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N PRFt iMINAfrY HVDROCEOLOCIC ASSESSMENT REPORT 1399 East Yooemite Avenue,Manteca,Cahromie Della Project No.50-88-980 Page 13 Samples of subsurface soils were obtained using a California-modified split-spoon sampler. Five samples were collected and examined from each of the four soil borings. Representative soil samples were collected in glass jars. Headspace gas measurements of total organic vapors were made with a PID. The PID readings are recorded on the soil boring logs presented in Appendix A. _., All drilling and sampling equipment w-s cleaned before drilling each boring using a high-pressure,steam- cleaning apparatus. The split-spoon sampler was cleaned with phosphate-free soap and rinsed with water following each sample collection. 6.7 soil Classification All soil samples were examined in the field by a geologist and described for color, grain size,moisture content,mineral content,and odor,and were classified in accordance with the Unified Soil Classification System. These soil descriptions are presented in the soil boring logs in Appendix A. 6.3 Well Construction and Development Monitoring wells MW-2 and MW-3 were constructed with flush-threaded,2-inch-inside-diameter,Schedule 40 PVC blank casing and 2-inch-inside-diameter,Schedule 40 PVC well screen with 0.010 inch well slots. Monitoring well locations are shown in Figure 2. Following the placement of the well casing and screen,a sand filter pack,extending from the bottom of the screen to about 2 feet above the top of the screen,was placed in the annular space between the well screen and the borehole. A 2-foot-thick bentonite seal was placed above the filter pack using bentonite pellets. The annular space above the bentonite was filled with a cement-bentonite grout which extended to the ground surface. �r Each well was fitted with a lockable water-tight cap and a steel protective-steel well cover. The monitoring construction details are presented in Appendix B. In order to remove natural aquifer fines and drill cuttings from the vicinity of the well screen, each monitoring well was developed by a dedicated hand pump. The dedicated hand pumps consist of a length of PVC tubing with a check value fixed to the lower end. The pump was inserted into the well within. "- 1 to 2 feet of total well depth. The tubing was raised and lowered at a rapid rate causing aquifer fines