CORRESPONDENCE_1990-1991 - Laserfiche WebLink

Home Browse Search

a Emcon ASSOCIATES Consultants in Wastes November 1, 1991 Management and Project 939-01.09 Environmental Control Mr. Gabriel Karam, P.E. County of San Joaquin Department of Public Works 1810 East Hazelton Avenue Stockton, California 95201 Re: Decommissioning and installation of gas monitoring wells Dear Mr. Karam: EMCON Associates (EMCON) is pleased to submit this letter report on the decommissioning of single-level gas wells and the installation and sam- pling of tri-level soil-gas wells at San Joaquin County's Harney Lane Land- fill in Lodi, California (figure 1). The tri-level wells were installed to allow lateral migration of methane from the landfill to be detected, in compliance with closure/postclosure maintenance requirements contained in California Code of Regulations Title 14. This report describes the procedures used in well installation, decommissioning, and monitoring, and discusses the data obtained from the initial monitoring of the new wells. SOIL-GAS PROBE DECOMMISSIONING PROCEDURES EMCON decommissioned five existing gas wells (P-2, P-5, P-6, P-7, and P-10) at the Harney Lane Landfill on October 1111 -1991. Two other existin gas wells scheduled for decommissioning (P t and P-8) could -ndt b located. Both the existing and the proposed well locations were deter- mined by the County and are shown in figure 2. To decommission each well, the probe casing was first pulled from the ground. The original well boring site was then redrilled to a depth at which native soil, rather than well construction material, returned to the surface on the auger, indicating that the .bottom of the original boring had been reached. The borehole was then filled to the surface with a nine-sack concrete slurry. PJ9 9390109.GOW ,lingwood Avenue, San Jose, California 95131, (408)453-7300