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permeable due to siltation. If a sheen is detected in either the pit, sediment pond or the trenches, a <br />petroleum absorbent "pig" will be placed around all pump intakes. Trench #1 will have an <br />adjustable metal gate spillway set at a desired elevation so that water above this elevation will enter <br />Trench #2. In this manner, high water levels in the trenches will always be maintained to try to keep <br />the contaminated plume to the north of the site. This arrangement will probably result in more <br />inflow into the pit, which will require more pumping, however, it is seen as the best solution to <br />ensure that the contaminated plume does not migrate south into the permit area. <br />The sediment pond will utilize a pump that will allow water to flow in an overland discharge pipe <br />to the Colorado River as shown on Map C-2. FMM has a NPDES permit to discharge pit water at <br />this location and significant monitoring requirements accompany this discharge. This permit is <br />included in Appendix D. A rip rap apron of approximately 8' x 10' in size utilizing minimum size of <br />12" riprap will be installed at the request of the landowner so that this discharge does not erode the <br />bank. The landowner, State Division of Parks and Recreation, has also included a letter stating that <br />they desire for this rip rap apron to remain after mining to provide a logical place for them to direct <br />discharge to the river and also to protect against erosion in the north branch of the river. This letter <br />is included in appendix A. A v-shaped spillway will be installed from the pond back to the pit as a <br />safety measure in case the automatic sensor fails. The bottom of the v-ditch will be at the level of <br />3.Ofeet, or 1.0 feet below the top of the sediment pond. <br />Once the sediment pond is functioning properly, [he mining of Phase 1 can begin. As described <br />eailier, all overburden will have been already stripped and permanently placed in the staging area. <br />Operations within the pit area will be limited to the hours of 6:00 A.M. to 7:00 P.M. Monday <br />through Saturday and will occur intermittently throughout any given year. Once the overburden is <br />placed on the staging area, a portable truck scale, scale house, portable crushing and screen plant <br />and portable asphalt plant will be brought to the site and setup in the staging area. <br />Mining will be done by dozers, front end loaders or excavators within the pit and a ramp will be <br />maintained to the staging area for the equipment. Mining will occur from the south to the northeast. <br />The mined pit slope will be 1.OH:1.OV although this slope will be later backfilled with overburden <br />Gilsonite Pi[ 1/04 12 <br />