Faraday and Charles Lyell to Samuel March Phillipps   27 March 1845

To S.M. Phillipps Esq | &c &c &c

London | 27th March 1845

Sir

In reply to your inquiry¹ whether we had any observations to offer to Sir James Graham respecting a report by the Coal Trade Committee², which you were so good as to send us, and which contained considerations and remarks upon our joint Report upon the Haswell accident³; we may observe that, with respect to anything which is a matter of opinion, we have nothing further to say, except that we are not aware of any part which we desire to change, but with respect to the proposition made for the ventilation of the goaf, a few words may be desirable.

On further consideration of the plan proposed, one of us sent a letter⁴ to the Editor of the Philosophical Magazine (who had published the first report⁵), containing certain results of trials and simplifications of arrangement, tending, as we thought, to facilitate the practical application of the plan, of which letter we beg leave here to introduce a copy:-

To Richard Taylor, Esq.

Sir

You have honoured the Report by Mr. Lyell and myself with a place in the Philosophical Magazine, p.16, and this induces me to send for insertion also certain considerations which have occurred to me since the Report was written, and also some practical results which were brought generally before our members here at the last Friday Evening meeting⁶. I need hardly say that the Report proposes to draw away the lower aërial contents of the goaf by an iron pipe laid down in one or other of the ways of the mine, and either entering into the return way, or having a fanner, or bellows, or other blowing apparatus, upon it. The points I wish to speak to now, are, first, the draught, and next, the nature and place of the pipe.

By experiments which I have made with a small furnace flue and pipes of 6 inches diameter and less, I am quite satisfied that such a draft as that of the return at the Haswell mine would be sufficient to effect that which we propose in the Report, without the use of any extra blowing or withdrawing apparatus, so that the plan is so far relieved from the necessity of keeping a man or boy working at such a machine.

With regard to the pipe, I think that, instead of laying it down in the floor of the mine, it had better be hung up or sustained upon props in the open space of that way or passage which may be chosen for its direction. If then, any derangement of position occur, it can easily be remedied. I have had pipes of 6 inches in diameter, made both of air-proof cloth and common sheet-iron; the former were kept open by whalebone rings run round then at equal distances of two feet, and answered in my trials exceedingly well. Square trunks, also, made by nailing four boards together with copper or iron nails, are easily available as tubes. Such tubes, it may be said, when placed as proposed in the air, would easily be deranged by falls. No doubt a fall might destroy a part of a tube, but if it did, there would be no great difficulty in restoring it; and further, if a judicious selection were made for the direction of the tube, there appears to be no reason why the roof over it cannot be as well and securely propped up as the roof of the mothergate, the rolley-way, or any other important part.

Finally, it is not necessary, on the principle proposed, that the goaf end of the tube should always be at the very extremity of the goaf towards the rise, but only that it should be 3, 4, or more feet above its upper edge, so that a jud or two may sometimes be drawn in advance before the goaf end of the pipe need be readjusted. Apparently there can be no difficulty in selecting the place of the goaf end of the pipe so that there shall be no interference with the general plan upon which the coal itself is worked.

I am, My Dear Sir, | Your faithful servant | M. Faraday

Royal Institution | Jan. 20, 1845.

This letter, published on the 1st of February, would have been sent to the Coal Trade Committee, had we been aware of the existence of that Committee, and it might, we venture to believe, have had some influence on their Report. The fair spirit manifested in that report assures us that the trade are really anxious to know of, and apply, any means of doing good which appear to them practical; and we, on our part, think still, that the principle of our proposition points to a practical result. Any further remarks, therefore, that we feel called on to make, will not be directed to the report generally, but to the proposed method of ventilating the goaf.

With regard to expense, this does not seem very serious, when wooden trunks are thought of as air-channels, instead of iron pipes. Thus, in reference to the Haswell mine, where the accident occurred, the distance, on the official plan of the works sent in with the former report, from the nearest part of the return way to the highest point of the goaf at which the accident is believed to have happened, is 126 yards; or from the same point of the return way to Williamson's Jud, the very place of the accident, 238 yards; therefore, a wooden trunk, made of boards nailed together, and 126 or 238 yards in length, would reach from the return way to these places, and we suppose that, with all the labour of fixing, &c., the longest could not cost more than £75. If men could go from 8 to 13 feet upwards into the goaves, as mentioned in the coal trade report, there does not appear to be much difficulty in elevating the end of such a pipe in the manner we ventured to propose, and the effect could not be otherwise than that on which we reckoned, a strong draught out of that part of the goaf into the pipe and return way.

