A renewed giant

Nearly 1.5 billion tonnes of crude iron ore have been extracted from the depths of LKAB’s famed Kiruna operation since mining began in 1898. Five hundred kilometres of maintained road run through the mine, widely considered one of the world’s most modern underground operations and renowned for a commitment to innovation and implementing pioneering technology.

Kiruna’s orebody is about 80 metres wide and four kilometres long, and reaches a depth of up to two kilometres. What started as an open pit has gradually grown to become a deep, high-tonnage underground mine. Kiruna surpassed the 1,000-metre mark in 1999, and in 2012 LKAB completed an even deeper main haulage level at a depth of 1,365 metres that is expected to support iron ore production until around 2035. The deeper the mine has developed, the more costly and complex ventilation has become.

“We had to scale up the mine and for that you need bigger machines, but we saw a lot of problems to take in diesel,” says Per Brännman, who oversees the mine’s 300-person loading division. “It’s not just that you have to put in more ventilation to get a good environment; you also have to do more tunnelling. Diesel was just not an option if we wanted to have big, productive machines down here.”

With no exhaust emissions, less heat, fewer vibrations and lower noise levels, electric motors improve underground conditions and operator comfort while considerably reducing ventilation requirements. Electric equipment can also reduce a mine’s energy costs to a fraction of that of a comparable diesel-operated unit.

“We proved a long time ago that you can achieve massive carrying capacity and productivity without the use of traditional diesel engines and fossil fuel,” Brännman says. “We have done this since the early 1980s. We know what the electric machine can do. We want to try better here.”

Since the decision to implement electric production loading, Kiruna has steadily replaced its diesel-powered machines. Today the mine relies heavily on a fleet of 17 Sandvik LH625E electric loaders, whose 25-tonne payload capacity is essential for achieving Kiruna’s daily target of 85,000 tonnes of ore feed material.

“We are a big mine, but we don’t have areas all over the place,” Brännman says. “We have a few areas that we can load in. The machine that is there has to work. We don’t want to be a bottleneck in the mine. And if you have a lack of 25s in the mine, we can’t do our daily production.

“Time travels fast, and what was the most advanced technology in the 1980s isn’t the most advanced today. Many parts are from the proven LH625E, but with new technology. We combined Sandvik’s know-how and expertise with this machine together with the knowledge our operators have gained from many years operating it, and out came Toro LH625iE.”

Sandvik collaborated closely with LKAB to customize the design of Toro LH625iE to meet Kiruna’s needs. These included better energy efficiency than the original model with the same industry-largest 25-tonne payload capacity, and a larger, more ergonomic operator’s cabin.

Toro LH625iE is 14 metres long and sports a four-metre-wide bucket. It connects to the mine network via a 350-metre trailing cable that enables an operating range of up to 700 metres. Its roomy cabin offers unrivalled space for operators and enables the inclusion of a unique 180-degree turning seat not possible in more compact Sandvik loaders. Operated on the steering joystick, the seat can be turned to face the direction of travel, improving operator ergonomics and eliminating the need to look over the shoulder.

“The chair is so important for me as operator,” says John-David Sundbris, who operated Sandvik LH625Es for two years and has since spent the past six months behind the controls of the mine’s first Toro LH625iE. A gold placard on the cabin identifies it as the 600th electric loader delivered by Sandvik globally.

“The swivel seat is much more ergonomic than a typical seat and it improves my visibility,” Sundbris says. “You’re following the flow with the chair and just turn it when you need to look in a different direction. It makes for much more comfortable working conditions.”

Toro LH625iE’s cable reeling system has also been re-engineered. The new low-tension closed loop system is designed to increase trailing cable lifetime and reduce cable damage on drift corners.

“It’s a significant improvement to increase the trailing cable’s lifetime,” Brännman says. “You can have an equal speed all the time and you then don’t get the pulls in the cable. It goes much smoother. And the cable is one big maintenance thing on the machine, so if we can improve that one, we have more production time.”

The new system initially presented some challenges, but LKAB and Sandvik worked together to overcome them.

“It’s a completely new system and you have to improve it so it works better,” Brännman says. “With some small adjustments, it works very well right now.”

Confident in testing performed at Sandvik’s factory, LKAB immediately put the prototype Toro LH625iE into a production environment in February 2020.

The display provides service information, easy system diagnostics and alarm log files to simplify maintenance. The Sandvik Intelligent Control System monitors and warns the operator before failures occur, preventing severe damage and potential loss of production.

“LH625iE is more digital and it’s easier to see if something happens,” Sundbris says. “Everything is more integrated in the panel. It’s a very trustworthy machine. It delivers exactly what we want, really.”

Kiruna received its second Toro LH625iE in November 2020. It will take delivery of three more in 2021 and a sixth in early 2022. With an option for two more, LKAB is changing its whole fleet to Toro LH625iE, Brännman says.

The mine also operates three automated Sandvik LH621 loaders, the largest diesel-powered loader in Sandvik’s fleet, while gases are cleared after night blasts. The third of its six Toro LH625iEs, expected in the third quarter of 2021, will also feature AutoMine.

“We’re excited about the potential of increasing our use of automation,” Brännman says.

He says the renewed giant has exceeded LKAB’s expectations.

“If you’re going to do a project like this together, you have to be very open-minded from both sides,” Brännman says. “I will recommend Sandvik because of their professionalism. In that I include open-minded, keen and very skilled. Win-win collaboration, I would say.”