SITE INFORMATION AND CORRESPONDENCE_1993-1996

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• Lincoln Center May 31 , 1996 Work Plan Page 3 If an off site agreement or encroachment permit is required, these must be submitted at the time of PHS/EHD drilling/destruction permit submittal. Once a drilling permit has been issued PHS/EHD requires a minimum of 48 hours notice prior to the initiation of the proposed field activities, so that an inspection may be scheduled. Volume I - Appendix B• Field Sampling Plan 2.21 Soil-Vapor Probe Installation and Sample Collection The work plan indicated that samples will be collected at 10 foot intervals, although the actual depths of the deep soil-vapor samples may be adjusted in order to collect samples from areas containing the highest relative concentrations of Hazardous Substances. The use of lithological information will be vital when evaluating sampling intervals to characterize the vapor concentrations of Hazardous Substances in the soil. Following the collection of deep soil-vapor samples, the boreholes must be grouted with an approved neat cement, an approved cement/bentonite grout, or an approved bentonite clay grout, using a tremmie pipe. 2.3.1 CPT Borings and 2.3.2 PIPP Borings and PIPP Groundwater Sampling Both CPT and PIPP borings must be grouted with an approved neat cement, an approved cement/bentonite grout, or an approved bentonite clay grout, using a tremmie pipe. 2.7 Groundwater Monitoring Well Installation Procedures The annular space above the bentonite seal of the sand pack must be sealed with an approved neat cement, an approved cement/bentonite grout, or an approved bentonite clay grout, using a tremmie pipe. 2.7.4.3 Pressure Grout Existing Monitoring Wells In Place Wells destroyed by pressure grouting are grouted first from the bottom up using the grout hose. Once the well is grouted, sufficient pressure shall be applied to ensure full grouting of the subsurface surrounding the well. PHS/EHD also recommends that the top 1 - 3 feet of casing be overdrilled and the borehole finished to grade with material consistent with site-surface conditions. 2.7.5 Fluid Level Measurements Monitoring Well Inspection Should a repair of a monitoring well seal be necessary, please also submit the repair plan to PHS/EHD for approval and/or permitting.