FIELD DOCUMENTS - Laserfiche WebLink

Home Browse Search

01 May 2002 AGE-NC Project No. 01-0875 Page 2 of 6 3.0. SCOPE OF WORK The scope of work included removal of oil/water separator, over-excavation of the pit area, advancement of two soil borings, backfilling of excavation cavity, and disposal of soil stockpile. 4.0. PROCEDURES On 16 January 2002, with the approval of Mr. Li, the oil/water separator was removed and the immediate area over-excavated to a depth of 10 feet below surface grade(bsg).In addition,two soil borings were advanced in the immediate vicinity of the oil/water separator on 06 March 2002, after field observations during the over-excavation indicated that hydrocarbon-impacted soil was still present at the north side of the excavation. The field work was conducted as outlined in the AGE- prepared,Phase 11 Site Assessment Work Plan dated 04 February 2002. 4.1. EXCAVATION ACTIVITIES Separator removal and over-excavation of impacted soil was performed by Mr. Jim Cornell of Valued Engineering. The oil/water separator was cut into multiple pieces for disposal, and the surrounding cement was cut to enlarge the pit area. A 5-foot by 7-foot width by 10-foot deep excavation was made utilizing a backhoe. During the over-excavation,it was determined that the depth of impacted soil was greater than first anticipated. At the north end of the excavation, a small area(3-feet long by 5-feet wide)of grayish soil remained at the floor of the excavation; a noticeable petroleum-hydrocarbon-like odor from the soil suggests that the soil may be hydrocarbon-stained (Figure 2). After this discovery, a determination was made by the on-site AGE geologist to stop work for additional site investigation; excavated soil was stockpiled on site and cement was disposed of by Mr. Cornell. 4.2. ADVANCEMENT OF SOIL PROBE BORINGS Applicable permits were submitted to San Joaquin County Environmental Health Department (SJCEHD) for advancement of two soil borings. On 06 March 2002,AGE advanced two soil probe borings at the site using a van-mounted Geoprobe 5400 direct-push probing unit equipped with 1.25- inch probing rods.The Geoprobe advances soil probe borings using a hydraulic hammer to drive soil and ground water sampling tools to specified depths. Both probe borings were advanced to a total depth of 25 feet below surface grade(bsg). Probe boring P-1 was advanced just outside of the Advanced GeoEnvironmen[al,Inc.