Show ELECTRIC LAMPS IN COAL MINES GRADUALLY REPLACING FLAME LAMPS the flame safety lamp is being Z 1 rapidly replaced by the electric lamp as a device for illuminating illumination an the miners world working rg place state department of the interior investigators in bulletin just issued in the united states the electric cap lamp has been widely adopted it being estimated that there are at present about of this type of lamp in use in 1911 approximately flame lamps and no electric lamps were bein being 6 used in the pennsylvania bituminous mines which were then producing I 1 35 per cent of all the soft coal mined in this country by 1918 the flame lamps had decreased to whereas electric lamps totaled nearly in great britian during he same years the total of flame lamps decreased to and the electric lamps gained rapidly f from rom to no later reliable figures are at hand though coal was known to the ancients the earliest mention being credited to Theoph ratus a greek writer about B C the first known record of coal mining was made in england about 1180 A D the bulletin points out it was at least years later before the flame safety lamp was introduced at f first coal was undoubtedly obtained f from rom outcrops and mining was done by daylight As the outcrops were worked out the miners advanced gradually further and further into tahe coal bed until the openings became quite extensive and somewhat resembled the small mines mines of today even the approximate date when lamps or tallow candles were first used in mines is unknown but some scourge of artificial light was probably used in metal mines long before coal mining began agricola 6 in a treatise on metals mining g published in 1556 gives sketches that show conditions prevailing in 6 in his time one of these sketches shows a miner carrying a lamp which apparently consisted of wick dipped in I 1 grease or oil of some kind this practice would naturally be extended to coal mines as need developed As the mine workings b were extended underground the amount of methane liberated into the mine atmosphere increased rendering 6 the open light a menace to safety and causing many disasters before flame safet safety y lamps were introduced the ini mining b of coal in gaseous mines was extremely hazardous 11 the steel mill invented by about 1750 was a thin steel disk so geared b that it could be rotated rapidly by a hand crank the li liht light ht was produced by the shower of sparks that resulted from froin holding a piece of flint against the rim of the steel disk numerous explosions were attributed to the use of these mills owin owing z to the distrust with which steel mills enill were regarded it is probable that many miners reverted to using open flame lamps a practice that was still more dangerous 6 this thiis undoubtedly brought about some of the disasters that occurred just before the introduction of the flame safety lamps altogether coal mining conditions were deplorable at the beginning of the nineteenth century and it is not strange that several men practically at the same time should attempt to develop a safer mode of lighting mines dr Willi william alii ried clanny was undoubtedly the first to design a closed flame lamp and the first to build a lamp and to have it actually tested underground in a gaseous atmosphere his first model was made about 1811 george stephenson made lamps of three distinct models and tested them underground in 1815 the first flame safety lamps devised by sir Hurn humprey prey davy were put in service in january 1816 by the end of that year they were in fairly general use in the mines of the north of en england b land district flame safety lamps are capable of doing in more ore than the name indicates first under normal conditions they can be used in a mine atmosphere that contains an explosive mixture of gas and air without great danger of exploding such a mixture though such use of a flame lamp should not be permitted second to an experienced man the they y indicate percentages of gas much lower than the explosive limit and thus can be used to indicate to workers the approach of an unsafe condition in the mine atmosphere third flame lamps will not burn in an atmosphere greatly de focient in oxygen and they therefore warn the users of such deficiency in time to withdraw to a place of safety flame safety lamps are still used rather widely in the united states for general illumination and to a still greater extent for detecting z t gas as many coal producing states require fire bosses to use these lamps in gaseous mines and them the re regulations al of several states specify that a given number of such lamps be kept available for emergency service in bulletin by J W paul L C isley and E J glein the bureau of mines has endeavored to compile a permanent record of a device which has served the mining industry for more than three generations and not only made possible the development of entire districts that otherwise could not have been worked but undoubtedly saved the lives of thousands of underground workers the bulletin contains an historical resume of the development of the safety lamp information on federal and state regulations governing the use of such lamps data relative to the design operation and main maintenance maintenon ce of flame lamps a description of lamp testing stations and data regarding tests of flame safety lamps in gaseous atmospheres tests of internal ig niters candle power measurements investigation of gauze fabrics and tests in dust laden atmospheres A special chapter i r is devoted to the subject of methane detection copies of bulletin flame safety lamps may be purchased from the superintendent of documents government printing office AT washington ashington f D C at a price of 50 cents |