SITE INFORMATION AND CORRESPONDENCE

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N with the Well Construction Diagram, Plate 1. The screened portion of each well will have 0.020-inch machined slots, and will extend from the bottom of the well to approximately 5 feet above ground water or to a depth of 5 feet below ground surface (BGS), whichever depth is greater. Blank casing will be used for the remaining portion of the well. Lone Star Sand No. 2/16 will be placed in the annular space from the bottom of each well to about one foot above the screen. A one-foot thick bentonite seal will be placed above the top of the sand pack, and the remainder of the well annulus space will be completed with a cement-bentonite grout seal. The well casing will extend to within 6 inches BGS and will be fitted with waterproof locking caps. Each well will be protected by a traffic rated water-tight circular vault installed approximately flush with the ground surface. A permanent identifying marker will be placed on the underside of each vault lid. The wells will be developed by bailing and/or pumping at least 10 well volumes until the produced water becomes relatively clear. The tops of the monitoring wells will be surveyed by a licensed land surveyor to within 0.01 feet in elevation, referenced to mean sea level, and to within 0.1 feet in plan. Install TVMPs Selected borings will be developed into TVMPs. These TVMPs will extend into the contaminant plume and will be used to monitor the progress of bioremediation. The TVMPs will be fitted with 2-inch diameter, Schedule 40 PVC blank and slotted pipe in accordance with the Temporary Vapor Monitoring Point Diagram, Plate 2. The pipe will be centered in the boring by a rubber cup (plumber's helper) placed concave up at the end of the blank section at 3 feet BGS. The annulus around the blank pipe above the rubber cup will be filled with a cement- bentonite grout seal to 6 inches BGS to provide a seal against surface spills. The blank pipe will extend to within 3 inches BGS and will be fitted with a waterproof locking cap. The slotted pipe below the blank pipe and grout seal will extend to the bottom of the borings. Each probe will be protected by a traffic rated water-tight circular vault installed approximately flush with the ground surface. A permanent identifying marker will be placed on the underside of each vault lid. Removal of Free Product Free product accumulations greater than 1 inch will be removed by a bailer or peristaltic pump from the wells. Free product of lesser thickness will be removed by absorbent socks (SpilCAT"). The material in the socks absorbs only petroleum hydrocarbons, is hydrophobic, and reduces free product to an absence of sheen. Used socks will be stored and transported in DOT containers for recycling. Quarterly Sampling of Monitoring Wells To obtain background data, quarterly sampling of the monitoring wells will begin after free product has been removed and before inoculation of the subsurface takes place. Wells in which no free product is found will be pumped or bailed until 3 to 5 well volumes have been removed or until successive measurements of the parameters pH, temperature, and conductivity of the ground water have stabilized. We will pump the wells at a constant low flow rate, which we have found routinely December 15, 1994 Job No. 1278.02.01 - 3 -