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PANCCHE BURN SITE REMEDIATION Sukut began preparing the retention dam area. Scrapers continued to use borrow material from the north plateau for foundation and barrier layers. An 8-ounce geotextile was placed between the foundation layer and barrier layer in the upper north canyon. After investigating the two lightly oil stained areas by the old check dam, a gravel lens con- taining pyrolytic oil was discovered. The CIWMB engineer directed Sukut to remove the oily gravel and place it over the ash in the designated fill area. As stained soil/gravel was removed, additional pyrolytic oil from the tire fire was discovered. A sample (GIS-1) of the oil stain was sent for analysis on November 13, 1996. Because the old check dam was removed while excavating the contaminated soil, Sukut constructed temporary earth embankments above the stained area to prevent rain and runoff from exiting the canyon. Week 9 - 11/18/96 through 11/22/96 Temporary drainage controls held over the weekend. Sukut continued to excavate and remove contaminated gravel. The oily material was placed in the designated fill area and covered with the foundation soil, geotextile, and the barrier layer. Additional lenses of pyrolytic oil were discovered. By November 19, 1996, approximately 3,000 cubic yards of oily material had been removed and placed in the upper canyon. Pyrolytic oil was observed seeping from the cut slope along the north face. The CIWMB and CH2M HILL engineers noted a strong odor emanating from the canyon bottom. The engineers assumed the odor was due to an aromatic hydrocarbon or naphthalene. On November 20, 1996, two additional samples (GIS-2 and GIS-3) of the oily material were collected and sent for analysis. Based on discussions with CH2M HILL and Sukut, the CIWMB engineer stopped work in this area until health and safety air monitoring was performed in the canyon. Air monitoring indicated the odor was not dangerous (i.e., no hydrocarbons or flammable levels were detected). The area was isolated to personnel wearing Level C protective clothing and respirator with organic filters. The CIWMB engineer met with the U.S. EPA to discuss the project and stained areas. After discussions and further field investigation, the CIWMB engineer notified the U.S. EPA that all pyrolytic oil could not be removed from the bottom of the canyon or the side slopes. Because the 40-foot vertical cut in the canyon could no longer be safely extended and the gravel lenses were propagating into the burn ash cell, an alternative containment was necessary. Rain delayed further work. The soils laboratory technician obtained three additional borrow samples to check the moisture content, grain size distribution, plasticity index, maximum density via optimum moisture determination, and permeability. Week 10- 11/25/96 through 11/29/96 Sukut continued removing and covering the ash and contaminated gravel. Construction of the new retention dam began. Scrapers moved soil from the northern plateau area to the middle of the canyon. Scrapers continued to compact the monolithic barrier layer by making a loaded pass over each previous lift. Lifts were placed from 6 to 8 inches. Geotextile rolls were CIWMB 14