(a) Influence of the Method of Working

The choice of the method of working the longwall face, by retreating, opening from a narrow heading, the roof in the waste being allowed to cave, was unfortunate.

If, as I believe, this led to the formation of large cavities in the waste in which firedamp accumulated and ultimately to the firedamp passing into the air current, it was a major cause of the disaster.

It is accepted mining practice that the beds overlying an area of goaf behind a longwall face shall be supported as soon as possible, either through packs or through heaps of caved debris.

For caving to be successful certain conditions must be fulfilled. As it is important that these conditions should be clearly understood, I repeat the quotation by Mr. T. A. Jones from the Second Report of the Durham Falls of Ground Advisory Committee

"Conditions essential for the success of the caving method are that

Both the regularity and the height of the fall depend not only on the nature of the strata but also on the efficiency of the waste edge support. Although the chocks used on the face proved sufficiently strong, the wood props, which broke when the weights occurred, were unsuitable for the circumstances that developed.

It may be that, as Mr. Fry suggested, fragmentation would have improved as the face advanced and full abutment pressures were established, but it was agreed by all that the fragmentation had not been satisfactory up to the time of the disaster. Thus, the caving did not achieve its purpose, cavities developed and excessive stresses were imposed on the strata ahead of the face and on the supports (Diagram I).

Mr. Carter, discussing the importance of the roof support measures adopted in the early stages of a face advancing from the solid, pointed out the great transition that occurs, in a few weeks, from the conditions of a narrow heading in which there is often practically no strata movement, to those of a longwall face which is itself in a partly dc-stressed zone but has a very high pressure zone ahead of it, a high pressure zone behind it, and the whole of the beds up to the surface in motion above it. During these vast alterations there are often periods in which the roof is easy to control but there is always a liability to sudden adjustments known as "first weights" and "second weights". Experience has shown that it is not inevitable that these major changes of stress lead to dislocations at the face. Adequate supports will often counter their effects.

I therefore agree with the view expressed by Mr. Carter and Mr. Collins that strip packs should have been built in the initial stages, and cannot do better than quote what Mr. Collins said in evidence :-

The management believed that they had had experience in situations sufficiently comparable with that of the Third South to justify the adoption of the method practised, but they had not in this area opened a longwall face from a narrow heading and I do not think they realised the difference this made. I feel too that the roof troubles that occurred were not given enough attention. Had they been studied sufficiently, particularly during the shift in which the supports were advanced, that is the shift in which the effects of loss of roof control are most apparent, the occasional firing of shots in order to release the chocks would, I think, have been discovered, and this would have focussed attention on the need for a change in the method of working.

As a consequence of the incompleteness of the caving, considerable cavities must have existed in the goaf area. Because the face was retreating and had solid sides, there was not the ventilating pressure difference across the waste which, with leakage through the packs into the return, leads to the gradual release of firedamp from the waste of an advancing face. The emission of firedamp, although it was by no means rapid, would thus gradually fill the cavities to the point of overflowing, and the effect of the ventilating current be, as shown in Diagram II, to conceal its existence.

Thus, while the retreating system, with or without caving, has advantages, the risks pecul iar to these methods and the conditions in which it is permissible to employ them must be clearly understood and the proper safeguards observed.

To summarise my views on this aspect, I would say that unless the natural conditions are suitable and the support of the waste edge is effective, caving will not be successful, but will lead to heavy weights at the face and to large cavities being left in the waste. Particularly on retreating faces the cavities are likely to fill with firedamp, and when weights occur or the barometric pressure falls, it will be forced out into the air current. Caving should not, therefore, be practised unless the natural conditions and method of waste edge support are such that the roof in the waste falls regularly to a sufficient height and in a suitably fragmented state. In most cases strip packs should be built in the initial stages of a face opening out from a narrow heading; they can be dropped gradually if and as the conditions developing as the face retreats show that caving is likely to be successful. On retreating faces, there being a greater liability to sharp increases in rate of firedamp emission, the quantity of air provided should be greater than that necessary on advancing faces in otherwise similar conditions. Investigations should be made to discover the extent of such variation in rate of emission.

Matters concerning the use of chocks call for brief comment. The firing of shots to release the chocks was a breach of the then existing rule in the Explosives in Coal Mines Order that, in mines where Permitted Explosives are required because of the possibility that inflammable gas may be present " . . . no shot should be fired in the roof of a longwall working between the coal face and the waste" without the written authority of the agent and the manager. The firing of such shots is now prohibited in safety lamp mines by Article 35 of the new Order and relaxation can be granted only by the Chief Inspector of Mines or a Deputy Chief Inspector of Mines acting on his behalf. Several of the chock releases were found after the explosion to have tripped spontaneously and evidence was given that during a previous weight selftripping had occurred. It was also said that sparks had been emitted when these releases had been operated under heavy load. The wide adoption of releases has enabled chocks to be built so as to resist roof movements effectively, and this has without doubt played a considerable part in the reduction in the frequency of accidents from falls of ground. Moreover, I appreciate that self-tripping of the releases is by no means common. It is nevertheless desirable that as forms of chock release free from this defect become available, they should be adopted.

The problem of the ignition of firedamp by frictional sparking is now the subject of active investigation by a Joint Committee of the Ministry and the National Coal Board. Meanwhile, in the present state of our knowledge it is necessary to avoid the possibility of sparking in the vicinity of firedamp, and where sparks are liable to be emitted on the release of chocks, or certain forms of prop, set at the waste edge, the releases should not be operated unless tests have been made with a flame safety lamp - particularly at the waste edgeand these have not revealed the presence of firedamp. I also urge the development and use of supports not liable to emit sparks on being released.

