Offering challenging conditions that range from tight, dark spaces underground to wide expanses of open, rough ground on the surface, mine sites may be the most difficult industrial setting of all to adequately illuminate. LED lighting packages with greater light output and lower energy usage are offered on many newer underground machines.
The most common lighting tools in mining are probably the trusty cap lamp or a sturdy flashlight, but new technologies found in the latest products shine brightly when it comes to lighting larger spaces
By Russell A. Carter, Managing Editor
Effective lighting is essential for productive, safe mining operations—underground, where illumination levels vary from pitch darkness to blinding brightness from one area to another; and on the surface, where half of daily mine activity takes place at night and even daylight operations can be obscured by dust, fog, rain or snow. Given the variability of conditions from site to site, and the particular needs of surface and underground operations, mining may be the most difficult industrial activity of all to illuminate properly.
Job site lighting is often taken for granted as being correct for the immediate environment, and to many workers the light emitted by one type of product often looks pretty much like the light coming from another. However, the performance characteristics of well-designed lighting products can be tailored in several ways to provide proper illumination for specific activities and local conditions, and when chosen and installed correctly can spell the difference between a safe or unsafe site, and a comfortable or unpleasant shift experience for miners.
Lighting awareness is of growing importance for an industry in which the workforce is skewed toward the extremes of the age spectrum, employing many older workers who typically have diminished night vision, and a rising population of younger miners who, although their night vision may be excellent, aren’t totally familiar with the hazards posed by darkness in their surroundings or work routines. Studies dating back several decades offer proof that inadequate or improper site lighting has been an ongoing complaint from miners, particularly underground workers.
Apart from safety considerations, newer lighting technologies can offer significant savings in energy consumption, maintenance requirements and replacement costs, all of which are hot-button budget items in a financially stressed industry.
Both above and below ground, non-wearable lighting equipment can be broadly categorized into units designed for mobile machine mounting, area or bay lighting and transportable work/inspection lights, although a number of lighting products are versatile enough for use on mobile and stationary structures, both above and underground. Further along in this article, some recently introduced products in each of these categories will be presented. But first, a look at why and how the latest lighting technologies can benefit the industry.
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Nordic Lights’ latest equipment lighting solution is the Scorpius LED N4401 QD work light (upper left), whichfeatures a proprietary vibration dampening system for improved service life. Hella’s HypaLUME LED flood light (upper right) contains 56 LEDs, producing more than 20,000 lumens of light; and the company’s Power Beam 1500 low-wattage, high-efficiency lights (middle) are ideal for use on battery-powered vehicles. Phoenix Products’ SturdiLED series (bottom) is available in AC or DC-powered versions with light outputs ranging from 1,600 to 2,900 lumens. |
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Lighting the Way
In the United States, the National Institute for Occupational Safety and Health (NIOSH) has for a number of years studied the types and methods of lighting used in mines, with the goal of reducing accidents through better illumination; specifically, the agency looked at ways to reduce slips, trips and falls (STF) underground, to reduce vision-robbing glare from lighting setups and to take a closer look at the visual needs of an aging workforce. Dr. John J. Sammarco, a NIOSH lighting expert who has published numerous papers on NIOSH’s lighting research activities, pointed out in a 2013 presentation that 80% of a worker’s perception of the environment around him or her is visual—and that lighting affects more than just a worker’s visual performance; it can influence physical body movements. Research indicates that good lighting enables better balance and body position for workers, leading to improved hazard recognition and less STF. Dr. Sammarco also noted that the introduction of light-emitting diode (LED)-based lighting offers a new and highly efficient route to better workplace lighting, providing a better quality of light at lower overall cost.
Although LEDs are not the only lighting technology that offers intense illumination in a mining environment—sodium, xenon and mercury vapor lamps, and even halogen bulbs are often used and familiar in industrial applications—LED fixtures potentially solve a number of issues specifically associated with mine lighting:
- Resistance to vibration damage – LED lighting employs solid-state components that aren’t as easily damaged as fragile internal filaments or glass elements used in incandescent and other lighting products.
- Performance improvements – With some areas in a mining operation requiring illumination up to 24 hours per day, energy consumption and maintenance or replacement requirements can be a significant factor in lighting costs and efficiency. LED lighting product suppliers claim that a changeover to LED lighting can save mine operators 50%–70% in energy (kWh) usage, and units will last 30,000–50,000 hours before failure. LEDs do not require a lengthy warm up to achieve peak brightness, are dimmable and don’t require the cool-down period needed by other lighting methods to reach a safe fixture-surface temperature when used around explosives.
