Arizona republican., 1898-08-08
EXPLOSIONS IN MINES.

In a lecture recently delivered at Nottingham, England, MT T. A. Southern suggested that falls Of roof may be not only an indirect cause or an explosion of iire-damp. but may be the direct cause, and that very small fall may cause serious explosion. Any fall of rock that causes spark in the presence of fire-damp is liable to start an explosion that is limited in its eff feet only ry the volume of firedamp present Every miner knows that falls of rock frequently cause sparks, but there are few miners, or mine off, cials either, who have ever considered these sparks an element of danger This has no doubt been due to the use, years ago, of the steel mill as a means of lighting in gaseous mines. When this old appliance is described, the fact that it was dangerous and that explo- sions had originated from sparks given off by it's contact with flint, is seldom mentioned. That such sparks did cause explosions is recorded fact, and as the sparks caused by falls of rock are of the same nature they will also start an explosion. Of course, the fire-damp must be present, and in our day, fortunately, mine ventilation especially in live workings, is so good that an explosive atmosphere is sell dom present. But in old workings, where the ventilation is sluggish or absent, an explosion may start from fall of top that may cause great dam age.
 In speaking of the possibility of ex- plosions being started by falls, Mr. Southern said:
 s'We have all heard of the possibil- ity of sparks from the workmen's s tools or from electric signal wires (to say nothing of the more intense sparks from an electric motor) igniting fire damp and thus causing an explosion in a mine. Sparks from a fall of roof have also been suggested as another possible source of ignition, and there can be no doubt that an explosion of fre-damp may be started from sparks from any of these sources, and that the only reason why it is undoubtedly rare for an explosion to be caused in this way, is that the conditions nec- eSSary seldom occur in conjunction Sparks from these sources vary in in tenSity; they are not always hot enough to ignite fire-damp, and then, happily< with our mines we'll ventil- ated, when the sperks are hot enough. the necessary proportion of fire-damp to make an explosive mixture is gen. erally absent A mysterious explosion occurred shortly before Christmas at a colliery in South Wales The ex- plosion occurred when no person, nor any light or fire of any sort was in the mine. It developed gres. violence and did a great deal of damage, and extended through considerable length of roadway, and, in fact, pre- scented all the features of great col fiery explosion, except that no one was in the mine at the time, and therefore no lives were lost, and the ventilating fan was uninjured. The explosion was stopped by a length of wet road way, and therefore did not extend to the shafts. From the information at hand. there appears to be little or nn doubt that this explosion was caused by spark (i. e., by concentrated gen. eration of heat) resulting from a large and heavy fall of roof-an exceedingly hard, gritty sandstone roof-in land ing or "double-parting," where the roadway was of double width and the roof came down in large blocks