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r <br />i <br />-2- <br />J 4. SEDII+D;FIT CONTROL/STORMWATSR <br />The mining operation is designed for a zero discharge. However, a washing <br />and screening plant as well ae settling ponds will be used. Therefore all <br />process water must be contained within the designated ponds. Please <br />provide the dimensions of the ponds to be built. Also, you will be <br />required to incorporate the etormwater management plan into the mining and <br />reclamation plan upon its approval by the Colorado Department of Health. <br />'/ 5. TOPSOIL <br />The application states that 6 to 12 inches of topsoil will be replaced. <br />This will be acceptable for shoreline areas. However, the Division <br />requests that a minimum of 18 to 24 inches of topsoil be replaced on areas <br />to be reclaimed to cropland. There will be a total of 220 acres of <br />reclaimed shoreline area and 515 acres of crop and grassland to be <br />reestablished following mining. This will require a topsoil replacement of <br />1.4-2.0 million cubic yards. Further, no topsoil may be used as backfill. <br />Flease address. <br />~J 6. HIGHWAY ACCSSS <br />Please address the status of the permitting requirements of the Colorado <br />Highway Department for access to Colorado Highway 50. <br />7. BACRPILLING AND GRADING <br />The application states that a slurry pipeline will be used to backfill the <br />side elopes of the excavated pit from 1:1 to 3:1, since 3:1 slopes will be <br />required for all shoreline areas. Therefore, the Division will expect to <br />see 3:1 aide slopes where there ie active backfilling during field <br />inspections. Please explain how stable 3:1 slopes will be achieved by <br />pumping sand and rock lees than 1/4 inch diameter through a submerged <br />slurry pipeline. <br />J 8. SLOPS STABILITY <br />The Division believes it is necessary for the applicant to demonstrate, <br />prior to excavation, through a slope stability analysis, that a factor of <br />safety of 2.0 or greater can be achieved for the initial 1:1 cutslope south <br />of the Atchison, Topeka, and Santa Fe Railroad. An alternative to the <br />stability analysis requirement would be for the applicant to notify the <br />Railroad Company of their plane to create a 1:1 slope up to 65 feet deep <br />approximately 200 feet from the rails and to receive their concurrence. <br />Please address. <br />1~ 9. RECLAMATION COST <br />The reclamation costs presented are for a maximum allowable disturbance of <br />113.2 acres. However, the mine plan specifies mining in 7 phases, with <br />each phase 170-200 acres in size. Ultimately there will be a total of <br />1302.3 acres mined. <br />The Division will allow the applicant to bond for the maximum disturbance <br />expected in each phase of mining, plus reclamation of the 41.5 acre <br />processing and rail spur area. <br />