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Turnpike Mining Resource AM-01 Adequacy Review <br />M-2004-009 <br />August 25, 2005 <br />Page 3 <br />11. Pursuant to the Minerals Program Policy Memo "Oil and Fuel Spill Containment Structures," dated <br />April 8, 2005, (copy enclosed) please submit documentation that the applicant has an SPCC plan for <br />this site and that plan has or will be implemented prior to storage of fuel or oil products. <br />12. To what depth and elevation will the pits be mined? What are the seasonal ground water depths and <br />elevations at the site? For cells that will be backfilled for reclamation, please commit to backfilling <br />them to a minimum of 2 feet above the prevailing high water table. The Reclamation Plan Map <br />shows the elevation of the bottoms of both the Cell 2 reservoir and the proposed Cell 4 dry <br />depression, which is closer to Boulder Creek, as 4925 feet. Will the Cell 4 "dry depression" expose <br />ground water? Please check these elevations, and amend the maps as necessary. <br />13. The Mining Plan for Cell 3 includes constructing a hydraulic barrier to hydraulically isolate the Plumb <br />& Dailey Ditch from dewatering operations. <br />Mine Plan Map C-2 shows the trench ranging from 18-20 feet from the ditch. Please clarify the <br />offset and amend the map as needed. Please indicate the width of the easement belonging to <br />the ditch company and provide an agreement with the ditch company that authorizes mining <br />within 200 feet of their structure. If an agreement is not available, please amend all relevant <br />permit documents to reflect a minimum 200-feet offset and/or offsets consistent with the results of <br />a geotechnical slope stability analysis of that situation and outside any easement held by the <br />ditch company. <br />• Mine Plan Map C-2 shows the hydraulic barrier parallel to the ditch and ending at the permit <br />boundary. How will the gas line on the south end of the hydraulic barrier be protected/offsets <br />maintained? The applicant should consider wrapping the hydraulic barrier around the north and <br />south sides of cells 3 and 6 to increase the hydraulic distance to the offsite portions of the ditch. <br />To minimize leakage, the applicant may want to key the barrier into the bedrock. <br />• Please specify what material will be used for the barrier, so the Division can properly calculate the <br />bond. <br />• The agreement to mine within 200 feet of the ditch, or the geotechnical slope stability and <br />hydraulic analyses must be provided prior to approval of this amendment. <br />14. Will the dewatering trenches all exist within the pit cells? If not, please locate the trench routing on <br />the Mine Plan maps. Please locate the sump on the maps. <br />15. The areas of cells 2, 3, and 4 presented in Table 6.4.4.1 - "Mining Timetable in Sequence" disagree <br />with the Mine Plan maps. Please correct these discrepancies and change the table or maps <br />accordingly. <br />Rule 6.4.5 Exhibit E -Reclamation Plan <br />16. Please commit to replacing topsoil to a minimum depth of 6 inches (0.5 foot). For the maximum 148- <br />acre disturbance described in the proposed Reclamation Plan, the 120,000 yd3 of topsoil the operator <br />is committing to replace equates to a 6-inch replacement depth. <br />17. The application proposes reclaiming Cells 4 and 6 as depressions. The Division has seen little <br />success reclaiming pits without positive drainage. How will you provide for positive drainage from <br />these cells at recamation? <br />18. When will the corrugated metal pipe routing the existing stream through Cell 6 be installed? Will it be <br />above or below grade at reclamation? Please provide design specifications, and the sizing basis and <br />calculations for the culvert. <br />