(b) Influence of the Ventilation

According to the statutory measurements the average quantity of air reaching the top of the intake drift to the Duckbill District was of the order of 23,000 cubic feet per minute. Let us consider what part of this was reaching the longwall face prior to the changes in the system of ventilation made within a few days of the explosion. It is a reasonable assumption that the normal flow exceeded the 3,200 cubic feet per minute found in the last measurements made before the explosion, on 16th May, for at that time the face was partly closed by a fall. I believe that it would amount to some 6,000 cubic feet per minute, which is the rough average of earlier measurements.

Although the normal yield of firedamp was low, accumulations of firedamp had been found in other parts of the district on several occasions. Often these were small, but a sudden large emission of firedamp from a fault side in the First South area was recorded. To quote Mr. Miron, the occurrence of firedamp "seems always to have been sporadic and unexpected". Moreover, a point I have already considered, cavities were being formed behind the longwall face and were likely to be filling with firedamp which might be forced out at any time. I conclude, therefore, that though this volume of air was adequate to dilute the quantity of firedamp normally appearing in the air current, insufficient account was taken of the possibility, indeed one might say the probability, of temporary increases in the emission.

Was the quantity of air on the longwall face sufficient, judged by other standards ? The cross-sectional area at the face was of the order of 70 square feet and, assuming a quantity of 6,000 cubic feet per minute, the velocity would be about 85 feet per minute.

Let me quote from the Third Report of the Research Committee of the Monmonthshire and South Wales Coalowners’ Association entitled "A Study of the Physical Condition of Mine Air" - "The best conditions would appear to exist when air velocities are between 150-450 feet per minute. These values are recommended for air having dry-bulb temperatures less than 75° F. Above 75° F. a higher range of air velocities is required in order to produce the necessary cooling effect". I appreciate that in thick seams compliance with these figures would require quantities of air greater than those usually provided, but, taking this considered opinion in conjunction with the evidence that sometimes the deputies in charge stopped the fan ventilating the headings and opened the adjacent door in order to clear shot firing fumes from the longwall face, I consider the volume of air passing along the face to have been below that required by good practice.

Shortly before the explosion a number of changes in the system were made - a fan was introduced for No. 24 heading, the fan feeding Nos. 21 and 22 headings, and the door associated with it, were removed from the Belt Road to No. 21 stenton, and on 27th May a second fan was installed in this stenton. Because the air taken by the fans passed direct from the headings into the return and was lost to the parent current, these changes must have substantially affected the quantity of air passing into the Third South face and it is to be regretted that the measures prescribed in the Coal Mines (Ventilation) General Regulations, 1947, that a determination of the firedamp content of the air current and a measurement of the quantity of air should be made as soon as practicable after the making of such alterations, were not observed. It is true that the interval between the last change and the occurrence of the explosion was short, but changes in ventilating arrangements may produce serious consequences quickly, and so when such changes are made, the position should be kept under observation until conditions have become stable again.

In the absence of such measurements of the air flow it is possible only to estimate very roughly an important figure - the quantity passing along the face at the time of the explosion. According to the statutory measurements, of the 23,000 cubic feet per minute already mentioned as reaching the top of the intake drift to the Duckbill District, rather more than 7,500 cubic feet per minute went to the Third West places and an average of some 6,000 cubic feet per minute to the First South places. There was available for the inbye end of the District - the Second South roads, with the two fans ventilating the heading ends, the longwall face and the three duckbill headings - some 9,000 cubic feet per minute. After 27th May, two and sometimes three auxiliary fans were drawing air away from the intakes to the duckbill headings. The fans were each of a type rated by the makers as being capable of deliveries of 3,400-4,000 cubic feet per minute with the lengths and diameter of tubing in use. The delivery tubes were said to be "snubbed", by means of cord tied round the tube, to restrict the flow. The last recorded measurements of the quantity delivered, on 21st May, showed that the single fan then ventilating Nos. 21 and 22 headings was passing 3,800 cubic feet per minute.

It is difficult to avoid the conclusion that at the time of the explosion the rate of air flow on the longwall face must have been well below the figure of 6,000 cubic feet per minute estimated to have been passing before the changes were made.

There is so much unavoidable uncertainty about the rate of emission of firedamp immediately prior to the explosion that it is not possible to say how a more ample supply of air would have affected subsequent events. It may be, however, that had the quantity been more in accordance with good practice, the firedamp explosion would not have extended far enough along the return to blow through into the First West intake roads.

Of the use of the auxiliary fans, Mr. Ronald Williams said in his closing speech :-

These are severe strictures, but I am bound to agree that they are not unjustified.

As has already been said, with about 9,000 cubic feet per minute of air available, five auxiliary fans were installed on the intake side of the longwall face and three were so arranged that the air passing through them, after ventilating the headings, was delivered into the return. One of these three, it is true, only worked occasionally and all were regulated, but as the method of regulation consisted merely of a piece of cord tied round the air tubes, a burst air tube between the fan and the constriction or a chance blow which severed the cord, could have caused re-circulation or a partial short circuit.

Other unsatisfactory features were

	(a)	The practice, adopted in respect of the fan supplying Nos. 21 and 22 headings when in its original position on the Belt Road and of the two fans in Second South, of placing a canvas door across the road at the point where the fan stood. An auxiliary fan as normally worked draws only a moderate proportion - Professor Statham¹1 recommends not more than 25 per cent. - of the air passing along the airway from which it takes its supply, the remainder passing on unimpeded. Though it is true that there were alternative paths for air to reach the longwall face, the doors placed at these fans constituted restrictions which, in my view, were undesirable.
	(b)	The stopping of fans ventilating places in which firedamp was liable to accumulate. Evidence was given of an occasion in Second South when, following the stoppage of the fans and the opening of the doors, firedamp accumulated in the headings. Obviously when the fans were restarted the gas must have been carried on to the longwall face.

In some cases auxiliary fans should be kept running permanently in order to comply with Section 29 of the Coal Mines Act, 1911, which requires that "an adequate amount of ventilation shall be constantly produced in every mine to dilute and render harmless inflammable and noxious gases to such an extent that all shafts, roads, levels, stables and workings of the mine shall be in a fit state for working and passing therein". If, for any reason, such fans have to be stopped, there should be alternative arrangements providing a sufficient flow to prevent the accumulation of noxious or inflammable gas, even when work is not proceeding in the place concerned.

