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<br />Revised 1 August 1994 <br />Initial work will consist of improvements (if necessary) to perimeter 4-strand barbed wire fencing, <br />erection of six foot chain link fencing around some or all of the plant areas, topsoil stripping and <br />stockpiling, plant construction, and Phase One area dewatering trench excavation. Topsoil berms will <br />be concentrated along County Road 20.5 and along the southern end of the eastern site boundary to <br />minimize the visual impacts of the operation. <br />Dewatering trench excavation will be performed with an excavator down to the top of or up to several <br />feet into the underlying clay shale bedrock. Trench sidewalls in bedrock will be excavated <br />approximately vertical. The trenches will he constructed to develop flow to discharge locations and <br />minimize evaporative losses. Ground water will drain from the alluvial sand and gravel, collect in the <br />trenches and be discharged to Boulder Creek under an NPDES discharge permit as shown on Figure <br />D-1. Dewatering trench flow will provide the source water far processing. Additional information <br />related to dry mining via dewatering trenches is included in Exhibit G -Water Information (Chapter <br />VIII). <br />Mining excavation will be performed by loaders and/or scrapers at temporary excavation slopes of 1:1 <br />(H:V). As mining progresses from the southeast towards the west and north, field conveyors, hoppers <br />and transfer points will be utilized to provide in-pit loading locations and conveyance to the gravel <br />plant area. No stockpiling is proposed within the 100-year floodway. Other possible equipment will <br />include a dozer and an excavator, and miscellaneous support vehicles. <br />A wash water pond will be established at the north end of the gravel plant area which will be filled <br />from [he dewatering trench. The plant will discharge wash water to an in-pit sedimentation pond <br />which will discharge clear water hack to the dewatering trench. Concrete and asphalt hatching will he <br />done on site and is anticipated to constitute the primary disposition of [he processed sand and gravel <br />(approximately 60 percen[). Concrete and asphalt, and to a lesser extent sand and gravel, will be <br />hauled from the site east on County Road 20.5 to Rinn. Trucks will then head north on County Road <br />7 to State Highway 119 to connect to destination roads. Hauling west on County Road 20.5 will be <br />limited to local deliveries within approximately five miles of the operation to the west and southwest <br />where County Road 20.5 west provides a more direct route. <br />RP07917.198 Al - 5 <br />K°A <br />