Australian Iron & Steel Pty Ltd v Krstevski

1. [1960] 1 W.L.R. 746. 2. (1963) 108 C.L.R. 362, at p. 365.

The decision in the former case was simply that the finding of negligence was correct in a case where "employers allowed an unsafe practice to be adopted, one which they knew or ought to have known to be unsafe, and one which they could have altered" - see per Devlin L.J. [2] . The learned Lord Justice did make the following observation in relation to the dictum of Viscount Simon L.C. in Colfar v. Coggins & Griffith (Liverpool) Ltd [3] :

I do not think it means that, in every case where an unsafe system of working is alleged, it is necessary for the plaintiff to undertake the burden of pleading, and proving, an alternative system of work which could have been adopted and which would have been safe. That is for the employer to provide. There may be cases in which the plaintiff will not get very far with an allegation of unsafe system of work unless he can show some practicable alternative, but there are also cases - and I think this is one of them - in which a plaintiff can fairly say: "If this is dangerous, then there must be some other way of doing it that can be found by a prudent employer and it is not for me to devise that way or to say what it is." [4] . That the case fell within this description depended upon the finding that the employers could have altered a system which they knew or ought to have known was unsafe. The foregoing observations of Devlin L.J. were considered by Taylor and Owen JJ. in Neill v. N.S.W. Fresh Food and Ice Pty. Ltd. [5] who, in commenting upon it and other cases cited, said: No doubt in many cases no more than common knowledge, or perhaps common sense, is necessary to enable one to perceive the existence of a real risk of injury and to permit one to say what reasonable and appropriate precautions might appropriately be taken to avoid it.

These observations, however, involve no departure from the proposition that in order to enable an injured workman to recover damages from his employer the evidence must be such as to justify a finding of negligence on the part of the employer and, if the negligence alleged is in relation to the system of work employed, the evidentiary material must be such as to enable the jury to find that the system unreasonably exposed the workman to risk of injury. In other words, it must appear that the employer failed "to take reasonable steps to provide a system which will be reasonably safe, having regard to the dangers necessarily inherent in the operation": see per Lord Tucker in General Cleaning Contractors Ltd. v. Christmas [1] . Whether or not there has been such a failure on the part of the employer may, in some cases be resolved, by the application of common knowledge; in others it may be necessary to show a departure from long-established practice in the type of work under consideration or by showing that an appropriate method which would eliminate or minimize the risk was reasonably available.

1. [1953] A.C. 180, at p. 195. In the course of his judgment in this case, Dixon C.J. said [2] : The burden of establishing that the plaintiff appellant suffered the injuries of which he complained through the negligence of his employers or someone for whose acts or omissions they were answerable rested upon the plaintiff who now appeals In effect the plaintiff says that he was injured at work, he slipped where it was slippery and where it could not but be slippery, something ought to have been done to prevent his hurting himself by slipping and it was for the jury to say what. Of course they did not say what; they simply said that the defendant must pay damages Neither by direct evidence nor reasonable inference did it appear that any course could be taken to protect the plaintiff from the danger in his task consistent with the full accomplishment of its evident purpose It must be remembered that the danger from which he claims that he should have been protected was that of injuring himself by slipping while crouching in a confined cylinder, not, so one would think a priori, an extreme risk of any fearful consequence. And evidence was not led to establish any high degree of risk or of danger. This final observation - which, in the context, meant no more than that, upon the evidence in that case, no precautions were called for - has been treated as establishing the proposition that, where there is an extreme risk of fearful consequences, evidence that some precaution, consistent with the full accomplishment of the evident purpose of the work being done, could have been taken to protect the plaintiff from danger, is not necessary and, the mere fact that in such a case no such precautions have been taken is, of itself, sufficient evidence of negligence. This inference is entirely unwarranted.
   1. [1960] 1 W.L.R. 746, at pp. 747-748.
   2. [1945] A.C. 197, at p. 203.
   3. [1960] 1 W.L.R., at p. 748.
   4. (1963) 108 C.L.R. at, pp. 368-369.
   5. [1953] A.C. 180, at p. 195.
   6. (1963) 108 C.L.R., at pp. 364-365.

