third seams of coal, at the Dodson colliery at Plymouth, for the purpose of working* therein at the same time any person or persons were at work in the fifth seam. This fifth seam was connected with the other workings (which were provided with two outlets) by only one passage.

The injunction was granted. The opinion of the court can be found in the Report of the Inspectors of Mines for 1881, pages 151 to 159.

The second openings are frequently used as upcasts,-a fan being placed at the top,-and the main winding shaft forms the downcast or intake. When the breaker is built over the shaft, the danger to those employed below in case the breaker catches fire, is terrible. In some mines when the miners and laborers are scattered through workings several thousand feet or even one mile distant from the outlet, the smoke from the burning breaker would certainly reach and overpower a large number before they could find their way to the outlet.

The fan might be promptly stopped to keep the smoke from entering the shaft, but this would be a dangerous expedient at fiery mines, as the air would reach the explosive stage at many points in a few minutes, and before the miners escaped up the ladders of the air shaft, or before they even reached it, explosions might occur that would destroy both life and property.

This difficulty might be partly overcome by the adoption of fans capable of being quickly reversed; but fans of this class are not efficient, because when the current is reversed the gangway doors are blown open, the air travels through by the shortest cut, and some splits may receive such a small quantity of air that the gas quickly becomes explosive. In the excitement attending an alarm of this kind, lamps will almost surely be left by some miners or laborers in working places, where they will fire any gas that may accumulate or be blown down upon them from adjacent workings.

Another circumstance which must always greatly decrease the miner's chance of escape, is the fact that the way to the

* Mining?.

second opening often leads through comparatively unused, and to many almost unknown, passages; and that even those knowing the way tolerably well may not know it well enough to find it readily when laboring under great excitement, or when deprived of the guidance (if the fan is stopped) the ventilating current always affords.

At shaft collieries the miners are commonly lowered and raised on the cage, ten or less at once, but at some collieries they have access through airways or breasts worked up and holed through to the surface.

At slope collieries on steep dips the men are raised and lowered in a mine car, double chains being attached in compliance with the law.

The law provides that "in no case shall more than ten men ride on any wagon or cage at one time in any of said mines," and this passage has been construed by some to permit the raising or lowering of twenty men when two cars are run in one trip on the slope-ten in each car-but the intention of the Act is evaded by such a construction, and the mine inspectors have very properly insisted upon a different interpretation, viz: That not more than ten persons shall be raised or lowered at once.

When the dip is less than twenty-five degrees the miners commonly walk down the slope or some traveling-way nearest the breasts in which they are working.

Traveling-ways in slopes are located on one side of the hoisting compartments; sometimes the pump-way is also used as a traveling-way; sometimes the traveling-way is on the opposite side, and is separated from the hoisting compartments by a vertical prop set in each frame of timber.

When the dip is slight the bottom sills, when filled in between with mine débris, break the descent into convenient steps; but when the dip is steep, and the timbers not set close together, a plank stairway is built (See Fig. 14,).

Air shafts used as second outlets when not provided with winding machinery, or when such machinery is not kept in readiness for immediate use, are fitted with ladders. These are cheaper and offer less resistance to the ventilating cur

rent than a stairway, but there are many obvious reasons why the latter should be preferred for second outlets.

The man-engine is not used in the anthracite regions, but there can be no doubt but that at some of the deep collieries of the future they can advantageously replace the method of raising and lowering the men on the cages used for raising coal.

One of the most powerful man-engines ever constructed is shown on Atlas sheet XXIII, designed by Mr. E. D. Leavitt, Jr., for the Calumet and Hecla copper mines in Michigan. It is geared to make five double strokes per minute and therefore lands five men at the bottom every minute, or three hundred in one hour.—to this must be added the time occupied in the descent of the first man, which necessarily depends upon the depth.

The chief advantage of the man-engine for use in the anthracite coal fields would not be the time saved the miner (as frequently stated) but will I think be found to be the facility it offers for the ascent and descent of persons independently of the winding machinery.

Coal could be raised and the breaker started without waiting until the miners have descended, and the winding of coal need not be suspended during or near the close of the day to allow the miners to ascend.

This advantage is frequently secured by the addition of a cage in a separate compartment used exclusively for rais ing and lowering men, tools, &c.

At large collieries the time consumed in raising and lowering the miners and other employés may exceed two hours, and as our mines become deeper and the average number of men employed inside is increased to five or six hundred the loss of time from this cause will become more and more serious.

The man-engine, however, offers no facilities for the transportation of miners' tools and supplies,-this is an almost fatal defect, but on the other hand it is claimed that it may be also used to operate pumps or for the transmission of power. While this is true, it is also true that a proper

regard for the safety of those who use it as a means of ingress and egress, should prohibit such a combination.

An independent cage set apart for the raising or lowering of men, tools, and mine supplies will probably give the best results at anthracite collieries. When the output is to be so large that two winding compartments will be insufficient, provision is now made for two additional compartments, (and a large air-way is at the same time secured) by sinking shafts of the large cross-sectional area mentioned in chapter IV.

When this is done the time necessarily occupied in raising and lowering the employés will have little influence on the output, even at collieries raising twelve or fifteen hundred or even two thousand tons per day.

Collieries putting out one thousand tons of coal per day (the Wilkes-Barre district can boast of several such) require not only rapid, but uninterrupted, winding for at least eight hours.

A car load of coal as it comes from the mine will yield about two tons of merchantable fuel; therefore, five hundred cars of coal must be raised to make an output of one thousand tons. To do this in eight hours (nett) the cages must average 62 runs per hour, and this result cannot be accomplished unless the maximum capacity of the winding plant is at least 70 runs per hour, or one winding including car shifting, signaling, etc., in about fifty-one seconds. The actual time of winding and seating the cage on the wings would be limited to about thirty-five seconds. If the depth is 600 feet the speed in the middle of the ran must be about forty feet per second.

As the speed of winding cannot be increased with safety much beyond forty feet, it is evident that at deeper shafts more time must be given to each winding, and eight hours will not be sufficient, so that if coal is to be raised for nine or ten hours, little time is available for raising and lowering the men.

At the Pottsville shaft one winding is easily made in forty-five seconds, the depth being about sixteen hundred feet, an average speed of thirty five feet per second, which

shows a speed of at least forty to forty-five feet per second in the middle of the run.

English engineers do not seem to have attained any better results in practical winding than can be shown at this Pottsville shaft, and at some of the Wilkes-Barre mines, where the machinery is lighter and the cost of the winding plants much less, and it is extremely doubtful whether any mining district possesses winding plants as cheap and as efficient as some of our anthracite collieries.