- Quality of light – Light from individual diodes inside an LED unit can aimed, through lens design, very accurately to achieve specific results in terms of illumination level and reduction of spillover or glare. NIOSH’s research, according to Sammarco, also shows that LED units provide a “whiter” light that offers workers better depth perception, color rendering and visual performance.
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| Phoenix Products’ HDL-LED Series (left) is designed to replace linear fluorescent fixtures in harsh environments, as is DTS’s line of linear tubular LED light fixtures (right). | |
Choosing Correctly
Probably nowhere else in the mining environment do lighting products encounter tougher conditions than those typically found in underground operations. To explore the problems and solutions that original equipment manufacturers (OEMs) must consider when designing lighting packages for mobile underground equipment, E&MJ asked Daniel Hawkins, a marketing support specialist for hard-rock mining vehicles in Caterpillar’s Underground Mining group, to comment on general trends and issues associated with underground equipment lighting.
E&MJ – What are the newest technologies for mobile mining equipment lighting? Are there any significant differences between OEM lights and after-market replacement lights for mining equipment?
The newest technologies for LED lighting focus on the internal controller and the quality of the light-emitting diode—which are steadily becoming more efficient and have a projected life expectancy of 30,000 hours or more. There is no significant difference between OEM and aftermarket lighting, although warranty terms and costs can reflect the quality of some lights.
E&MJ – What should a mine fleet operator consider when replacing or upgrading mobile equipment lighting, in terms of effectiveness, cost and maintenance?
The highest-priority attributes that mining customers consider are cost and ability to perform. Lighting machinery in any underground application can be a challenge due to unique environments. With high temperatures, humidity and a small working area, underground mining equipment is subject to some of the harshest working conditions in the world. Cat LED lights, for example, are designed for long life and zero maintenance.
E&MJ – How does lighting on underground mobile mining equipment differ from surface lighting systems in terms of hardware design, illumination pattern, quality of light, etc.?
The design of the light does not change between surface and underground. Gener-ally, [lighting products] can be utilized across many applications, with some products more suitable than others. For Cat’s underground equipment, the illumination pattern is determined by the narrow galleries of underground mines. Underground loaders and articulated trucks are equipped with the right selection of narrow/spot beam and flood/wide beam lights to cater for all conditions in an underground mine. The flood/wide-beam lights light up wide areas during digging and truck loading, while narrow/spot beams light up the gallery for maximum visibility while tramming or hauling. Trucks in a haulage application will depend on sufficiently wide-angled beams for cornering and maneuvering while narrower beams light up the incline/decline ahead.
E&MJ – Are there any well-known standards for mine equipment lighting?
The typical standard for any light in the underground environment is to be robust, shockproof, dustproof and waterproof. Typically, 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 when washing the machines on which they’re mounted.
E&MJ – In the absence of a standard or guideline, how can a mine operator determine what type of lighting is considered adequate for safety and productivity in any given area?
The color temperature of an LED light can affect visibility in an underground mine. The Kelvin temperature (light color) will either increase or decrease the visibility in dusty or humid situations. The lower the light temperature, the more effectively the light beam will penetrate. A yellow light rated at 4,300 K will penetrate through dust and water while a higher-temperature light rated at 5,000–6,000 K (white to light blue) color mimics daytime light and illuminates completely dark environments well. Caterpillar’s LEDs are selected to provide a balance of color temperature between yellow and blue light to accommodate any likely environment.
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Lights for Underground…
Many of the latest mine-duty work light models are versatile enough to be used both underground and on the surface, and on both mobile and stationary applications. A wide selection of beam patterns, mounting options and power ratings allow OEMs and equipment owners to tailor lighting packages for general use or specific needs. Here are a few examples from some of the industry’s leading suppliers.
Finland-based Nordic Lights develops and manufactures LED, Xenon HID and halogen work lights for heavy-duty off-road applications. The company said its latest offering, the Scorpius LED N4401 QD work light, is designed to provide superior illumination with an evenly distributed light pattern, providing an operational output of 4,200 lumens at 50 watts of power. The light is available in four light patterns; high beam, low beam, wide flood and flood, measures 108 x 104 x 116 mm and weighs 1.6 kg. The “Quake” version of the light is equipped with the company’s Quake dampening system, which distributes vibrations and shocks uniformly to improve durability.
