Featured Project

Peninsula Harbour Sediment Remediation

Marathon, ON
Key Services
  • Dredging and Dewatering

Milestone Environmental Contracting Inc. was awarded a contract to install a thin layer sand cap over a 23.4-hectare area of PCB, mercury and metals contaminated sediment within Peninsula Harbour, Marathon, ON. Funded by Environment Canada and the Ontario Ministry of the Environment, this first-of-its-kind project in Canada was undertaken to create clean habitat for plants and animals and to accelerate natural recovery within the aquatic environment. 

Key Challenges
  • Pioneering a project previously unprecedented in Canada with aggregate requirements for the capping material. 
  • Dealing with the remoteness of the project location on Lake Superior. 
  • Navigating seasonal weather patterns that could have impacted the project’s timeline and execution. 
Key Solutions
  • Collaborated closely with subcontractors and the consulting team to devise innovative technical strategies for the remediation process. 
  • Established an efficient staging area using a floating barge, streamlining equipment transportation to and from the site.  
  • Milestone implemented meticulous planning and adept logistical management to accommodate the limited timeframe imposed by seasonal weather conditions. 

Project Scope

  • The installation of a continuous 15 to 20 cm clean sand layer over 23.4 ha of PCB, PHC, and metals contaminated sediment.
  • The delivery of this project at the remote site on Lake Superior required mobilizing all equipment, material (>35,000 tonnes) and supplies by barge from staging areas in Lake Huron (Manitoulin Island) and Sault Ste. Marie.
  • Establish all environmental controls, including silt curtains and fencing.
  • Imported sand was installed from a spud barge, supplied by rotating material barges, using a RTK‐GPS tracking and control system. An initial 10,000 m2 test cell was completed followed by an extensive QA/QC testing program.
  • Once the installation and sampling method was proven and the installed sand cap thickness was verified, the remaining area was capped.
  • Throughout the installation of the sand cap, continuous turbidity monitoring was completed at various locations around the work area.

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