pf_02570 - Laserfiche WebLink

Home

Independent School District #623 STS. Project #95 192- YF March 20. 1991 Page 2 ~~ TABLE 1 Tank Information Summary Tank No. Tank Age Tank Size (Gallons) Contents Task (1991) I 2 3 1951 1957 1957 10.000 10.000 3.000 Fuel Oil Fuel Oil Fuel Oil Soil borings Soil borings Remove Exploration Procedures Three soil borings were drillcd along the perimeter of one tank. Two soil borings were drilled along the perimeter of the second tank. Soil borings are identified on the boring logs as 8-6 through B-IO. The location of the two tanks is identified on the Tank Location Diagram (Figure 2). The drilling performed on the site was conducted on February 8. 1991. The soil borings were advanced with a 0-50 truck-mounted rotary drill rig using 3-1/4 inch hollow stem augers. Representative samples were obtained using the split-barrel sampling procedure in general conformance with ASTM Specification 0-1586. Boring B-6 was drilled to auger refusal due to unidentified plpmg at a depth of 6 feet below the ground surface. Borings B-7 and B-IO were drilled to 14 feet below the ground surface. Borings 8-8 and 8-9 were drilled to a depth of 16.5 feet below the ground sufi"ace. When completed. the soil borings were backfilled to the ground surface with a cement grout. Soil samples were classified by a field geologist in general accordance with the Unified Soil Classification System (USCS). Boring logs showing the soil types are included in this letter. The borings are identified as B-6. 8-7. B-8. 8-9 and B-IO on the Boring Location Diagram (Figure 3). An HNU photoionization detection (PID) meter calibrated to a benzene reference was utilized during the soil sampling procedure to screen soil samples for petroleum impacts in the soil borings. The HNU meter is a portable instrument used to detect and measure a variety of organic compounds in air as HNU units. The HNU meter screening procedures were conducted in gencral conformance with the Minnesota Pollution Control Agency (MPCA) "Jar Head Space Analytical Screening Procedure". ExplOl'ation Results The soils encountered in the borings were primarily sandy clays with a Unified soil classification designation of CL with silt seams designated as ML. Detailed soil descriptions at each of the boring locations is presented on the individual boring Jogs included with this letter.