WORK PLANS - Laserfiche WebLink

Home Browse Search

Geolo kaI redmirs lxr. � Page 3 Site Closure Plan 4 Project No. 750.2 August 11,2005 � I L concurred with SJCEHD's recommendations in a letter dated July 28, 2005. Both E correspondences are included in Appendix B. i In a letter dated August 3, 2005, SJCEHD requested a� work plan for destruction of all groundwater monitoring and remediation wells at the ii site. The following work plan addresses the destruction of all wells associated with the COE site. 2.0 WELL ABANDONMENT . i f There are five (5) water table, one (1) deep monitoring and four (4) vapor extraction wells associated with the COE site. GTI proposes properly decommissioning these wells in an effort to meet requirements leading to a "No Further Action Letter". All monitoring wells associated with the site have been monitored regularly' and are in good ,condition. No obstacles have been observed in any well. A summary of well construction:,Is included as Table 1 in Appendix A and well locations are denoted in Figure 2. A competent C-57 well driller (selected through bidding iprocess after workplan approval) will be employed to decommission the wells associated with the site. Permits will be secured as necessary and the local regulatory agency will be notified 48 hours prior to commencing work. i The wells will be divided into two categories: Category 1 Water table and deep monitoring wells'including: MW-1, MW-2, MW-3, MW-4,MW-5 and MW-101. * Category 2 Vapor extraction wells including: VEW-1, VEW-2, VEW-3 and VEW-4.. E � Category 1 Wells: These wells will be filled with grout via a tremie pipe followed by pressurizing the grout filled wells. Approximately 35 psi of pressure will be applied to each well:for up to five i minutes. The pressure cap will be removed and the process will be repeated if there is more than three feet of headspace above the grout slurry.. The upper five feet of the borehole will then be drilled out using 8-inch hollow stem augers guided down the center of the well casing via a guide rod attachment on the drill bit. The upper five feet will be backfilled with clean material. The surface will be capped with the appropriate material (i.e. rock or asphalt) to match the surrounding surface conditions. r Special Conditions y MW-3 is located in the median along Escalon Avenue. Encroachment permits will need to be secured and both a north and a southbound lane will be closed during well abandonment L (approximately 3 hours). GTI proposes the following procedure to abandon MW-3:; Tim �h �� I