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fa3 ( i was drilled to 20 feet in an effort to recover or drill out the casing However, no evidence of casing was observed in the augers or on the flights The evacuated boring for former monitoring well MW-4 was grouted using tremae hose from bottom to 2 feet below grade with neat cement INSTALLATION OF GROUNDWATER MONITORING WELL In accordance with the "Workplan for Site Investigation" submitted to the PHS/EHD on August 11, 1995, Smith Environmental installed groundwater monitoring well MW-4R on August 21, 1995 to replace the abandoned groundwater monitoring well MW-4 The Iocation of well MW- 4R is illustrated on Figure 3 Drilling was conducted by Spectrum Exploration, Inc using a hollow stem auger drill rig The boring was advanced to approximately 18 feet below grade using eight-inch outside diameter continuous flight augers Drill cuttings and core samples were logged for characterization of contamination and soil type by an experienced geologist using the Unified Soil Classification System Descriptions of soils encountered and monitoring well construction details were recorded on the boring/well log presented in Attachment 1 Soil samples were collected at least every 5 feet Three soil samples were submitted to Argon Mobile Labs (Certification No 1873) of Modesto, California for analysis of benzene, toluene, ethylbenzene, and total xylenes (BTEX) using EPA Method 8020, and total petroleum hydrocarbons as gasoline (TPHg) and total petroleum hydrocarbons as diesel (TPHd) using modified EPA Method 8015 During drilling, soil encountered was monitored for organic vapors by placing a small amount of representative material in a sealed container, then measuring the concentration of volatiles collected in the head space of the container with a photoionization detector (PID) calibrated to the benzene molecule The values obtained at each measurement point were recorded on the boring logs No evidence of soil contamination was noted during drilling Soil cuttings generated during the drilling process were contained on-site in a DOT approved 55-gallon drum The soil boring was converted to a two-inch diameter groundwater monitoring well The well was constructed of two-inch diameter threaded PVC well screen and casing Screen slot size is 0 020-inch The sand pack material is #2112 prewashed silica sand The well casing was surged with a surge block prior to placement of the annular seal in order to ensure settling of the sandpack The well annulus above the sand pack was sealed with hydrated bentonite, in accordance with California Well Standards Due to the shallowness of the top of the well screen, 2 feet bgs, only a bentonite seal was installed in the annulus, per discussion with Michael Infurna of PHS/EHD prior to the well installation After installation, the monitoring well was developed on August 22, 1995 using a pump and surge method Development water was contained in a 55-gallon drum approved for hazardous �� N U5007512QR-1995 WP5 2