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loose pieces of roof as you go toward the working face. All the untimbered roof in the space through which you work during the day should be carefully tested before you do anything else. If a loose or threatening piece is found it should be pulled down, or else a prop or props set under it, or, when necessary, bars, straps, or collars should be used. This should be done before any other work is started.

At intervals in the day, or whenever you change your working point in the room, entry, or heading, the roof should be examined and tested. If you are running a machine, you should see that the roof is carefully tested before each cut is made and is tested again after the cut.

Do not take the risk of finishing a cut or loading a car before putting up a prop; a moment's delay may cost your life.

If you have difficulty in getting timber promptly, you have a just cause for complaint to the mine foreman. No responsible operator will support a foreman or superintendent in refusing to give you timber enough, and to give it promptly. It is not to the operator's interest to do so, and, moreover, he would not be obeying the law of the State. Even in those States where the wording of the law is not explicit in this respect, no court will support his refusal. That, however, does not help you at the time; the blame for working when timber is not provided rests on you.

TIMBERING A WORKING PLACE.

Frequently a miner says to himself, "I will load another car before timbering." Again, he will say, "I will set a temporary post that is, a post without a cap piece and not in a proper position. Sometimes, too, a miner says, "The top is good; I have been a miner for twenty years and know when to set a post," giving the foreman or boss to understand that instructions are not needed.

It is impossible in a brief circular of this kind to describe the methods of timbering that should be followed under each of the various conditions of coal mining in this country. Generally certain methods of timbering (not always the best methods) are used in each district. In some cases the State inspectors have made certain rules. for placing timbers in advancing rooms and drawing pillars. Where such rules have been made, or there are mine rules, they should be carefully followed. But these rules are not always sufficient; they cover the average case, but not an extreme or special condition-that is, it may be the rule of the district or mine to set two or three lines of props in a room, the props to be not over 5 or 6 feet apart, whereas in some rooms four or five lines of props may be necessary.

It is important to set the props at regular intervals and in some places to set extra props as they may be needed. If the roof seems to be in bad condition, do not be afraid to set a temporary post at the

face to protect yourself while loading a car. necessary, even though the post is in your way.

Timber the place, if
Don't wait until the

car is loaded, for the roof may fall on you. Keep proper tools on hand with which to do timbering.

When you are undercutting the coal, especially in a room, do not mine an indefinite width and depth without setting a sprag; the same care applies in top mining. In many places roof coal or bone overlies the coal worked, and failure to put up props before cutting or mining often results in a serious accident.

Do not neglect to timber your place properly, even if you are in a hurry or feel that the top is all right because it usually is good, nor neglect to do so because timber would not allow you the same freedom to work. This neglect, if continued, will result in some one being hurt or killed.

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One of the things that causes a large number of accidents is the "draw slate" in the upper part of the coal bed or just above the coal. In the Pittsburgh district this is called merely "slate "; it is a "slate" (really a clay shale) that is hard when first exposed to the air, but rapidly softens and falls. Props will not keep it up— that is, it will "cut" around the head of the prop or cap piece. Therefore, the best thing to do is to take it down immediately and stow it in the gob. When similar "draw slate " is found in mines in other districts no time should be lost in pulling it down.

In coal mines in France, which generally have a weak shale roof, the rules require that the props shall be placed not over 1 meter (31 feet) apart each way and that there must be hitches cut in the coal face and straps or bars put in, supported by the props behind, before the miner is permitted to undercut the face. The good result of this law is shown by the records of accidents in the French mines. In spite of the poor roof the number of accidents from roof falls in proportion to the number of underground employees is lower than in any other country.

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FALLS OF ROOF OR SLATE" IN DRAWING PILLARS.

Drawing, or pulling, pillars requires experience and skill. If you have both, you may do this work. Otherwise you should not go among the pillars without an experienced partner, or "buddy." No matter how much experience you have had, never neglect to set a line of “breaker props" so placed that if the roof weight comes on suddenly the line of props will break the roof there and prevent its breaking off at the edge of the pillar and burying you.

A common cause of injury from falls is the attempt to recover loose coal in the gob or goave. Unless there is timber protection for the miner, this should not be attempted. The recovery of props from the gob is a good thing to do if you are careful, but you should use chains and levers, so that you will be in a safe place when the prop is drawn out by the chain.

EFFECT OF EXPLOSIVES.

Great damage is done to a roof by the use of too much explosive for a shot and by not placing shots properly.. If the hole is drilled too close to the roof, the blast tends to shatter it. Do not place the shot too near the roof. If the coal is not undercut or properly sheared, a great deal of the force of the explosive is spent in shattering the roof. Also, props may be blown down.

You should watch closely to see that you use just enough explosive to bring down the coal. This will not only lessen the cost of the explosive and increase the proportion of lump coal, but it will lessen the risk of accident from an explosion or fall of shattered roof which might kill or cripple you.

When you go back after firing a shot, it is particularly necessary that you thoroughly test the roof in the way previously described. You should not go back under any condition while the smoke is thick, both on account of the poisonous gases and because you can not then properly observe the condition of the roof or whether props have been thrown down.

