WORK PLANS - Laserfiche WebLink

Home Browse Search

Geo(ogicaf?echnics inc. ti` Page 3 C&B Equipment Revised Work Plan Project No. 336.2 March 15,2000 Reference locations of wells in Figure 1 Site Map. The following work will be performed: • The well casings will be grouted with neat cement slurry installed by pumping grout under pressure (for estimated grout volumes see Table 1) and allowed to mushroom over the top of the casing. • The monitoring well's traffic rated well box will be removed and the well boring will be drilled out to four (4) feet. Reference the schematic drawing in Figure 2 of well destruction. • The excavation will be backfilled with clean fill material and capped with concrete finished flush to surface grade. This work will be scheduled in conjunction with the closure of the domestic well. 1.4 New Domestic Well Installation Prior to the closure of the old domestic well, a new domestic well will be installed and connected to the piping system for the shop and restroom. Based on soil test results that show contamination down to 25 feet using a photo ionization detector (PID), the San Joaquin County Public Health Service Environmental Safety Division (SJCPHSEHD) is requiring that an annular well seal be placed at 200 feet. Information from both the USGS publications (Figures 2 and 3) and Mr. Brian Hennings of Calwater Drilling suggests that the presence non-Corcoran clays above 200 feet and Corcoran clay below could be a problem for any well between 70 to greater than 300+ feet deep. This information is as follows: • Mr. Hennings reports that a test well dug at a location less than '/2 mile from the proposed site encountered non-Corcoran clay between depths of 67 and 202 feet, the maximum depth to which the well was drilled. • Geological Map 1 (Figure 2) indicates that the top of the Corcoran clay (E clay) is located at depths between 100 and 250 feet in this area. • Geological Map 2 (Figure 3) indicates that the thickness of the Corcoran clay in the proposed well area is between 80 and 100 feet. From this information,it appears that the bottom of the Corcoran clay should be encountered at a maximum depth of 350 feet. It is therefore recommended that the well be drilled to 400 feet deep. The well driller in evaluation of the water production capacity of the formation and water quality test results will determine the construction of the well and may alter its depth with the qualification that it may not be shallower than 200 feet as per SJCPHSEHD. Bids will be obtained from at least two well drilling firms and these costs will be included in the Cost Pre-Approval package prepared for the USTCFP. 2.0 SCHEDULE & REPORTING Geological Technics Inc. anticipates beginning field work in April 2000 following work plan approval, cost pre-approval from the USTCFP, and coordination of schedules. Dr. Ray Kablanow, a registered professional geologist responsible for the work, will supervise the