The coal trade report says that there are 14 goaves in the Haswell mine. We had only under consideration the goaves of the Little Pit, in which the accident occurred, and it will be seen by the plan already referred to, and attached to our Report, that these are four in number, and the impression was conveyed to our minds, at the time and since, by the arrows placed in various directions over them, to show the course of the ventilating air, that there was a comparatively free air-way from one part to the other of each goaf. If such be the case, we should propose, in accordance with the principle before explained, to have one wooden trunk extending from the nearest point of the return way to the furthest, or Low Brockley Whins goaf, passing in its way near the upper edges of the other goaves, & having branches proceeding from it to each of these goaves respectively. This, by the plan, would perhaps require 546 yards of the wooden trunking (costing about £136) and that would be the whole apparatus necessary for the Little Pit.

The Coal Trade Report states that goaves are often divided into portions not aërially connected with each other, and that all parts are not accessible. We cannot, therefore, doubt that such is the case. Yet if goaves be dangerous, and if, according to our late proposition, the expense in many cases would be but moderate, there seems no reason to come at once to the conclusion, that, because every part is not accessible, none should be protected against accidents.

In making these remarks, we still wish them only to be viewed as suggestions made to practical men for their judgment and trial, and we hope that they will look favourably upon, and in some convenient locality, try the power of the principle, by which only its economy, effect, and applicability to practice can be decided. It is a truth well known to every experimental investigator of nature, by the tendency of his own mind in the creation and collection of facts, that the success or failure of such a proposition as that made in our report, often depends upon the animus with which it is carried into practice. Our first announcement was, if literally followed, very probably impracticable, but it was more the expression of a principle than a practice, and was the natural precursor of simpler views as respects detail; which again, we expect, would become still more simplified if finally carried into effect.

At p.16 of the Coal Trade Report, the Committee express an opinion that the atmosphere above the goaf end of the pipe would be left unaffected by it, and that, therefore, dislodgement of gas from a fall within the goaf would still take place. It will be as well, therefore, to state that fire-damp in a goaf vault is not exactly comparable to water in a pond, there being this great difference, that the gas continually tends to mingle with the air beneath, by a property peculiar to gases and vapours (expressed by the term "diffusion"), and so would, under such circumstances, be brought down to the level of the exit pipe. On the same property depends, in a great measure, the circumstance that a goaf which contains fire damp one day may be found perfectly free from it on subsequent days, that being the condition which the Haswell goaves themselves were in at the time of a more recent careful examination⁷ (p.17).

The sole object of our visit to the Haswell mine and inquest (we being closely limited by our time and duties at home) was to enquire into the cause of the accident there, and to suggest, if we could, some means of preventing the recurrence of similar events. That accident, from all the information then obtained, appeared to be due to an explosion originating at a goaf, and there was evidence tending to show that a second goaf had assisted in increasing the fire. To the means of obviating such mischief, our Report was directed. Now, it would appear, that goaves in general are not so dangerous, and that out of eleven great explosions that have occurred in fourteen years, exclusive of the Haswell accident, the goaves had no connexion with the origin of the accident in at least ten of the cases (p.15). The consideration of these and other circumstances, such as the use of naked candles and gunpowder in the whole, where the gas is said most to abound, suggest the expediency of a body of evidence being collected together and put on record, respecting the casualties in mines, with descriptive particulars of the part of the mine where they have occurred, the state of the workings and of the ventilation. The publication of a detailed and accurate account of all such facts might afford the scientific public philosophical data for arriving at safe and useful conclusions, and the evidence thus obtained would be free from all suspicion of having been biassed by partial views and local interests, and that excitement which cannot but occur on the occasion of any serious catastrophe.

Certain incidental observations in different parts of the Coal Trade Report, as at pp. 6, 10, &c., and the system now in course of adoption of making the goaf central, and working the whole all round and nearly up to it, induce us to put forth the expression of a thought relative to ventilation generally, which has been in our minds from the beginning. It is, that all the air which passes through the mine should pass through the goaf, i.e. that the goafs should be the beginnings of the return way, the return way not being, as now, on the level and at the side of the workings, but over them and the goafs. This idea seemed at first sight objectionable, from the assumed breaking down of strata into goaf, and we now put it forth, not with any degree of confidence, but as a suggestion; for we have not had opportunity sufficiently to consider it in relation to the circumstances of the mine and the strata above.

With respect to the mistake into which we are said to have fallen as to the inability of a master-wasteman to write⁸, we can only say that we rested on the certified evidence taken by the Coroner at the Inquest⁹, in which the mark of the person, and not his signature, is used.

We have the honor to be | Sir | Your very Obedient | Humble Servants | M. Faraday | Cha Lyell

To S.M. Phillipps Esqre | &c &c &c