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Electrical potential: Could batteries replace diesel?

Suddenly it seems all pieces of the technological puzzle are falling into place. The battery revolution is under way – and one multinational OEM is convinced it can significantly change the energy landscape of the mining, and by extension the quarrying, industry.

June 2018 was a peak period of activity for Epiroc in Örebro, in central Sweden. An entire new generation of battery-powered mining machinery was to be launched in the following season, and a key person involved in that launch was Erik Svedlund, Epiroc’s marketing manager of vehicle electrification.

Svedlund has been involved in outlining Epiroc’s vision of emission-free mining environments, made possible by battery power. “Electric will replace diesel,” he said. “The machines that we’re developing here already perform equally well or better than diesel machines, except for one thing – running time. But with the rate at which batteries are developing, it won’t be long before that has caught up too.”

According to Epiroc, there has been “an explosion” in the market for electric-powered mining machines because the technology – primarily battery technology – has matured. Previous trials using electricity from cables or rails involved fixed and awkward solutions, and the flexibility required in a mine environment meant the decision traditionally came down in favour of diesel machines. At least, that is, until now.

Svedlund became interested in battery-powered machines in 2010 and started studying the possibilities. “At the time I was head of products and I quickly realised that battery power could not just replace diesel, but could become a profitable business for both us and our customers. I started lobbying internally to start the development of such solutions. This went rather slowly until 2013, when we received a request from a customer in Canada. It then took less than a year from prototype to launch of the Scooptram ST7 Battery, and the machine’s performance exceeded expectations.”

The Scooptram ST7 Battery was among the first generation of battery machines launched by Epiroc in 2016. The machines that were subsequently launched in the second half of 2018 were second generation machines and included not just loaders but also mine trucks and drill rigs. “Loaders and mine trucks account for around 80 per cent of fuel consumption in mines,” Svedlund said. “These types of machines are the key – if we don’t come up with these, we won’t solve anything.”

The Epiroc E2 battery-operated underground drill rig.
The Epiroc E2 battery-operated underground drill rig.

Soundless engine

At Epiroc’s test mine in Kvarntorp outside Örebro, a Scooptram ST7 Battery stands with its bucket full of gravel. If you close your eyes there is nothing to indicate that the loader is running, until it starts to move – and all you hear then is the sound of the gears and axles, and the crunch of tyres on gravel. There is no engine noise. As the loader releases the gravel, the jangling can be clearly heard in the otherwise quiet site.

Anders Lindkvist, Epiroc’s project manager for technological development, and his team learnt a lot while working on the first generation. “For the first generation we basically took existing loaders, removed the engine and fuel tank, and put in an electric motor and battery instead,” he said. “But it worked. We were placing bets in the office on how long the machine could run on a battery, and all the guesses were between one and three hours. But it proved to keep going for five hours.”

The second generation machines were designed for battery operation from the outset; the mine trucks, for example, have motors on each axle. But it is the batteries that are responsible for the biggest change. “Quite early on we started developing a modular battery system that allows the modules to be used in any kind of Epiroc machine,” Lindkvist said.

One advantage of the new battery design is that it can be replaced quickly. In less than 10 minutes a fully charged battery can be in place, so even energy-intensive operations can continue with only a brief interruption.

It has been nearly three years since Epiroc’s management gave the green light to developing the second generation machines, and from that point Lindkvist and his team worked at full throttle.

“This is a new way of working that’s fun and exciting,” Lindkvist said. “It’s tremendously enjoyable to be able to introduce so many new things in such a short time. And on three machines in parallel, too.

“Now we need our suppliers to come up with new solutions at the same rate that we need them.”

Sofia Bratt has been responsible for Epiroc’s project office, which has co-ordinated the work to develop the second generation. “There’s been very close collaboration in the group and with our suppliers,” Bratt said. “It’s been huge fun and has developed all those involved, and I think this type of project will become more common in the future.”

