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• Mr. Ross Atkinson September 3, 2002 Interim Construction Certification Letter,WMU-D02 Construction Page 2 subgrade, placement of the compacted clay liner, installation of the geosynthetic clay liner (GCL), HDPE geomembrane placement, geotextile and gecomposite installation, and placement of the LCRS granular drainage layer and protective layer. During installation, Vector provided continuous inspection of all liner and LCRS components with a staff of one quality assurance monitor and a registered CQA Manager. Documentation of all field activities was maintained throughout the course of construction. After the completion of the excavation, the Contractor placed and compacted 24-inches of the clay liner on the floor of the cell. In-place density tests were performed and approved by Vector's CQA Monitor. The method for the density testing was the nuclear density gauge. In addition to the field density tests, conformance tests on the clay liner were performed. These tests included modified Proctor, Atterberg limits, sieve analysis, and laboratory hydraulic conductivity. The results of these tests were reported directly to the Contractor and were available for review. The nuclear density and conformance tests were all within the specified requirements. No area of the clay liner was accepted until all of the required properties were observed by Vector's CQA Monitor and the grades verified by the surveyor. Vector's Monitor observed the smooth rolling and preparation of the subgrade on the west slope and the clay on the floor and advised the Contractor of areas where ridges or rough areas were present so that these areas could be reworked. When the subgrade and clay preparation was completed, Vector and the liner installer walked the area and an Acceptance of Surface Condition form was signed. After approval of the subgrade and clay, GCL was placed over the prepared subgrade on the west slope and HDPE was placed over the prepared clay liner on the floor. Prior to delivery to the site, the geosynthetic materials were tested at the manufacturing plant and the third party geosynthetics laboratory. As the rolls were delivered to the site, they were logged in and covered. After approval of the testing data, the 60-mil HDPE geomembrane and GCL were then placed. All HDPE geomembrane rolls and GCL rolls tested met the requirements set forth in the specifications. As each roll of GCL was placed on the west sideslope, Vector's CQA Monitor recorded the date, time, wind conditions, panel number, and roll number on a panel deployment log. In addition, our Monitor inspected the overlap to ensure proper installation. HDPE was deployed on the sideslope concurrently with the GCL deployment. As each HDPE panel was placed, Vector's CQA Monitor recorded the date, time, temperature, wind conditions, panel number, roll number, thickness, and location on a panel deployment log. Prior to any seaming activities, at the beginning of each day and once during the middle of the shift, a test seam (start-up trial weld test)was prepared for each of the wedge and extrusion welders used for that shift. The Contractor's seaming technicians prepared a test specimen and marked the sample with the machine number, machine temperature, date, time, and their name. Vector performed shear and peel tests in accordance with ASTM D-6392. If the start-up weld sample failed to meet the project specifications, the welding technician and the liner installation supervisor were notified and advised to take corrective action or place the machine out of service. No welding machine \\Vector-gv\Projects\Forward\021605.00-Fwd WMU D02 CQA\Certification Letter.doc T7ECTOR ENGINEERING,INC.