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SWMU B-33 Closure Report

Section 2 - Closure Activities

SWMU B‑33 consists of pipe bedding material that contained spent projectiles from the Building 90 weapons testing operations. As explained in Section 1, some of this material was excavated and disposed of in 1997; however, some contaminated material remained near the foundation of Building 45. Based on the RFI sampling results, excavation and disposal of the remaining waste material and confirmation sampling was required.

2.1 - Excavation and Disposal

Excavation of the remaining contaminated bedding material at SWMU B‑33 was conducted on March 6 and 8, 2004. To complete the excavation, the buried water line was shut down and the power line to Building 45 was turned off for worker safety. The power and water were restored after excavation, sampling, and back-filling activities were completed. Excavation was initially conducted with a backhoe, then hand shovels were used to excavate around the power and water lines.

A total of 18 cubic yards of material were removed. Excavated material was stockpiled onsite so the material could be characterized for disposal. Waste was disposed under waste profile CG‑25591, C‑17. Manifests are provided in Appendix A. Toxicity characteristic leaching procedure (TCLP) results from the stockpiled waste indicated the material met non-hazardous Class 2 criteria and the waste was disposed of at Covel Gardens in San Antonio, Texas. The following photographs show excavation activities at the site.

Start of Excavation at SWMU B-33. 1997

Start of Excavation at SWMU B-33. March 6, 2004

Hand excavation at SWMU B-33. March 6, 2004

Clean sidewalls of excavation at SWMU B-33. March 6, 2004

2.1 - Confirmation Sampling

Confirmation sampling was conducted March 6, 2004 for the excavated portion of SWMU B‑33 near Building 45. A total of five samples were collected. One sample was collected from the bottom of the excavated area (B33‑BOT01), and four samples were collected from the sidewalls of the excavated area (B33‑SW01 through B33‑SW04). Sample locations are shown in Figure B33-8.

Each closure sample was analyzed for barium, chromium, copper, nickel, zinc (by method SW6010B), cadmium (by method SW7131A), and lead (by method SW7421) by APPL Laboratory in Fresno, California. The metals sampling suite was determined by the RFI results. All results were below RRS1 criteria and are presented in Table B33‑2 (Table B33-1 summarizes RFI sampling results and is presented in the SWMU B-33 RFI Report).

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