Dealing with fire risk in a mining environment

Dealing with fire risk in a mining environment

Mining vehicles such as excavators, haul trucks, and even draglines are high-value assets that operate in arduous conditions where there is a high risk of fires. This means that pre-shift and weekly inspections on mining vehicles are essential to ensure that the fire prevention system is in good working order.

The design and installation of a vehicle fire-protection system requires that mining vehicles are subjected to a Hazard Identification and Risk Assessment (HIRA) of potential fires. Each vehicle needs to be assessed carefully within its specific operating environment to understand its exposure to specific hazards and fire risks.

Inherent fire risks include overheating of the turbochargers and brake system, as well as the potential for high-pressure hydraulic systems and electrical equipment to ignite a combustible or flammable component of the vehicle.

Although Dry Chemical Powder (DCP) extinguishers are highly effective in firefighting, they offer minimal cooling properties. This may result in reignition of flames, especially in liquid fuel and rubber fires, thereby increasing the risk of property damage and loss of life. The powder inside DCP extinguishers may also compact due to vibration when placed on a moving vehicle.

Compacted powder increases the risk of a malfunction when an extinguisher is activated. As a result, DCP extinguishers placed on mobile equipment need to be serviced more frequently. DCP extinguishers also pose serious operator and environmental hazards. When used in confined spaces, they can affect visibility and the fire respondents’ capability to effectively suppress the fire, or to safely evacuate an area should the fire spread out of control.

A much more effective and “greener” solution comes in the form of water-mist handheld fire extinguishers. Utilising water as the main agent and nitrogen as a propellant, these can extinguish most types of fires, including rubber, plastic, diesel, and petrol fires, as well as electrical fires rated up to 245 kV.

The atomised mist generated by the extinguisher increases the surface area of the water by more than a hundredfold. Micro-droplets rapidly turn into cold steam on contact with very hot or burning materials, increasing the surface area by a further 1 600 times, while the endothermic reaction effectively cools down any hot surfaces in the immediate environment.

In other words, not only is the fire extinguished, but any hot spots also cool down without any thermal shock. The thermal heat radiation barrier created allows the operator to approach the fire to deploy the extinguisher without sustaining burns. A protection mechanism, meanwhile, eliminates any false alarms; a heat-sensitive pressurised activation tube ruptures when exposed to heat, opening a differential valve on the main cylinder to activate the system.

“We assist mining operations to mitigate any risk posed by fire, which can affect productivity and profits,” says ASP Fire CEO Michael van Niekerk. “The fire engineering expert designs systems to suit individual vehicles and their specific requirements. This means examining the conditions not only inside the vehicle, but also within the surrounding environment.”

ASP Fire operates across the entire African continent, designing, installing, and maintaining a full range of fire detection and suppression equipment.

Apart from the water-mist handheld fire extinguishers, ASP Fire also offers an Aqueous Film Forming Foam (AFFF) for fire-extinguishing and vapour suppression of hydrocarbon fuel fires. The AFFF blanket blocks oxygen supply to the fuel and cools any hot flammable liquid by effectively sealing the surface.

Published by

Jaco de Klerk

JACO DE KLERK is editor of SHEQ MANAGEMENT and assistant editor of its sister publication FOCUS on Transport and Logistics. It’s nearly a decade later, and he is still as passionate about all things SHEQ-related since his first column, Sound Off, which he wrote for this magazine as well.
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