CORRESPONDENCE_1990-1991 - Laserfiche WebLink

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San Joaquin Count q Y January 4, 1991 Page 2 ' Task 2. Install Probes and Monitor We will obtain a driller, procure materials delivery, and make field preparations in advance of the drilling date. We will plan to complete a minimum of four (4) borings in each day of drilling work with a total of 12 three level borings. Probes will be manufactured and installed as shown in the details supplied to EMCON by the county, with the modifications agreed to by the county. The county will determine the probe locations and submit a copy of the plan to EMCON for review prior to the site visit. A qualified EMCON geologist will log the borings, as required by the CIWMB and Title 14 regulations. EMCON staff will monitor the probes at the end of each drilling day and prior to leaving the site. EMCON staff will return one week later to monitor the probes a second time. Task 3. Probe Decommissioning Six existing probes specified by the county will be decommissioned by removing the PVC probe casing and drilling a bore hole to the necessary depth to remove the existing granular backfill. The bore hole will be backfilled with a grout of portland cement and bentonite. The decommissioning procedures will conform to county Health Department requirements. Any additional probes that require decommissioning can be done at a cost of $750 per probe, assuming the work will be continuous with Task 2, and that the drilling equipment is still available on- site. The cost for the decommissioning of probes beyond the initial six is not included in this scope of work. Task 4. Prepare Reports EMCON will prepare a technical report summarizing the probe installation procedures, the initial gas probe monitoring results, and will prepare a record drawing indicating probe locations, as surveyed by county staff. ASSUMPTIONS AND CONTINGENCIES EMCON assumes that San Joaquin County will provide sufficient background information to allow timely execution of probe installation, including accurate topographic base maps identifying all underground and overhead utility locations. The County will also provide access to the approved probe drilling sites prior to and during the work, and negotiate suitable easements from adjacent property owners, if required. We have assumed that drilling conditions will be in alluvial soils, as typically found in the Central Valley. If hard rock or other slow production drilling is unexpectedly encountered, the proposed probe locations may require revision, installation may be delayed, and costs may increase. Any required permit fees for well drilling are not included in this cost estimate and will be paid by the county. Precise coordinates and elevations for the installed probe locations will be surveyed by the Public Works Department and provided to EMCON for plotting on the final record drawing.