Mining has long moved on from the simplistic Davy safety lamp; early advertisements for electric lighting stressed the role of such equipment not only in supplying illumination but also in combating sight-related problems such as nystagmus.
Underground lighting products have to be resilient and reliable; harsh conditions in British coal mines, for example, mean that specifications for lighting are stringent forcing mining companies to meet highly demanding standards.
Good lighting - the cost effect
Mining operations are today supported by a lighting industry whose technological advances improve cost-effectiveness and safety. Cap lamps are lighter and more reliable – the era of "sealed for life" lamps requiring minimal maintenance is now a welcome feature of the industry.
LED technology is acknowledged by many as offering longer operating autonomy; a nickel headpiece used as the heat sink for the light source can help produce a guaranteed wattage. Batteries too can play their part with the arrival of ultra-light-weight lithium-ion units, which can keep a lamp going for the longest possible shift underground.
From its beginnings in north-east England in 1929, Victor Products has seen its market expand well beyond the UK. The company's new ML102 flameproof Ex d LED product, aimed at providing light at the coal-face itself, has been developed with markets in India in mind.
ML102 is currently undergoing approval in India, where Victor is looking forward to winning major orders. To support its Asian sales drive, Victor has opened a sales office in Beijing and a factory in Shanghai.
In overall terms, the company is shifting from traditional fluorescent lighting to a full range of LED products. Manufactured in corrosion-resistant gunmetal, ML102 will operate in temperatures from -20C to 45C, and at voltage options from 80V to 240V AC/DC.
The traditional British market has not been neglected despite the almost total disappearance of coal mining in Britain. For example, Victor has equipped a new face at Kellingley Colliery coal mine with 100 units.
Of course, rough mining conditions are not a monopoly of the UK. Shafts in South Africa run miles into the bowels of the earth – the last place you would want your batteries to run out. Rustenburg, South Africa, hosts the head office and manufacturing facility of Optimac, and is located near some of the largest mining operations in the world.
Leading Optimac's range is the HaloLite miner's cap lamp, manufactured to ISO9001. The lamps exploit the latest lithium-ion battery and LED technology and are exported worldwide to countries including Peru, Chile, Zambia, Australia, Mexico, Zimbabwe, Botswana, Germany and the USA. Claims by Optimac for the H1 include a weight one seventh that of lead-acid lamps and a lamp-life 80 times longer than lead-acid.
Battery technology for mining
Also sold in South Africa are the products manufactured by First National Battery, which made its first batteries in 1931. More particularly, the range of batteries can be used with automotive starters, mining traction and materials handling machinery, and miners cap lamps, and for solar power storage.
Standby batteries are also extremely important. Several major gold, coal and platinum mines use locomotive traction and mine lighting batteries produced by First National Battery (as do local power generation utilities, railways and telecommunications companies). They in turn rely on standby batteries which feature in the company's range.
First National Battery's annual output is over 2.2m batteries, which are used locally or exported to more than 30 countries worldwide.
There is, in addition, a facility for recycling old lead acid batteries through an in-house battery breaker and smelter; lead and polypropylene can thus be reused in the manufacture of high quality lead alloys and plastic components.
Based in Canada but selling its products worldwide, NL Technologies (NLT) designs and manufactures underground lighting and digital communications solutions for the mining and tunnelling industries. It has manufacturing / assembly locations in Canada, Australia and Chile along with global distribution partners. NLT's largest market is the USA but substantial sales are recorded in Europe and South America.
The company's Northern Light cap lamp systems are designed to offer integrated radio-lighting and power-take-off systems as well as RFID and Wi-Fi tracking tag options. NLT's Eclipse cap lamp incorporates LED technology and lithium-ion battery technology to provide what it describes as "a lighter, brighter and more cost-efficient lighting system. "Its Polaris cordless all-in-one cap lamp integrates the battery and light source in one enclosure, and is approved by MSHA, IECEx and ATEX.
Not every customer requires clear lighting from traditional strip-lights or cap lamps. KSE-lights of Germany offers signalling systems which incorporate a signal lamp with high-power white LEDs when seen from the front and red, green and yellow SMD-LEDs viewed from the rear. There are also hand-held lights as required.
Low cost and green – emerging lighting technology
China's Xi`an Liyuan Optical $ Electricity Technology Company manufactures an LED mining lamp with a lithium manganate (LiMn2O4) battery. Here the stress is on green technology and energy saving, as well as maintenance-free operation and low weight.
The light is designed to avoid sparking; the manufacturing processes are aimed at avoiding poor soldering, ensuring that protective paint is used and employing plastics that are anti-static. Maximum battery box dimensions of 93mm x 41mm x 120mm and a weight of 550g help portability.
Sometimes a mining company will work with an equipment manufacturer on a lamp which meets particular specifications, a "bespoke" solution. Manchester, UK-based Mutech has a single-site electronics design and manufacturing business specialising in providing these solutions. A key element of Mutech's operations is formulating designs that work in increasingly demanding marketplaces.
The manufacturing service includes purchasing, tooling, CAM preparation, through-hole assembly, inspection, testing and packaging, with a fast turnaround if required.
Mutech cannot be accused of insularity; its talented employees are happy to communicate with you in fluent Polish, Spanish, Hindi, Gujarati and Marathi, and even a spot of French and German.
When it comes to the old-fashioned Davy lamp, they are found less and less frequently and Queensland, Australia has actually banned them after an underground explosion at the Moura Mine. Perhaps it is for the best that the safer modern lamps are being adopted all around the world.