Mine Lighting and Improving Effectiveness and Safety with LEDs|
Article- December 2011 By Magnalight.com
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Ever since electrically powered lighting became the dominant form of illumination in mining operations, little has changed in mine lighting technology. Despite major improvements in lighting technology as a whole, lighting for mines has remained somewhat unsophisticated and unimproved due to a host of factors including the abusive conditions within mines, the ever changing illumination requirements as mine size increases, and the need to provide power. The last decade has seen significant improvements however as lighting technology has continued to make inroads against the issues. Issues of durability and providing power have been reduced with the introduction of LEDs, and the ability to provide compact light sources that can be moved as the mine expands has also improved with the introduction of the LED as well.
Electrical lighting for mines has predominantly been of a few specific types including incandescent lamps, HID luminaires, and fluorescent tubes. The problems with such mine lighting technologies stems largely from their power requirements and low durability factors. Each of these lighting types is of a construction that utilizes fragile materials such as glass and thin wire filaments that hold little resistance to abusive handling and conditions. Compounding the durability issue is the hazardous nature of the mine atmosphere and the potential for fires or explosions should a hot filament or escaping gas from a shattered lamp ignite flammable mine gases. Because of these durability issues, mining lights have been typically lower powered if possible, and the fixtures used to house and protect them oftentimes excessively bulky and weighty, making them difficult to relocate as the mine increases in size
Power issues for mining illumination is also compounded by traditional lighting technologies due to the inefficient nature of incandescent lamps and the higher wattages needed with HID and fluorescent lamps to produce adequate illumination. Providing power is difficult due to the large amount of power needed, the long distances it must cover before reaching the lamps, and the non permanent nature of the mining environment. Because of these issues, mine lighting is predominantly comprised of equipment mounted fixtures or portable systems carried on the mine workers person.
In order for mine lighting to be effective, it must accomplish several goals with a maximum degree of practicality.
Good mine lighting will make potential hazards more visible and thus increase safety. Damaged lines and cables, supports and equipment left lying in the workspace, and faults and potential shifts in rock faces are all more easily noted and identified with an increased level of illumination. Furthermore, lighting of higher quality, with better color rendering and contrasting provides a higher degree of visual acuity, further improving the effectiveness of visual inspection. As a result, the incidence of accidents and injuries can be reduced with an improvement in mine illumination. Additionally, providing illumination with greater scope offers improvements in visual acuity as well. Since much of the lighting within mines is from cap lamps and narrow beamed equipment lighting, detecting movement or details outside the local light beam is difficult. Increasing the spread of lighting to include more of the peripheral field provides mine workers with a greater degree of visual awareness, allowing them to spot potential problems sooner, and thus avoid or address them more effectively.
As well as safety, effective mine lighting provides the potential for improved work performance. Many studies across several industries have established the effectiveness of increased light levels in regards to improved productivity. With higher light levels comes improved worker alertness, greater attention to detail, and a reduction in performance reducing mistakes and errors. The incidence of worker ailments and fatigue has been shown to drop, with a lower reported number of cases involving headaches, lethargy and fatigue. Also, effective lighting has been shown to have an effect on moral and overall psychological perception of the workplace, providing the potential for further improvements through reduced worker absenteeism and greater importance placed on tasks.
In order for these improvements in mine lighting to take place, the aforementioned issues with durability and power supply must be addressed. New lighting technology like solid state lighting or LEDs, provides effective solutions to these issues and provide for increased lighting effectiveness as well. Since LEDs are solid state, they have no glass or gases used in their construction. Their design is more akin to that of a transistor than a light bulb, making them extremely resistant to damage from impacts, vibrations and shocks. This durability makes the LED an ideal choice for mine lighting where abusive conditions are a normal part of operations. Since providing power for illumination within mines is problematic, most lighting is typically equipment mounted or portable worker carried units. This exposes lighting equipment to extreme duress from the oftentimes repetitive and occasionally violent movement of machinery, and the frequent jarring and dropping of workers as they perform their duties. Normally, traditional lighting is easily damaged by such abuse, but since the LED has no fragile glass or filaments, sensitivity to such treatment is greatly reduced.
LEDs provide further improved effectiveness through their lower power requirements. A typical illumination grade LED is up to 80% more efficient than an incandescent lamp. This allows the LED to produce more light per watt, resulting in a lamp that can create as much light as the incandescent while using only a fraction the amount of electrical power. This allows workers to reduce the size and thus the weight of battery packs, and the number of replacement batteries used in portable lighting. Equipment benefits through increased light levels with reduced drain on electrical systems, allowing longer run times on limited power reserves
As well as increased durability and efficiency, LEDs offer improvements in safety. Illumination grade LED lighting produces brighter light that is whiter and of better contrasting ability than incandescent lamps. This improved light quality results in better visual acuity through clearer contrast between objects and details, allowing more effective inspection and identification of potential safety issues. The high quality illumination of LEDs lends itself well to improved worker alertness and productivity through better color rendering and color contrasting which has been shown to have a direct effect on worker moral. More important from a safety aspect however, is the cool operation and durable design of the LED and its suitability for hazardous atmospheres. With mines often a source of flammable gases, cooler running lighting with no fragile glass or hot filaments provides an increased degree of safety when used in explosion proof approved fixtures.
While it is only in the last decade or so that mine lighting has begun to really benefit from new lighting technology like LEDs, current rapid advancements in design and technology are quickly closing the gap between mine lighting and other industries.