In a later case, Vozza v. Tooth & Co. Ltd. [3] , Windeyer J., with the concurrence of the other members of the Court, reiterated the law, as stated by Taylor and Owen JJ. in Neill's Case [4] , in these words [5] :

For a plaintiff to succeed it must appear, by direct evidence or by reasonable inference from the evidence, that the defendant unreasonably failed to take measures or adopt means, reasonably open to him in all the circumstances, which would have protected the plaintiff from the dangers of his task without unduly impeding its accomplishment. To quote a sentence from one of the cases to which counsel referred, "What is "a proper system of work" is a matter for evidence, not for law books": per Lord Denning in Qualcast (Wolverhampton) Ltd. v. Haynes [1] .

The case is not like those referred to in the judgment of Taylor and Owen JJ. in Neill v. N.S.W. Fresh Food and Ice Pty. Ltd. [2] - cases in which a jury could of their own knowledge say that something could and should have been done to obviate a risk, without any evidence being needed of any particular means that might have been adopted.

1. (1963) 108 C.L.R. 362, at p. 369. In Neill's Case, Kitto J. put the point pithily as follows [3] : At the trial the burden lay upon the appellant of satisfying the jury that some protection was reasonable, and that his injury resulted from the absence of it.
   1. (1964) 112 C.L.R. 316.
   2. (1963) 108 C.L.R. 362.
   3. (1964) 112 C.L.R., at pp. 319, 322.
   4. [1959] A.C. 743, at p. 760.
   5. (1963) 108 C.L.R. 362, at p. 369.
   6. (1963) 108 C.L.R., at p. 365.

The foregoing statements are no more than a reiteration of well-established law. The law of negligence is, by its very nature, incapable of development into a law which imposes liability without default.

If, therefore, there was here an extreme risk of fearful consequences, and if despite reasonable precautions there were an explosion of molten material from the furnace near where the plaintiff was working and the defendant took no precautions against the plaintiff suffering injury from such an explosion, that, of itself, did not constitute evidence of negligence and the Court of Appeal was in error in deciding that it did.

However, we for our part are far from satisfied that the evidence of what happened, in or about the furnace, before and at the time the plaintiff was injured, discloses an extreme risk of fearful injury. His occupation was that of a slagger, cleaning and remaking channels along which molten slag ran from a furnace in which iron was being smelted by a continuous process. After each tapping of the furnace the channels in the earth of the cast house floor, along which the molten slag passed, had to be put in order again. The plaintiff was working about twenty-five feet from the furnace. While he was so engaged a tuyere - no. 14 - burnt out and there spread from the furnace, through an aperture so formed, part of its contents in a burning or molten state. This material reached the plaintiff and he suffered severe burns.

A tuyere, which is a salt-water-cooled copper jacket fitting into the wall of the furnace and protruding into the furnace, is the inlet through which super-heated air is forced under pressure into the furnace to light and to support the combustion of the coke which is burnt to heat the metal and limestone fed in automatically at the top of the furnace. Tuyeres burn out from time to time. They will do so if the water cooling is interrupted, either by a blockage or by a leak involving the loss of water pressure. They are also likely to burn out if, in the operation of the furnace, molten material collects on or near the mouth protruding into the furnace. This may happen, for instance, if, by reason of the leaking of water, part of the contents of the furnace in the vicinity of the leak hardens and obstructs the flow of molten material which would otherwise pass down to the floor of the furnace. It is, therefore, part of the task of the furnace foreman to inspect the tuyeres regularly and, in case of fault, to adjust or replace any one which is not working properly. It is good practice, when a tuyere is replaced while a furnace is working, to reduce its capacity by filling the six-inch aperture with fire clay and, by means of a bar, making in that fire clay a two-inch aperture. This, with the operation of adjoining tuyeres at full bore, tends to prevent any collection of molten material at the mouth of the new tuyere. In an hour or two - long after any build up of cooled material upon or near the mouth of the tuyere has fallen down and the molten material is descending normally - the fire clay blows into the furnace and the tuyere operates at full bore. When a tuyere does burn out, and this happens occasionally despite regular and proper inspection and maintenance, there is a discharge of part of the contents of the furnace through the aperture so created. The plaintiff gave evidence that he had seen such a discharge seven times in six years and the furnace foreman, Anderson, said he had seen such a discharge four or five times in thirteen years. There was no evidence of any person having previously suffered injury by reason of any such emission of burning or molten material. In the circumstances so described, to describe the risk of a slagger working in the vicinity of the furnace as an extreme risk of fearful consequences seems to us to be something of an exaggeration. There was some risk that a tuyere would burn out and allow the spraying from the furnace of burning or molten material and there is no doubt that to any person caught in such a spray the consequences would probably be fearful. Fearful consequences, however, may ensue from something less than an extreme risk. It seems to us, upon the evidence, that Anderson was accurate when he described the risk as both real and unusual.

