51 E-Mobility Engineering | September/October 2025 Mining electrification | Insight proof to MSHA/IECEx standards, meaning that their electrical and electronic systems must not expose flammable gases and dusts to sparks. Operator cabins have to be sealed against dust and provided with HEPA air filtration. Operators are also provided with sensors such as 360° cameras and Lidar to counter the inherent visibility limitations of low-profile vehicles. Furthermore, their designs emphasise modularity for improved maintenance access to make them easier to work on in tight spaces. In terms of terrain, relatively smooth graded haul roads on the surface contrast with rough, uneven and steep roads underground. Temperature variations are also much larger above ground, with vehicles typically designed to operate from -40 to 50 C, contrasting with a stable average of around 15 C underground, although deeper mines can get significantly hotter. High humidity is an extra challenge underground, driving the use of corrosion-resistant materials. Navigation and communication are critical both above ground and below, but the solutions differ because of the limitations of radio propagation underground. Both will remain critical as mines become increasingly automated and digitalised, and vehicles are given increasing levels of autonomy. Underground LHDs and hauls Electrification has progressed further among underground mining vehicles than among their surface counterparts. Three broad classes are commercially available and in regular operation. The first such class comprises LHD machines – articulated vehicles designed to load, transport and dump fragmented rock, shuttling ore from the blast face to crushers or haul trucks. In 2024, around 30% of new LHDs sold were BEVs, rising to around 50% in Canada and Scandinavia. At the same time, at least 53 underground mines worldwide had trialled or adopted BEVs, with more than 270 vehicles of different types acquired. Early adopters include operations in Canada, Sweden, Norway and Australia, and some (such as Macassa in Canada) have transitioned more than 80% of their fleet to BEVs. Typically carrying payloads of up to 18 t, BEV LHDs are offered with LTO, LFP and NMC battery chemistries. The Swedish Epiroc Scooptram ST14 SG, for example, is an articulated vehicle with a payload of 14 t. This vehicle has a liquidcooled NMC battery pack of Epiroc’s own design with a quoted useable capacity of 300 kWh, and an integrated thermal management system that enables it to operate safely over a temperature range of 0–40 C. The pack can accommodate both onboard charging from an external charger through a CCS2 type 1 or 2 connector, and can be charged from zero to 90% in 1 hour 50 minutes. The battery can also be swapped to allow slower, gentler charging with minimal downtime. Size, C rate and swapping For BEVs, Epiroc recommends using the largest practical battery pack – not only to maximise range between charges but also to allow faster charging for a given C rate, as this measures the charge rate as a proportion of battery capacity. This allows the cells to remain cooler while charging, which extends their service life and reduces the amount of heat that Design divide The biggest divide in mining vehicle design characteristics is to be found between underground and open cast (surface) operations. Those that work underground generally must negotiate narrow tunnels with low ceilings and therefore must be relatively compact, which typically limits the payloads of workhorse load haul dump (LHD) vehicles to around 50 t, much less than that of surface working haul/dump trucks, the largest of which carry up to 600 t. Underground, limited ventilation makes vehicles with internal combustion engines a major health and safety risk, and with the BEVs that are taking over, battery safety is a fundamental concern. Here, more stable battery chemistries such as lithium titanate oxide (LTO) and lithium iron phosphate (LFP) are chosen for this reason as well as for their long service lives. Their limited energy density compared with lithium nickel manganese cobalt (NMC) chemistries are accommodated with fast charging and/or battery swapping systems. Those underground vehicles that do run NMC batteries need robust thermal management systems. Naturally, fire safety requirements are much more stringent underground – vehicles must be certified as explosionUnderground LHDs such as Epiroc’s Scooptram ST14 SG were among the first types of mining vehicle to be successfully electrified, relying on swappable or rapidly chargeable battery packs (Image courtesy of Epiroc)
RkJQdWJsaXNoZXIy MjI2Mzk4