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4.4 Description of Facilities 4.4.1 Plant - The processing plant (Plant) is located south of the quarry. The Plant consists of the aggregate processing plant and the settling ponds. Figure 3 shows details of the Plant, Office, and Vehicle Maintenance Shop. a .I The aggregate processing plant consists of wash screens and drums, crushers, and vibrating screens for size-separation of the aggregate. The processing plant is surrounded by processed sand and gravel products which are available for sale. Makeup water for the processing of aggregate is provided by a groundwater well and by storm water retained and pumped during the storm season. Makeup water is captured and pumped to a series of settling ponds. The water is pumped from the set- tling ponds and is recycled through the system. The settling process involves pumping the water into an initial settling pond. The water then flows, via pipeline, into a secondary holding ' pond. The water is then pumped back into the Plant. 4.4.2 Office And Vehicle Maintenance Shop - The office and vehicle maintenance shop shown in Figure 3 , includes the truck loading area, scales, offices, shop and equipment wash area. The area is generally flat with a slight slope to the east. The vehicle maintenance shop is an enclosed work area. The equipment ' wash area comprises a concrete pad adjacent to the shop. Storm water coming into contact with the wash area is directed towards g+. the sand and grease trap which is part of the wash area system. F � 4.4.3 The Water System - The aggregate plant uses approx- imately three million gallons of water per day. The scrubber receives 4000 gallons of water per minute (gpm) to remove the clay from the sand and gravel. After the sand and gravel are discharged to the screen, another 2000 gpm of water is applied for a final rinse. The discharge from both of these operations t is sent to a primary settling pond where flocculating agents are applied to settle most of the fines, i.e. clay and silts. The water is then pumped into a secondary settling pond (make-up water pond) located southwest of the plant. This pond has been expanded from a farm reservoir and subdivided into two sections by an earthen dike. The process water drains from the southern section of the pond into the northern reservoir where it is then pumped back to the plant. Little additional water is required for the process plant because all water is recycled and the fines that settle out of the process water form a natural liner for the pond. When addi- tional water is required, such as during summer months when evaporation rates are high, the make-up pond is augmented 'by the production well. This well, as described in the groundwater section, is drilled to a depth of 700 feet and is capable of pumping more than 1000 gpm. Supplemental water requirements during the summer months are typically 10% of total process needs or 300, 000 gallons/day. i KRC Aggregate, Inc. - 3 - April 1, 1994