PARROT TAILINGS WASTE REMOVAL PROJECT

Butte, Montana

The Parrot tailings are remnants of the historic Parrot Smelter that operated in Butte, Montana along the banks of Silver Bow Creek in the late 1800’s/early 1900’s. Tailings, slag, and miscellaneous mine waste were left in place after smelter shutdown, serving as a major source of contamination to both groundwater and surface water resources, including Silver Bow Creek. As the lead firm supporting the Montana Department of Justice, Natural Resource Damage Program (NRDP), WET aided NRDP in evaluating remedial design options and developing recommendations for the preferred alternative. This effort included evaluation of multiple options for excavation, hauling, and disposal. Following NRDP remedy selection, the WET team (in coordination with its engineering team partner and with input from other project stakeholders) developed the remedial design, design specifications, and a construction bid package for implementation of the remedial design to remove contaminated media at the Parrot Site. WET assisted in the bidding and contractor selection process. Once a contractor was selected, the WET team was responsible for providing construction oversight and construction quality assurance for the excavation of approximately 1,350,000 cubic yards of material, including 550,000 yards of contaminated tailings and clay and 100,000 yards of slag. WET also supported NRDP during negotiations with other project stakeholders by working through extensive site access requirements, ensuring staff members received the proper access clearance and training for both railroads right of ways and an active mine site. In this role, WET developed an integrated project management and technical work plan that included:

• • Remedial design/design specifications
  • Contractor bid package
  • Remedial action work plan
  • Waste management and disposal plan
  • Field sampling plan
  • Quality assurance project plan (QAPP)
  • Health and safety plan
  • Excavation plan
  • Dewatering plan
  • Traffic control plan
  • Resource loaded project schedule

As part of our comprehensive support of NRDP, WET senior technical staff provided technical reviews of prospective general contractor bids for adherence to the statement of work contained in the bid package, and the specific remedial design elements and provided input on adherence and deficiencies of the prospective bidders to NRDP. The project required coordination with multiple federal, state, and local agencies, PRPs, private companies including two railroad corporations, and Montana Resources. Our support extended to the preparation of deliverables, meeting materials, and providing senior staff to participate in presentations and public meetings, as well as interactions with stakeholders and other regulatory agency representatives throughout project planning and implementation. This included weekly meetings with representatives from Montana Resources, Burlington Northern Railroad, and leaders and operation staff from the Butte Silver Bow Government. Throughout construction, WET provided daily field X-Ray Fluorescence (XRF) sampling and analysis to verify compliance with construction plans and the QAPP. This included analysis of thousands of daily samples which were used to direct solid media for proper placement or disposal. Samples from truckloads of excavated media exceeding soil screening levels, were directed to the waste repository for disposal. Samples from loads exhibiting concentrations below the screening levels were retained for backfill. Confirmation samples were also collected on a pre-designated frequency and were submitted to the contract laboratory for analysis to ensure field XRF screening was providing adequate results to direct the remediation. The first phase of the project was successfully completed in December of 2018 on schedule and under budget with no lost time accidents or injuries. The second phase of the project was substantially completed in November of 2022 also with no lost time accidents or injuries. Site restoration / reseeding will be complete in the summer of 2023.