Epiroc battery-powered machines are being tested at Kittilä mine in Finland, operated by Agnico- Eagle. This field test is ongoing as part of the Sustainable Intelligent Mining Systems (SIMS) project, which is included in the Horizon 2020, the European Union’s research and innovation programme.

Epiroc is the coordinator of the test, which involves three machines: the Boomer E2 Battery, the 14t loader Scooptram ST14 Battery; the 42t Minetruck MT42 Battery.

Franck Boudreault, Epiroc global manager for electrification, explains that the Boomer rig is onsite for six months and the test has been going very well since the beginning. “The Boomer drill rig has been well-accepted by the operators and it is being used as a normal machine everywhere in the mine. “The battery is only used for moving the rig from one area to another one. The drilling is performed while you connect to the grid – just as you do during normal drilling – and the battery can recharge during this time. Once you have completed drilling, your battery is fully charged and the rig is ready to move to another area.”

The Scooptram ST14 Battery and the Minetruck MT42 Battery started the test in August in a dedicated area, not fully integrated into the mine’s fleet. “These machines are still being tested and they are performing very well, showing good reliability, utilisation and the lifetime of battery is according to the expectations,” Boudreault says. “The operators appreciate the low level of noise and heat as well as an increased performance.”

The test with the loader and the mine truck will probably continue until May 2020, while the one with the Boomer E2 Battery has not been decided yet. Overall, more hours are required to get even more experience and learning.

Boudreault announces that in a few months they will start delivering the second generation of battery machines to customers. “We had several orders as the acceptance from the market has been very positive,” Boudreault says. “We have received orders from a wide geographic coverage including Australia, Europe, Canada and South Africa. Thus, some people are ready to take the first step and others need a bit of time to be convinced and once these battery-powered machines are proved by others, they will be more confident on them.

“The current orders are from mines but not from tunnelling yet even though there is a particular interest on this.” Boudreault explains that the real benefit of going over battery electrification is for loaders and trucks because they use the engine at all time to perform their work. The drillers only use the engine as barrier function to move from one area to another and the drilling has been always done by electricity.

“Some orders are for drilling for several reasons such as no change in the working patterns for doing things on the battery electrification drill rig; no need for infrastructure; no need for charging stations or swapping the battery,” says Boudreault. “Instead of using a diesel engine into the machine, you use an electrical power battery and you can continue working as used before. Because of this easy transition, the response has been very positive for drill rigs.”

The same process might happen for tunnelling projects as well.

When it comes to ventilation in tunnels, it is well suited for ventilation on demand, which means that you adjust the speed of your ventilation fan based on the need that you have. Boudreault explains that if you have just blasted and you have a lot of gases, you want to make sure that your fans are at full speed and you clear the front as soon as possible, and then the next task would be to remove the blasted rock with a loader and trucks. If done with battery powered equipment, this means that you can reduce the speed at which you run the ventilation fans. He adds: “As soon as you don’t burn any diesel, you can lower your ventilation rate. This is also why the battery electrification can work very well in tunnels and there would be a significant cost reduction on ventilation up to 50%.

“Traditionally, the biggest diesel consumers are mine trucks and loaders, and if you go to zero emission, you can absolutely reduce ventilation costs for a much cleaner work environment at lower costs.”

Boudreault says that Epiroc also has had requests from customers in the construction sector. “Our loaders and mine trucks, which are special for mining, are also used in tunnelling applications as they are considered very good for zero emissions material handling in the tunnel,” he adds.

When it comes to drilling, the carrier needs to be electrified www.tunnelsandtunnelling.com | March 2020 | 25 and it is used for face drilling or rock reinforcement and also for long-hole drilling.

Boudreault says that Epiroc has 11 different drill rig models, which are available with that battery technology as they use the same carrier. The recent orders are for Boltec E, Boomer M2 and Boltec M.

In terms of conversion from a diesel to battery, Boudreault explains that Epiroc is busy working on it and they want to make sure that the existing machines are stable and robust.

“Of course there is a cost in converting machines,” says Boudreault. “Once people will be fully aware of the battery benefits, they can require conversion for a better performance and for a sustainable solution.”

Regarding the concern for fire underground with batteries, he says that the risk exists but it can be controlled.

“We selected to partner with Northvolt, who introduced extremely high quality batteries in terms of safety and performance,” he says.

“We have a thermal management system on board of these batteries. We have monitoring and management systems with a number of safety features on top of each other, which can address risks before something happens.”

“We have chosen to work with NMC battery chemistry. This choice was driven by safety and energy density. We also chose to work with relatively small cells, to minimise the risk in case of a thermal event.”

“We did a lot of tests to cause intentionally thermal events, and the results have been very good so far with no propagation from one cell to another, even in the toughest conditions.”

Epiroc aims to be able to offer its complete range of underground mining equipment as battery electric versions by 2025.