Generally, however, the starting and stopping of fans is to be deprecated as the resulting redistribution of ventilating pressure may produce effects over a considerable area.

I think the reason for these makeshift methods is to be found in Mr. Jones’ examination of the Assistant Agent, Mr. H. E. Morgan :-

No. 14 (5) of the Coal Mines (Ventilation) General Regulations. 1947, lays down that "in respect of any section of narrow or panel workings the ventilation of which involves the use of two or more auxiliary fans drawing air from the same air current, a plan shall be prepared showing the general system of ventilation and the directions and quantities of the air currents; and a copy thereof, and of any subsequent plan showing any change in that system, shall be delivered as soon as practicable to the Inspector of the Division". No such plan was sent to the Inspector following the opening of the Third South and the manager, in answer to Mr. Jones, said that he "did not consider it a change".

Whatever the legal position may be, there can be little doubt that had a plan even been prepared the potential danger in the arrangements would not have been overlooked.

I recommend that all existing systems of ventilation employing multiple fans should be reviewed and new systems studied to ensure that :-

	(i)	the volume of air is large enough not only to avoid the possibility of re-circulation in any place ventilated by an auxiliary fan, but also to provide for the adequate ventilation of all other working places;
	(ii)	no fan is stopped unless there is alternative means of providing adequate ventilation;
	(iii)	if it is necessary to regulate a fan, it shall be done in such a way as to prevent unauthorised or inadvertent alteration.

(c) Ignition by Frictional Heating or Sparking

It was clearly established by the evidence that sparks were produced by coal cutter picks in various parts of the Duckbill District. Most of the witnesses, it is true, referred to sparks produced in the headings by shortwall machines when jibbing in and unfortunately the men best qualified to speak of conditions on the longwall face were killed in the explosion. One of the mechanics, however, said that he had seen sparks in the undercut on this face and I see no reason to suppose that it was any different from other parts of the district in this respect.

It has, of course, been known for many years that firedamp could be ignited by the action of coal cutter picks on pyrites and on certain types of rock or inclusions containing quartz. I have purposely avoided using the word "sparks" because with pyrites at least it would seem that ignition is not caused by the sparks themselves so much as by finely powdered pyrites dust which is heated by friction until it bursts into flame. This distinction in the mechanism of ignition is important because it accounts for the fact that blunt picks are more likely to cause ignition than sharp ones.

Many of the men in the Duckbill District had seen sparking often and, as nothing untoward had occurred, they may have formed the impression that it was not dangerous. Indeed, as Mr. Miron said, some such impression appears to exist amongst mining people as a whole. But an analysis of all reported cases of ignitions of firedamp from 1937 to 1951 has shown that, excluding ignitions from naked lights, coal cutter picks are second only to explosives as an igniting medium, 91 ignitions have been caused by cutter picks and 100 by explosives. It has not been possible to establish the number of cases in which pyrites was involved, but there is no doubt that they were many.

Attempts have been made to reduce the risk by introducing an inhibitor into the cut. Wet cutting, especially if the water passes through the jib so as to wet the picks as they are entering their cutting path, must have a sup. pressing and cooling effect, but it is not possible to say that it would always prevent ignitions. Carbon dioxide has been tried, but it is not easily practicable to provide the volume necessary. Atomisers have been used, as Professor Poole stated in evidence, referring in particular to the successful results obtained with them by Mr. R. D. Beilby². However, not enough is known about the incidence of firedamp in the cut, though we do know that it may vary most widely in place and time on the same face, and there is much more to be learned of the action of suppressors. Following a recommendation by the Safety in Mines Research (Advisory) Board, a Working Party consisting of members of the Ministry of Fuel and Power and of the National Coal Board has been formed to investigate the problem. As hazards of ignition from friction are not confined to coal cutters, the terms of reference are :-

Pending the findings of the Working Party the following precautions should be taken :-

	(i)	Wherever coal cutters are in use or are to be used, a survey should be made for the purpose of selecting a cutting horizon, as far as is practicable, clear of any material from which sparks may be struck.
	(ii)	The general policy in gassy seams with no clear horizon should be to adopt one of the alternatives to cutting, or to adopt measures such as stowage or draining of the wastes to prevent accumulation of firedamp at the waste edge.
	(iii)	Every effort should be made to ensure that only sharp picks are used.
	(iv)	Water hose with an ample supply of water should be provided within easy reach.
	(v)	Having regard to the dust and sparking problems, it should be the general policy to avoid dry cutting.

(d) Firedamp Detectors

The Coal Mines General Regulations (Firedamp Detectors), 1939, require that firedamp detectors shall be provided at certain places and for certain men. In compliance with these Regulations the coal cutter men on the Third South face were provided with a detector in the form of a flame safety lamp. One of the other men working on the face at the time had also been supplied with a flame safety lamp although this was not required by the Regulations. Neither of these lamps was at the face when the explosion happened, both of them having been left in the intake.

It is impossible to say whether the firedamp would have been detected in time if the lamps had been at the face, but the chance that it might have been was lost when they were left in the gate road.

By and large, detectors are issued only to men working in places where firedamp may be a hazard; if they are to be of any real value they should be kept constantly within sight. For this reason the Regulations prescribe that a man who is provided with a flame safety lamp as a detector shall not have any other light, except with the written permission of the manager. This permission is, however, usually given to men such as coal cutter operators who need a good light and the use of both hands. The detector lamp is then just one more thing to carry and - human nature being what it is - it is the first thing likely to be jettisoned. Confirmation of this, striking in its simplicity, came from one of the witnesses - a duckbill operator - who with an admirable absence of equivocation said that if he had a lot to carry he sometimes left his safety lamp behind because it was the thing most easily dispensed with. Evidence given by the lamp-man showed that the duckbill operator was not alone in these views, and I am afraid that they are not confined to Easington nor to any one coalfield.

