ARCHIVED REPORTS XR0010495 - Laserfiche WebLink

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r� San Joaquin County EHD That report discussed the latest work done in January, 1994, and recommended that further assessment work was not necessary and the two sites should be closed. However, the County EHD did not concur, and recommended two (2) additional soil borings be placed in order to determine current levels of contamination that may still be in the soil. A copy of that letter, dated May 24, 1994, is ,included as EXHIBIT B. After reaching agreement upon the locations of the two auger holes, a workplan addendum was submitted on July 6, 1994, by WJH for complying with those instructions. Details of the work per- formed are discussed below. DETAILS OF LATEST WORK: On July 20, 1994, Wm. J. Hunter, RG, from Wm. J_ Hunter & Assoc_ arrived on location at 0800 and reviewed the workplan with Peter Voskes of Normac Inc. , & Don Light, geotechnici.an of Del-Tech- The locations of the two soil borings were measured from a known reference point, & marked with paint for identification purposes. An auger rig from Osterberg & Stewart Drilling Co. , Wally Maggert, driller, arrived at 0845, and was mobilized on Location "A" , on the Hammertown site The work was performed udder previously issued drilling permits #001425 & #001426. Refer to PLATE B for the location of that auger hole. Drilling equipment consisted of 5 foot lengths of clean, 8 1/4" OD, hollow stem auger flights; the bottom flight was equipped with a latching mechanism to hold a 30" core barrel which is lowered and retreived from the drilling assembly with a wireline. The core barrel holds 5, 6" long, 2 1/2" diameter clean brass tubes which allows continuous sampling if desired. Two coring assemblies were prepared; while one is in use, the other is emptied of tubes, decontaminated, & filled with fresh tubes for the next core Auger flights were advanced to 20 ' bgl, at which depth a core barrel filled with clean brass tubes was lowered in the drilling assembly with a wireline & latched into the bottom flight_ Drilling advanced from .20' to 22' 6" , at which point the core barrel was retrieved and laid on a clean, flat surface. A blank- ing plug was inserted into the assembly, and the augers were ad- vanced to 25' , at which point a second core barrel was inserted, and coring continued. The first core was carefully opened; recovery was recorded, lithology described, and a portion of the core was placed in a plastic bag, promptly sealed, and set aside for checking response with a PID meter. One tube was quickly sealed by covering the ends with teflon tape, plastic end caps & 3