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Mine Lighting
Generally, mine lights can be divided into seven general classifications: saucer type open grease lamps, hanging oil lamps, candles, oil wick lamps, safety lamps, carbide lamps and electric lamps. Miners in the 1700s used the saucer-type open grease lamp with a wick laid in grease or animal fat. A good supply of matches was needed as the slightest breeze left the miner in the dark. By the 1790s these lamps were fitted with covers to protect the flame. Some lamps were adorned with good luck charms, e.g., European miners used the rooster as a sign of good luck. Later, candles became the popular source of light in the mines. They were made of hard tallow which would lose its shape in the high temperatures sometimes encountered below the surface. The candleholder 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 protrusion. Next, the oil wick lamps became popular in the mines. They were cheaper to burn than the tallow candles and also easier to balance and carry in the mines. Oil wick lamps differed in shape and size, but the basic principle of operation remained the same. A small conical font 1½ to 2½ inches tall and about one inch in diameter held the fuel. 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 was Sir Humphrey Davy, with his 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 firedamp. 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 either a
padlock, keyed setscrews, melted soft-metal locking inserts, or magnetic spring
loaded latches.
In 1892, while working with a lime, coal tar and carbon mixture, Major James T. Morehead and Thomas L. Willson developed a brownish-grey substance which they called acetylene. Within eight years the first carbide lamp was offered and soon after that, they were adapted for underground mining. The first carbide mining lamps burned approximately four hours with a one-inch flame. A three-inch reflector directed light of 10-foot-candle power. These lamps could be carried or rested on any flat surface. The flame safety lamps were replaced by the electric lamp, beginning in the 1920s. The advantages were a stronger light and less chance of an explosion. These lamps were powered by a battery fastened to a miner's belt. This type of lamp would be used for general mining, while the other types were used for the testing of gas. The points considered in choosing a gas testing lamp are: 1) free entry of air below the flame; 2) a sliding glass or metal shield to protect the flame from strong currents; 3) no reflecting surfaces behind the flame; 4) a scale for measuring the height of the flame cap produced. The points considered in choosing a lamp for general use are: 1) maximum illuminating power; 2) safety in strong currents; 3) minimum liability to accidents; 4) diffusion of light upward; 5) simplicity to construction and security of lock fastenings; 6) appliance for relighting the lamp when extinguished without opening the lamp. |
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