Laserfiche WebLink
action that were carried out immediately. Corrective action included addition/reduction ofslurry <br />• added to backfill material and adjustments to the mixing operations. <br />Visual inspection of excavated soils and bedrock were extensively conducted during trenching to <br />detect when adequate bedrock was encountered. As the trenching progressed, the depth of the <br />• trench was periodically checked to determine if the bedrock key trench depth was maintained and <br />• not filling with sediment or other material. Depth monitoring confirmed that athree-foot key into <br />approved bedrock was maintained (Appendix B). <br />Comparison of quality control requirements to the field testing and observations indicate that the <br />project requirements were adequately met. Adjustments were made when required by test results <br />and visual inspections. <br />DISCUSSION <br />General <br />i• <br />Slurry wall construction began in early Apri12007 and was completed in mid-June 2007. <br />Construction was delayed temporarily on occasion due to equipment maintenance, material <br />supplies, or logistics. Field adjustments to the slurry wall alignment were made when necessary. <br />The alignment was adjusted at both corners along the south boundary of the site, as well as the <br />northwest corner. These adjustments were made to accommodate existing obstructions such as <br />power poles, fences, and irrigations ditches. The alignment adjustments were minor and are shown <br />on the as-built drawing. The slurry wall as-built alignment is shown on Plate 1. <br />Station Change <br />Shortly after construction began, the slurry wall alignment was adjusted. The alignment was shifted <br />closer to the property line to maximize the mining area. Excavation of the slurry wall began at <br />station 49+30. Adjusting the stationing to account for the new and longer alignment would have <br />caused a discrepancy in the end station at the completion of the wall. To avoid this discrepancy the <br />stationing was changed to 100+00 at the southwest corner of the site. <br />Desandin~ Operations <br />The desanding equipment consisted of a submersible pump, tank reservoir, and screened shaker <br />mounted to a reinforced steel sled with a diesel generator attached. The equipment used was <br />specifically manufactured for use in cleaning sand from the trench bottom and reducing the volume <br />of sand suspended in the slurry. The desander was estimated to have been in operation for <br />approximately 95 percent of the slurry wall construction. <br />Backfill uality <br />Backfill quality was maintained within acceptable standards. Testing results are summarized in <br />Appendix A. <br />-4- <br />September 2007 <br />Aeit Construttion Report <br />L• <br />