It’s not simply ‘plug & play’ for BEVS: new risks for mine operations must be considered, says Marcello Sanchez
The technology for battery electric vehicles (BEVs) is continually evolving, and mining companies need to go ‘back to basics’ to safeguard site operations effectively. The fire risks presented by the global shift towards BEVs must be considered so that operators and OEMs can minimise these risks effectively.
Mobile equipment fires are increasingly common in the mining and resources industry, and several key factors should be considered to improve how the sector understands and applies fire prevention and mitigation measures.
Typically, mobile equipment fires cause significant risks for operators, maintainers and any emergency responders. They can have catastrophic consequences in underground operations and can create a wider operational and commercial issue for earthmoving equipment owners and operators. Such fires have mandatory statutory reporting in most mining jurisdictions and they will be extensively analysed, as regulators now expect mine operators will improve mobile equipment fire management performance.
Facilitating Low-Carbon Mines
The mining industry is continually searching for eco-friendly alternatives to align with global sustainability targets. This is causing a shift from the combustion-engine vehicles and diesel-powered machinery often used to fulfil intense work schedules.
There are further benefits of BEVs that make them arguably more suitable in underground mines than in any other industry. Diesel engines create emissions, noise and heat, which negatively affects the underground work environment. This is seeing many mining businesses make the move towards BEVs, not only as a sustainable alternative for onsite equipment, but also to improve conditions in the mine. BEVs are being used across the mines – from production, such as LHD and drilling rigs, to utility support equipment, such as boom trucks, scissor trucks and personal/service carriers.
There are opportunities to reduce costs and enhance safety by electrifying underground mine vehicles, as BEVs minimise the need for expensive ventilation measures and improve the overall air quality for workers.
Emergency Response And Battery Chemistry
Within batteries, any heat is generated by current flow (the Joule effect), and temperature management is influenced by a battery management system (BMS). The BMS will monitor the mean temperature of a battery pack and temperatures of the individual cells, in addition to the intake and output of coolant temperatures – if a coolant is used. Typically, high-temperature conditions are the result of an external heat source, or voltages and/or currents being out of range.
If the internal temperature becomes too high, separator failure can occur, which leads to internal short-circuiting. With some chemistries, this can lead to a process called thermal runaway, which ultimately causes venting of hazardous gases and/or flames and potential explosion of the battery assembly.
When in thermal runaway, batteries produce their own source of oxygen, feeding flames from within and self-sustaining the fire. This process makes traditional fire suppression methods more challenging, requiring a unique solution to minimise fire risk effectively. It’s important to detect potential battery failure quickly, to take action by cooling – using a wet chemical suppression agent, for example. This will stop, or delay, the potential consequences effectively, by preventing the fire from spreading.
There is currently no standardisation in regulations for BEV vehicles, meaning battery chemistries can vary. However, if BEVs are being used in situations that might structurally damage a battery or cause a vehicle fire, it’s important to take special considerations before and during their use.
Introducing Bevs Into Mining Operations
Important questions to consider when introducing a BEV into your mining operations, include: are you aware of the BEV’s battery chemistry and the associated fire suppression techniques and are the mine maintenance personnel aware of the battery chemistry?
It’s also worth asking whether the necessary fire detection and suppression solution for the battery chemistry is installed in the BEV and whether operators are trained to appropriately respond should a fire occur.
Another key question is: do emergency services have appropriate training and fire suppression equipment?
When it comes to mixed fleets, to identify onboard battery chemistry in a BEV and select appropriate suppression techniques, two questions must be asked. Firstly, can the battery chemistry be identified quickly from a distance by emergency personnel? And secondly, have operators been trained to identify battery chemistry and the unique response they should take?
Minimising Risks
Alongside general best practice fire prevention measures implemented in mines, there are several key steps operators should take to minimise the risks.
Risk Assessment
OEMS should incorporate certain control measures into the design of EV batteries used in underground mines to ensure safe operation of the vehicle and minimise fire risk. They should also provide end users with the sufficient information to effectively implement emergency management strategies during a fire.
Mine operators should ensure all new processes and equipment are subjected to a full risk assessment before integration into a site’s operations. This assessment goes beyond considering vehicles and machinery in isolation and towards considering their use within the whole operating environment. The assessment should additionally consider the risks posed by a battery’s chemistry throughout the battery’s life cycle.
Select A Suppression System That Meets Individual Risks
Once these risks are identified, mine operators should ensure effective management by implementing additional control measures to ensure maximum safety. A fire suppression solution should be adapted to an individual site and its risks. This is especially important to ensure minimal false system activations.
Fire Suppression Technology Considerations
The fire suppression system in a BEV should be appropriate for the vehicle type and battery chemistry. Local mining regulations or site risk assessments might require automatically activated systems, however, if a system is automatic, it should also be able to be manually activated by BEV operators. In addition, there should be fire-fighting information to train operators, electrical and mechanical personnel.
For OEMs, integrating an effective fire suppression system into the manufacturing process will ensure the protection of BEVs and that relevant site regulations are met from the outset. For operators, appropriate fire suppression systems can be retrofitted into existing vehicles and machinery for maximum operations and maintenance safety.
Maintaining vehicles’ fire suppression systems should be integrated into routine vehicle maintenance to service them as part of the machine rather than in isolation.
Safeguarding The Mining Industry’s Future
As the mining industry evolves at pace, adapting the existing processes and systems to meet the new and changing risks brought by BEVs is vital. A fire suppression solution should seamlessly integrate with the work environment to save lives and ensure the maximum operational uptime.
Marcello Sanchez is with Dafo Vehicle Fire Protection