ACCIDENTS FROM FALLS OF ROOF AND COAL.

By GEORGE S. RICE.

INTRODUCTION.

Great mine explosions shock the public, but falls of roof and of coal in the coal mines of this country in 1914 as in 1911 killed three times as many miners as were killed by explosions, and as many as were killed by all other accidents underground. Very few recover from the injuries they receive in an explosion; usually it is a matter of no injury or death. On the other hand, each year thousands of coal miners are caught by falls of roof and coal, and hundreds are killed or are crippled for life. The table following gives the number killed from this cause during the past eight years.

Number killed in coal mines of the United States, and ratios per 1,000 employed, 1907 to 1914.

It is easy to see why the public believes that explosions are the greatest danger in coal mining; large numbers of lives are snuffed out in a few moments; there are pathetic scenes; rescue parties are in danger from afterdamp or a second explosion.

On the other hand, falls of roof or coal seldom kill or injure more than one or two men at a time, and such accidents, occurring at

widely scattered mines, are not reported except by the local newspapers and by the State inspectors. Nevertheless the totals are appalling. Each working day an average of five men lose their lives and a dozen men are injured from falls of roof or coal in the work of supplying the Nation with fuel.

Can these accidents from falls be prevented? Probably not wholly, on account of the natural dangers of mining, but in large part they can be. Even if only one-half of these deaths and injuries were prevented, then 565 lives would have been saved, and, on the basis of the statistics of injuries for 1911, the last year for which official figures are available for the United States, perhaps 1,800 serious injuries would have been avoided during 1914. Even then our record would have been worse than that of many other mining countries.

FALLS OF ROOF IN ROADWAYS, HEADINGS, OR PASSAGEWAYS.

Accidents from falls of roof are less frequent on roadways, headings, or passageways than at the working face, because the roof is constantly inspected by foremen and other bosses. If loose pieces are noticed, they are taken down or are supported by timbers. Only when derailed cars knock out timbers so that the roof comes down can injuries from roof falls be considered at all excusable, and not always then.

The burden of preventing falls in entries and passageways rests largely upon the foremen and the company inspectors. But whenever a miner or anyone passing along the roadway discovers a loose or dangerous place it should be his duty to mark the place and report it to the nearest foreman. If possible, he should not pass under the place, but should go around another way to reach the man in charge. Figures showing the number of accidents from falls of roof in entries, roadways, or passageways as compared with similar accidents at the working places have not been gathered for the whole country, but the department of mines of Pennsylvania has compiled such figures for its own State and has brought out some valuable facts. Pennsylvania produces nearly one-half of all the coal mined in this country, so that the Pennsylvania ratio between accidents from falls of roof in roadways and similar accidents in working places may be regarded as about the same as the ratio for the United States. The Pennsylvania figures indicate that in the coal mines of this country probably only about one-tenth of the accidents from roof falls happen in entries or gangways. This and other valuable data are shown in the following table, prepared from the report of the State department of mines at Harrisburg, Pa.:

Fatal accidents from falls of coal, “slate," and roof in Pennsylvania in 1913, arranged by locality in mine where accident occurred.

FALLS OF ROOF AND COAL IN ROOMS AND WORKING PLACES.

The above table shows that in Pennsylvania in 1913, slightly over 90 per cent of the deaths from falls of roof, "slate," and coal happened at the face and in pillar workings. Sixty-seven per cent, or about two-thirds of the whole, happened at the face of rooms or chambers, and 23 per cent, or about one-fourth, happened in pillar workings. However, it would not be proper to reason from the smaller number killed that there is less danger in pulling or drawing pillars, as that plainly is most dangerous work. The chief reason for the smaller number of men killed in pillar drawing is the smaller number employed, because a great many mines do not draw pillars; moreover, drawing pillars is work that is given, or should be given, to the most expert miners, and they are less likely to be caught by falls, if they use good judgment.

In comparing reports of accidents, it is very difficult to tell from the figures gathered in different States or even in different parts of the same State whether an accident has been caused by a fall of roof or by a fall of coal. "Slate" in some districts means "draw slate," as in the Pittsburgh district, but in other districts it may be considered "roof." Where the coal bed is thick and a layer of coal is left up as roof, a fall of the roof coal should be considered as a "fall of roof."

PREVENTION OF ACCIDENTS FROM FALLS OF roof or

"SLATE."

It is the belief of the writer, and of many mining engineers, that most falls of roof, coal, and "slate" are not necessary. The principal causes of accidents from falls are the following:

(1) Failure to use sufficient props or timbers or improper setting. (2) Going back to pick, shovel, or prepare other shots at the face without testing the roof after shot firing.

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(3) Undermining the inner edge of a block that seems to be safe, because too heavy to vibrate when struck, but actually is loose.

(4) The sudden loosening of a concealed "pot," "kettle bottom," "bell," or a fossil stump.

The first two causes, which result in the largest number of accidents, are generally avoidable; the second two may generally be avoided by setting the props or timbers close enough together, but some accidents from these two causes may be considered unavoidable.

A WORD TO THE MINER.

Now, how can you, the miner, escape harm from a fall of roof in your working place? The answer is: Be careful at all times.

Two parties are interested the operator and yourself. In this case, at least, the interests of the operator and your own are alike—falls should be prevented. If an accident happens, the operator suffers a money loss, but you may be made a cripple for life, a burden on your family or the community; or you may be killed and leave a dependent family. Hence, it is necessary that you, as the one most vitally concerned, must take the most extreme care to prevent these accidents.

Remember, it is the unexpected that often happens. On the other hand, the operator, or the foreman or boss who represents him, must do his part-that is, furnish the timber.

The laws of nearly all the coal-mining States require the operator to furnish the necessary props or timber at or near the working place. Sometimes, through delays in the haulage, or more rarely through the carelessness of a foreman or boss or driver, the timber is not received at the time you need it. If the timber does not arrive, you should not take a great risk in going without it and work under an unsafe roof. Important as your daily earning is to you, the delay of one or two hours, or even a whole shift, is as nothing compared with being killed, or becoming a cripple for life, by having a piece of roof fall on you. Remember your family or those dependent on you, and wait for props.

Occasionally a miner thoughtlessly pushes a car close to the face and then goes between the coal and the car and proceeds to mine off the coal freed by the shot. If the coal breaks and falls suddenly, the miner may be pinned against the car and killed or crippled, when if he had left the car standing some distance back he might have escaped injury.

TESTING THE ROOF.

When you enter your room or working place in the morning you should proceed slowly, watching the roof carefully with the light from your lamp thrown upon it. If any place seems doubtful you should

test it by striking it with a pick or bar, touching the roof or doubtful piece with your free hand. If any vibration is felt, the piece is unsafe and must be picked down or timbered at once. The "sound" of the roof may often be deceptive if the loosened piece is large. If the roof is too high to reach with the hand, a stick should be held against the doubtful piece, and if the piece is loose you will feel the vibration through the stick. This is the approved and adopted method of certain large mining companies who have found from experience that the old method of "sounding" the roof is unreliable. Take a pick or bar with you for testing and pulling down 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, because the unsupported roof span is increased by the distance undercut.

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, "The top is good; I have been a miner for 20 years and know when to set a post," and then he fails to follow the instructions of the foreman, sometimes with disastrous results to himself.

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.