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EGG ,MAR 25 <br /> GREGG DRILLING, LLC o'v'Eim' Ae/9 <br /> SPECIALIZING IN ENVIRONMENTAL, GEOTECHNICAL AND IN-SITU TESTING MFA <br /> March 25, 2019 <br /> Lor Xiong <br /> San Joaquin County Environmental <br /> Health Department <br /> 1868 E Hazelton Ave. <br /> Stockton, CA 95205 <br /> LXion.gC@_SJCHED.com <br /> 209-468-2807 <br /> Dear Mr. Xiong: <br /> On January 14-30, 2019 Gregg Drilling, LLC installed extraction well EW-18B at the Simplot <br /> site in Lathrop, permit number WP0039124 dated December 2018. When we started <br /> developing it we discovered that the screen had somehow been compromised and gravel pack <br /> was coming into the well. The well currently has 10 feet of sand in the bottom. Gregg Drilling, <br /> LLC proposes to destroy the well in accordance with the California Well Standards and Section <br /> 6 of the San Joaquin County (SJC) Well Standards and drill a new well adjacent to the existing <br /> one (20'-25', actual location to be determined by Geosyntec). For the abandonment we <br /> propose the following: <br /> Air knife around the casing to 3' below ground surface and cut the casing (SJC Well <br /> Standards 6.3.6). <br /> Set a temporary conductor into the excavation. <br /> Mud up and flush the sand out of the well and clear obstructions that might interfere with <br /> effective sealing procedures (SJC Well Standards 6.3.1). <br /> Perforate the section of casing above the screen with a Pneumatic Perforator (tool Spec <br /> sheet and instructions attached) to approximately 16 feet above the screen (SJC well <br /> Standards 6.3.3). <br /> Fill the well with neat cement grout from the bottom of the well to 5' below the ground surface <br /> and apply 25 psi of pressure for 5 minutes, remove the pressure apparatus and create a <br /> mushroom cap (SJC Well Standards 6.3.2 and 6.3.4). <br /> Backfill the remainder of the excavation with native soil (SJC Well Standards 6.3.6). <br /> Over drilling the well is not recommended for the following reasons: <br /> SOUTHERN CALIFORNIA: 2726 WALNUT AVE, SIGNAL HILL, CA 90755(562)427-6899 FAX(562)427-3314 <br /> NORTHERN CALIFORNIA:950 HOWE ROAD, MARTINEZ, CA 94553 (925)313-5800 FAX(925) 313-0302 <br /> www.greggdrilling.com <br />