Laserfiche WebLink
24 July 2012 <br /> AGE-NC Project No. 10-1801 <br /> Page 3 of 5• <br /> As required by SJCEHD permitting, a health and safety plan will be prepared in <br /> accordance with Occupational Safety and Health Guidance Manual for Hazardous Waste <br /> Site Activities (National Institute for Occupational Safety and Health Administration, U.S. <br /> Coast Guard and U.S. Environmental Protection Agency, 1985). Prior to drilling activities, <br /> the work area will be clearly marked and an utility clearance obtained through Underground <br /> Service Alert (USA). <br /> 3.1. MONITORING/EXTRACTION WELL OVER-DRILLING <br /> In accordance with an EHD directive letter dated 13 July 2012, AGE is proposing to <br /> remove monitoring wells MW-313, MW-3C, MW-413, MW-4C, MW-613, MW-6C, MW-713, <br /> MW-813, MW-20B and extraction wells EW-813 and EW-913 by removing all material within <br /> each borehole utilizing industry standard drilling-out techniques (Table 1; Figure 2). Each <br /> well will be destroyed in accordance with Section 13.17 of the San Joaquin County Public <br /> Health Services Environmental Health Division Well Standards. <br /> Over-drilling will be performed by All Well Abandonment(AWA) utilizing a CME-75 mobile <br /> drill rig and equipped with either 8'/4-inch or 10'/4-inch hollow stem augers; hollow stem <br /> auger diameters will be selected based on the original borehole size diameter (Table 1). <br /> Initially, AWA will utilize a cable pulley on the CME-75 mobile drill rig to remove each <br /> bolted traffic well box, thereby exposing the top of each polyvinyl chloride (PVC) well <br /> casing.Thereafter,a stainless steel drill-rod will be inserted down the total depth of the well <br /> casing to keep the augers centralized during over-drilling, and the borehole will be <br /> completely over-drilled to the total depth of each well utilizing hollow stem augers. Upon <br /> reaching the bottom of each well, the well casings will be removed from the over-drilled <br /> borehole and visually inspected by a representative of the SJCEHD. Following inspection, <br /> all well casings and soil cuttings will be containerized in a 10-yard soil bin and temporally <br /> stored at the Flag City Shell site for future disposal to a Class II landfill (i.e. Forward <br /> Landfill). <br /> Following well casing removal, the total depth of each over-drilled boring will be verified by <br /> tape measure. Thereafter, the excavated boring will be completely back filled (to surface <br /> grade) with a cement grout mixture (portland type ll) in accordance with San Joaquin <br /> County Well Standards (Section 13.12.5). The grout mixture will consist of a ratio of three <br /> gallons water for every 50-pound sack of portland type II cement. The drill rig hollow stem <br /> augers will be utilized as a tremie pipe during deployment of the grout mixture. For each <br /> well destruction, a grout inspection will be scheduled with the SJCEHD. <br /> Advanced GeoEnvironmental,Inc. <br />