Durham Mining Museum - Ince Hall Coal and Cannel Works, Arley Pits Explosion Disaster Report (original) (raw)

18th February. — Ince Hall Coal and Cannel Works, Arley Pits Explosion. — 89 lives lost; 37 of the deceased were burnt, 18 of them being badly burnt; the others appeared to have died by suffocation by afterdamp only. This great explosion so soon succeeding the great explosion in the same pits on the 24th of March last year, when 58 were killed, has obtained for this colliery an unenviable notoriety. On the occurrence of the first of these explosions, discipline appeared to be so lax, and the workings so disadvantageously arranged for ventilation, that the result was what might have been expected. Subsequently, however, discipline appeared to have been amended, and the amount of air nearly doubled; the system of working remaining complicated as before.

Simplicity of arrangement in working even flat seams is a main safeguard in ventilation. But in steep seams, like those of Ince Hall, where workings are carried on extensively to the rise of the shafts, and the return air mixed with light gases requires drawing a considerable distance down hill, its importance can scarcely be over-estimated. The changeable proportion of gases in return air, and the varying velocity at which it travels, preclude defining any set limit whence it may be safely drawn downwards. Any descent is objectionable; and when extended, as in this Ince Hall case, to the carrying on of extensive workings 70 yards perpendicular above the entrance of the return air to the upcast shaft, with airways so contracted as to require by furnace ventilation a pressure of two inches of water-gauge at the bottom of the shafts, it seems positively dangerous. Were friction the only consideration, it would be surmountable by an increased number of shorter splits, or by enlarging the area of the air-courses. But light elastic gases, even under the most favourable circumstances, do not readily flow down-hill; and if the velocity of the currents and pressure of air so mixed be great, the balance seems more easily deranged by slight matters, such as fluctuations of temperature, the lengthening or shortening of an air-course by cut-throughs as they progress, or the greater or less length of bratticing used, and variations in the area of the space behind it, or by storms such as raged at the time of this explosion, matters, which in well-ventilated flat seams, or in steep seams ventilated on the ascensional principle, are of minor importance.

At the time of the Ince Hall accident, workings were in full operation at almost every available part of the seam; some in fresh coal at the face of the numerous levels, and others in a tract close to the shafts. An upper seam also, to which further allusion will not be made, was being worked by mouthings or openings into the same shafts, and ventilated by them. With air at the pressure named, — two inches of water, — a pressure seldom exceeded in furnace ventilation, the closeness of the stoppings, crossings, air-doors, &c, would at all times be under severe test and liable to leakage. Doors, especially near the shafts, should have been avoided. With workings, however, at all points, such an arrangement was out of the question, and the ventilation at the outset had to depend, first, upon a pair of doors in constant use between the shafts, then upon another pair about 100 yards along the main level, and again at about 160 yards further in upon another pair leading into the workings extending back to the shafts. Leakage at any one of these points, situate close to the shafts, and before the air had fairly set out on its course, would at once have cut off the air from the inner workings and fouled them.

The pits being deep — 414 yards — would greatly counteract atmospheric influences. Nevertheless, it is worthy of note, that at the time of explosion such influences, with the exception of the barometer, which had been rising for some hours, were extremely unfavourable ; and if the ventilation was in any way overstrained, they may have turned the balance. The wind was boisterous, and had been so for some days; and the hour of the occurrence, too, early in the afternoon, was just the time when the temperature is highest, and the amount of ventilation consequently at its lowest, both as regards the quantity and quality of the air. It was also the time when the workmen had been in full operation for several hours, and numerous fresh feeders had doubtless been opened, from which firedamp would be actively issuing, all tending to overpower the ventilation. The centre of the explosion too, was found at two rise drifts situate about 140 yards from the shafts, at a point where a large body of return air passed. These drifts were chambers driven uphill, and naturally fitted to hold firedamp; and the fire had evidently been keen in them, the coal at the 6ides being blistered. The flame could be traced from them to near the furnace, and for about 300 yards back into the workings in the opposite direction, by some door fittings near the furnace, and a tarred brattice cloth in the workings being found on fire, and also by the clothes and bodies of the deceased within that range being burnt; but these drifts were the only place where the coal was charred. And further, as no person had been at work in the drifts that day, defective bratticing might have been, therefore, more readily overlooked, or a tub found in the place contrary to rule might have interrupted the ventilation, and the places may have been standing full of firedamp; or as a fresh holing, affecting the return air-course had that day been made, close to the floor of the air-way, near the bottom of these drifts, it may have disturbed the balance of the numerous splits into which the ventilation was divided, and have fouled a return, and an eddy may have been occasioned and the gas caused to settle in the drifts. The drifts themselves would hold about 3,500 cubic feet of firedamp, which would spread out to a great distance in flame; and as the workings were very dusty, it would be aggravated by the burning of the coal dust raised by the blast, and by these alone may the mischief have been occasioned. If the return air was laden with gas, as supposed, the flame would spread out still further, and we have thus the elements for the charge accounted for in a simple and natural way.

