Lighting
When underground mining first began, workers probably used ordinary household lamps in order to see what they were doing and where they were going. Only gradually were special miners’ lamps made, responding to particular underground needs – a technological evolution which lasted for thousands of years. The best innovations were certainly those made between late Medieval times until the end of the 19th century.
The oldest form of mine lighting in Central Europe was simply a wooden torch. Pieces of highly resinous larch or pine wood, 10-15 cm long, were cut into flat or rectangular strips, often impregnated with wax. The first findings of the Celtic mining industry for rock-salt at Hallstatt go back to 900-400 B.C. These early miners held their torches in their mouths. When they lost their teeth, they were obliged to abandon their means of livelihood.
Later, torches were set in metal brackets, and some were used in the Tyrol right up to the 19th century.
In Egypt, open lamps burning oil or fat, made of gold, bronze or clay, were already in use thousands of years ago. The first clay lamps were probably brought to Central Europe by the Roman legionaries, and there were even some very simple lamps in stone. Vegetable oil or animal fat was used as fuel. The first lamps in wrought iron go back to the 16th century. Later, single parts were welded with brass, and finally proper lamps were made in one piece. Simple lamps were always open, but later, in the 17th century, oil lamps were closed, to stop the oil from spilling out. We do not know why this type of lamp is called Froschlampe or Ölfrosch (Frosch means frog). Around the mid-18th century, a special oil lamp came into being, small and light: the Schelle or Kopfschelle (head-lamp): as its name implies, it was worn on the front of the miner’s cap, clearly illuminating his working field and leaving his hands free. This advantage was also given by the Freiberger Blende, a lamp used mainly at Freiberg (Saxony) and Harz (another region), with a container in lime-wood, slung round the miner’s neck on a cord. The source of light was a spherical oil lamp, or simply just an open lamp or even a candle. It should be recalled here that in the Alps, ever since Roman times, candles were often used on all kinds of supports. They were in bees’-wax or tallow, with wicks made of dried animals’ tendons, or wool or linen thread.
The age of oil lamps ended quite suddenly with the introduction of carbide lamps, around 1900. They gave a light at least ten times brighter than traditional lamps, and were also more resistant to draughts and percolating water.
According to where they were used, all these lamps had various shapes, from simple hand-lamps to the head-lamps on miners’ caps, and special decorated lamps.
The carbide lamp consisted of two separate parts. The lower container, mainly in thick sheet metal or cast iron, held the carbide, and the upper part, generally in brass, was filled with water. An adjustable aperture allowed the water to drip on to the carbide, thus producing acetylene, which came out of a nozzle and burnt with an extraordinarily bright flame.
Carbide is a compound of carbon and calcium (CaC2), produced by intense heating (to 2,570°C) of quicklime and coal or coke (CaO+3C) = CaC2+CO). The contact between carbide and water produces acetylene (C2H2).
It should also be remembered that oil and petrol lamps, safety lamps, were mainly used in coal mines, where the danger of their blowing out as a result of draughts was high. At great depths, easily inflammable methane gas was encountered, and the use of open-flame lamps caused terrible explosions.
The last stage in the development of mining lamps was the introduction of electric head-lamps in the 1960s. However, there are still some carbide head-lamps today, the container of which, like the battery of an electric lamp, is fixed to a belt round the miner’s waist. The advantage of an open-flame lamp is that, when there is little oxygen, the lamp goes out, and the miners are thus warned of their danger.
Steady illumination in mine shafts is now of course provided by compressed-air lamps, which work like dynamos but function by compressed air.
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