Keller, the world’s leader in geotechnical solutions, announces the completion of its first interlocking pipe pile (O-pile) system for Alamos Island Gold Mine in Dubreuilville, Ontario. 

Keller installs O-piles at the Alamos Gold Mine.

When the Gold Mine encountered unexpected ground conditions at the proposed site for their tailings dam expansion, a 40-metre (131-foot) long cut-off wall was required. Various solutions were considered but with several meters of thick sand and gravel till, cobbles, boulders underlaid by bedrock, and flowing water conditions, O-piles were chosen as the preferred solution.

Other benefits of using O-piles include rapid construction using a rotary percussive drilling process in a single pass and a watertight seal using mechanical interlocks. Like sheet piles, the O-pile system creates a cut-off wall and can be used for excavation support. However, while sheet piles would refuse to drive through rock and boulders, a down-the-hole hammer is used to advance the O-pile through these conditions.

Keller crews installed 68 O-piles with lengths varying from five metres (16.4 feet) to 11 metres (36.08 feet) as required. O-piles were 610 mm (two feet) in diameter.

“We were involved early on in the process to explain the pros and cons of several potential cut-off wall techniques.,” says Anojan Siva, project manager. “We were able to discuss and resolve anticipated constructability challenges, technical considerations, and address the time-sensitive requirements for this critical project.”

Overall, Ledcor and Alamos Gold, the client and owner respectively, were extremely pleased with the team’s professionalism and resourcefulness, and execution of the cut-off wall. During construction, Keller provided high caliber experienced personnel working six days a week for six weeks.

“We were able to provide a high-quality solution using a pile guide/template to ensure pile location and verticality, and performed a continuous inspection and monitoring of all activities,” Anojan said.

The project was completed on schedule and Keller has already planned future projects using O-pile technology. 

For more information on O-pile services offered by Keller, contact Business Development Manager Dan Maclean at 519-853-3216 or

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About Keller 
Keller was founded in 1860 and is the largest independent geotechnical contractor in the world with ongoing operations in over 40 countries across six continents. With a North American presence of over 100 years, Keller operates as the market leader with over 50 offices throughout the US and Canada.

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