Bratt described a process in which the project office succeeded in breaking new ground. “We’ve looked at areas such as battery cell chemistry, drivelines and control systems, and have been able to evaluate what’s most optimal for our applications. An incredible number of people have been involved, which has made great demands of dialogue and communication. It’s required time and resources from everyone involved, but it’s also been very effective.”

Frederik Engman, technician (left), and Anders Lindkvist, project manager, discuss the best placement of powertrain components on an Epiroc Scooptram ST14 battery.
Frederik Engman, technician (left), and Anders Lindkvist, project manager, discuss the best placement of powertrain components on an Epiroc Scooptram ST14 battery.

Calm, steady pace

In the Epiroc workshop, the first second generation batteries were tested calmly and steadily ahead of their launch at a specially convened event in Örebro in late 2018. These machines included the Scooptram ST14, Boomer E2 and the Minetruck MT42.

According to Epiroc, more customers are starting to demand battery machines. Although diesel machines can reliably do the job, they are not without problems: harmful exhaust emissions, noise, waste heat, high maintenance costs, unplanned stoppages for servicing, rising fuel costs and an increasingly complicated infrastructure.

By comparison, according to Epiroc, battery-powered machines need significantly less maintenance, not least because an electric motor contains a fraction of the number of moving parts in a diesel engine. They give off marginal amounts of waste heat and have no exhaust emissions. If the batteries are charged using renewable electricity, they have no climate impact either.

Safety and sustainability are also an important part of Epiroc’s strategy, and can contribute to its customers’ sustainability work and environmental impact. The company also believes battery-powered machines can help achieve one of the United Nations’ Sustainable Development Goals: access to affordable, reliable, sustainable and modern energy for all.

“Diesel machines are actually poorly suited for use in enclosed spaces underground,” Svedlund said. “A lot of cooling and ventilation are required to deal with the exhaust emissions and heat, and this has become the single largest energy cost in mines.

“If we take away the diesel engine, the situation changes completely. Ventilation costs reduce dramatically and you can go even deeper while still being cost-effective.”

Unlike the shift to electric cars, therefore, the transition in the mining industry is not primarily driven by legal requirements and more stringent rules on emissions. Underground, the driving force is instead a desire for a safer work environment – and pure and simple economics. The potential savings are enormous.

Aftermarket component

A technician works on the battery for Epiroc’s second generation of battery machines.
A technician works on the battery for Epiroc’s second generation of battery machines.

The person keeping an eye on the aftermarket aspect is Fredrik Martinsson, Epiroc’s marketing manager of service electrification. “Solving the financial model and at the same time strengthening the tie to our customers is a key activity,” he said.

Martinsson’s task is to devise a new business model that will make it as easy as possible for producers to switch to electric operation. The basic idea is that the producer buys the machine, but has a subscription for the batteries. The advantage is the investment is lower, operating costs are predictable and Epiroc takes all the responsibility for the training, maintenance and servicing associated with the batteries.

If a customer needs more or less power, the subscription can be adjusted. “We want to dramatically lower the threshold for electrification,” Martinsson said. “We want it to be easy. This is a major change, and it will require hard work by many people over a long period. But everyone – suppliers, customers, the environment and ourselves – will be a winner.”

A test truck travels along a 700m electric trolley route at the Boliden Aitik copper mine, Sweden.
A test truck travels along a 700m electric trolley route at the Boliden Aitik copper mine, Sweden.

Boliden Mines Energy Program

Boliden is a high tech metal company that employs about 5800 people in mine and smelter operations in Sweden, Finland, Norway and Ireland. Its end products include zinc, copper, lead, nickel, gold, silver, sulphuric acid and iron sand. It is also committed to a number of sustainability initiatives, including secondary material recycling and synergies, water management, mine automation and electrification.

