Underground coal mining requires safe, effective and durable lighting solutions. By improving visibility, reducing glare and decreasing maintenance requirements LED technology is enhancing safety in these environments.
Improved visibility is critical in maintaining a safe working environment underground, with poor lighting cited as a contributing factor in many underground accidents.
Glare is a significant issue in determining the design of illumination systems for underground coal mining. Traditional fluorescent lighting creates a wide and broad dispersion of light which generates spill light that can contribute to reflection or glare off PPE cap shields.
In comparison,LED light sources are directional where 100 per cent of the light emission from the LEDs is directed onto the task area, maximising lighting efficiency, minimising spill and reducing the instances of glare. The white light emissions from LED sources also allows for more precise colour recognition when compared to that of fluorescent lighting. This provides a strong contrast to black backgrounds and a high perception of illuminance.
Reducing maintenance requirements
By design LEDs reduce maintenance requirements and increase safety through reduced downtime, instances of failure and maintenance. Also, LEDs last significantly longer than fluorescent lighting options reducing maintenance costs and the instances of individuals conducting lighting maintenance in hazardous areas. LED manufacturers state a useful working life in excess of 50,000 hours, equating to over five years of 24 hour use. In comparison, the working life of a fluorescent light is significantly less than five years and therefore requires more frequent changeout of the light source, more maintenance activity and potential operation impact. LEDs do not typically catastrophically fail, as is usually the case with fluorescent lighting, but rather the light output generally decreases over time. This allows for a regular maintenance schedule and replacement prior to failure, maintaining consistency of lighting thus improving safety underground.
Durability is paramount underground where lighting is required to withstand high levels of vibration and mechanical movement as well as high pressure washes and cleaning to remove surface dust. LED fixtures for underground mining are made of clear solid resin and are IP66 rated making them more compact and robust.
Decreasing power requirements
The industry is trending towards intrinsically safe low voltage lighting. This trend is due in part to LED technology that operates at lower voltages in comparison to traditional lighting options operating at higher voltages. Specialised low voltage power supplies provide regulated 12VDC power that has multiple levels of over voltage and over current protection circuits to ensure that should an overload or short circuit occur, there is not enough current to create sparks to ignite any presence of volatile gasses.
Longwall lighting solutions
Burn Brite, a Member of the Ampcontrol group, has developed an innovative IS LED Lighting System that mounts high intensity, long-life LEDs into a low profile static dissipative light enclosure. Designed with safety and ease of maintenance in mind the lighting system has been installed in many Australian longwall mines.