2002-07-25_REVISION - M1983208 - Laserfiche WebLink

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SNAVANO GRAVEL, EXxiBirD (eont/nued/ Worked-out areas of fmished excavation shall be graded smooth and utilized for stockpiling and processing operations during the remainder of the extraction and production operations. Acreage not needed for such operators shall be prepazed for industrial yazdsite post-permit use with revegetated revegetated sideslopes, per the Exhibit E Reclamation Plan", for release from the permt azea. [c] There aze no water impoundments and diversions other than limited surface rainfall runoff. That runoff shall be duetted to the lower elevations of the excavated gravel pit. The hydrologic balance shall remain unchanged at the site, since no ground water is to be encountered. The surface of the mesa top shall be lowered by 15 to 20 feet in the form of a lowered bench, which is to be `daylighted' to the north, northeast, and to the west in portions of the southwest perimeter. Surface moisture shall be retained for utilization in the re-vegetation effort by flat grading and 3-foot retainment berms incorporated into the bench crest. [d] Mining shall continually proceed at the full width and depth of the mesa-top resource deposits from the current highwall toward the southeast end of the permit area, with no particular "sequencing" or "mining units" prescribed. Excavation shall daylight out to the mesa downslope at the north, northeast, northwest, and portions of the southwest edge of the permit azea, except where prevented by proximity of the property boundary. The northeast, easterly, and southeast boundaries of the excavation shall terminate in athree-horizontal to one-vertical slope bank adjacent to the cemetary access road, cemetazy, and east wooded slope bank of the mesa. Pre-existing pit excavations and overburden stockpiles cover about 18 acres of the 51.48-acre proposed permit azea. Continued extension of mining to the southeast shall add about 23 %2 acres of gravel resource excavation. [e] Non phased operations shall resume in the former 112 permit azea excavation approximately in the winter or spring of the yeaz 2002 and proceed to exhaustion of the available gravel deposit resources at the site at a rate of approximately one acre per year. Completion of the remainder of the excavation to the southeast excavation limit is expected to take 15 or more yeazs depending upon needs of the County Road Department within the region. Mining shall proceed southeast in an exposed face approximately 400 feet wide, bordering atwenty-five foot setback at the cemetary and its access road at the northeast end, and the mesa downslope or property boundary at the southwest end. A sloped headwall face shall be maintained throughout the mining operation. [fJ Sand & gravel deposits to be mined are well rounded, well-graded, 10-inch-minus alluvial rock deposits lying in depths of fifteen, up to about twenty feet deep (t)(i), judging from excavated portions of the site. Test pits dug in un-mined portions of the site revealed gravel resource as deep as the backhoe could reach (16 feet). Clay, shale, and sandstone beds underlie the alluvial gravel deposits to be mined. (t)(ii). Gravel depths and the surface of their original deposition aze typically inconsistent. [g] Sand & gravel mined and processed is to be used as rock aggregate in local county road/ highway construction and maintenance projects. [h] The only incidental product is rock rip rap derived from the Dakota Sandstone beds encountered in the pit bottom at the west rim of the mesa. Some stockpiles of that material aze already stockpiled within the permit azea. [i] No explosives aze to be used in conjuction with any site operations. Temporazy stockpiling of gravel, sand, rock rip-rap, and topsoil are to occur concurrently with resource mining and screening/crushing production operations at the permited site. Operation of a hot asphalt mix plant, utilizing produced rock aggregate, shall also occur intermittantly on the site. 13