SITE INFORMATION AND CORRESPONDENCE FILE 2

Home Browse Search

I� San Joaquin County oP" " ` " Environmental Health Department dtFe-eroR Donna Heran, REHS 1868 East Hazelton Avenue Stockton , California 95205-6232 PROGRAM cookorNAroas •, ? ' Robert McClellan, REHS _ Jeff CarrueSCo, REHS, RDI a`p. > WelaSide : WWWSJL�OV. OYG/ehr/ Kasey Foley, REHS C Foa Phone : 209 468-3420 Linda yEstr Estrada, ( � Rodney Estrada, REHS Fax : (209) 464-0 '138 Adrienne Ellsaesser, REHS September 18, 2014 Atlantic Richfield Company Volpi Family I LP Mr. Sergio Morescalchi C/O Nancee L. Volpi PO Box 1257 4719 Quail Lakes Dr. STE G # 336 San Ramon , CA 94583 Stockton , CA 95219 Subject: ARCO #2130 7906 N . EI Dorado Street Stockton, CA 95210 The San Joaquin County Environmental Health Department (EHD) has received and reviewed Well Destruction Work Plan, dated 6 August 2014, prepared and submitted by your consulting firm , Stantec Consulting Services, Inc. (Stantec) , on your behalf for the above-referenced site. In the work plan, Stantec proposes to destroy monitoring wells MW-7, MW-14, MW-19, and MW-21 by pressure grouting. For these four wells, Stantec proposes to fill the well and filter pack with neat cement through a tremie pipe from total depth to the top of the well casing , allow the grout to settle and then top off the grout before applying 25 pounds per square inch (psi) of pressure for ten minutes. After pressure grouting, the top 3 feet of the well boring will be cleared with an airknife, creating a hole at least one foot larger in diameter than the original auger used to install the well . The well casing is to be removed from 2 . 5 feet below ground surface (bgs) to grade and a grout sealant mushroom cap installed to 2 feet bgs. Stantec proposes to destroy an additional 15 wells by pressure grouting following the same methodology above; however, Stantec requested a variance to install a limited mushroom cap within the borehole diameter due to subsurface structure and/or utilities. This variance request was approved by Adrienne Ellsaesser, Program Coordinator. Stantec proposes to destroy 18 wells by over-drilling as follows: Air-knife approximately 6 feet 6 inches bgs around the borehole to a diameter of 110 percent to determine if underground facilities exist in the area to be drilled; ® Clear the top 3 feet of these wells to a diameter at least one foot larger than the original borehole diameter to allow for a mushroom cap; a Over-drill the wells to remove all original materials within the boreholes; The resulting boreholes backfilled from the bottom up to approximately 3 feet bgs with neat cement through a tremie pipe; Top off the grouted wells with a mushroom grout cap.