Laserfiche WebLink
Backfilling the Pit and Final Slope Configuration <br /> At the conclusion of mining,the quarry will consist of a series of benches and highwall slopes. As stated <br /> above,the overall gradient of the benches and walls will be 0.5H:1.OV. <br /> When the last of the mining stage ceases, only a third of the pit floor will require backfilling. The last <br /> overburden will be pushed into the pit from the stockpile area above, or moved by scraper or <br /> truck/loader teams into the pit. Approximately 12 inches of overburden or more will remain on the <br /> benches. On the floor, it will be compacted and shaped. <br /> During each stage of the pit development, once the overburden is in place,topsoil will be placed on the <br /> benches and pit floor. Topsoil will be placed on the benches by loader. Topsoil will be placed on the pit <br /> floor by truck/loader teams and spread by dozer. Please refer to Exhibit E for the topsoil depths. <br /> Topsoil will be spread on the finished benches so that they can be revegetated. It will be placed about 6 <br /> to 12 inches deep on the benches and pit floor. <br /> Nearby Structures and Setback Distances <br /> Overhead powerlines, owned by Sangre de Cristo Electric Assn,extend east to west, 200 feet north of <br /> the northern boundary of the 112c permit. The nearest edge of the easement they are in is 150 feet <br /> outside the permit boundary. The only mining activity to occur along the northern boundary is <br /> stockpiling of overburden. This activity will be 200 feet or more away from the structures, and there is <br /> no opportunity for any damage to occur as a result of any mining or reclamation activity on the site. <br /> A house owned by Danny Ray Cherry is located within 200 feet of the 112c eastern permit boundary, but <br /> the affected area boundary will be 200 feet from the house. The specific onsite activity that is nearest <br /> to the house will be stockpiling of overburden in the first year of mining,then removing the overburden <br /> during later years while final reclamation is being carried out. Again,there is no opportunity for mining <br /> activity to damage Mr. Cherry's house. <br /> No county roads or other structures are known to exist within 200 feet of the proposed permit <br /> boundary. <br /> Equipment Used on the Site <br /> All the various types of equipment presently in use on the site will be used in the proposed new plan, <br /> though there may be more pieces of equipment. Moving large volumes of overburden, during the short <br /> pre-mining stage over these distances, may require teams of trucks and loaders or scrapers. <br /> Blasting will be carried out to break the obsidian for excavation, processing and removal. An explosive <br /> storage area will be designated in or near the pit area (see conceptual location on Exhibit C maps). A <br /> detailed blasting plan is included in this exhibit. <br /> Fuel and lubricants will be present on the site, but stored and handled in designated locations,with <br /> adequate secondary containment, and appropriate spill containment equipment on hand. <br /> Water in the Pit <br /> It has been noted during past operations that some water is often impounded in the existing quarry, <br /> since the material is impermeable. It has been observed that there is no aquifer in the obsidian deposit; <br /> rather, impounded water is the result of collection of precipitation and upland runoff. After <br /> precipitation events,the pit must be dewatered. It is expected that this will continue to be the case, <br />