In 2025, crews lifted a 3,100-tonne mining machine 2.5 metres off the ground and placed it on 140 SPMT axles; it traveled 27 km in 10 days

A dragline was never meant to be moved the way it was in August 2025. The machine was a 3,100-tonne Marion 8050 dragline operating at BHP Mitsubishi Alliance's (BMA) Peak Downs coal mine in central Queensland, according to Mammoet's own case study and trade coverage from Project Cargo Journal and World Coal. Normally, a dragline relocates by "walking": shoes or pontoons alternately lift and shuffle it forward. Mammoet's own case study says a dragline moving this way covers only about 1 km every 12 hours and typically takes more than a month to cover a distance like this 27 km route. In August 2025, Mammoet relocated the dragline the full 27 km across the lease in just 10 days, which the company and trade press, including Mining Magazine, described as a new benchmark for dragline transport. Mammoet's own case study puts the average at about 8 km a day, though 27 km divided over 10 days works out closer to 2.7 km a day. The higher figure likely reflects only the days the convoy was actively moving, since the 10-day window also covered jacking the dragline up, building the rail crossing, and jacking it back down, none of which involved forward travel.The machine had to cross a live export rail lineThe mine sits in Queensland's Bowen Basin, where BHP Mitsubishi Alliance (BMA) runs several large open-cut coal mines, including Peak Downs, as BHP's own site describes the region. HLPFI reported that the dragline was needed for coal extraction in the southern pits. Between the two sites runs an Aurizon rail line that Mammoet branch manager Laura Ewen described as "a critical line, transporting coal from different mines in the region to the coast for exporting." A conventional dragline move over that distance would have kept the crossing shut for weeks, so rather than letting the machine walk, BMA brought in heavy-transport specialist Mammoet.Jacking towers lifted 6.8 million pounds clear of the groundRather than letting the Marion 8050 walk, Mammoet's crew used eight JS500 jacking towers to raise the 3,100-tonne machine about 2.5 metres off the mine floor, according to World Coal, HLPFI, and Crane & Transport Briefing. Traditional dragline jacking in Australia instead used climbing jacks with timber stacked manually underneath the load, added to as it rose, Mammoet project manager Jack Whittaker said. After jacking, the dragline was lowered onto five groups of SPMTs with 28 axles each, 140 axles in total, HLPFI reported.Ten days, eight kilometres a day and one fixed deadlineMammoet said the convoy covered the 27 km in 10 days at an average of about 8 km a day (a figure that, as noted above, likely reflects active-travel days rather than the full 10-day window), well below the SPMTs' top speed of 5 km an hour. The gap reflects how much of each day went to scheduling around inspections, heat, and the rail crossing rather than to driving. Mining Magazine and other trade outlets covering the project described the pace as record-breaking for dragline transport in Australia.Mammoet and BMA had only a 72-hour window to build a temporary ramp and tow the dragline across the Aurizon line; missing it would have delayed the project by three months, since the next rail closure wouldn't come around again that soon, Mammoet branch manager Laura Ewen said. Distributing a load this heavy across rubber rather than steel tracks or hydraulic feet is a well-studied engineering problem in its own right. In the year 2020, the paper “Optimization Solutions for Self-Propelled Modular Transporter (SPMT) Load-Outs Based on Ballast Simulation” by Haiming Zhu, Zunfeng Du, Dong Xu and Yougang Tang discusses the distribution of weight in an SPMT such that none of the suspension groups carry weight above the capability ofGround bearing capacity is the limiting factor, not horsepowerThe same reasoning is central to the Manual on the Use of Self-propelled Modular Transporters for Removal and Replacement of Bridges that was prepared by the United States' Federal Highway Administration, along with its state and industry collaborators. The section on ground-bearing capacity in its design chapter elaborates on how engineers determine the maximum force that the soil/pavement can withstand without the risk of a transporter sinking or moving. This factor is more important than engine horsepower when routing. That is what Mammoet had to contend with at Peak Downs: The machine being old, there were no records on how it distributed weight, which meant that its center of gravity had to be estimated using other similar machines.A record built on logistics, not raw sizeMammoet previously used the same jack-and-carry method in Queensland in 2017, relocating another dragline for BMA over a shorter distance, according to the company's case study. What made the 2025 relocation notable, in Mammoet's own account and in trade coverage that called it record-breaking, was less the distance than the constraints: a 3,100-tonne machine on a fixed schedule with a live export railway in its path. In the end, it was ground bearing capacity, not top speed, that shaped how Mammoet moved the dragline across Peak Downs.Catch the latest World News and Live updates. Download the TOI app.