In particular, Boliden has been engaged in a pilot project at its Aitik copper mine in northern Sweden, where it has been replacing elements of its transport system with electrified trucks, to move most of the 70 million tonnes of rock extracted at the open pit each year without the assistance of fossil fuels.

As a result it has installed a 700m electric trolley route with overhead wires (much like a tramway route) to power the electrified trucks. This potentially saves up to 830m3 of diesel fuel per year and reduces up to 80 per cent of greenhouse gas emissions along the electrified routes.

The pilot project, being run over a two-year period, is supported by the Swedish Energy Agency, and it is being implemented with several partners, including ABB and Eitech (electrical infrastructure), and Caterpillar and Pon Equipment (truck conversion).

Jonas Ranggård, manager of the Boliden Mines Energy Program at Aitik, discussed the successes of the program so far.

Q: What does your electric future look like? Why is Boliden working on the electrification of vehicles?

A: There are a great many advantages to running vehicles on electricity rather than diesel. You can reduce ventilation and maintenance costs, and improve the work environment. From 2023, for example, the EU will be lowering the limit values for NOx in mining environments. Electricity is definitely the best way to deal with these requirements, but such a transition takes time. That’s why we have to start testing the technology now.

Q: How far have you got?

A: We are still in the starting blocks. In August [2018] we began an 18-month project [to] test overhead lines and four mine trucks with current collectors in the open pit copper mine in Aitik. We decided to start with open pit mining because we use most diesel aboveground. Once the project has ended, we’ll assess whether the savings meet expectations, how good the availability of the vehicles was and what problems we encountered.

Q: What will be the next step?

A: With our switch to autonomous drilling, we’re able to improve upon the rate of production, the accuracy of the holes, and the fragmentation, leading to downstream improvements in our processes as well as improving our safety.

Zero Emission Initiative

Epiroc’s goal is to offer a zero emission alternative for all its underground mining and tunnelling equipment. The complexity and demands of these kinds of products are high, and, in addition to its own know-how in-house, Epiroc is drawing on external expertise from battery cell and electric drive train manufacturers.

  • The technical solution will vary depending on the type of machine, but everything evolves around the battery electric driveline.

  • Customer interaction has always been a key factor in Epiroc’s development work, in addition to increased demands on safety, health, quality and the environment.

  • With the zero emission product portfolio, Epiroc is improving health and safety. As a leading OEM, Epiroc considers the mining industry’s carbon footprint and shoulders its responsibility as an industry leader.

Sustainable Intelligent Mining Systems

Sustainable Intelligent Mining Systems (SIMS) is a three-year European Union-financed project to produce demonstrations of future products for the mining industry. Under the project management of Morgan Rody, the SIMS senior project manager, Epiroc is co-ordinating a collaboration of 13 partners, including manufacturers, mining companies and universities.

Q: What is the EU’s expectation of SIMS?

Morgan Rody, senior project manager, Epiroc.
Morgan Rody, senior project manager, Epiroc.

A: Our focus is on “innovation action”. We start from a research project and produce functioning products to demonstrate that the theory works in practice. The EU has high expectations of concrete results. Seventy per cent of our budget – 13 million Euros [more than $AUD21 million] – comes from the European Commission. So we have to deliver.

Q: What type of projects are you working on?

A: Battery solutions are a big thing and there’s a lot happening in this field. For example, we compared how great the difference is between diesel and batteries. What level of particulates does diesel operation result in? We also have lots of other projects in progress, such as drones, the next wireless mobile standard 5G, better positioning services, thermal imaging and assisted driving systems for diesel-free machines. Also virtual reality, which has become really hot again. We’re aiming to construct a mine in VR so we can demonstrate solutions at events such as trade shows. Many of the projects are concerned with safety, and we’re proud of that. Each person that can be moved out of a dangerous environment is a gain.

Q: Has the SIMS collaboration worked well?

A: Extremely well! It’s useful to meet up properly. And all the partners are aware that what they are doing now will change the mining industry.

Source: Epiroc Australia

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