The function of a firedamp detector is to give timely warning of the presence of firedamp. If it is left behind because it is a cumbersome extra for a heavily laden man, it will give no warning to anybody of anything. Properly used in the proper place it may be the means of saving many lives. It gives a chance and it is tragic if that chance is thrown away. Both men and officials have a duty to see that it is not thrown away and I appeal to the National Coal Board and the National Union of Mineworkers to do everything in their power to ensure that that duty is discharged.

At the same time I recommend that research should be undertaken to develop a combined cap lamp and detector. Accuracy within fine limits is not necessary, but it must be reliable, easy to wear and give a good light. Also I endorse the view of Mr. Robert Yates, H.M. Deputy Chief Inspector of Mines, in his report on the explosion at Eppleton Colliery, that there is need for a device which would automatically cut off the electric power in an atmosphere containing a pre-determined percentage of firedamp.

In view of the conclusion that the spread of the explosion was caused by coal dust, it is necessary to review the measures taken to meet the requirements of the General Regulations (Precautions against Coal Dust) 1939.

(a) Method of Sampling

All the sampling in the North Pit was done by one man. His method was to start at the outbye end of the district and to collect samples from the roof, floor and sides respectively of each consecutive length or zone of roadway whether the road was one used for the transport of coal, a materials road or an airway. As his monthly quota of samples for the Duckbill District was 72, the maximum number of zones from which he could take samples was 24, and as each zone was 176 yards long and as he continued to sample the same zones month after month, only a little over 4,200 yards of the 16,000 yards of roadway estimated to have been traversed by the flame had been sampled within the period of six months covered by the evidence.

The Regulations require that all accessible roads must be systematically sampled. On roads used for the transport of coal and in return airways within 200 yards of the face, it is laid down that the number of samples collected monthly shall not be fewer than in the proportion of ten per mile, except with the consent in writing of the Inspector or unless the natural conditions ensure compliance with the Regulations. For other roads the requirements are less specific, but as it is provided that a road may be sampled at intervals not exceeding three months if it has been shown that the application of stone dust is not required more than once in six months, the inference is that without such evidence the intervals should be considerably less than three months.

It is also laid down that "if since a sample was last collected over such a section of road, some part of that section has been treated with incombustible dust more frequently or more recently than other parts, separate samples shall be collected over the several parts irrespective of their lengths". This clearly indicates that in the vicinity of transfer and loading points, where, according to the evidence, stone dusting was done much more frequently than elsewhere, samples should have been taken over lengths shorter than 50 yards.

Sampling in itself cannot, of course, make a pit safe - it is only a means to an end - but it is an essential part of any system of dust control. It is disturbing therefore to find that it was carried out with so little understanding and that roads could remain unsampled for so long without the higher officials becoming aware of it. The sampler said in evidence, and it was not refuted, that he had continued the method of sampling used by his predecessor, the only person from whom he had received any instruction in his duties. He admitted that he had never drawn attention to the fact that parts of the roadways were not being sampled; on the other hand, his superiors seem to have concerned themselves only with observing whether the incombustible contents of the samples taken were within the proper limits.

(b) Suppression, Removal and Treatment

For the suppression of dust the management relied on the use of water sprays at the transfer points - wet cutting and water infusion having been abandoned after short trials. Sprays when used in conjunction with some form of enclosure so designed that the dust is driven on to smooth surfaces to which it adheres, and from which it is subsequently collected in such a way as to prevent its escape into the air, are effective. With sprays used as at Easington the wet dust particles settle on the roof, floor and sides and subsequently dry out.

Evidence was given that on the stone-shift from eight to ten men were wholly engaged in cleaning up spillage and stone dusting, and up to 18 men were so employed for part of the shift. In addition there was a man on the fore-shift who cleaned up and stone dusted the trays of the conveyors. It is right and proper that spillage should be cleaned up, but the amount of spillage must have been excessive to necessitate the employment of so many men and more attention should have been given to its prevention. The spillage was loaded on to the belts and thence into tubs and, though it was wetted, a great deal of dust would be raised into the air during both operations; some would stick to the belts and, as it dried out, would be deposited over the whole length of the conveyor structure.

The local application of stone dust at transfer and loader points was carried out by the men who cleaned up spillage. There was also a man on the backshift who stone dusted the roads near the face. What was described as the strategic stone dusting of the mine was carried out by a team of seven men under a leader known as the stone dust man. According to this man it took three to four weeks to stone dust the Duckbill District and it was re-treated about every four weeks. It is difficult to reconcile this with the needs of other parts of the mine, but as no written records were kept the position remains obscure. He admitted, however, that no stone dusting had been done in the Third West since it was finished and that he left the stone dusting in the Main Coal Training District to the people in charge of training.

There was, however, evidence which I accept, that beginning on the 16th April, the intake roads in Third South were stone dusted right up to the face and that the Third South Return between the face and the First West Materials Road was treated during the week before the explosion. Indeed, most of the team were still engaged in the District and were killed in the explosion.

Although he kept in touch with the sampler and re-treated any zone from which an adverse sample had been taken, the stone dust man otherwise used his own judgment as to where and what treatment was required.

(c) General

Almost haphazard as the sampling and stone dusting may have been, it must be noted that the incombustible contents of the samples taken before the explosion were well above that required by statute, and it may be that had samples been taken in other lengths of road which had been stone dusted in the same way, similar results would have been obtained. The results of the samples taken after the explosion by Mr. Badger tend to confirm this view. Excluding the Main Coal Training Area where, as I have already mentioned, the treatment was left to those in charge of training, 113 out of 135 samples contained more than 75 per cent. of incombustible matter, and Mr. Collins quite properly pointed out that the average incombustible content, including the samples from the Training Gallery, was 75 per cent.