Davy-lamps were used exclusively in the inner workings ; and, except in the levels about the bottom of the down-cast, which were lighted with gas conveved from the surface,* and the furnace, which was fed with return air, no naked light was allowed down the pits. Gunpowder for blasting was permitted, under the restriction of the shots being fired by specially appointed persons only. Although guarded by these precautions, it was nevertheless to the firing of a shot that the explosion was almost unanimously attributed. Close to the bottom of the drifts referred to, a fusee of safety fuse was found burnt into a hole, the powder remaining unfired. A coil of the same fuse laying on the floor in the same place, was a little scorched, doubtless by the flame of the fire-damp, but not lighted; and, though the fire would be less intense on the floor, still, as the coil of fuse was not lighted, it tends to show that the fusee for the shot was lighted by hand. The body of the collier also, whose place the shot was in, was found where it appeared likely he would be on his shot being fired; and the body of the fireman, whose duty it was to light the shot, was also found close to the same spot; — all indicating that the shot was being lighted at the moment of the explosion, and, from its contiguity to the charred drifts, that by it the firedamp was ignited.

The supposition that the explosion occurred from a sudden and unexpected outburst of firedamp from a fall of roof was put forth, and as it afforded an easy and pleasant way of explaining the accident, without involving responsibility, besides being plausible, it was generally adopted as the favourite solution. It was not, however, unattended with improbabilities. No fall in these pits had ever before been known to give off firedamp. The Company's "metal" man, who did the roof and floor work, and had seen falls of roofs of all kinds take place, spoke to the apparent absence of firedamp on every occasion. A local viewer, who for twenty years had worked the same seam extensively in a neighbouring colliery, never knew the roof in question give off any hurtful amount of firedamp. Precedent for the supposition was therefore wanting. Fissures whence firedamp might have issued were looked for at the place, but none detected. Still it might have issued without fissures being found, or, as was supposed, a cavity might have been occasioned by a subsidence or "swag" of the strata, which became filled with firedamp before the fall took place, and was given off, as not unfrequently happens, on the fall occurring. Circumstances, however, did not well bear out such a view in this instance. The swag, if any indeed did exist, had not extended into the sides beyond the fall. It is therefore questionable whether sufficient firedamp could have been thus liberated to account for the wide-spread flame. The absence of dust, too, both upon any part of the fallen materials and in the cavity whence they had fallen, whilst everything around was set in with the dust of the explosion, indicated the fall that had occurred after the explosion. The fact also of there being other falls of roof as well as the one referred to, and that arching had fallen, showed the blast to have been powerful, and that the falls were in all probability consequent upon it. In the absence of dust on the fall or in the cavity, it was then further supposed that part of the fall had occurred before the explosion, and the remainder after it; and it was stated that such could be traced by a substratum of dust extending the whole length of the upper fall. Neither myself nor my colleague, Mr. Wynne, whom I had called in to assist in the investigation, could see any such trace, although we were the first to look for it, and had examined one of the cuttings into the fall, where it was said to have been afterwards found. Had the supposed first fall been shown to be small, its subsequent covering would have been more probable; but being a large one, said to be traceable throughout the entire length of the upper fall, about fifty yards in length, its entire obliteration both in the roof and on the floor, as effectually as though a scale like a tablecloth had been taken off one and spread over the other, is not so easily realized. But the greatest difficulty, perhaps, in the way of the supposition of an outburst, is in the fact of the two rise drifts being the centre of the explosion. The firedamp, to have got there from the outburst, as supposed, must have passed through sundry intervening workings, and been arrested by the shot at the identical moment of its reaching the rise drifts, — places, it may be repeated, which formed in themselves natural receptacles for firedamp, and where, as no one had that day been working, firedamp might have been lurking undetected.

