Risk reduction strategy

Louise Davis

Holger Pfriem details how to suppress the fire risks of mining equipment

The nature of the mining industry means that heavy equipment, for both underground and overground operations, must often operate for long hours to meet a mine’s tight work schedules.

Operating in high-risk environments – experiencing high dust levels, prolonged vibration and use for extended periods – the risk of overheating is much greater, which can influence already high fire risks.

There are undoubtedly a number of risks associated with the equipment used in mines, especially as the technology evolves, but there are also approaches operators can take to effectively address those risks and to minimise downtime while maximising safety.

What’s influencing fire risks in mining?

A site’s specific risks will depend on an individual risk assessment, as this will take the mine’s entire operations into consideration, including how the vehicles operate in their particular environment. However, there are several fundamental fire risks that will affect a mine’s heavy-duty vehicles or mining machinery.

Hot topic - overheating vehicles

The first is overheating. In its harsh operating environment, the equipment used in mines is prone to accumulating dust and dirt during its use. A clean engine compartment will reduce risk, but when dust is unavoidable, as it often is in the mining industry, it’s more complicated to ensure vehicles are kept clean. However, if mines don’t control vehicle cleanliness, this can increase the risk of overheating.

Overheating on its own doesn’t necessarily result in fire risk. However, as a result of long hours and tight schedules, mining vehicles are likely to operate for lengthy periods of time, prolonged vibration can increase the fiction between a vehicle’s components. This can often result in wear and tear, which in turn, increases the risk of overheating.

Should this wear and tear lead to a loose cable, sparks or damage to the injection pipe for combustion engines, for example, when combined with overheating, this can cause a dangerous electrical or spray fire, which can spread quickly to cause damage to other equipment and life.

Electrification in mining vehicles

As the mining industry drives for sustainability, more and more sites around the globe are switching from traditional combustion engine vehicles to electric vehicles (EVs).

Although they’re less likely to overheat, EVs use lithium-ion batteries, which bring about different fire risks. There are four factors that can influence these types of fires: over/undercharging; mechanical influences – eg crashes or failures; exposure to heat; and production fault – where particles enter battery cells.

Each of these factors can lead to an internal short-circuit, which will put the li-ion batteries at risk of thermal runaway – a volatile state where temperature increases rapidly and, in turn, increases the risk of fire – in addition to toxic gas emissions and potential explosions.

Thermal runaway is especially dangerous, as the fires it creates are often extremely difficult to extinguish without submerging a vehicle’s battery in water for an extended period of time – which isn’t always possible in a mining environment.

These risks require a unique solution that can detect toxic gases ahead of an increase in temperature. Traditional detection solutions are often unable to identify thermal runaway until this stage – which can be too late to prevent it from progressing.

Automation in mining

As a result of the Covid pandemic, automation has grown rapidly in mining, as driverless vehicles supported remote operations during lockdowns. This allowed mines to increase uptime and reduce health risks for those working in the mine, and its application has continued beyond the pandemic.

However, with fewer personnel on site or operating mining equipment from further away, detecting a potential fire can be more complicated. This means that automated detection and suppression is essential to increase the response time, in addition to decreasing the risk of downtime and damage.

How can mine operators reduce the risks?

First, the operator needs to understand their mine’s individual risks. As the technology develops, it’s important to carry out a risk assessment to define the necessary fire detection, as well as suppression, solutions. It’s important to understand the mine as a whole, as new types of vehicles and machinery are introduced. These risk assessment maps should understand how a battery’s risks will change throughout its lifetime, and mine operators should update their risk assessments accordingly.

Every vehicle, electric or diesel, automatic or manual, has its own unique risks, and these should be addressed when choosing a fire protection solution. However, when it comes to EVs, it’s extremely important that the suppression system is appropriate for the type of battery it is protecting. Consider the suppression agent, reaction time and ensure that manual activation is possible, in case of
an automatic system failure.

Suppression solutions should be tailored to suit unique risks effectively. If a suppression solution isn’t adapted to an individual site environment and its risks, this can cause false system activations, resulting in unnecessary downtime. To minimise downtime while maximising safety, a suppression solution that reflects all of a site’s unique risks is key.

Holger Pfriem is with Dafo Vehicle Fire Protection.

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