Mr. Badger’s samples were taken in the manner prescribed in the Regulations and, as was pointed out in the Inquiry into the explosion at Valleyfield Colliery in 1939,³ samples taken in this way do, viewed as a whole, give a rough guide to the general composition of the road dust as determined in a similar way before the explosion. Moreover, in explosions in which the stone dust and the coal dust have been intimately mixed the composition of the dust, as determined by such samples, has not differed greatly from the composition of special samples taken to include as far as possible only dust which had been in the explosion cloud. The wide difference in the results of the two types of samples in this explosion - it will be remembered that Dr. Tideswell gave the incombustible content of a large majority of the samples of the explosion dust as between 30 per cent. and 55 per cent. - is quite consistent with the theory that the explosion was propagated on its main path by coal-rich dust from transfer points, from the structure of the conveyors, from the belts, including any coal in transit, and to some extent from the stentons.

Before I continue with this main problem - coal dust in conveyor roadsI should deal with the spread of the explosion off its main path.

The spread of the explosion off its main path to the faces of the Straight North and Third West places and elsewhere was mainly due to coal dust picked up from disused roadways. Such roads, unless they are sealed off, tend slowly to accumulate airborne dust and if they are driven, as these roads were, in the seam, they accumulate coal dust through spalling of the sides.

Mr. Robert Yates, H.M. Deputy Chief Inspector of Mines, found that coal dust deposited in disused roads contributed to the explosions at Murton* and Louisa** Collieries. As Mr. Yates said, if and so long as such roads are accessible they should be treated fully in accordance with the Regulations. Otherwise they should be sealed off permanently or special measures of protection should be arranged at the mouths of any inaccessible places - for instance by shelf barriers or an arrangement of walls with a sandwich of stone dust. Clearly, the existence of passages in which fine coal dust may accumulate and which are open to any explosion that may occur in the workings defeats care taken in maintaining the working roads in satisfactory condition. This matter is of particular significance in County Durham where, as Mr. Yates pointed out, disused roads abound in bord and pillar mining.

The sources of the coal dust in the main path of the explosion were mainly peculiar to conveyor roadways. Attention was drawn to the importance of this problem in the Report† of the Royal Commission on Safety in Coal Mines published in 1938. The Commissioners foresaw that the importance of the problem would grow as the use of conveyors became more extensive. Tragic confirmation of this view has been afforded by this explosion and those which occurred at Whitehaven William and Louisa Collieries in 1947. Additionally, the numbers of fires which have been caused by conveyors, culminating in the disaster at Creswell Colliery in 1950, leave no doubt about the degree of risk attending their use.

The time has come to take stock of the position.

(d) What can be done?

Transport by road conveyors has its advantages, but there is reason to believe that there is an optimum length beyond which the method becomes uneconomic. I was, moreover, surprised to find at Easington that there were so many men engaged primarily on cleaning spillage. The installation and maintenance costs of the additional safeguards against fire and explosion, which bitter experience has shown to be essential, will not I think be light. Thus it may well be that in many instances the economic advantages of road conveyors will disappear entirely. I have no doubt that all these matters will be subject to fresh review by the National Coal Board and it is possible that the use of long roadway conveyors may tend to decrease, but even so the hazard would diminish only gradually over a considerable number of years and a more immediate remedy must be sought.

The Royal Commission proposed that a Joint Committee should be set up by the then Mines Department to work out appropriate methods of dust prevention and collection on conveyor roads. Such a Committee was appointed and did some preliminary work but, owing to the outbreak of war, it was allowed to lapse. In the meantime these problems have received a good deal of attention. Particularly as a result of the work carried out to limit airborne dust because of its effect on health, there has been a realisation that effective dust prevention and suppression at the working face can reduce the rate of dust deposition on conveyor roadways. But the problems are by no means solved and I therefore revive the Royal Commission’s suggestion in a somewhat amended form by recommending that a Committee should be appointed, representing the various interests, to investigate the use of roadway conveyors with a view to determining the limits within which they may be safely and advantageously employed.

In the meantime everything possible should be done to accelerate progress in the direction of preventing the formation of dust, and of suppressing such dust as is unavoidably produced, as close to the point of production as is practicable.

The progress should, of course, start at the coal face by such measures as improved roof control; by a reduction in shot firing; and, where appropriate, by water infusion and by wet cutting, supplemented with spraying where necessary.

The conventional type of coal cutter, in addition to its liability to produce dangerous sparks, a matter with which I have dealt, is by its design a maker of dust. At present there is no universally practicable alternative to its use, but there are a number of promising lines of investigation. One of these arises from the fact that in some places where water infusion has been adopted, the coal has been found to work so much more easily that the use of coal cutters has been discarded. So far it has been considered possible to adopt water infusion only where the natural conditions have been particularly favourable, but I believe that the technique can be developed so as greatly to increase the range of these conditions. For example, seams which cannot be infused by a steady hydraulic pressure might behave quite differently if a shock wave could be sent through the water column. Another possibility is the development of machines operated by slow moving forces as, for instance, the coal plough. Here again existing machines of this type have had only a limited success in this country, but it should not be beyond the wit of man to overcome their limitations.

I therefore recommend that investigation should be undertaken (a) with a view to extending the range of applicability of water infusion and to developing its possibilities for working coal, and (b) to hasten the development of coal getting and loading machines operated by slow moving forces.

During transport, dust is both produced and released into the air wherever the coal falls freely. Every practicable measure should therefore be taken to eliminate spillage and to reduce to the minimum the height of the free fall in the transfer of the coal from conveyor to conveyor or from conveyor to tub. Both can be reduced by the use of properly designed chutes. Far too often conveyors deliver on to other conveyors moving at right angles without any provision to bring about a smooth change in the direction of motion of the coal. And here I would call attention to a most useful paper by Mr. J. V. Spence, one of H.M. Inspectors of Mines.‡

Some spillage at loading points may be unavoidable and arrangements should therefore be made for it to fall into hoppers containing water or fitted with sprays, from which it may be subsequently loaded out without releasing dust into the air. Provision should also be made to clean and collect the dust from the surface of the return belt.

