COMPLIANCE INFO - Laserfiche WebLink

Home Browse Search

during drilling activities will be containerized for proper disposal. An estimate of the grout volume to destroy each well using the drill out method is included in Table 1. Ground Zero recommends drilling out twenty-five (25) wells including monitoring wells MW-4, MW-5, MW-6, MW-8, MW-9, MW-11, MW-12, MW-109, GP-1 through GP-3, OW-1 through OW-3 and injection wells 1W-1 through 1W-11. Pressure Grout Ground Zero recommends using the pressure grout method to destroy the following wells: MW-1 and MW-2 Due to the lack of groundwater or soil contamination noted in these wells during the UST investigation work, Ground Zero recommends using the pressure grout method to destroy these wells. MW-3, MW-7, MW-10 and MW-13 These wells have reported random, trace concentrations of various constituents of concern, however soil data collected during the installation of these wells was reported to be non-detect for all constituents of concern. Ground Zero recommends using the pressure grout method to destroy these wells. Groundwater analytical data for the shallow and deep groundwater monitoring wells are included in Table 2 and Table 3 of Attachment C, respectively. The soil analytical data is included in Table 4. Wells will be destroyed by pressure grouting based on the San Joaquin County and California State Well Standards. Each well will be tagged for total depth to insure there are no obstructions within the well casing. A neat cement grout (containing less than 4% bentonite) will be pumped under pressure through a tremie pipe to the bottom of the well. After the groundwater has been removed and the grout has been filled to the top of the well casing, a pressure cap will be fitted to the casing and the well pressurized to 25 psi. If the grout settles, additional grout will be pumped into the well casing. This assures grout is pumped into the filter pack. Following grouting, at least the top three (3) feet of the well will be drilled out with an auger that is at least one (1) foot larger in diameter than the auger originally used to install the well. In addition, the soil around the cut-off casing will be removed to a depth of an additional six (6) inches below the top of the cut-off casing. Upon filling the rest of the casing, grout sealant will be allowed to spill out of the top of the well casing to form a mushroom cap seal, with at least six (6) inches of grout both below and above the casing. All soil will be properly containerized for disposal. All groundwater displaced to the surface during grout installation will be pumped out of the excavation and containerized for proper disposal. Ground Zero recommends pressure grouting six (6) wells including monitoring wells MW-1, MW-2, MW-3, MW-7, MW-10 and MW-13. The estimated volume of grout required to destroy each well by the pressure grout method is summarized in Table 1. The grout calculations are included in Attachment D. Page 2 of 3