However, because we reject the principle enunciated by the Court of Appeal, we are of the opinion that - a case of res ipsa loquitur having been abandoned at the hearing - the verdict in favour of the plaintiff can be supported only if there was evidence that the employer failed to take some reasonable precaution for the safety of the employee which would have lessened the risk of injury in the event of a blowout from the furnace.

Two possibilities were suggested by counsel for the plaintiff to the jury. The first was the provision of barriers or shields behind which the employee would work. The second was to restrict the work of the employee to times when the furnace was not operating under pressure.

The only evidence relating to the first suggestion was given by Anderson and was as follows:

Q. And so would this be right, to achieve a considerable degree of protection of the men working on the floor, it would be effective to some extent to try and protect them in those two areas where they most frequently work, is that right?

Q. What I am trying to get in simple language is this: the real problem to give men some protection any way would be to protect them where they generally work, is that right?

Q. That would be the object of the exercise if it could be achieved, to protect them in that area? A. I really cannot say.

Q. Are you familiar with other areas in the steelworks or only the blast furnace? A. Mostly with the blast furnace, I am afraid. I do not know much about any other section. I have spent most of my working life with the blast furnace. I have been to the open hearth once but I do not know much about it.

Q. I was wondering if you have noticed in your movements around the steelworks any mobile protective barriers which you use from time to time?

Mr. Langsworth: I object. I submit we are concerned here only with this location and we are not concerned with other locations and other situations.

His Honour: But the question is, has he noticed mobile barriers anywhere. Their particular use might be the next question, but it is just the same as if he were asked, have you seen mobile cranes anywhere?

Mr. Langsworth: My submission is that it would be just as irrelevant.

Mr. Cantor: Q. Have you noticed anywhere in your movements around the steelworks mobile protective barriers? A. I have seen mobile flash protection barriers as used by welders, that is all. I do not recall any others.

Whether or not this evidence was accepted, it left the plaintiff with no evidence that some form of shielding or screening was reasonably practicable. Furthermore, it could not be predicated, as a matter of common sense, that, in the circumstances, it would have been possible to provide barriers or screens to protect those working in the vicinity of the furnace.

The other suggestion was to arrange for the cleaning of the channels at times when pressure within the furnace was reduced so that there would be no rush of material through any tuyere which might burn out. Isaacs J., in his charge to the jury, put the suggestion in these terms:

The other suggestion put forward by Mr. Cantor on behalf of the plaintiff was this; that there has been established in the evidence - whether it has or not is for you to say because you are the judge of the evidence - that from time to time the furnace has to be cooled down either in toto or when slagging has been almost completed and pressure can be taken off. Cases where the wind is taken off completely are where the tuyeres have to be repaired and replaced. The cooling off process takes about twenty-five minutes and the replacing of the tuyere about an hour. Roughly about one and a half hours elapses. The operation of cleaning channels and repairing them also takes something between one and two hours or one and a half or one and three-quarter hours. So it is said there at present arise occasions when this work could be done when the pressure is off and the furnace is cold or when the temperature and pressure have been reduced so that this risk of explosion does not exist. It has also been said that occasions arise when workmen and maintenance men have to go down and get into the furnace and repair this and that and the people that work around it are required to go and assist. There are also occasions when there is a quiescence or reduction to a cold state so that this work can go on.

What Mr. Cantor has been putting by way of argument is this: If it can be done for those occasions why then cannot the company so arrange the work of these men doing these channels that it will coincide with periods when either the pressure is not on or when the pressure and heat is reduced substantially so as to reduce the risk of explosion?

