NA TURE 



21 



THURSDAY, NOVEMBER 8, 1877 



EXPLOSIONS IN MINES 



AFTER the occurrence of great colliery explosions 

 such as those which took place recently in Pem- 

 berton and Blantyre collieries, one very general and 

 pertinent question presents itself to most minds, namely, 

 What has been done or attempted with the view of 

 preventing these disasters? It would be impossible to 

 condense into an article hke the present all that could be 

 said in reply to this question, but I shall endeavour to 

 give a brief outline of the subject, and point out, as well 

 as I can, what appear to be its most prominent features. 



Before the invention of the safety-lamp, the only means 

 of guarding against the ignition of firedamp consisted in 

 the employment of an apparatus called the " st^el mill." 

 The light obtained by its aid was feeble and uncertain, 

 and Mr. Buddie informs us that explosions were known 

 to have been caused by the sparks emitted by it. When 

 Davy made his brilliant invention in 1 815-16, the 

 steel mill was laid aside for ever, and it was then 

 imagined that colliery explosions had also become phe- 

 nomena belonging to a past order of things. So con- 

 fident, indeed, was Davy in the efficacy of his lamp, that 

 he believed it could be safely employed for carrying on 

 work in an explosive atmosphere ; and he even went so 

 far as to propose to make use of the firedamp itself as 

 the light-giving combustible. These fond expectations 

 were soon roughly dispelled, as one explosion followed 

 another in an apparently unaccountable manner ; and at 

 length they were succeeded by a feeling of positive dis- 

 trust, which found expression in the report of a select 

 committee appointed, in 1835, to inquire into the nature 

 of accidents in mines. 



In 1850 Mr. Nicholas Wood made a series of experi- 

 ments, which proved that when a Davy lamp is subjected 

 to an explosive current travelling at the rate of eight or 

 nine feet per second, the flame soon passes through the 

 wire gauze. This was corroborated about 1867 by experi. 

 ments conducted by a committee of the North of England 

 Institute of Mining Engineers. 



Lastly, in 1872-73, the writer demonstrated, also by 

 experiment, that when a lamp burning in explosive gas is 

 traversed by a violent sound- wave, such as that produced 

 by a blasting shot, the same result follows, that is, ignition 

 is communicated to the outside atmosphere. These are 

 weak points inseparable from the construction of the 

 ordinary Davy and Clanny lamps ; but as it is now a 

 thoroughly-recognised maxim that work must never, 

 under any circumstances, be continued in an explosive 

 atmosphere, they are seldom put to the test. 



The atmosphere of part of a mine may, however, become 

 explosive before the men can escape, either by the sudden 

 influx of a quantity of firedamp from some natural cavity 

 in which it had existed in a state of tension, or by a partial 

 or total cessation of the ventilating current ; and I propose 

 in the next place to consider how such an event could 

 produce an explosion supposing all the men to be pro- 

 vided with safety lamps. 



This will happen, firstly, if the inflammable gas 

 passes over a furnace at the bottom of the upcast j 

 Vol. xvii, — No. 419 



secondly, if it is carried against a Davy or Clanny lamp 

 at a greater velocity than seven feet per second, or if the 

 lamp is traversed by a sound-wave ; thirdly, if a blasting 

 shot is fired directly into it ; and lastly, if it reaches a 

 safety lamp that has been opened by one of the men. 



The means that have been provided for guarding 

 against these contingencies are as follow : — i. Furnaces 

 have to a large extent been replaced by ventilating fans 

 in fiery collieries. 2. Davy and Clanny lamps are still 

 almost universally employed, and little importance seems 

 to be attached to their known imperfections by those who 

 are supposed to be capable of deciding the question. 3. 

 Shot-firing having been found to originate many explo- 

 sions, although probably in a manner not yet understood 

 by most people, is now carried on under certain re- 

 strictions which it could easily be shown are still 

 insufficient. 4. Much nonsense has been talked and 

 written about miners opening their lamps. That they 

 sometimes do so is beyond a doubt ; but why should this 

 state of matters be allowed to continue when it can be 

 easily put an end to ? The present flimsy pretence for a 

 lock is not a necessity but a cheap convenience ; and who 

 is responsible if say a hundred men are killed through its 

 being opened by one ? Is there no responsibility attach- 

 ing to the owners or the legislature for placing the lives 

 of ninety-nine innocent men in danger ? I think surely 

 there is. 



The influence of changes of weather on the internal 

 condition of mines has been remarked since the remotest 

 times, and for the last fifty or sixty years at least many 

 have asserted that firedamp is more prevalent when the 

 barometer is low than in the opposite case. The 

 explanation of the?e phenomena is easily found by any- 

 one who has an elementary knowledge of the physical 

 properties of gases. On the other hand, when vigorous 

 artificial means of ventilation are employed, and ordinary 

 skill practised in distributing the air, the effects of changes 

 of weather become much less perceptible. 



Hence if a large proportion of explosions can be shown 

 to occur simultaneously with, and therefore, presumably, 

 in consequence of, those atmospheric changes that would 

 tend to augment the amount of firedamp in the workings, 

 there is a strong argument in favour of the supposition 

 that they are preventible, and cannot therefore be consi- 

 dered as accidents in the true sense of the term. With 

 this object in view diagrams have been made from 

 time to time by Mr. R. H. Scott and myself, and also by 

 one or two others, showing the connection that exists 

 between the two classes of phenomena, and an examina- 

 tion of these is sufficient to convince unbiased persons 

 that there is a striking coincidence between the explo- 

 sions and the favourable atmospherical conditions. As 

 might, perhaps, be expected, some persons engaged 

 in mining either fail to see the connection, or possibly 

 they do not understand it. Nevertheless a general rule 

 was inserted in the Coal Mines' Regulation Act (1872) 

 making it compulsory for mine-owners to place a baro- 

 meter and thermometer at the entrance to every mine in 

 the coal-measures. 



It has always been difficult, and sometimes impossible, 

 for mining men to give an adequate reason for the extent 

 of great explosions, and more especially when it is 

 known thatj immediately beforehand, little or no inflam- 



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