The light provides an optically consistent distributed light pattern and requires minimum maintenance, according to the company, featuring a replaceable lens, waterproof construction, and protection against load dumps, over voltage, reverse voltage and overheating. It is built to IP68, IP6K9K standards as well as SAE J1455, and withstands salt mist in accordance with ISO 9227 for more than 240 hours. The LED N4401 QD meets the EMC standards of ISO 13766, ISO 14982, ISO 7637-2 and CISPR 25 Class 3. It is available with five different lens colors.
Hella recently introduced its HypaLUME LED flood light, designed for reliable performance across an extreme temperature range of -40°C to +50°C (-40°F to +122°F) with no decrease in light output. The lamp incorporates 56 LEDs to produce more than 20,000 lumens. According to the company, the HypaLUME’s LED driver electronics ensure that the light output remains stable from 18 to 52 volts. Consuming 240 watts at 24 volts DC power, the product provides a usable light level equivalent to a 400-watt metal halide light. It is available in flood, close range and long-range illumination models.
The HypaLUME is protected from reverse polarity and short circuit faults, and sealed and tested to IP6K9K. A variety of bracket options along with a wide range of aiming options are available, including a 50G mobile equipment bracket, a 15G fixed lighting bracket, and pole and cable suspension mounts.
Another new Hella product is the Power Beam 1500, an LED work lamp that is claimed to provide the light output of a standard 55-watt halogen light while using only 22 watts of power. This capability, according to the company, makes it ideal for use on vehicles that operate by battery or where a vehicle’s alternator is already heavily loaded. The lamp’s compact design (4.4 in. H x 4.4 in. W x 2.3 in. D) is convenient for use on small vehicles and equipment and in tight mounting areas.
The Power Beam 1500 LED’s light output of 1,300 lumens is produced by six LEDs with a service life of approximately 16,000 hours. The product is available in several configurations featuring a choice of illumination patterns and a stainless steel trunnion bracket or pendant mounting. It can be used with both 12- and 24-volt systems and features polarity reversal protection, an LED fault bypass, and protection against EMC interference. The LED fault bypass or LED error recovery ensures the work light will function even in case of an individual LED failure.
…and Surface Equipment
On the surface, lighting packages for mobile equipment must withstand most of the same hazards and conditions encountered by underground equipment, including vibration, moisture, dirt and temperature extremes, while providing performance to meet the lighting needs of much larger equipment.
Phoenix Products’ newest mine lighting innovation is its SturdiLED series. The mid-level LED floodlight offers an AC or DC driver with multiple output options ranging from 1,600 to 2,900 lumens. Two optical packages (28° and 45°) accommodate applications including shovels, drills, cranes, haul trucks, utility and emergency vehicles, and lighting towers. Phoenix uses marine-grade die-cast aluminum housings with a powder coat finish for additional protection against corrosion. The SturdiLED also utilizes a replaceable, impact-resistant, and UV-stable lens, as well as a conformal coated circuit board and fully potted driver. The fixture is ETL listed to UL 1598 and 1598A, IP67 rated, and is pending for CE Certification. The SturdiLED comes in six finish options including black, gray, white, bronze, silver and green.
J.W. Speaker’s Model 526 XL 6- x 6-in. (15 x 15-cm) square LED work light is available in flood, trapezoid and spot beam patterns, as well as a new anti-glare beam pattern. According to the company, conventional haul truck lights create unsafe glare that can blind oncoming vehicles, but angling them downward impairs their effectiveness; to solve this problem, the 526 XL’s anti-glare beam pattern has been engineered to maximize visibility without blinding oncoming vehicles. The Model 526 XL is available with either a durable glass or polycarbonate lens, and is constructed of a die-cast aluminum housing, which is sealed to IP69K. A specially designed driver board provides advanced thermal management.
Enclosed spaces found at typical mining and processing operations may be safe from some environmental threats such as direct exposure to rain, snow, wind or temperature extremes—but they’re still subject to harsh operating conditions that may include constant vibration and corrosion, just to name a few.
Earlier this year, Phoenix Products introduced the HDL-LED Series, designed to replace linear fluorescent fixtures and featuring marine-grade construction, conformal coated circuit boards and a potted driver to withstand harsh conditions. The standard fixture is suitable for continuous row mounting in machine houses, engine rooms, mining equipment, conveyor lighting and other similar applications. The HDL-LED Series lights provide several output levels, lens options, mounting capabilities and emergency battery backup. The series includes 30-, 60- and 90-W configurations delivering 3,000, 6,000 and 9,000 lumens, respectively. The fixture features an AC or DC driver with a dimmable option, and is retrofittable in existing Phoenix installations.
