Fire is a serious hazard in underground mines and outbreak conflagration can be extremely dangerous because of the following reasons:
- Constricted nature of excavations
- The potential quantity of noxious fumes and smoke
- Limited ability to quickly excavate from the mine.
As an employer, you have a duty of care to provide and maintain a safe working environment for your employees and equip them with the necessary fire safety training. In fact, the prevention of fires in underground mines should be your top priority since an accident can result in smoke inhalation, asphyxiation, serious or deadly burns, and even explosions. Thus, you must have a comprehensive mining fire protection plan.
Here is a list of considerations you need to take while preparing a mining fire protection plan.
1 – Conduct A Proper Risk Assessment
A comprehensive risk assessment is extremely important as it allows you to identify the relevant risks and create a plan that helps to mitigate those risks. Moreover, risk assessment also help in prioritising risks and determining where you need to place the most effort in prevention and control.
Risk assessment primarily encompasses the potential hazards listed below.
Sources of Fuel
Anything that can burn is potential fuel for a fire or even an explosion. Some of the most common fuels present in mines include:
- Firedamp (a naturally occurring mixture of hydrocarbon gases)
- Coal and/or coal dust
- Plastic materials and tyres
- Grease and mineral oils
- Plastic and paper
- Rubbish and other waste products
- Bottled gases such as propane and acetylene
- Other explosives
Sources of Ignition
You need to consider all the factors that can ignite a fire or result in an explosion. A source of ignition is anything that can get hot enough to ignite a substance or material in the underground mine. Some sources of heat may include:
- Internal combustion engines – air inlets, exhaust systems, hot surfaces
- Spontaneous heating of coal present in the waste
- Mechanical and electric equipment and machinery
- Incendiary sparks from cutting machinery picks
- Electrical sparking and hot surfaces from electric equipment and distribution systems
- Short circuits due to faulty wiring
- Natural sources such as lightning and electrostatic discharges
- Detonators and explosives
- Compression of gases or air
- Thermite reaction between steel/iron and light alloys that contain metals such as titanium, magnesium, or aluminum.
- Work that involves heat such as grinding, welding, and burning
- Smokers’ material such as matches, lighters, and cigarettes.
Sources of Oxygen
The main source of oxygen for a fire is generally the air that is present in the mine. Mines typically have a ready oxygen supply as the mine’s ventilation system continuously draws air from around the mine. Other sources of oxygen that you need to consider when carrying out risk assessment include:
- Oxygen-releasing chemicals such as hydrogen peroxide
- Bottled oxygen
- Compressed air
Once you have carried out a comprehensive risk assessment, you should provide fire safety training to all your employees on how to manage and mitigate these risks.
2 – Include Fire Compartmentation
The risks of a fire multiply as underground mines become wider and deeper. In such cases, building techniques and non-flammable building material are imperative in your fire safety plan.
It is extremely important for you to have airtight fire gates that are made with non-flammable material and equipped with penetration seals for cables, pipes, etc. Moreover, ventilation ducts that pass through the different partitions of the underground mine should also be made of non-flammable material.
3 – Ensure Proper Ventilation
Ventilation in underground mines plays a significant role in fire prevention. Noxious fumes spread quickly and they are often the biggest risk in an underground mine fire.
4 – Have Appropriate Electrical Installations
The electrical installations used in an underground mine for power supply or for the control of the ventilation system are highly likely to cause a fire. Thus, the location of electrical installations and the material of the electrical equipment must be selected with the utmost care. Ideally, you should use fire-resistant halogen-free cables that do not contain PVC.