REV102492 - Laserfiche WebLink

Home Browse Search

• • Banks and Gesso, LLC the limestone until the sandstone is encountered. Subsequent blasting should effectively remove the overlying limestone, leaving the sandstone layer intact. This sequence has worked successfully at the Queens Canyon Quarry. Some excavation and backfill may be required near the top of the remaining sandstone, to improve the ability of the topsoil application to remain in place. Should any unforeseen problems arise with mining through the sandstone formation, another section of 60 degree slope in the underlying granite may be required to correct this situation, prior to backfilling and revegetating the slope in this area. Minino Methods The Applicant proposes to mine the additional property using drill and blast quarrying techniques. The material excavated in the Pikes Peak granite and Saguache sandstone will be used predominantly for reclamation fill material, whereas the limestone will continue to be processed and sold as commercial aggregates. All remaining limestone is within the current permitted area. Typical mining benches and reclaimed slopes are illustrated in Exhibit C-3. Earthmoving Operations Initial access roads will be "pioneered" to the top with bulldozers. Earthmoving operations will begin near the top of the proposed mining area, by removing trees, shrubs and other vegetation. The minimal topsoil existing on these slopes will be stripped and stockpiled with the grubbed vegetation on the west side of the mined areas for future reclamation. Weathered granite materials will be stripped by ripping and dozing with bulldozers, until competent materials requiring blasting are encountered. These stripped materials will be pushed northward from each ridge to allow construction of better access roads for haul trucks. The sloped high-walls, which will be designated as "cliffs" hereafter, will be constructed by pre-split drilling and blasting the granite in the ridges at the western edge of the mining area. The slope of the cliffs will be 60 degrees from the horizontal, as recommended in the rock mechanics report. The cliffs will be pre-split for each 30 foot (vertical) bench, with a small horizontal offset (approximately 1-5 feet) between cliff faces. The production drill holes for the subsequent bench below the cliffs toe will be terminated prior to penetrating the 60 degree projection line (indicated in Exhibit C-4), so that the backbreak will not undercut the toe of the cliff. Prior to the excavation of the next lower bench, the slope will be roughly graded to a 1.5H:1V slope with granite materials to the base of the cliff. Topsoil materials will be pushed up this slope with a bulldozer, resulting in a layer approximately one to two feet thick, ready for subsequent seeding and revegetation. Typical bench configurations, drilling and slope backfill details are shown Exhibit C-3. Pikeview quarry • Construction Material g 20006.WD Regular 112 Permit Amendment September 22, 2000 Castle Concrete Co.