Evidence enough, however, has been received to establish the danger of the mine ; and if it be from sudden outbursts or natural fouling, explosions seem no longer excusable in the absence of any apparent precaution. The firedamp in the pits in question was stated in evidence at the first explosion to be sharper in firing than the firedamp commonly met with, a view which, with the exception of that of a few other collieries, my own opinion coincides. Firedamp generally when mixed with fresh air explodes with a very small bluish cap to the flame, but, circumstances being similar, the firedamp of this and a few other mines has appeared to me to give unusually little indication before firing. It may possibly appear by analyses that olefiant gas is present in some of the quicker firedamp, or that it is mixed with less then the usual proportion of nitrogen or carbonic acid. The fact, however, of its being known or supposed to be more than usually subtle from the sudden manner in which it fires in the lamp, sometimes before any cap has been detected, shows the great care required in ventilating, and the mode of lighting and using lights in this mine.

With regard to future operations, the points to be guarded at, as they have occurred to me, are set forth in my letter to the Company, of the 11th of May last, as follows : —

"Having on the 11th instant made further inspection of the Arley Pits, at the Ince Hall Coal and Cannel Works, and also ascertained particulars as to the additional precautions intended to be taken in carrying on the mine, I beg to submit for your consideration the following observations.

"1st. With reference to the recommendations in Messrs. Forster and Elliots Report of the 5th instant, which may be summed up as follows, viz.;

"That the air-courses be enlarged.

"That all the return air be passed through a dumb drift, clear of the furnace.

"That the return air from goaves or large wastes do not pass working places or along main rolley ways.

"That naked lights and gunpowder be discontinued except in particular places where permitted by the viewer. The shots to be fired by good experienced overmen.

"That the safety lamps have glass cylinders to prevent tobacco being lighted at them.

"The first three of these recommendations have my concurrence. The remaining two I consider incomplete. It having been proved that two awful explosions have occurred by firing shots in this mine — the shot in the latter instance having been fired by one of your most careful and experienced foremen — it seems necessary that gunpowder be entirely prohibited. And with regard to the safety lamps, if it be determined to use glass lamps, I think they should be of such construction that the light becomes extinguished when in an explosive atmosphere.

"2nd. It appears of importance in a firey mine dipping at the rate of 1 in 6 or 1 in 7, like the mine in question, that the workings should not extend beyond a certain distance to the rise of the shafts. The rise workings have now reached 500 yards from the shaft levels, or about 70 yards perpendicular above the bottom of the shafts. It is questionable whether this limit be safe, but I am quite satisfied it ought not to be exceeded; and it is highly desirable that an air pit be sunk to the rise to relieve it. The point in the Mesnes property spoken of for an air pit is about 1,100 yards to the rise of the present shaft levels, a distance which should not be attempted uphill, and which is such as to point to the necessity and desireableness of an intermediate pit.

"3rd. As the present system of working entails greatly increased risk of explosions, it seems highly important that it should he altered to the most approved system of working in similar seams. Having men getting coal at so many points along the numerous long levels necessitates openings from the main roads at points where the pressure of air is great, and where, if leakage take place, the inner workings may be almost entirely deprived of ventilation. Driving the levels to the boundary, and working the coal backwards from the extremities, seems the safest method ; but if your determination be, as I understand it is, to work the coal forwards as at present, it would add much to the safe working if the working places were confined to near the face of the levels, and not scattered from the pits to the face of the levels, as at present. Keeping the workings in a compact form would enable you to secure the air to the face of the workings by permanent stoppings without the intervention of the numerous air doors and crossings."

* Forced down 414 yards by a pressure stated at 5 inches of water.