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.
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