87-4375 - Laserfiche WebLink

Home Browse Search

s � . r DESCRIPTION OF SAMPLING AND SAMPLE HANDLING PROC }L} j. . ., L1r1 Auger flights are hollow-stem types with an inside diameter of 3. 25 inches and an outside diameter of 8 .0 inches . Individual auger flights are five feet in length. Soil samples will be collected at five foot intervals. A retractable plug prevents soil from entering into the auger flights during the boring pro- cess . The plug, 1which is inserted or retrieved by a wireline, is at the end of a 140 pound drive hammer. When a target depth is reached, a Modified California Sampler is placed at the bottom of the hammer and lowered by wireline to the bottom of the boring. The sampler is then driven into the soil by repeatedly raising and dropping thelhammer 30 inches until the sampler has been advanced 12 inches. This driving action forces relatively undisturbed soil into the sampler barrel. Details of the com- ponents of the Modified California Sampler are described below. Following the driving operation, the hammer and sampler are retrieved from tYe boring and separated; soil is removed from the sampler and prepared for shipment to an analytical laboratory. The Modified California Sampler consists of an outer sampler barrel and an inner, thin-walled set of rings. As soil is forced into the sample barrel by the driving action described above, a soil sample is collected in the inner rings . For this applica- tion, two 6-inch long by 2.5-inch diameter brass rings will be used. After retrieval from the boring and subsequent detachment from the hammer, #the sampler is dismantled and the inner rings I containing the soil sampler are removed. The lower ring is sealed by covering the ends with aluminum foil , placing plastic f caps on each tube end, and securing the caps with duct tape . jr Each sample is hien labeled and placed in an ice chest for cold storage for shipment to an analytical laboratory. t To avoid cross-contamination between samples and boreholes , the Modified California Sampler and the brass ring inserts are cleaned before each use. The sampling equipment is washed with an aqueous solution of trisodium phosphate, rinsed with potable water and distilled water and allowed to air dry. Each soil sampleicollected will be analyzed for possible hydro- carbon contamination by use of an organic vapor meter (Gastechtor model 1314 ) . A portion of the sample is placed in a sealable ( ziplock) plastic bag. After the bag has been sealed for a mini- j mum of 5 minutes 'the sample is "sniffed" and the meter readings (parts per million) recorded on the boring log. The model 1314 CM-9 Gastechtor-Hydrocarbon Surveyor is a battery-powered instrument that can detect and indicate concentrations of combustible gas or vapor in air in the parts per million range. Samples under test are drawn continuously by means of a built-in pump and analyzed for combustible gas on a heated catalytic platinum element. This r instrument will respond to at least 23 different gases including various petroleum products . Results of the Gastechtor are given in parts per million and are used only as a qualitative field measure of potential soil contamination. HYDROTECH CONSULTANTS. INC.