The suggestion so expressed was, as we have said, made by counsel to the jury but it was not put to the furnace foreman, Anderson, or to any other witness. If the suggestion was that the cleaning and repairing of the channels could be confined to breaks, due to mishaps, in the continuous operation of the furnace, it would appear clearly enough to have been fanciful. Channels have to be cared for regularly after use. Mishaps occur both irregularly and rarely. It is hardly surprising, if that were the suggestion, that it was made to the jury and not to a witness. If, however, the suggestion was that pressure in the furnace should be reduced regularly to enable work to be done about the furnace, including the care of the channels, that should have been put to the furnace foreman, or to some other witness, as something that was feasible, to find out whether or not it was. Simply to assume such feasibility is to come to a conclusion of fact, not a matter of common sense, without evidence. It seems to us that Jacobs J.A. did carry the suggestion to its logical conclusion when he said [1] : The negligence in my view lay in a system which allowed the plaintiff to be in the vicinity at all when the furnace did that which it was occasionally prone to do, namely, to eject the burning slag over a widespread area. The operating of the furnace in these circumstances exposed the plaintiff to unreasonable risk of injury. If this be correct, any person working in the vicinity of the furnace, injured by the ejection of burning or molten material from the furnace, would be entitled to damages called damages for negligence. The case of such a person would not simply be one of res ipsa loquitur; it would be that negligence is proved by permitting the operation of the furnace with a workman in the vicinity, whatever his task and whatever other precautions were taken for his safety. Were this so, liability for negligence would, we consider, have been converted into absolute liability for operating a furnace. 1. [1972] 2 N.S.W.L.R. 592, at p. 602.

Moffitt J.A., while agreeing with Jacobs J.A. put forward what his Honour described as "an alternate view of the facts, which provide, what appears to me, an even stronger case of the type to which he" (i.e. Jacobs J.A.) "has referred in principle" [1] . His Honour, after reviewing the evidence, said [2] :

A view of the evidence well open, and one I would take, was that a particular risk of a serious explosion, to the appellant's knowledge, existed soon after the shift commenced, and that the procedures then adopted provided at best a hope, short of knowledge, that the danger would in time be removed, that it had not in fact been removed and led to the explosion. Although there was a theoretical possibility that the cause of no 14 tuyere blowing out was otherwise, the history of events that night and concessions of the foreman provide strong evidence that this blowout was a direct consequence of the dangerous condition the existence of which was well known and appreciated by the foreman. When the furnace was first put back on pressure, after the two tuyeres were replaced, first low then high, there were various intervals when it was taken off full pressure for various purposes such as to correct escaping air from no. 14 blowpipe and later to allow the "overburden to come down". It had gone back on high pressure for twelve minutes before the explosion.

On the view of the facts to which I have referred the explosion which injured the respondent was not without any warning. The appellant had warning of the symptoms which led to it. The appellant appreciated the significance of these symptoms and the chance that they might lead to another of these known explosions perhaps without any further warning. The appellant took some steps in the hope that the danger would be removed but it could not know the danger was removed. It was a danger of a direct and immediate causing of grave personal injury to persons working nearby. In this setting the appellant continued its operations. For quite some time prior to the explosion the gang of slaggers were working round the furnace and the respondent continued to do so when the others took their meal break. The appellant knew of this particular danger but the respondent did not. The appellant did nothing to protect the respondent from this danger and allowed (and therefore because it was his duty required) him to continue in ignorance of this danger. This in my view provided evidence of negligence.

His Honour, it is to be observed, referred to the replacing of the no. 14 tuyere and the subsequent operation of the furnace, first at low pressure and then at high pressure, as providing "at best a hope short of knowledge" that the trouble which had arisen had been remedied. In our opinion the contrast drawn between "hope" and "knowledge" is neither accurate nor of significance in the circumstances. What was done was the accepted procedure for replacing a damaged tuyere and it was not suggested that there was any lack of reasonable care in the employer and those for whom it was responsible relying upon the efficacy of what had been done. No case had been made that the furnace foreman was negligent in doing what he did in replacing the tuyere and adjusting the operation of the furnace, a course which he himself described as "a normal safety precaution if the tuyere had been leaking for some time". Accordingly, unless it was negligent to operate the furnace with workmen in the vicinity, as Jacobs J.A. decided and Moffitt J.A. agreed, the alternate view of the facts stated by Moffitt J.A. provided no sound basis for concluding that there was evidence of negligence and it is not necessary to examine the remainder of his Honour's reasoning in the passage quoted. 1. [1972] 2 N.S.W.L.R. 592, at p. 602. 2. [1972] 2 N.S.W.L.R., at pp. 604-605.

In our opinion there was no evidence of negligence and there should have been a verdict and judgment in favour of the defendant.

I agree with the conclusions stated in the joint judgment of the Chief Justice and Menzies J. and with the reasons given by their Honours for those conclusions. I wish to add some observations relating to the reasons for judgment of the members of the Court of Appeal from whose decision this appeal is brought.

