <br />RECEIVED <br />AUG 51993 <br />Divisir,n o. ~~~in6rais ~ Geology <br />Re: Twin Pines No. 2 Mine, Permit No. C-83-058; Notice of <br />Violation No. C-93-104 <br />Dear Ms. Smith: <br />In regard to subject "Notice of Violation" please consider the <br />following in assessing the facts concerning the spoil area: <br />1). Prior to any work on the Twin Pines Mine Site, what is <br />known as the North Spoil Area was a previously stripped <br />area. All drainage from the area, the slope above, and that <br />collected by the old power line road and dumped into the <br />area had to run-off aver the down slope. Erosion of the <br />slope was visible at that time; (See pre mining contour map <br />included in the Permit Application) <br />2). In original designs for the permit application ditch's <br />to divert run-off from above the stripped area were <br />considered, but were thought to be impractical due the the <br />steepness and roughness of the existing slope; <br />3). The spoil area was located in this area, basically to <br />attempt to reclaim the old strip; <br />4). A 10 foot high earthen toe dike was constructed on the <br />downslope side to contain the spoil and a gravel underdrain <br />placed on the sandstone base of the cut to prevent build-up <br />of water behind the dike; <br />5). The spoil was placed in 2 foot lifts behind the dike and <br />compacted. The spoil was generally sloped into the highwall <br />to prevent run-off across the slope. When the elevation of <br />the spoil in the pile was below the elevation of the toe <br />dike run-off was contained within the area. When the spoil <br />volume reached the elevation of the access road ditch the <br />run-off was directed to that ditch. A gap (10 to 12 ft. <br />wide) was left between the spoil slope and the dike. <br />Compaction tests were taken in the spoil semi annually; <br />b). During a major storm event which occurred September 17, <br />199 washing across the spoil did occur which filled the gap <br />between the pile and the toe dike with spoil and created <br />some additional erosion of the down slope; (An account o~f <br />the storm event and damage inflicted was reported to the <br />Division). <br />1 <br />