Even where these precautions have been taken, it may still be necessary to make provision for the suppression of dust raised into the air at transfer and loading points. As I have already mentioned, sprays are not effective unless steps are taken to confine and collect the wetted dust particles. Complete enclosure is not essential. All that is required is that the dust particles shall be driven on to surfaces to which they will adhere and from which they can subsequently be collected.

Measures based on these general principles will, if thoroughly carried out, effect a material reduction in the quantity of dust deposited on the roof, floor and sides of roadways. They will not, however, prevent it entirely and it remains to consider further measures to deal with the residue. The need for regular and thorough cleaning and for the application of stone dust on the “little and often” principle is well known. Attention should, however, be given to the way in which the cleaning is done - shovelling dust and spillage on to a conveyor belt or into tubs merely results in moving the finer and more dangerous dust from one place to another. Experiments with a form of vacuum cleaner originated jointly by the National Coal Board and H.M. Inspectors will, if successful, go a long way towards a solution of this problem. In the meantime, when cleaning is being done, the dust and small spillage should be well wetted and loaded carefully into bags for transport to the surface. Needless to say, when a place has been cleaned it should be re-stone dusted immediately.

As has already been pointed out, one of the factors tending to increase the dust hazard on conveyor roads is that the stone dust and the coal dust are not intimately mixed. The "little and often" principle attempts to overcome this but even if stone dusting is done several times during a working shift, it does not produce a really intimate mixture of coal and stone dust. To some extent at least this could be overcome by a device which puffs out small quantities of stone dust automatically throughout the shift. This is not a new idea but it has never found favour because it may cause discomfort and inconvenience to workers by increasing the total amount of dust in the air. If, however, the amount of coal dust is kept down to the practicable minimum the quantity of stone dust needed would not be excessive. In any event it is a method which might be worth a trial at transfer and loading points.

When all these measures have been taken there will still remain the problem created by the ease with which coal dust can be raised by the blast of an explosion from the conveyor structure and from the belts. The only practicable solution at present in sight seems to be the provision of some form of dust or water barrier at suitably chosen sites. There is still much to learn about barriers, but experience in Germany with dust barriers of the shelf type has been sufficiently favourable to justify their adoption in this country until something better is devised. Research should be carried out in the further use of dust barriers and in the development of water barriers, and in the meantime shelf type barriers should be installed on conveyor roads.

As regards sampling, I have already pointed out that the present statutory procedure was designed to show the average composition of the dust. On travelling and rope haulage roads, where the dust on the floor is mixed and raised by the passage of traffic, the composition as so determined would not in general differ greatly from the composition of the dust cloud raised by an explosion, and the prescribed standards of incombustible matter provide a reasonable safeguard against continued propagation. It is clear, however, that these results are not achieved in the very different circumstances produced by conveyor transport. Unfortunately, until more is known about the rate of deposition of coal dust at different places and under differing conditions, it is impossible to prescribe either appropriate standards or methods of sampling by which to ascertain whether they are being observed. I recommend therefore that (a) tests should be made under actual working conditions to determine the rate of dust deposition primarily but not solely on conveyor roadways, and (b) experiments should be carried out for the purpose of evolving an improved sampling technique.

Here it seems appropriate to say that no sampling procedure can be effective unless the object is clearly understood and the method is applied conscientiously and with intelligence. It was probably with something of this in mind that Professor Poole suggested in evidence that sampling should be "placed completely in the hands of the scientific staff of the National Coal Board". I am in sympathy with the idea behind this suggestion, but if it were carried out it seems to me that it might create a situation similar to that which led the Lord Justice General, in his judgment on the appeal of the Crown in the Knockshinnoch Castle Colliery proceedings, to say "What was everybody’s business was nobody’s business". The scientific staff would not be responsible in law and the mana ger could not be held responsible in justice. This is, of course, an instance of the general problem - the problem of the responsibility of specialists in the industry. Fortunately there is, I think, a solution in this particular case which in no way encroaches on the responsibility of the manager. Merely as a matter of common prudence colliery managements should consult the scientific staff about the organisation of their sampling and stone dusting arrangements. Colliery dust samplers and men in charge of stone dusting should be given a course of training under the supervision of the scientific staff and should work as a team and to a plan under responsible supervision. From time to time the management should call on the scientific service to make check surveys and to advise on precautions desirable at special points. In addition, as frequent sampling and quick results are vastly more important than high degrees of accuracy, the assessment of samples should be speeded up by the more widespread introduction of optical methods. I recommend accordingly.

What must be exercising the minds of many who read this Report is the fact that in spite of the labour expended on cleaning up coal dust and laying stone dust, and although the sampling done before the disaster showed the presence of high percentages of incombustible matter, yet, according to the findings, a coal dust explosion occurred. Though they may accept the criticism of the way in which the operations were performed, they may nevertheless feel a loss of confidence in stone dusting and cleaning up as safeguards. That more must be done I have already said, but I trust that nobody will think that these measures are valueless. They have stopped the spread of a number of explosions and though many good lives were lost at Easington, if the roads had not been stone dusted the explosion might have acquired such violence that it would have spread far beyond its actual confines and caused one of the greatest disasters in mining history.

John Young Wallace, a fully trained rescue man of 26 and an overman at Easington, was acting as the captain of a rescue team when he met his death. About half an hour after leaving the fresh air base the team was exploring the West Materials Road in the neighbourhood of No. 10 stenton when, without any previous signal of distress, Wallace sank to his knees, said a few words from the side of his mouth about sweating, sat down and then fell over unconscious. Probably he died almost at once as his jaw would sag when he lost consciousness and the lethal external atmosphere leaking past the mouth piece would prove fatal within a few moments.

Apparently the team had been walking rather more quickly than is usual or prudent in rescue operations and they had had to negotiate a number of obstructions, but they had travelled only about 700 yards from the base and no other member of the team was distressed.

