Case Study

Rail Site Restoration and Remediation (CAN)

A large rail car release of perchloroethylene (PCE) solvent occurred at the client’s facility in the 1990’s.  Despite early clean-up programs, lingering Dense Non-Aqueous Phase Liquids (DNAPL) were still present near the historic spill area, possibly transferring impacts across the property line.

SLR was retained by the client to execute the first major phase of a MOE-approved Remedial Action Plan (RAP):  Excavation and Clay Wall Installation to address the immediate property line issue.

Location:

Canada

Sector:

Industry

Project Objectives:

The main objective of the program was to excavate soils along the property line and replace them with imported, impermeable, compacted clayey backfill to limit groundwater flow and the potential movement of free product off site.

The targeted excavation zone limits spanned 110 m long to a depth of 7 m below ground surface, where native soils were observed to be less fractured (over 17,000 tonnes).  Management of existing pumping wells and infrastructure within the excavation footprint, including three hydro poles, was required.

Our Role

  • SLR provided design and contract document preparation, full-time excavation and backfill supervision, documentation soil-sampling, site perimeter air monitoring, water treatment system monitoring, health and safety support,  subcontractor invoice approvals and final reporting
  • excavation design, clay backfill specifications and fill source approval
  • tendering  of the subcontractor documents and approvals from off-site property and hydro-electric utility owners
  • maintaining existing pumping wells and infrastructure (hydro poles no-dig zones and stability)
  • SLR was also responsible for daily site operations documentation and reporting, subcontractor billing and unit rate disposal tracking.