Post-Closure Inspection Report for Corrective Action Unit 424: Area 3 Landfill Complexes Tonopah Test Range, Nevada Calendar Year 2001; TOPICAL

Corrective Action Unit (CAU) 424, the Area 3 Landfill Complexes at Tonopah Test Range, consists of eight Corrective Action Sites (CASs), seven of which are landfill cells that were closed previously by capping. (The eighth CAS, A3-7, was not used as a landfill site and was closed without taking any corrective action.) Figure 1 shows the general location of the landfill cells. Figure 2 shows in more detail the location of the eight landfill cells. CAU 424 closure activities included removing small volumes of soil containing petroleum hydrocarbons, repairing cell covers that were cracked or had subsided, and installing above-grade and at-grade monuments marking the comers of the landfill cells. Post-closure monitoring requirements for CAU 424 are detailed in Section 5.0, Post-Closure Inspection Plan, contained in the Closure Report for Corrective Action Unit 424: Area 3 Landfill Complexes, Tonopah Test Range, Nevada, report number DOE/NV-283, July 1999. The Closure Report (CR) was approved by the Nevada Division of Environmental Protection (NDEP) in July 1999. The CR includes compaction and permeability results of soils that cap the seven landfill cells. As stated in Section 5.0 of the NDEP-approved CR, post-closure monitoring at CAU 424 consists of the following: (1) Site inspections conducted twice a year to evaluate the condition of the unit. (2) Verification that landfill markers and warning signs are in-place, intact, and readable. (3) Notice of any subsidence, erosion, unauthorized use, or deficiencies that may compromise the integrity of the landfill covers. (4) Remedy of any deficiencies within 90 days of discovery. (5) Preparation and submittal of an annual report. Site inspections were conducted on May 16, 2001, and November 6, 2001. The inspections were preformed after the NDEP approval of the CR. This report includes copies of the inspection checklist, photographs, recommendations, and conclusions. The Post-Closure Inspection Checklists are found in Attachment A, a copy of the field notes is found in Attachment B, and copies of the inspection photographs are found in Attachment C