The DTS division of Thomas & Betts Corp., part of ABB Group, offers emergency lighting, linear tubular lighting and floodlights employing LED technology. All three fixture types, according to the company, offer ATEX and/or IECex Zone 1 certifications.
DTS said its XFFL Range tubular LED fitting has an operating life of more than 100,000 hours, output of 5,000 lumens with 100% yield, components mounted on a sliding gear tray to facilitate installation and maintenance, and may be retrofitted into existing fixtures mounted with T8 lamps. The DTS XFFL LED tubular luminaire includes a cable gland and brackets, and is available in polycarbonate or glass.
The DTS XLF Range LED floodlight is claimed to provide an operating life of more than 50,000 hours, narrow-beam output of 9,000 lumens and wide-beam output of 7,000 lumens, along with instant start and re-strike. It will operate in cold environments without warm up.
Spreading Out
The need for lighting larger spaces often requires tower-mounted lights to provide illumination throughout active mining areas, dumps and stockpiles—such as the recently introduced QLT H50 light tower from Atlas Copco Portable Energy. The QLT H50, which replaces the previous QLT H40 model, uses four 1,000-watt metal halide lamps mounted on a vertical hydraulic mast with a maximum height of 9 m (29.5 ft), 340° rotation and four stabilizers for safety and support.
The QLT H50 has an integrated control panel, with the light controller built into the canopy to avoid contact with hot or moving parts during operation; it sequences the startup of each lamp to minimize the typical risk of alternator and ballast failures. Pulse and Pause Ballast technology is utilized to prevent lamp filament damage through ballast pulse repetition.
Key elements of the light tower, including pulleys, steel cables, cable clamps and lifting beam, have been certified as European Union (EU) safety yield factor 5, signifying that these elements are five times “over-specified” according to EU safety norms. The vertical hydraulic mast is designed to remain stable in winds of up to 80 km/h (50 mi/h).
According to the company, service costs during the unit’s lifecycle are minimized by the long service intervals. Large hatches reduce maintenance time by facilitating access to all key components of the light tower, including the engine, alternator, hydraulic system and electrical system. The oil and water drains are alsoeasily accessible.
Larson Electronics’ LM-30-8-5S-4X1000W-EW-SM-RD five-stage telescoping light mast features a 360° rotating boom and a removable mast head that is equipped with four 1,000-watt metal halide lamps on a telescoping boom that can be extended to 30 ft (9.1 m) for maximum area coverage and collapsed to slightly more than 8 ft. The mast is elevated using an included 3,500-lb-capacity (1,600 kg) electric winch with 3/16-in. galvanized braided cable. The high output metal halide fixtures produce a combined total of approximately 440,000 lumens at 4,000 watts in a wide flood light pattern capable of illuminating approximately five acres.
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In a departure from typical industrial light-tower configurations, Pennsylvania, USA-based 8:12 Illumination launched a new energy-efficient LED light-balloon product. Available in 200- and 400-watt models and offering a low amperage draw—the 200-watt version pulls 2.5 amps of power vs. a 2,000-watt halogen light pulling 16 amps, for example—the units are claimed to provide nonblinding light in a compact, easy-to-move and instantly re-strikeable package. Both the 200- and 400-watt models can be powered from common electrical outlets, a small solar panel or a battery pack in remote locations. The low amperage draw also allows an inverter to be used instead of a generator, and two lights can be run from a single 1-kW generator.
Portable Lights for Personnel
ECCO’s new EW2461 Series magnetic rechargeable LED work lamp features a high-intensity 600-lumen flood beam and three operating modes (100% intensity, 30% intensity and SOS flashing) and a long-life, lithium rechargeable battery that allows the work lamp to be operated for 3–4 hours before recharging is required. A cigarette socket charging lead is supplied and an AC adapter is also available.
J.W. Speaker offers a kit version of their popular Model 523 rectangular magnetic mount LED scene light. This kit features the Model 523 with magnetic feet, a 32.8-ft (10-m) vehicle charging cord, a 25-ft battery power cord, and a carrying case. Providing 3,900 effective lumens of light, this product is claimed to be an ideal lighting solution for anyone looking for a powerful, portable scene light that can be easily mounted and removed from their vehicle.
This light is constructed with a polycarbonate lens, die-cast aluminum housing, and is sealed to IP67 for protection from dust entry and water immersion up to 1 m. The shock- and vibration-resistant LEDs produce bright, white light in a wide flood beam pattern.