FALLS OF COAL.

Figures compiled by the Bureau of Mines indicate that in the calendar year 1911 the number of men killed by falls of coal (other than roof coal) in the entire country was 148 out of a total of 1,321 killed by falls of all kinds, or about 11 per cent. In the bituminous mines of the country the proportion of deaths from falls of coal to deaths from falls of all kinds was 120 to 1,039, or about 11.5 per cent; in the anthracite mines the proportion was 28 to 282, or about 10 per cent.

Some figures gathered by the State mining departments of some of the States that have large outputs of coal are given below. In 1910, in the Pennsylvania anthracite field, 80 men were killed by falls of coal out of a total of 253 killed by falls of all kinds. In the Pennsylvania bituminous fields 54 were killed by falls of coal, as compared with a total of 306 killed by falls of all kinds. In West Virginia 32 were killed by falls of coal out of a total of 215 killed by falls of all kinds. In Illinois 19 were killed by falls of coal out of a total of 65 killed by falls of all kinds. In these three States 185 men were killed by falls of coal out of a total of 839 from all kinds

of falls, or 22 per cent of the total. The number injured by falls of coal is much larger than the number killed. For example, in West Virginia 119 were injured by falls of coal as compared with 461 injured by all kinds of falls. However, the statistics for the whole country are not complete.

The responsibility for preventing accidents from falls of coal is almost wholly in the hands of the miner. Most of these accidents occur through failure to block or sprag the coal while undercutting it, or, in a thick seam, while slabbing it off. The miner working among the lumps of coal may have his foot caught when a large mass of coal rolls over. There is particular danger from rolling coal in pitching seams, where the face may sometimes break and "run."

Every miner knows that before starting to undercut the face, either by pick or by machine, he should carefully sprag the coal. This takes only a few minutes, and is a most necessary precaution. It also helps to keep the coal from spalling off if there is any weight from the roof that tends to make the coal break at the back of the cutting. As you continue the undercutting you should put in blocks or more sprags. When you are ready to bring down the coal, knock out the sprags in order, starting at the inner end, so that you may not be caught between the coal and the gob in case the coal rolls over in a block. Special care needs to be taken in long-wall work, as in the northern Illinois district or the Canyon City (Colo.) field, where the long-wall system is employed, and there is little room between the face and the gobbed material. In a thick seam particular care must be taken in slabbing off coal that has not come down as a whole and where the coal face is high above your head.

SUGGESTIONS FOR FOREMEN AND ASSISTANT FOREMEN.

Your positions carry great responsibility in caring for the mine and in caring for the lives of the men under your direction; the prevention of falls of roof is one of your most important duties. The responsibility of taking care of the roof in the entries, headings, or passageways is yours. Unsafe roof in these places should be promptly attended to, and making it safe should be considered more important than getting out coal.

In keeping rooms and working places safe you share responsibility with the miner, except that it is your duty to see that timber supplies and tools are promptly furnished at the request of the miner, or as your own inspection has shown to be necessary. Systematic records should be kept of the supplies furnished each miner, and it should be a matter of suspicion that requires inspection if the miner is not using at least the average supply of timber furnished other miners. Dealing with a large body of men you will always find a certain number of miners careless of their own safety. These men should

be closely watched, and any miner who persists in not using the necessary amount of timber should be given other less dangerous work to do, or should be placed as the partner or "buddy" of a more experienced and careful miner.

It is sometimes thought because the roof is strong that little or no timber is required. Such mines or places are often the most dangerous, because when a loose block of roof is undermined there is no protection. Where the roof is good there is a tendency for the miners and the foremen to become careless. You should bear in mind that you must always be prepared for the unusual condition. The loss of one life or the crippling of one man will pay for a vast amount of timbering, not only from a humanitarian standpoint, but in dollars and cents.

INSPECTION OF WORKING FACES.

Constant inspection of the working faces is of the utmost importance. The mining laws of some States specify that the foremen or inspectors shall inspect the face at least once in two days. This is not often enough. It is far better, if the work can be so arranged, that an inspection be made every day by the foreman or assistant foreman in addition to the preliminary inspection by the fire boss; and it would be still better if inspections were made several times a day-if not by the foreman or pit boss or his assistants, by special inspectors or face bosses.

When there are a large number of miners who do not speak English, you should either learn their language sufficiently to explain how and where the props are to be set, or should have an interpreter explain to the men what is required in timbering, as well as in other matters pertaining to safety. In such cases it is doubly important that a foreman who orders additional timbers to be set should return to see that his orders have been obeyed.

IMPROVEMENT IN METHODS OF TIMBERING.

It should be your constant thought to improve the methods of timbering so as to prevent accidents. Sometimes the method of mining is improper and affects the method of timbering. This is particularly true in machine mining and in drawing pillars. Where breast machines are used a large amount of space is required between the face and the nearest timbers. In many cases temporary props should be set up, and reset as the undercutting proceeds. There is particular danger in machine mining when the work is so subdivided that no one man is responsible for the condition of the timbering, either temporary or permanent, in any one room or entry.

You should arrange this work so that the timbering will be carefully looked after, and some one will be responsible for each room

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