According to the evidence, when Wallace collapsed his mouth-piece and nose clip were in place; air was flowing normally into the breathing bag from the liquid air pack; and he had not previously spoken.

Subsequently the Ministry’s Rescue Apparatus Testing Officer, Mr. J W. Calder, one of H.M. Senior District Inspectors of Mines, examined and tested the apparatus in the manner prescribed for the approval of rescue apparatus and found it to be in order.

Nevertheless, Wallace undoubtedly died from carbon monoxide poisoning and it is therefore necessary to try to find how it got into his system. Postmortem examination revealed in both lungs a degree of emphysema sufficient to cause breathlessness on heavy physical exertion, especially if such exertion were undertaken whilst wearing self-contained breathing apparatus under conditions of both mental and physical stress. In answer to questions by Mr. T. A. Jones and myself, Dr. W. C. Sharp, H.M. Medical Inspector of Mines, expressed the opinion that as a consequence of his exertions Wallace might have experienced sufficient difficulty in breathing to cause an involuntary opening of the mouth; that this would allow the outside atmosphere to leak past the mouth-piece ; and that with the high concentration of carbon monoxide existing—probably of the order of three per cent. - even a slight leakage would induce a sufficient quantity into the breathing circuit to cause him to collapse.

This appears to be the most likely explanation of what happened.

Three days after the death of Wallace, H. Burdess, a trained rescue man, died in somewhat similar circumstances.

About 35 minutes after leaving the fresh air base, Burdess signalled to his captain that he was in distress. His breathing bag was inflated and functioning normally and his nose-clip and mouth-piece were in place. Although the team had only travelled between 600-700 yards and the other members were quite cool and comfortable, he was sweating heavily.. His captain and another man tried to help him out but after going ten to 12 yards he collapsed. Eventually he was carried out on a stretcher, but on arrival at the fresh air base was found to be dead.

Examination and tests of the apparatus carried out by Mr. Calder showed that the automatic relief valve was set at 2.6 inches water-gauge instead of 3.5 inches water-gauge, and that one of the teeth grips of the mouth-piece was torn. Otherwise the apparatus was in order.

The effect of the relief valve being set at 2.6 inches water-gauge would be to bring down the volume of air in the breathing bag to rather less than the six litres normally held when the valve is set at 3.5 inches. This, however, should not have had any adverse effect as the quantity of air produced by the Aerophor apparatus is much in excess of that normally required; to quote Mr. Calder, "I would not expect it to affect a man’s breathing in any way other than to reduce the resistance against breathing". As regards the torn teeth grip, it is impossible to say when the damage took place. It may have happened before or after Burdess collapsed, but in any event I do not think it had any particular significance. This view was confirmed in part at least when the apparatus, re-charged but otherwise as it was taken from Burdess’ body, successfully passed one test in which the wearer walked for two hours at four miles per hour and a second test of two hours in which various operations were carried out in an irrespirable atmosphere.

Thus again the question arises as to how the carbon monoxide was inhaled and once more I think the explanation is provided by the post-mortem evidence. A condition known as bullous emphysema (distension of air sacs to blister like formations on the surface of the lungs) was found at the post-mortem examination. One bulla, or blister, on the left lung had ruptured, permitting air from within the lung to pass into the chest cavity and so causing a partial collapse of the lung. Dr. Sharp explained that when the bulla burst it would produce "reasonably acute pain" accompanied by violent efforts to breath and that, as with Wallace, leakage of air past the mouth-piece might then occur.

If these explanations of the way in which these two men met their deaths are correct - as I believe they are - the question arises as to whether the physical defects from which they were suffering could or should have been discovered.

Under the Coal Mines General Regulations (Rescue) 1928 rescue workers (a) are examined every 12 months by a qualified medical practitioner in accordance with specified rules, and (b) when engaged in actual rescue operations are examined by a qualified medical practitioner before undertaking a second spell of work. No rules are laid down for the way in which the latter examination shall be carried out.

I understand that the degree of emphysema found post-mortem in Wallace’s lungs would have been extremely difficult to detect during life by ordinary examination methods, and it is, of course, possible that the condition had developed in the interval between the time of his last annual examination and the date of his death. It is unlikely that it would have been detected in the course of the less exhaustive medical examination that it is possible to make during emergency operations. Wallace was a member of one of the earlier rescue teams and he was not medically examined before going on the spell of duty that ended in his death. Later, arrangements were made for the medical examination of all rescue men, whether on their first or subsequent spells. This practice should be made general forthwith. In the early stages of a disaster when minutes may make the difference between saving and losing lives, it would of course be quite wrong to hold back rescue workers until they are medically examined. As soon as conditions permit, however, they should be medically examined before they undertake any duty requiring the use of apparatus, as was done at Easington. Furthermore, I recommend that they should be examined medically at six-monthly intervals and that the most careful inquiry should be made regarding any illness which may have occurred between one examination and another.

The case of Burdess is somewhat similar except that he was medically examined before starting on the spell of duty - his first - during which he died. This serves to emphasise the difficulty in diagnosing a moderate degree of emphysema by ordinary routine examination. Mine rescue work imposes both mental and physical strain upon those engaged in it and it is desirable, therefore, that the requirements regarding the medical examination of rescue workers should be reviewed in order to ensure that only those attaining a high degree of fitness are selected.

Although there is no reason to suppose that it had any bearing on his death, it was brought out in the evidence that Burdess had been at the colliery for about eleven hours. It is true that suitable provisions were made for the comfort of the men who were standing by, but I suggest that wherever possible they should be allowed to remain at home on call until they are needed.

