Laserfiche WebLink
March 16, 1988 <br />Roberts Oil Company <br />Page 7 <br />drilling, installation and sampling of additional ground water quality <br />monitoring wells. The additional assessment work will be required to <br />adequately define the intensity, the lateral and vertical extent, and the <br />migratory patterns of the contamination, in order to formulate an <br />appropriate and applicable remedial action plan for eliminating or abating <br />the contamination. <br />PHASE 2 <br />Task 4: Exl2loratory y. <br />Task 4 will consist of drilling additional soil sampling boreholes (up to 4) to <br />determine the horizontal and vertical extent of refined petroleum product <br />contamination in the underlying soil profile, in the vicinity of the transfer <br />block/loading area. Borehole drilling and sampling operations will be <br />conducted using a truck mounted drill rig and hollow stem auger. The auger <br />and other tools used in the borehole drilling and sampling operations will be <br />steam cleaned before use and between drilling and sampling subsequent <br />boreholes to minimize cross -contaminating borings. Sampling tubes will be <br />washed in a mixture of trisodium phosphate and clear water, rinsed in clear <br />water, and allowed to air dry prior to collecting subsequent soil samples <br />downhole. Each borehole will be continuously sampled using a standard split <br />tube sampler, for the purpose of describing the vertical variations in the soil <br />profile encountered. Soil samples for laboratory analyses will be collected <br />at five (5) foot intervals using a modified California split tube sampler with <br />internal brass liners. The borehole will be advanced to the desired sampling <br />depth and the modified California sampler will be lowered to the bottom of <br />the borehole. The sampler will then be advanced ahead of the auger string <br />using a 140 Ib. hammer. The sampler will then be removed from the borehole <br />and broken down into its component parts. The collected soil sample will <br />then be qualitatively screened for ambient total volatile hydrocarbons using <br />an HNU meter. If the HNU analysis indicates a high concentration of total <br />volatile hydrocarbons, the sample will be capped, labeled, logged on a chain <br />of custody form, and placed in a cooled ice chest for transport to a State of <br />