MINE FIRES AND HOW TO FIGHT THEM.

By JAMES W. PAUL.

INTRODUCTION.

The history of coal mining shows that many men have been killed and much loss of property has resulted from mine fires. Most fires are small at the start and may be quickly put out if proper means are at hand and are used promptly. Larger fires may result from gas or dust explosions. Delay in examining a mine after an explosion may enable a number of small fires in different parts of the mine to gain headway and get beyond control.

The rate at which a fire spreads varies greatly. In some parts of a mine the progress of a fire may be slow, while in others a fire may spread rapidly and soon fill a large area. A fire within a mine soon makes itself known by the smell or the appearance of smoke or by the air getting warmer in the vicinity of the fire.

Mine fires should always be considered as sources of danger to miners as well as to property, and every effort should be made to keep them from starting and gaining headway. If a fire does start, it may be kept from spreading and be confined to a small area by the use of suitable equipment and the observance of proper rules and regulations. Thoughtless acts have started many fires, and care, vigilance, and discipline are even more necessary in guarding against mine fires than against surface fires.

The chief purpose of this circular is to call attention to some methods of preventing a fire in a mine and of quickly getting control of it after it has started. The methods are those that the miner himself may use and are not those that should always be adopted in fighting fires that have gotten a good start. The fighting of a fire that has made good headway is a matter for the mine management, and is not described in this circular. Methods of sealing off or flooding fires or putting them out by water or gases, as well as methods of flushing and opening up fire areas, are being studied by the engineers of the Bureau of Mines. The fighting of mine fires that have gained headway and have not yielded to the remedies presented in this paper will be described in a bulletin to be published by the bureau. The

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hints and suggestions given in this circular are offered in the hope that they will prove useful as a guide to miners in preventing fires and in putting out fires that have not gained headway. These suggestions are based on the assumption that the operator has provided certain apparatus and fire equipment for the miners' use.

SPONTANEOUS COMBUSTION.

Spontaneous combustion, or the heating of gob or waste material that burns easily, has long been considered a cause of underground fires. In some kinds of coal, especially when loose and finely divided, chemical changes occur that produce heat enough to cause a fire. The reason why one coal heats and takes fire and another does not heat is now being studied by the Bureau of Mines. The facts collected by the bureau show that the composition of a coal has much to do with its liability to heat and take fire spontaneously. In mines working some coals, heating will result and a fire occur if fine coal collects to small depths only. Where fine coal dust has accumulated in old workings the crushing of coal pillars may make enough heat to Waste timber, such as props and ties cause the coal to take fire. which may be partly or wholly covered with dust, and fine coal in the gob assist the spontaneous firing of the coal. The danger of fires from this cause may be greatly lessened by removing from the workings all small coal, bone, sulphur balls, and unused timber.

In many mines the old workings, in which spontaneous combustion may occur, are ventilated and emergency doors are provided for closing an area air-tight whenever a fire starts within it. The miner should learn where these doors are placed and know when to use them. If it is possible to fight such a fire at close range, water should be thrown on the fire, and the partly burned material should be removed and taken outside of the mine.

Oily or greasy cotton waste is dangerous, for it is liable to heat and take fire spontaneously. All greasy or oily waste, when not in use, should be placed within a closed sheet-iron vessel and taken outside of the mine every day. Do not allow waste to remain in the mine unless kept within a closed metal box.

USE OF EXPLOSIVES.

Through the improper use of explosives the coal at the working face may be set on fire, particularly if the detonators are too weak. The use of a weak detonator may cause the explosive to burn and thus set fire to the coal. In some coal beds inflammable gases are set free by a blast, and the explosive used in blasting may give enough heat and flame to set fire to these gases, and thus gas feeders that could not be detected before a blast catch fire from the flame of the

blast and in turn set fire to the coal. To reduce the number of fires from blasting and to prevent the spread of a fire so started the working face should be examined soon after each shot is fired.

If a miner finds a feeder burning, a good way to put it out is to wet a piece of brattice cloth or canvas and place that over the fire, thus excluding some of the air and confining some of the gases, and helping to smother the flame. In some mines water in barrels or in pipe lines, boxes of sand, or dry fire clay are placed near the working faces, where they can be used in putting out a fire or a burning gas feeder. If no water, sand, or clay is at hand, the fire may be put out by throwing lumps of coal against the flame, or, if this fails, the miner should shovel the coal back and smother the flame by throwing shovelfuls of fine coal on or against it. Open lights should be kept away from the working face for at least five minutes immediately after a shot is fired. In the examination of the working face with an open light after a shot has been fired inflammable gas is often lighted. This may result in firing the coal. Be careful to put out any fire thus started.

GAS AND DUST EXPLOSIONS.

