Challenge of building storage dome at Detour Lake met by Greatario

By Gregory Reynolds

The challenge was immense, build a covered dome under time constraints in the Northern Ontario wilderness 185 km northeast of the Town of Cochrane.

The client was Detour Gold Corporation and the storage dome was to be a key part of the $1.5 billion Detour Lake Gold Mine.

Greatario Engineered Storage Systems, based in Innerkip Ontario, has been designing and building storage systems for municipal and industrial markets since 1986. Leading edge technology, engineering support and sound construction methods, along with innovative designs and expertise, have allowed Greatario to become one of the largest field erected tank builders in Canada.

It knew it could do the Detour Lake Project but first it had to win the contract.

Detour Gold continually strives to go above and beyond the existing health and safety and environmental standards of the mining industry. Constructing a covered structure for its operation to house a conveyor needed to be done in a safe, environmentally responsible, timely and cost effective manner. The company’s requests were threefold: first, to ensure worker safety by minimizing the amount of dust created by the stockpile; second, to minimize the release of dust into the environment and third, to manage the amount of material awaiting transport to the mine’s ore processing facility.

In early 2011, Greatario Engineered Storage Systems president Scott Burn responded to a bid request by Detour Gold for its stockpile containment solution. As part of the bid process, Burn met with BBA’s structural engineers, Detour Gold’s engineering team, AMEC, Greatario and CST Covers met to discuss the specifications of the bid.

By partnering with its parent company, CST Covers, Greatario was able to offer a customized ‘turnkey’ containment solution for the mine.

Following review of the proposal and site visits to other CST bulk storage domes, Detour Gold felt confident that Greatario could handle the project.

Greatario assumed the role of general contractor and installer of the dome with CST Covers providing engineering, and manufacturing and supply of the dome.

Construction began in July 2012. Burn and construction manager Ken Connell met with AMEC project manager, BBA structural engineers, and a CST consultant to determine final construction methods and time frames.

“Detour Gold had a very specific timeline for us to complete our portion of their project,” Connell recalls. A typical design-build would be ‘tower build technology’ in which a tower is built 150 feet high and the dome is built from the inside-out, in which inner frames and poles are constructed and raised by a pole crane.

However, as the existing conveyor eliminated the opportunity to use the tower build technology, an outside-in cover construction method was used. The outside frames and panels were constructed on the walls of the structure.

The frames and panels were then constructed inward until the dome was complete. Man lifts and cranes were used as the dome rings were completed. The construction team built one complete ring at a time and then moved up to the next ring. A total of 25 rings were assembled.

In total, 3,363 beams were constructed to slide into aluminum gussets to form the structure. Greatario’s construction team built the dome as deliveries from CST Covers arrived on site. As the prefabricated beams slid easily into aluminum gussets and held securely, the assembly process required no welding of the dome itself. This was a huge advantage.

This precise assembly process allowed the construction team to assemble the dome during different weather conditions. The finished frame was then clad with aluminum sheets. Over 2,240 sheets were installed.

In November, the stockpile containment structure was completed. It is a dome 97.5m in diameter and 52m in height – the largest dome that Greatario has built and the largest aluminum geodesic dome in Canada.

The dome is designed to withstand snow loads and wind speeds typical for the Far North. Material is transported from the dome to the mine’s ore processing plant via an existing underground tunnel.

Burn is very proud of the successful design-build project his team has completed.

“It is by far the largest dome we have built. While we had our challenges along the way, we were able to develop solutions and move forward. The workmanship and ambition put forth by our team of project managers, consultants and building crew is obvious when you look at the completed dome. It is impressive.”