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WMU D-99 Construction September 1999 Forward Landfill Job No.986011.02 of these tests are presented in Appendix G. Additionally, large-scale direct shear tests were performed at Vector's Grass Valley laboratory on the clay liner and geosynthetic interfaces. Results of the tests (adhesion and friction angle) indicated that the material met the design specifications. Large-scale direct shear test results are also included in Appendix G. 4.3.2 Clay Liner Placement A minimum 24-inch thick clay liner layer was placed on the floor of WMU D-99. The clay liner was placed in the lined area using CAT 623 and 633 scrapers; compaction of the liner soils was performed using a CAT 815 sheepsfoot compactor. The compactor made a minimum of 8 passes. As each lift was placed, Vector's CQA Monitor verified that the surface of the lift was scarified and not smooth to assure that no distinct layers developed within the clay liner. In-place density tests were performed by Vector's CQA Monitor during clay liner construction. The primary method for the density test was the nuclear density gauge while sand cone methods were used as necessary to check the gauge. The clay liner was placed at a minimum of 90 percent of the maximum dry density at plus two to five percent moisture content. Summaries of the nuclear field moisture/density testing and the sand cone testing are included in Appendix H. The clay liner was initially placed and compacted to a minimum 2-foot thickness and rough graded. Six soil core samples (120-S through 120-X)were collected during placement and compaction of the clay liner and tested for permeability in the laboratory. Falling head, rising tail water tests were performed in the laboratory according to the procedures outlined in ASTM D-5084. The permeability of these samples all met the specified value of 5x10$ cm/s or lower. Results of the laboratory permeability tests of the clay liner are presented in Appendix G. When the Contractor and CQA Monitor determined that the desired thickness and grade had been accomplished (see survey verification on Exhibits 2 and 3), the top of the compacted clay was fine graded using a motor grader and was prepared to a smooth finish using a smooth drum compactor. Vector Engineering, Inc. - 12438 Loma Rica Dr.,#C - Grass Valley, CA - (530)272-2448 -8-