I sincerely trust that the deaths of these two men and any comments which I may have made will not impair confidence in existing rescue apparatus. It is true that the two main types of apparatus now in general use can be improved; for example, they can be reduced in weight and it should be possible to evolve a better form of mouth-piece or a mask. I am glad to be able to say that measures have already been taken by the Ministry and the National Coal Board to ensure that these and other improvements are effected and that new types are developed. Let there be no mistake however - rescue apparatus in its existing form has stood the test of time and has enabled magnificent work to be accomplished with remarkably few failures. Given a proper understanding of its limitations, attention to detail and strict discipline, it will still do so.

The Inquiry brought to light a number of bad practices and even direct contraventions of the Act and Regulations not causally connected with the explosion. They must nevertheless be considered in forming an opinion of the way in which the colliery was managed.

It was admitted that the provisions of the Explosives in Coal Mines Order were not complied with in that some at least of the deputies had not been instructed as to the maximum number of shots they were permitted to fire in any one hour or any one shift. Moreover, no tests had been made since 1948 to determine the time required to fire a shot.

The same Order was contravened in spirit at least by the practice of allowing the deputies to take into the mine more detonators than they required for use in their own districts in order that they could fire shots in other districts.

After the disaster 11 pounds of explosives were found buried under dirt in No. 21 heading. It must have taken some time for such a quantity to be accumulated and, evidently, not only was there a breach of the provision of the Order requiring that any explosive unused at the end of a shift should be brought out of the mine, but also the methods of control must have been woefully defective.

Evidence was given by two deputies that they had neither been given a copy of the Explosives in Coal Mines Order, 1948, nor had they been informed of the prohibition of the firing of shots in the roof at a longwall face other than with the permission in writing of the agent and manager. As I have already mentioned, there was evidence that on several occasions shots had been fired in the roof at the face for the purpose of releasing very tight chocks. The agent and manager denied any knowledge of the practice. The under-manager said that it came to his notice only the day before the explosion and that he immediately gave orders for it to cease. Although I accept the word of these officials, the fact that this method of releasing tight chocks remained undetected is a reflection on the value of the supervision exercised.

As regards matters other than shot firing, there was evidence that auxiliary fans had been started by unauthorised persons contrary to the requirements of the Coal Mines (Ventilation) General Regulations, 1947 ; the stoppings between the main intake and return airways in the Duckbill District did not conform with the requirements of General Regulation 91 ; a man in charge of an electric drilling machine had not been provided with a firedamp detector as required by the Regulations; and on one occasion electrical apparatus which had been removed and re-erected in a new position had not been tested.

Singly some of these matters might not be of great moment. Collectively and taken in conjunction with unsatisfactory features discussed in earlier parts of this Report, they indicate a disquieting lack of control and direction.

In his closing address Mr. Ronald Williams said, "We have or had a situation prior to the explosion completely inconsistent with good management". Mr. Williams made it clear that he was not referring to a particular individual but to all who were responsible for the management side of the colliery, and later added, "I cast no doubts about the sincerity and good intentions of the men concerned, but I do say that in the organisation at the managerial level at this colliery there were grave defects which have been shown in the evidence-and these defects are very closely related to the causes of this explosion".

This is a not unjust summing up.

The officials who gave evidence impressed me as being hard working and conscientious men but they seemed to lack that ability to anticipate events and that comprehensive knowledge of what was happening at the colliery which is characteristic of good management. In the main this seemed to me to be due to weaknesses in the organisation. The manager appeared to be so fully occupied himself in day to day details of administration that he was unable to exercise effective supervision and direction of the mine as a whole. Still less had he time to think out all the possible consequences of a major change of policy such as the decision to adopt longwall retreating with full caving in a district originally planned to be worked by other methods.

Because of their duties in connection with the two other large mines in the group under their charge, the activities of the agent and his assistant were too widely dispersed to permit of their giving any effective help and guidance to the manager or, indeed, to allow them to gain the close knowledge of the conditions at the colliery which would have enabled them to do so.

In short, nobody seemed to be in a position either to see the situation as a whole or to think it out if he did.

It is not within my province to deal with the managerial organisation in general, but, in so far as I believe it to have a bearing on the disaster, it seems to me that in this particular instance there were good grounds for the appointment of a full time agent.

On the planning of the Duckbill District there was evidence that full use was made of the specialist consultant services and that, before it was decided to adopt longwall retreating, consultation took place right up to Divisional level. I am, however, left in some doubt about the value of consultations which did not make provision for the particular difficulties in roof control likely to be encountered when opening out on the caving system from a narrow heading in a virgin area, and which overlooked the ventilation problem resulting from the change.

In his submission on this subject, Mr. Miron said, "It seems clear that in this case, when the decision was first taken in 1947 to plan this entire district as a duckbill district, there was adequate consultation and avail made of those services at Divisional level. Subsequently the what I might call detailed day to day operations in the development of particular faces and changes of work at different points must be left to those on the spot, and it would not be good organisation to do otherwise.

I hope from my questioning of Mr. Fry I made clear to you, Sir, the position of the Area General Manager. He is in effect the Chairman or the Managing Director of his Area, and he is responsible for the co-ordination of all the Area activities. In the same way as at Divisional level so are there available to him a certain number of specialist or consultant advisers. I would ask you to accept on that point that the organisation of the planning of this work was adequately carried out, that the subsequent development of the district and the working of this face was undertaken by those whose duty it was to do such work without reference to other people".

I cannot accept the implication that the original planners escape all responsibility no matter how unworkable their plans prove to be, and that the man on the spot must be responsible for all the possible consequences of the changes which he has to make in order to make the plan workable.

Far be it from me to suggest undue interference with the man on the spot, but if the planning of a colliery is not to be left in the hands of the officials with the direct responsibility of management - and that may be unavoidable in a nationalised industry where the working of a coalfield may have to be planned as a whole - those directing the planning must surely accept their share of responsibility. At the same time the colliery management has an equal responsibility for keeping the planning organisation informed of changes either in the plan or in the working conditions. To define precisely the duties and responsibilities of the various officials is by no means easy. However, I am able to report that the legal position in regard to this and other problems connected with the status and responsibilities of various specialist and other officials is now under review.