Lighting plays a crucial role in mining industry. The miners depend upon visual cues to detect threats related to falls of ground, slips/trips/falls (STFs), moving machinery, and other safety hazards.All the major countries in the underground mining sector have their set own set of guidelines regarding safe mine lighting systems. These specifications are mostly set according to the type of mining and the internal/external environment of the mines. Usually the lighting devices are tested in government facilities. Also there are set guidelines for the amount of illumination needed in mines and these guidelines vary according to the workplaces.
Methane that is given off during coal mining can cause underground explosion. Thus, accounting to the threatening conditions, the lighting source used in mining activities should have two basic properties: intrinsically safe and explosion proof. An intrinsically safe light is one in which the current in the light is of low energy to avoid sparks and explosion in case of short circuits. In explosion proof lights, the explosion started by the source is contained in the device itself. Also the device will not become too hot to cause explosion.A low-pressure sodium lamp could not be licensedas the sodium in the lights could leak and mix with the water causing explosion.
The lighting system for underground mines should also have features such as high-levels of brightness and intensity, high output per unit of watt, low-voltage and current requirements, low radiated heat, lightweight, resistant to shock, vibration and atmospheric pressure fluctuations. The light source should draw constant current instead of constant voltage. The usual standard for any light in the underground setting is to be vigorous, shockproof, dustproof and waterproof. Ingress Protection (IP) is rated at a minimum IP67, but recent advances allow lights to be uprated to IP6K7 and IP6K9K, which provides more protection against high-pressure sprays used while washing.
The type of lighting source available in the market are LED, tungsten filament, incandescent lamps, fluorescent lights, xenon and mercury vapor lights, metal halide, high and low pressure sodium. The lighting industry have facilitated the development of many innovative tools to ensure safety in mines. The lightning market can be differentiated by the product type as portable and non-portable devices. The portable devices mostly consist of cap lamp and flashlight. The non-portable types of lighting tools are segmented asmobile machine mounting, area or bay lighting and transportable work/inspection lights. However most of the equipment are versatile enough to be converted forstationary or mobile use. Current used in this equipment can be AC or DC. The stationary devices mostly use alternating current. The portable equipment such as caps run on DC batteries.
Light emitting diode is the most preferred type of technology in the mining industry. LED can provide around 50,000 hours of useful light that is nearly about 50 times more than the other available technologies. They do not have glass coverings or filaments that can break. As a result of the efficiency provided by LEDs, they occupy a major share in underground lighting’s market.
The trends in mining industry directly affect the demand of underground lighting systems. The fall in commodity prices has affected the mining industry globally. The developed regions such as North America and Europe have slowed the growth rate formining activities. However the developing countries such as India and China may provide a steady growth for mining industry. The infrastructure and industrial development projects sanctioned in Asian and African region will supplement the demand in underground mining industry in forecasted period. Thus the market of lighting systems for underground mining may grow in coming years.
Some of the companies that operate in this industry are: MineARC Systems, Elign Equipment Group, Wye Valley Associates Ltd, Coolon Pty Ltd., Mine Supply Company, Atlas Copco AB, Xerebrus Inc., Voltex Lighting, Hudaco Industries Ltd., Eaton, Victor Products, Metindustrial (Pty)Ltd., and Northern Lights Electronic Design, LLC.