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WMU D-99 Construction September 1999 Forward Landfill Job No.986011.02 4.0 EARTHWORKS CONSTRUCTION During the construction of the WMU D-99, Eastern Ash Pit Closure, and the Class II Leachate Impoundment composite liner systems, Guinn personnel performed earthworks construction on several components. As this construction was implemented, Vector performed CQA monitoring. The elements monitored by Vector and discussed within this section include: excavation/fill and subgrade foundation preparation, clay liner soils processing, clay liner placement, LCRS granular drainage material placement, and placement of the operations layer. 4.1 Earthworks Preconstruction Meeting An earthworks preconstruction meeting among Forward, Inc., Lewis Engineering, Guinn, and Vector was conducted at the site on May 7, 1999. The main issues discussed during the meeting consisted of communications, site safety, submittals, clarification of materials used, and work schedule. The minutes of the earthwork preconstruction meeting are presented in Appendix D. .2 Excavation/Fill and Sub rade Foundation Preparation Excavation and subgrade preparation was accomplished by utilizing excavators (CAT 320L and 325), CAT 633 and 623 scrapers, dozers (CAT D4, D6R and D8), a CAT 140G Motor Grader, water trucks, and a smooth drum roller. As the material was excavated, Vector's CQA Monitor observed the material being removed and assisted the Contractor in determination of the material type and subsequently the appropriate stockpile. Minimal excavation was needed during this construction. Most of the activities during excavation/fill operations were finish grading to the design grades and placement of foundation material from the stockpile area on the slopes. Foundation fill, consisting of on-site silty-sandy soils, was placed by Forward to a minimum thickness 5 feet over the WMU D-99 Extension. Site personnel also placed the foundation materials for the Ash Pit closure. As the fill was being placed, density tests were performed by Vector's CQA Monitor. The method for the density testing was the nuclear density gauge. The results of these tests were reported directly to Forward and were available for review. The nuclear density tests were within the specified Vector Engineering, Inc. - 12438 Loma Rica Dr.,#C - Grass Valley, CA- (530)272-2448 -6-