ARCHIVED REPORTS XR0012869 - Laserfiche WebLink

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on site This permit was for 400,000 gallons of discharge into the sanitary sewer The bottom of the excavation was ten feet below the groundwater surface Submersible pumps were installed to remove groundwater from the excavation before backfilling • BACKFILLING THE EXCAVATION The bottom 18 feet of the excavation was backfilled with material from the commercial source owned by Bob Allen The source is located on Peltier Road near Lodi, California The low permeability soil from the Allen source was delivered to the site by end-dump trucks The imported backfill material was placed in the excavation with a Cat 966 rubber tired wheel loader Water was added for compaction Soil compaction was completed by a Cat 815B steel wheel compactor in six inch layers Kleinflder and Associates of Stockton, California was assigned the duties of project Geotectnical testing for both the soil compaction and soil moisture The top 14 feet of the excavation was backfilled with imported material from the Port of Stockton dredge sand spoil source This material source was a pervious silty sand This source was tested for both hydrocarbons and heavy metals at the request of the PHS/EBD All test results were non-detect for the required substance The silty sand material from the Port of Stockton source was conditioned and processed in the same manner as the material from the Allen Source and compacted in six inch lifts All compaction test samples meet the required 95% of ASTM 1557 method using the nuclear field test method All backfilling of the excavated area was completed to the finish sub-grade on November 1, 1995 REPLACING UTILITIES . During the excavation of the contaminated soils all the original utilities on the site were destroyed and could not be salvaged The sanitary sewer that serviced the shop was removed during excavation and was replaced in like and kind Steel telecommunication conduits that were in place before excavation were replaced with new schedule 40 conduits A new surface drain was installed to drain the area originally occupied by the concrete equipment loading ramp SURFACING OF THE EXCAVATED AREA Aggregate Base was placed on the prepared subgrade to a depth of 6" and compacted with a Cat single drum vibrating roller Reinforcing bars for the concrete paving were placed at three inches above finish subgrade and secured to concrete dobbies Number five dowels were drilled into the existing concrete adjacent slab The concrete paving was placed in two pours The south half the area was completed first A water cure was used for all concrete placement Two inch contraction Joints were placed on twenty foot centers - REPLACING MONITORING WELLS Spectrum Exploration replaced monitoring wells MW1 and MW5 removed during excavation The wells were drilled to a depth of 45 feet from the surface All work was under the direction of the PHS/EHD Due to the low permeability of the original soil and the backfill material, percolation of water into the wells is slow PROFILE OF THE EXCAVATED AND STOCKPILED SOILS On December 7, 1995 stockpile profile samples were taken under the direction of the author from • a eight point grid established on top of the stockpile of excavated soils A total of eight samples from gnd lines A,B, and C were extracted from a depth of six to ten feet A hand driven sampler was used to fill BX sample tubes All samples taken from each lettered gnd line were combined by Sherwood 3