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COAL OUST
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See also:COAL OUST . UN the enactment of See also:laws to protect the lives of the men engaged in underground See also:work. These laws are enforced by mine inspectors who are empowered to See also:call upon the courts and other See also:government See also:air current, or back-See also:draught from the See also:fire. Further, the burning of the See also:timber produces falls of ground, making necessary the excavation and removal at times of hundreds of tons of heated See also:rock and burning coal, in See also:order to reach the fire. When See also:direct attack is no longer practicable, it is possible to extinguish the fire by sealing the mine workings, and exhausting the See also:supply of See also:oxygen. It is necessary, however, to keep the mine sealed until the burning timbers, or coal, and the red-hot rocks have become cool, or the fire will again break out. This sometimes requires two or three months. Where an effective sealing of the mine is impracticable it is sometimes possible to extinguish the fire from the outside of the mine by constructing a large See also:reservoir or tank in the upper See also:part of the mine-See also:shaft and suddenly releasing a large See also:volume of See also:water by opening See also:discharge-doors. The See also:mass of water falling down the shaft is converted into spray, which is carried by the force of the fall See also:long distances into the workings. Where the fire is in or near the shaft this method has proved very effective. Mine fires may sometimes be reached by See also:bore-holes sunk for the purpose from the See also:surface, and the burning workings below filled by See also:flushing with See also:culm and water. As a last resort the mine may be flooded with water. This is an expensive operation as it entails the cost of pumping the water out again and repairing the resulting damage. If the fire is in working places to the rise the water may not reach the burning portions of the mine, but will effectually See also:seal them. But sufficient See also:time must be allowed to elapse before pumping out the water, as otherwise the fire may break out again. Mines may become flooded by the inrush of surface See also:waters in times of See also:great rainfall or sudden floods, or by the undermining of Flooding of surface waters. The mine workings may also be flooded by large bodies of underground water. The surface Mines, floods must be provided with channels of sufficient See also:size to carry them safely past the mine openings, and intercepting ditches should be excavated for this purpose, and dams and embankments constructed to divert the See also:flood waters. That it is possible to work with safety beneath See also:rivers, lakes and even the ocean has been proved in numerous instances; mines in different parts of the See also:world having been extended long distances under the See also:sea. In such cases preliminary surveys should be made to determine the thickness of rock over the proposed workings. Under favourable conditions See also:mining may be conducted under the See also:protection of a few yards of solid rock only, as in the submarine work for the removal of reefs in the harbours of See also:San Francisco and New See also:York. At See also:Silver Islet, See also:Lake See also:Superior, mining was successfully carried on for years under the protection of a See also:coffer See also:dam and an See also:arch of See also:rich silver ore less than 20 ft. thick. At Wheal See also:Cock near St Just in See also:Cornwall the protecting roof was so thin that holes bored for See also:blasting more than once penetrated to the See also:bed of the ocean, and wooden plugs were kept on See also:hand to drive into such holes when this occurred. In storms the boulders could be heard striking each other overhead. When large areas are undermined, as in submarine coal mining, it is best to have several See also:hundred feet of protecting rock. In Great See also:Britain the See also:law requires that the workings shall be protected by 120 ft. of solid strata. When the presence of underground bodies of water is known or suspected, advance bore-holes should radiate from the end of the advancing working See also:place so as to give warning of the position of the See also:body of water, these holes being o 'such length as to ensure a safe thickness of solid rock. The caving in of mine workings results from the excavation of large areas supported upon pillars of insufficient size. While the mine workings are small the overlying rocks support themselves Cavingof and the full pressure does not come upon the mine Mine pillars. As the workings increase in size the pillars Workings, support an increasing See also:weight until finally they are strained beyond the limit of See also:elasticity. When this occurs, the pillars begin to crack and splinter with a See also:noise like musketry firing, and the roof of the mine shows signs of subsidence. This may continue for See also:weeks before the final See also:crash takes place. At first a fall of the roof occurs locally, here and there throughout the mine, and these falls may succeed one another until the See also:settlement of portions of the roof has so far relieved the See also:strain that the remaining areas are sup-ported by the stronger pillars, and by the fallen rock masses. While abundant warning of the caving-in of the workings is thus given in advance it may happen that men are unexpectedly imprisoned by the closing of the See also:main passage ways. The caving-in of the mine, however, is rarely so See also:complete that avenues