Electrifying underground operations
How one electrified hauling system nudges a Swedish mine towards an all-electric future.
Beneath the surface of the Malå municipality in northern Sweden, an underground mine has been in operation for over 80 years. With a production capacity of around 750,000 tonnes per year, the Kristineberg mine is the largest contributor to the Swedish mining company’s Boliden Area Operations process plant, and produces minerals such as copper zinc, gold, silver, and lead.
Operations such as those at the Kristineberg mine, however, continue to face rising pressures to balance increased outputs of critical minerals and metals with lower carbon emissions and energy usage. Demand for minerals critical to society’s clean-energy transformation is predicted to increase between 1.5 to seven times by 2030, according to the International Energy Agency (IEA).
According to experts in the field, haul fleet electrification is one of the most effective and realistic ways to reduce CO2 emissions in mining and help the industry reach its sustainability targets. To realise the all-electric mine of the future with sustainable, productive operations and improved working conditions, Kristineberg mine’s operator Boliden and equipment manufacturers Epiroc and ABB have passed a new technology milestone by successfully deploying the first fully battery-electric truck trolley system on the mine’s underground test track, with a 13% incline.
Coinciding with reducing carbon emissions, the electrification of mining also promises improved health and safety for the industry’s workforce. By deploying this system, the collaboration partners aim to prove that the underground working environment can be significantly improved, with reduced emissions, noise and vibration while lowering the total cost per tonne.
“Over the past three years, we have worked in close collaboration with the ABB and Epiroc teams to bring the electric mine of the future one step closer,” says Peter Bergman, general manager of the Boliden Area at Boliden. “The most important thing for us is of course that the technology works in our own operations, but we also see added value in working with our partners to drive technology development so that the system can be used in other mines.”
Collaborative efforts
Each partner has provided a unique set of expertise to this development process, demonstrating the value of industry collaboration. One of the technologies seen in the underground hauling fleet electrification system is Epiroc’s battery electric Minetruck MT42 SG.
Epiroc’s largest battery-operated mine truck boasts high capacity and productivity, thanks to its efficient drivetrain configuration ensuring low energy consumption and extended driving range. As it is a zero emissions truck, operators are not exposed to diesel particulates, and toxic gases such as nitrogen oxides, hydrocarbons and carbon monoxide (NOx, HC and CO).
Meanwhile, the trolley solution is equipped with ABB’s DC converter, HES880 inverters and AMXE motors to enhance the power. The truck features a trolley pantograph connected to an overhead catenary line, a concept which is highly suitable for long haul ramps. The electric trolley line gives additional assistance to the battery-electric mine truck on the most demanding stretches up-ramp while fully loaded, enabling further reach and battery regeneration during drift, which increases productivity.
ABB created the infrastructure from grid to wheel, including the electric truck trolley system design and the rectifier substation for the test track. According to its developers, the eMine Trolley System can help mining trucks decrease diesel consumption by up to 90%. A trolley assist operation also gives the trucks under load an additional boost as they climb the gradient on the hauling route.
Within the trolley system, rectifier substations are needed to supply and control power to the overhead line system and trolley trucks. AC power is distributed through a medium voltage for the rectifier transformers and auxiliary systems in the mine’s substation and overhead line system. These rectifiers, attached to an e-house, convert the AC voltage to suitable levels for rectifiers. These then further convert the electricity from AC to DC, making it suitable for the mining trucks.
According to ABB, the entire trolley system can also be embedded into the ABB automation platform meaning mining operators can remotely control and monitor the system and optimise energy usage for the highest efficiency and lowest costs.
An all-electric future
ABB wanted a solution that could adapt to voltage fluctuations along the system, and so collaborated with partners to build a digital twin to simulate all scenarios. This resulted in the trolley system, with intelligent switchgear, measurements and transparency as well as the ability to adjust power where needed at any given moment.
“Together we can accelerate the transformation and reach a steep curve in mining technology innovation like we have done in Kristineberg,” says Wayne Symes, president of Epiroc’s underground division. “In a short space of time, we have implemented and delivered technology that has reduced CO2 emissions, substantially extended travel distance for battery-electric driven vehicles on heavy ramp haulage, reduced operating costs, and improved the health and safety of mining environments.”
“We are passionate and committed to creating real progress for the mining industry,” adds Max Luedtke, global business line manager of Mining at ABB. “Seeing the industry’s first battery electric truck trolley system live is not only the result of a collaborative achievement with Boliden and Epiroc, but it is an industry milestone. We launched the ABB eMine concept of methods and solutions to bring electrification to the whole mining operation, from the grid to the wheel, and the installation at Kristineberg demonstrates the power of these capabilities.”
Boliden plans to implement a full scale, autonomous electric-trolley system in its Rävliden mine, a satellite orebody and extension of the Kristineberg mine, and has placed an order for four Minetruck MT42 SG Trolley trucks from Epiroc. The total distance will be 5km at a depth of 750m. The company hopes that once achieved, Rävliden will have both reduced carbon emissions compared with a mine using conventional technology, and set a new standard for the all-electric mine of the future.