This evil, however, is limited in extent by the act of 1885, which provides that no more than seventy-five persons shall be employed at the same time in any one split or current of air.
The wonder is that the health of these mine workers does not sooner fail them, especially when we take into consideration the wet condition of many of the mines. It is a fact, however, that miners as a class are not more subject to disease than other workmen. The decimation in their ranks is due mostly to accidents producing bodily injuries and death, not to diseases which attack them as a result of their occupation.
Next in importance to the matter of ventilation in mines is the matter of drainage. The first difficulty experienced from water is while the shaft or slope is in process of sinking. It is usually necessary to hold the water in one side of the opening while work is going on in the other side. A small pumping engine is generally sufficient to keep the pit clear until the bottom is reached, but occasionally the amount of water is such that a large engine and pumping appliances have to be put in place at once. In Europe much trouble is often experienced from the excessive flow of water while sinking the shaft, and a watertight casing has frequently to follow the shaft downward in order that work may go on at all. Such appliances are not as a rule necessary in this country, though much difficulty has been encountered in sinking shafts through the quicksand deposits of the Susquehanna basin in the Wyoming valley.
The general principle of mine drainage has been already explained. It is, in brief, that the floor of the mine shall be so graded that all water will gravitate to a certain point. That point is near the foot of the shaft or slope, and is at the mouth of the drift or tunnel. But from the sump of the shaft or slope the water must be raised by artificial means. A powerful steam pumping engine, located at the surface, is employed to do this work, and one compartment of the shaft or slope, known as the pump-way, is set aside for the accommodation of pipe, pump-rods, and supporting timbers, which extend from the top to the bottom of the shaft. The most powerful of these pumps will throw out a volume of twelve hundred gallons of water per minute. It is seldom that the tonnage of water pumped from a mine falls below the tonnage of coal hoisted, and in some of the wet collieries of the Lehigh district eight or ten tons of water are pumped out for every ton of coal hoisted. In the Wyoming district a thousand tons of water a day is not an unusual amount to be thrown out of a mine by a single pump.
In driving gangways or chambers toward abandoned workings that have been allowed to fill with water much care is necessary, especially if the new mine is on a lower level, which is usually the case. The act of 1885 provides that “whenever a place is likely to contain a dangerous accumulation of water, the working approaching such place shall not exceed twelve feet in width, and there shall constantly be kept, at a distance of not less than twenty feet in advance, at least one bore hole near the centre of the working, and sufficient flank bore holes on each side.” It often happened, before accurate surveys of mines were required to be made and filed, that operators would drive chambers or gangways toward these reservoirs of water in ignorance of their whereabouts. The firing of a blast, the blow of a pick, perhaps, would so weaken the barrier pillar that it would give way and the water breaking through would sweep into the lower workings with irresistible force, carrying death to the workmen in its path and destruction to the mine. Some very distressing accidents have occurred in this way. It is customary now for operators, when approaching with their workings a boundary line of property, to leave a barrier pillar at least one hundred feet thick between that line and the outer rib or face of their workings; and this whether the area on the other side of the line is or is not worked out. Under the present system of accurate surveying and mapping, accidents resulting from flooding by mine water should be rare, since the location of boundary lines may be calculated almost to the inch, as well as the location of all workings in their relation to each other.
But accidents due to a flooding by surface water are not always to be obviated. Sometimes when a stream crosses the line of outcrop the water will break through into the mine and flood the lower levels in an incredibly short space of time; and this too when good judgment and prudence have been used in leaving sufficient coal for protection. The continuity and character of the strata lying between the earth’s surface and the coal face cannot always be determined. It is not often that accidents from flooding occur while mining is going on under large bodies of water. The precautionary measures taken in presence of a known danger are sufficient to reduce that danger to a minimum.
Disasters occur occasionally as the result of a peculiarly deceptive condition of the overlying strata, whereby a rush of earth, quicksand, or mud into a mine causes loss of life and destruction of property. The bed of a stream cut deep into the rocks in some former geological period, and then filled to the level of the surrounding country with drift in some later age, leaves a dangerous and unsuspected depression in the strata which the miner’s drill may pierce or his blast break into at any time with disastrous results. One of the most characteristic of this class of accidents occurred at Nanticoke in the Wyoming region on the 18th of December, 1885, in a mine operated by the Susquehanna Coal Company. A miner by the name of Kiveler broke into a depression of this kind while blasting, and immediately through the aperture a great volume of water, quicksand, and culm came rushing down. It filled up that entire portion of the mine, burying twenty-six men and boys beyond possible hope of rescue and endangering the lives of hundreds of others. Energetic efforts were made to tunnel through the masses of sand and culm packed in the passages of the mine in order to reach those whose avenues of escape had been cut off, many believing that they had been able to reach high enough ground to escape the flood. These efforts, lasting through many weeks, were wholly unsuccessful. The men were never reached. Bore holes, drilled into the chambers where they were imprisoned, both from the inside and from the surface, proved conclusively that the passages were crowded full of sand and culm, and that the men must have perished immediately upon the occurrence of the disaster.