Featured Project

Hamilton, ON
Key Services
  • Dredge and Dewatering
  • Water Treatment

The Randle Reef Sediment Remediation Project Stage 2 was to dredge 400,000 m3 of contaminated sediments and place them in an Engineered Containment Facility (ECF), treat and dewater the ECF contaminated water prior to placement of fill materials, and isolation capping and thin layer capping of remaining contaminated sediment over some of the work area. 

Milestone completed this project within a Joint Venture with FRPD. Located in the southwest corner of Hamilton Harbour, in the Port of Hamilton, the Randle Reef site is roughly 60 hectares in size. 

The site contains approximately 695,000 cubic metres of sediment contaminated with polycyclic aromatic hydrocarbons (PAH) and other toxic chemicals – the largest PAH-contaminated sediment site on the Canadian Great Lakes. The dredging of the contaminated sediment was completed using a cutter suction dredge that removes material from the lakebed and transports it as a slurry through a pipeline to the ECF. As the slurry containing contaminated sediments was pumped into the ECF, the solids were allowed to settle out, and then the water was pumped mechanically to an upland water treatment plant where it was treated, tested, and discharged back into the harbour. The water treatment system involved removal of total suspended solids and treatment of PAH and metals impacted water. 

Key Challenges
  • Operating within a bustling harbour environment with ongoing commercial marine traffic and the presence of public pleasure craft. 
  • Navigating precise dredging and water treatment requirements. 
Key Solutions
  • Implementation of Milestone’s specialized scheduling and operational procedures to effectively navigate the complexities of working in a high-traffic harbor. This included the establishment and management of robust environment, health, and safety controls.  
  • Utilization of hydraulic suction dredging techniques for the careful removal and placement of contaminated sediments within an Environmental Control Facility (ECF).  
  • Conducting a second pass dredging process to ensure thorough and comprehensive sediment removal.  
  • Designing, constructing, and operating a water treatment plant dedicated to the dewatering of materials within the ECF.  
  • Implementation of measures for turbidity and sheen mitigation and control to minimize environmental impact. 

Project Scope

  • Mechanical debris removal. 
  • Metal works and welding for the pump platform and overflow structure on the ECF. 
  • Construction and installation of the underliner drainage pipe and risers in the ECF. 
  • Rock backfilling of the ECF between the anchor wall and face wall. 
  • Isolation capping of stelco channel. 
  • Thin layer capping and thin layer backfilling. 
  • Maintenance of staging pad. 

For more information about Randle Reef click here. 

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