Saucer-type Open Grease Lamps
The first type of mine light, the open saucer-type grease lamp, was popular in the 1700’s and was often decorated with ornamental figures such as roosters. These figures acted as good luck charms for the miner.
Later, candles made of hard tallow became a popular source of light within the mines. The candle-holder was adopted for use in the mines as well. It consisted of a 3/8-inch iron rod twisted into a looped handle at one end and a sharpened point at the other. Often there was a hook on the holder and when the point could not be driven into a suitable support, the holder could be hung from any overhang or protrusion in the mine.
Oil Wick Lamps
As mining progressed, oil wick lamps became increasingly popular because they were cheaper to burn than tallow candles and easier to balance and carry in the mines. Manufactured between 1860 and 1920, these lamps differed in size and shape but operated on the same basic principle.
A small conical font 1½ to 2½ inches tall and about 1-inch in diameter held the fuel and a hinged snap cap sealed the top. The long neck or spout extended up and outward from one side on the font. Opposite the spout, a wire hook was fastened to the font to fit on a miner’s leather or cloth cap. It looked like a small teapot with a brush hanging out the spout. The wick brought the fuel from the font to the tip.
The man who made the real breakthrough in this area was Sir Humphry Davy when he invented what is known as the Davy Lamp or a gauze-enclosed lamp. Although gauze alone could not guarantee that the flame would not come into contact with gases outside the screen, Sir Davy reasoned that a metal mesh would cool down the flame before it came into contact with any fire damp. These gases explode at certain temperatures but will extinguish a flame that is cooler.
To prevent miners from opening their safety lamp underground, considerable attention was paid to locks. Most safety lamps were equipped with a padlock, keyed setscrews, melted soft-metal locking inserts or magnetic spring-loaded latches.
In 1892, while working with lime, coal tar and a carbon mixture, Major James T. Morehead and Thomas L. Willson developed a brownish-grey substance that gave off a pungent smelling gas when mixed with water. This gas burned with a bright yellow-white flame and they called it acetylene. Within eight years the first carbide lamp was offered to the public.
Carbide Cap Lamps
The first carbide cap lamps weighed approximately four ounces and were four inches high and 1 ½ inches in diameter. The lamp consisted of two compartments that screwed together. The upper part contained water whose flow into the lower chamber containing the carbide, was controlled by a drip valve. A three-inch reflector directed a light of ten-foot candle power and was a great improvement over the tallow candle.
Miners are now equipped with battery powered or electric lamps. At first the electric light was too heavy and required a liquid electrolyte, which proved undesirable for several reasons.
A portable lamp is composed of two parts, the battery which furnishes the current, and the bulb. The bulb was perfected quickly but the battery was troublesome. In fact, none of the early experimental lamps proved successful, as the bulb required too heavy a battery. Also, leakage of acid was a serious problem. Today, the cap lamp uses a non-spillable battery and a parabolic reflector equipped with safety features that hooks onto the miner’s cap. Electric lamps came on market around the year1902 and have a lifespan of approximately five years.
The dawn of the electric lamp allowed the miner to work in any position without restraint, as it did not interfere with the free motion of the body. Lamphouses at the various collieries had facilities for charging, cleaning, and filling both electric lamps and oil safety lamps.
The methanometer is an instrument to measure the percentage of methane in the air in underground coal mines and has been designed to alert miners to the presence of potentially dangerous concentrations of this gas.
The first electrical methanometer for use in coal mines was developed in 1949. It was known as the W8 methanometer and was powered by an Edison cap lamp battery. Several types of hand held electronic methanometers were developed around the world during the 1950’s but the first independently powered instrument, the GP (general purpose) methanometer, was not introduced until 1961. The C4 methanometer was introduced in 1966 and was later replaced by the D6 which is still the main hand held electronic methane detector.
This instrument has been a useful tool enabling mining personnel to prevent thousands of explosions or fires and has undoubtedly saved many lives and helped to avoid countless injuries. The methanometer is arguably the most beneficial safety device ever developed for use in underground coal mining. It has helped improve the quality of life for hundreds of thousands of people involved in or dependant upon the coal mining industry.
Early Coal Cutters
Early coal cutters were either compressed air punching machines or electric cutting machines that made their first appearance in mines somewhere between 1861 and 1873.
The main purpose for coal cutting is to provide the coal with more room to expand when it is shot. The more room the coal has to expand in the shooting, the less it will be shattered. The cutting machine working ahead of a mechanical loader must be fast, because a place is loaded out many more times during a shift by a mechanical loader than is possible with hand loading. The cutting machine must be speedy enough to keep the cutting sufficiently ahead of the mechanical loader so as to give time for drilling and shooting and for other details that must be attended to before the mechanical loader returns to the working place.
A huge piece of machinery called a rotating steel toothed cutter runs along the coalface tearing at the coal. As the coal is broken away from the wall it falls onto a conveyor belt and is sent to the surface. Longwall mining requires less men to operate machinery as it usually only uses one massive cutter and the shafts or rooms underground do not have to be as big.
Central Machine Shop
The main function of the central machine shop is to repair and maintain electrical and mechanical equipment used in the mine. Typical jobs include the rebuilding of longwall stageholders, continuous mining machines, ram cars, scoops and roof bolters, overhauling longwall shields and fabricating chutes and hoppers for coal preparation plants at the mines.
Underground communications with the surface was an urgent factor when considering the isolation and other problems with which the miners could be confronted.
The telephone was invented in 1874, and three years later, in 1877, the first underground telephone network was installed in the Caledonia Mine, Glace Bay, Nova Scotia. The Caledonia mine phones were the first regular commercial or industrial telephones in Canada and the oldest electrical coal mine telephones in the world.
They were designed to be held in one hand and the person would talk into the “mouthpiece” which was then held to the ear and used as a receiver, or “earpiece.” Four slightly differing styles were produced during the latter half of 1877. Later, a separate transmitter and receiver replaced the inconvenient alternating of one piece between mouth and ear.
A pump-type extension post made of steel that can support massive amounts of weight, used as a temporary roof support and in the placement of the wooden roof support.
Wooden posts, jacks, roof bolts and beams are used to support the rock overlying a coal seem in an underground mine. A good roof support plan is part of mine safety and coal extraction. These supports are built around the mine tunnels just after they are dug.
Hydraulic Jacks (chocks)
Hydraulic jacks or chocks are modern jacks used to replace the conventional roof support in preventing a collapse in the mine tunnel. Hydraulic jacks lift through the force transmitted to the moveable part of the jack by a liquid.