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46. Please describe how the lower pit area will be reclaimed, including pit slopes and the final depth of <br />the pit. <br />Rule 6.4.6 Exhibit F- Reclamation Plan Maa <br />47. The reclamation plan map does not show the proposed topography of the area with contow lines of <br />sufficient detail to portray the depth and slope of the reclaimed areas (i.e. benches, contour furrows <br />and waste pile area). Please revise the reclamation plan map to include contour lines of the reclaimed <br />area. <br />Rule 6.4.7 Exhibit G- Water Information <br />48. The operator notes that water flows from former mine workings early in the summer months above <br />the affected land boundaries. Please provide an estimate rate of flow and locate these aeeas on the <br />map. <br />49. The Division received comments from the Office of the State Engineer (OSE) regarding the proposed <br />application, According to the OSE, if stormwater is contained on-site (i.e. captured in the lower <br />pond) it must infiltrate into the ground or be released to the natural stream system within 72 hours, or <br />all work must cease until a substitute water supply plan, or augmentation plan approved by water <br />court is obtained. See the attached OSE letter for further detail. Please address accordingly. <br />50. The operator states that a closed system wash facility may be used in the futwe. The operator intends <br />to use swface water flow from diversion ditches located above the highwall area on the western side <br />of the affected land. Please explain and provide documentation for the legal use of the estimated <br />5,000 gallons per day proposed for the wash plant facility. In addition, please depict the location of <br />this diversion ditch on the mine plan map. <br />51. The Division has the following questions regarding the watershed map and storm volume projections: <br />o The operator states that ditches above the west of the mining area and the mining area itself <br />will reduce the overall acreage of the basin draining into Taylor Gulch to less than 150 acres. <br />Please locate on a map the location of the ditches that reduces the watershed area to less than <br />150 acres. Upland diversion ditches are recommended and need to be designed and installed <br />to route flows away from the mining area. <br />o The Division is uncleaz if the storm volume projections are intended for runoff within the <br />mining boundaries, or limited to the projected flows in Taylor Gulch, The operator will need <br />to clarify the storm volume projections for the undistwbed drainage of Taylor Gulch, and the <br />projections within the mining limits to enswe that ditches and berms can handle the projected <br />flows. <br />o The Division calculated the peak runoff rate using the information provided by the applicant <br />(with exception to the 100-year/24-how precipitation event, a 3.8" event was used rather than <br />the operators 5" based on information in the NOAA Atlas). The information was entered into <br />the SEDCAD 4 surface water hydrology program and resulted in peak discharge of 403 cfs. <br />The operator estimates a peak discharge of 175 cfs. Attached is the SEDCAD report for <br />further detail. Please provide additional detail and documentation that supports the operator's <br />peak discharge rate of 175 cfs, or revise the model accordingly. <br />o The operator designed the channel with a maximum dischazge rate of 175 cfs. Assuming that <br />175 cfs is correct (refer to the previous question), the Division used the operator's values to <br />determine if the channel and riprap sizing is adequate. Based on the values provided by the <br />operator, the Division calculates that the D„o„ is 12", the Dso is 15" and the D„~x is 24". See <br />