Mammoet is helping Ledcor with the construction of the largest potash mine in Canada.
Production at BHP’s new Jansen potash mine is in Saskatchewan, about 140 km east of Saskatoon, is expected to begin in mid-2027. Once the mine is fully ramped up, Jansen will become one of the world’s largest potash mines, producing about 8.5 million tonnes per year.
The key scope for Mammoet was to remove the lower section of an existing headframe unit and replace it with a larger one to increase mining capacity. A mine’s headframe is positioned above the shaft, delivering people, equipment and materials below and above ground.
Mammoet also assisted with the complex lifting of a staircase tower module from inside the building where it was to be installed.
With Jansen’s remote location, modular construction techniques enabled the units to be prefabricated, delivered, assembled on site and installed efficiently.
Mammoet’s heavy lifting and transport expertise enabled the approach and limited the amount of construction equipment and operators on site. This enabled parts of both components to be built in parallel, shortening the project schedule relative to other methods.
Planning
The project had been in planning for several years. Mammoet began work at the site in 2013, when the original headframe unit was constructed.
The modules for the new headframe were prefabricated at specialist facilities in the Edmonton and other locations in Alberta.
The parts were transported to site on platform trailers fitted with transport beams. This phase wasn’t without its challenges.
“Jansen is mainly farmland, so you will often see agricultural equipment and machinery being transported on its roads, but shipping these large modules presented issues when staging our trucks overnight,” said Mike de Wilde, Project Manager at Mammoet. “We couldn’t just pull into a normal layby because the trucks would fill the entire area. The schedule had to be carefully planned and managed.”
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During the planning phase, ground conditions were an important consideration. During the spring, the ground becomes soft and wet, so the team performed a ground-loading test between the laydown area and the mine shaft.
Self-Propelled Modular Transporters (SPMTs) carrying counterweights tested the route so that areas of potential sinking could be identified. As a result, more than 400 crane mats were mobilized because the ground was too soft.
Near the shaft opening, a section of ground also required reinforcement to support the weight of the new headframe module. A shoring system, constructed of 21-metre towers, was constructed at a basement level to provide stability.
Due to the size of Mammoet’s global fleet, extra steel supports could be mobilized from its yards in Dubai and the United Kingdom, reducing overall risk, despite the tough conditions.
The real heavy lifting
With the modules on site, the team began removing the existing headframe and prepared for the installation.
A 22-axle line and 20-axle line SPMT combination, both fitted with steel supports, were driven underneath the 796-tonne headframe module. The supports were necessary as using crane mats would have exceeded the ground-bearing pressure limits.
The SPMTs lifted the headframe using their onboard stroke, allowing Ledcor and BHP teams to remove the temporary steel supports. Then, the unit was driven to a laydown area.
Before the new headframe could be installed, Mammoet helped install a 60-tonne staircase tower inside it.
A Liebherr LR1300 crawler crane lifted in strand jacks and other equipment through an opening at the top of the building. The team then assembled the intricate winch system to lift the staircase tower.
The system comprised strand jacks and spools to secure the 61-metres of cable required to pull the staircase tower module from the bottom to the top of the building.
The removal of the original headframe left a large opening at the base of the building, providing enough space to manoeuvrer the staircase module in range of the strand jacks and LR1500 crawler crane.
Once the unit was inside the building, its position was manually adjusted using pullies and chain hoists so it could be secured and lifted.
Overcoming obstacles
The last phase of the project was the installation of the new headframe, which weighed 2,090 tonnes, an almost 1,300-tonne increase from the previous headframe.
A configuration of two double SPMT trains, with a combined 80 axle lines, were used for the movement. Finding the best configuration proved the biggest challenge.
“We had to find a trailer configuration where we could carry the additional weight, be under the permissible ground-bearing pressure, plus be short enough to not clash with the existing structure,” de Wilde said.
Making this installation even more difficult was the fact that a section of the new headframe had to dock inside the staircase tower building.
“We were pretty much stroked out with the SPMTs, so it was a very tight fit,” de Wilde said.
“We had to align the head frame precisely with bolt positions specified in the engineering plans. Ledcor arranged for guidance lasers to be set up at the end of the platform, and our SPMTs had to align with them perfectly.
“Because every deviation could cause serious problems when it came to setting the module down, it was a very precise manoeuvrer.”
The project is an example of Mammoet’s skill when it comes to modular construction and efficient fabrication-to-foundation solutions. The option to use fabrication facilities and deliver everything to site was a benefit in terms of schedule and cost-efficiency.
A great deal of specialized engineering went into making sure everything arrived on schedule and was connected smoothly
