PERMFILE49223 - Laserfiche WebLink

Home Browse Search

ExH~eir D MINING PLAN Rub 3C32Si°1- B.~A (a) Extraction of the rock shall be by pattern drilling and shooting the monolithic sandstone bed to specified rough size, then sorted and piled by a tracked bulldozer to rip rap (over-size) and crusher-sized piles. A wheeled front-loader shall be used to load the crusher intake hopper, and to place piles of sorted rip rap in stockpile. Crushed and screened (sized) rock and reject-fines will be conveyed to stockpiles by means of belted conveyors and stackers and sometimes by front-loader. Processing and stockpiling of aggregate products will be performed both within the pre-existing quarry excavation and initially on the un-mined area to the west of the pre-quazry. (e) Minimal soils cover the beginning east portions of the mining azea. What soils can be dozed shall be piled against the east boundary of the initial area to be extracted. Grassy and woody vegetation and shall be included in any stripped soils. Earthwork is relatively minimal due to the very shallow soils at the east side of the site. Western portions of the extraction areas, which are to be mined later, bear deeper soils, up to 4 feet deep, which when stripped by front-loader for each area's extraction of the underlying sandstone, shall be stockpiled or spread in the completely excavated portions of the extraction area that aze already mined- out. Portions of that stripped soil shall be used to spread over mined-out portions of the quarry floor for reclamation plant growth media. Sufficient soil shall be retained in stockpile to reclaim eventually mined- out portions of the West-Side extraction area. (<) Plateau Creek borders the east side of the permitted azea. A usually-dry small west-to-east tributary arroyo borders the north boundary of the extraction area, and separates two portions of the reclaimed pre-existing quarry. Another southwest-to-northeast normally-dry tributary branch of that tributary divides the easterly and westerly portions of the current extraction area. There will be no disturbance of the W-E tributary channel except the culvert & earth-fill crossing into the pit for access road. The SW-NE tributary channel will be [eft unmolested until the easterly portion of the extraction azea is entirely mined out. As mining extends across the SW-NE tributary channel its streambed shall be lowered considerably at a time when there is no nznoff and the channel is dry. A spill-down constructed of "rip rap" shall be placed at the upstream (southwest) limit of the lowered-channel azea. No operations will be conducted within an actively discharging drainage channel. An unaffected small livestock-water pond lies upstream to the southwest, at 750 feet outside of the permitted azea. (a Areas to be extracted by drilling and shooting, known as "shots", shall be approximately two-thirds of an acre, or roughly 150 feet by 200 feet. Drilling depths for each shot azea shall be in approximately 25-foot deep benches to the base elevation of the worked out floor (approx elevation 7,550 MSL) of the "pre- quarry" at the north end of the East-Side extraction azea. (e) (i) c ~ The initial extraction "Shot 1 "will extend the pre-quarry to the east extraction boundary, a 25-foot remnant "berm" that will separate the extraction azea from the natural steep west side-wall of the bordering Plateau Creek gorge. Highwall heights shall increase from the initial 15 to 20-foot depths in the northeast part of the mine, to about 65 feet deep at the south boundary. A 10 to 15-foot wide bench shall be left in the neaz-vertical highwalls for approximately every 25 vertical feet of extraction. Each extraction explosive shot will employ a workable vertical face of approximately 200 feet long and 150 feet wide which shall be `drilled and shot' in up to 25-foot vertical feet deep into the caprock (to approximately the base floor elevation of the pre-quarry). Following processing of the first shot east of the pre-quarry, successive shots (with processing) back into the caprock to the south and west permit boundazies will follow with the typical three-quarter acre size shots. The final shots at the property boundazies shall be drilled to incorporate a roughly quarter-to-one ((/.-H : 1-~ final backwall, between 10-15- foot wide horizontal benches for each 25-foot depth of slope, for astaggered-bench backwail effect. Overall backwall slope will be about a 57% slope, from rim to toe. -73- LS/1P86 DMG 111 AppL