of See also:escape are not open. In many cases, however, it has been found necessary to reopen the mine through the fallen ground, and even to excavate openings through the solid See also:mineral. The See also:history of mining is full of dramatic episodes of this See also:character. `Accidents from the misuse and careless handling of See also:explosives are unfortunately too frequent in mines. The conditions under Accidents which explosives may be stored, handled and used are from carefully formulated in the mining laws of most states, Explosives. but it is almost impossible to secure obedience to these regulations on the part of the miners, who are, as a See also:rule, both careless and reckless in their use of See also:powder. In some states it has become necessary to provide for fines and even imprisonment of men disobeying the regulations regarding explosives. Mine See also:Hygiene.—While mining is not necessarily an unhealthy occupation, miners are subject to certain diseases resulting from vitiated air, and from unusual or See also:special conditions under which at times they are forced to work. See also:Recent investigations have shown an alarming Increase in mortality from miners' See also:phthisis in Cornwall, 1898 ; G. F. See also:Williams, The See also:Diamond Mines of See also:South See also:Africa (New York,' South Africa and elsewhere. This seems to be due to the dust abundantly produced in mining operations, and especially by See also:machine drills when See also:boring " dry " (rising) blast holes. See also:Drill runners, who are compelled to breathe this dusty air daily, furnish most of the sufferers from phthisis. The increased mortality seems to be due to the See also:general tendency toward forced See also:speed in development work, which is secured by rapid drilling, and by an increase in the number of machine drills used in a single working-place. The miners, to See also:save time, often return to their work after blasting before the powder-See also:smoke and dust have been sufficiently removed. It is probable that the See also:carbon monoxide seriously affects the general See also:health and vitality of the men, and renders them more likely to succumb to phthisis. More effective See also:ventilation will materially lessen the See also:death-See also:rate. In the See also:metal mines of Cornwall and See also:Devon special rules are now in force requiring the use of water in drilling, and other pre-cautions. to lessen this danger from dust. In some mines dust seems to have but little effect on the health of the miners; indeed it is even claimed by some that coal dust decreases the mortality from phthisis. On the other hand, as in mining ores containing See also:lead, See also:arsenic and See also:mercury, the dust may be poisonous. The climbing of ladders from deep mines not only lessens the efficiency of the men by See also:reason of fatigue, but often tends to increase the mortality from diseases of the See also:heart. In See also:cold climates men coming from the warm See also:atmosphere of a mine, often in wet clothing, are liable to suffer in health unless proper See also:provision is made for the necessary See also:change of clothing. In such cases the See also:establishment of dressing-rooms, properly heated, and connected with the mine by covered passages will be necessary. These " change-houses " are provided with washing and bathing facilities, and arrangements for drying wet clothing. See also:Ankylostomiasis (q.v.) is a disease which finds a congenial See also:habitat in the warm See also:damp atmosphere of mines, and has become a veritable See also:scourge in some mining regions. The disease yields readily to treatment, but is difficult to eradicate from a mine without stringent sanitary regulations to prevent its spread. The care of the health of the working force should be entrusted to competent mine physicians, thoroughly See also:familiar with the conditions under which the miners work, and with the special diseases to which they are subject. The men 'should be instructed in the laws of sanitation, and in the proper care of injured men.
Mine Law.—Mine law is that See also:branch of the law of real See also:property See also:relating to mineral and mining rights as distinct from rights pertaining to the surface of the ground. Under the See also:common law the owner of the surface possesses all mining rights as well, unless these have been reserved by some previous owner of the property. From very See also:ancient times deposits of See also:gold and silver have in most countries been held as the property of the See also:crown. In public or government See also:land the minerals as well as surface belong to the See also:state, and not infrequently these rights have been separated by law and granted or otherwise disposed of to different owners. It is to the public See also:interest that deposits of mineral should not be permitted to remain idle and undeveloped. This has been recognized from the earliest times, and laws have been framed in all countries for the encouragement of mining enterprise. In many cases the state or the ruler has sought to obtain a See also:share in the profits of mining, or even to work mines for the individual profit of the ruler or of the state. But in most cases it has been found better policy for the state to divest itself of all interest in mining property, and to extend all possible encouragement to those who undertake the development of the mineral See also:wealth of the nation. The mining laws of most civilized states See also: (H. S. Additional information and CommentsThere are no comments yet for this article.
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