The history of mine explosions shows that after many explosions fires have started in different parts of the same mine, brattice cloth, timber, gob, and coal often being found on fire when the mine is explored. The following precautions should be taken in order to prevent fires from being started as the result of an explosion or to put them out in case they have started.

Disconnect the electric power wires, if any, that lead into the mine. The force of the explosion may have disarranged the wires, and thus caused short circuits that may start a fire; or, men within the mine in their effort to escape may come in contact with live wires and receive injury.

If men are caught in a mine in which compressed air is used see that the air compressor is kept in operation.

Get a supply of water into the mine. At many mines water boxes and chemical fire extinguishers are provided. If conditions permit, these should be taken into the mine without delay and used immediately.

If breathing apparatus are at hand, they should be put into service at once by men who have been thoroughly trained in the use of such apparatus and are familiar with the workings of the mine.

If the mine liberates explosive gas do not restore the ventilation in the advance workings until they have been explored by men using breathing apparatus. Any fires found should be put out before ventilation is restored unless tests of the atmosphere within the mine indicate the absence of explosive gas.

If the mine does not liberate explosive gas, it is better to restore the ventilating current at once for the benefit of any persons who may be alive within the mine.

Much care should be used in entering a mine after an explosion, as a second explosion may occur by reason of explosive gas being present, even though no explosive gas may have ever been detected previously within the mine. As the exploring parties advance, tests of the return air current should be made at frequent intervals at some place in the return air current in order to find out whether there is probably a fire within the mine. A fire would be indicated by smoke, smell, or a rise in temperature.

ELECTRICITY.

Many fires in mines are started by short circuits of electric current setting fire to coal, timber, brattice, doors, or track ties. To prevent short circuits the electric wires should be insulated at all points of contact. Bare wires should not come in contact with the coal, timber, doors, or any material that will burn.

In the event of a short circuit the current should be immediately thrown off the wire, and any fire that has started should be put out. Many mines are provided, at convenient places in the workings, with boxes of dry sand or barrels of water and galvanized buckets. If a fire starts the employees should not be afraid to use these, even though the fire be small.

OPEN LIGHTS.

The careless use of open lights often results in serious mine firestimber, stoppings, brattice, or gas feeders being set on fire in this way. If open lights are used in a mine, the following precautions will reduce the danger of fires:

Use a safety lamp or a lantern to furnish light when wooden stoppings are being put up or repaired.

Do not use open torches for testing wooden stoppings for leakage of air.

Keep open lamps away from brattice cloth, unless the latter is fireproof.

In places where brattice cloth is used a barrel of water is often placed near by, with a bucket or other vessel for throwing on water in case of fire.

At points where timber cribs are in use in dry places, the barrels of water for fire protection should be kept filled at all times, and buckets should be kept in place ready for use.

HAY.

Hay, when taken into a mine, should be handled in bales, covered with a fireproof canvas, and inclosed within a car, or, if no canvas is

at hand, the hay should be dipped in water. Hay should be taken into a mine only when the miners and other workmen are out of the mine. Open torches should not be used near hay. Safety or electric lamps should be used at all times when hay is being handled or stored. Do not store hay in passageways between the hoisting and air shafts, unless there is ample protection against fire. If hay is stored in a compartment separated from the stable by a door, the door should be kept closed except when hay is being stored or removed. If loose hay is stored in break-throughs or along the haulage roads, which is bad practice, it should be covered with fireproof canvas and a barrel of water with buckets should be placed near by. The barrel should be placed so that the ventilating current will pass it first; otherwise, if the hay catches fire, the smoke and flame from it may prevent anyone from getting at the water.

UNDERGROUND STABLES.

Stables under ground often furnish conditions favorable to the starting of a fire, and especial care should be taken in using lights in a stable.

Do not use open lamps within the stable, but use electric or safety lamps if they are provided.

If lines of water pipe with hose connections and automatic sprays are provided they should be kept in working order; barrels of water with buckets should be kept in the stable.

Chemical fire extinguishers should be kept near the entrance to the stable, and the miners should learn to use them.

Underground stables, even though they are made fireproof, should not be used for storing any material that burns easily.

Should a fire start in a stable within a mine and the stable has iron doors, these doors should be closed at once, to prevent the fire from spreading.

LUBRICATING AND OTHER OILS.

Loss of life and damage to property have been caused by lack of proper care and by not using common sense in handling and using oils within mines.

Oil should not be stored within a mine. Daily supplies should be taken into the mine in closed metal vessels. Do not use open lamps when handling oil of any kind, not even when greasing or oiling car journals.

Keep oil away from dry timber, loose waste, or hay.

When mine-car journals are oiled within the mine, this work should be done in the special place provided by the company. The track at this place should be ballasted with broken stone. No timber should be used along this part of the track. Keep plenty of sand in near-by places to be thrown on a fire in case one starts.