Port Hope Canadian Nuclear Laboratory Project

In 2018, the Port Hope Area Initiative (PHAI) advanced a major environmental remediation program focused on the long-term management and containment of historic radioactive waste materials in Port Hope, Ontario. As part of this initiative, new containment infrastructure was required at the Port Hope nuclear storage facility and harbour area to prevent the migration of potentially contaminated groundwater and protect the surrounding environment.

Marathon Underground was engaged to complete specialized marine-based construction, sheet piling, and grout curtain installation works in support of the harbour wall containment system. The project required highly controlled execution within a regulated nuclear facility environment and presented several logistical and environmental challenges, including limited site access and construction over water.

The first phase of the project involved constructing wave attenuators to protect both the work area and marine construction crews during harbour operations. Because direct land access for heavy equipment was not available, all construction activities were completed using barges and marine-based drilling platforms. A pile-supported template system was installed to guide the placement of sheet piles for the attenuator structures before the assemblies were filled with waste rock to create stable protective barriers.

Following completion of the wave attenuation system, Marathon Underground advanced construction of a large-scale grout curtain designed to seal fractured rock formations beneath the harbour wall and minimize the risk of seepage from the containment area. The grout curtain design was developed by Marathon Underground’s in-house engineering team using experience gained from previous complex grouting and containment projects.

The completed grout curtain measured approximately 200 metres in length and 5 metres in width and required the installation of more than 1,000 drilled and grouted holes. Diamond drilling techniques were used to core the holes in five distinct rows, each installed with a slight batter angle to account for the potential presence of vertical rock fractures and improve grout coverage within the subsurface conditions.

Drilling and grouting operations were carefully sequenced to allow multiple crews to work simultaneously while maintaining production efficiency and strict quality control requirements. After every 20 metres of completed grout curtain installation, Marathon Underground’s engineering team conducted performance testing and evaluated grout hole spacing to further optimize the installation program and ensure effective subsurface sealing.

The Port Hope Canadian Nuclear Laboratories project demonstrated Marathon Underground’s ability to successfully execute highly specialized marine, grouting, and containment infrastructure projects within complex environmental and regulatory conditions. Through the combination of practical construction expertise and in-house engineering capabilities, Marathon Underground delivered the project safely, efficiently, and with minimal environmental impact.