Jacobs J.A. referred to what he described as a "special class of case" [1] and was of opinion that the present case fell within that special class. On the first occasion on which his Honour used that expression, it appears from the context that he regarded the case as special simply because in his view the evidence showed that the respondent had been exposed to an "extreme risk" attended by "fearful consequences". Later in his Honour's reasons there appears to be involved in the special character of the class of case to which he refers a requirement that the employee is unaware of the existence or of the extent of the extreme risk, the reason for this requirement being that his lack of awareness and of acceptance of the risk prevents it from being properly regarded as an "inherent" risk of the employment. In my opinion it is erroneous to regard the matters to which his Honour's judgment refers as warranting the application to a case in which they are present of any legal principles different from those applicable to other cases in which the relevant duty of care is that which an employer owes to an employee, but in which those features are not present. In the present case, as in other cases in which an employee sues his employer for damages for injury caused by negligence, there was no issue as to the existence of the duty of care or as to its nature and content. The issue was whether or not it had been established that there was a breach of that duty which caused the accident in which the respondent suffered injury. There is no doubt that such matters of fact as the magnitude of the risk of an accident and the seriousness of the injury that may be expected to be suffered if an accident does occur may be taken into account in appropriate cases in deciding whether or not the employer has fulfilled his obligation to take reasonable care for the safety of his employees. So, also, in some cases, it may be of importance to consider whether an employee should have been warned of some particular risk, whether grave or not, attached to the task which he is directed to perform. But this does not mean that different principles are applied in such cases. It means that in deciding whether or not in a particular case a breach of duty has been established, all the facts which might be reasonably supposed to have a bearing upon what in the circumstances a reasonable man would do or refrain from doing ought to be considered.

An illustration of what I have said concerning the manner in which the existence of a grave risk of serious injury may affect the result in an action in negligence against an employer and a recognition of a distinction that may need to be drawn between cases in which it appears plain that some practicable and safer alternative method of working was available and cases in which this does not appear is provided by the case of Hamilton v. Nuroof (W.A.) Pty. Ltd. [1] . There, the majority of the Court took the view that the risk of accident was a real and evident one and the injuries likely to occur as a result of an accident were extremely serious. They said that these were matters that a reasonable and prudent employer was bound to consider. They decided that the respondent employer was liable because it was clear in their opinion that the buckets containing molten bitumen which the employee was required to handle could have been raised in a different way without any real difficulty or danger. If no alternative method of performing the task and at the same time ensuring greater safety had been available, the conclusion reached by the majority of the Court would have been different [2] . The two members of the Court who dissented from that conclusion did so because they took a different view of the facts. No member of the Court dealt with the case as belonging to a special class of case which was to be determined on the footing that if the degree of risk and seriousness of the injury which might result were very great the respondent, who had taken no precautions, must be found liable. No member of the Court said anything contrary to the view expressed by Williams and Taylor JJ. who [3] discarded from consideration "the bare proposition that the handling of potentially dangerous substances by an employee is an operation which exposes him to an unnecessary or unreasonable risk".

1. (1956) 96 C.L.R. 18. 2. (1956) 96 C.L.R., at pp. 24, 33. 3. (1956) 96 C.L.R., at p. 30.

In the present case, Moffitt J.A. considered that there was an alternative ground upon which it should be decided that there was evidence of negligence. This conclusion depended upon a view of the facts and of the inferences to be drawn from them which I am unable to share. The facts upon which his Honour relied were these. There was a leakage in no. 14 tuyere which had continued for two hours. The tuyere was replaced but as a result of the leakage a condition "productive of danger" was likely to have been created by reason of the cooling of material near the tuyere. This was a continuing danger. The end of the new tuyere might be burnt out, water would escape, and pressure from the furnace would cause an explosion of hot material through the opening. The foreman knew of the chance of these sequences occurring. The foreman adopted what he called a "normal safety precaution" by reducing, temporarily, the opening in the tuyere. The purpose of this was that the cold material would be undermined and removed. The inference was open that it had not been removed before the explosion occurred and that it was because of the continued existence of the danger created by the presence of the cold material that the explosion did occur. The foreman could not know whether the danger had been removed. Those being the facts which in his Honour's view could have been found, he based on them the following conclusions. Soon after the shift commenced a particular risk of a serious explosion existed, to the appellant's knowledge. The procedures adopted "provided at best a hope short of knowledge" that the danger would be in time removed, but it had not been removed, and it led to the explosion. Therefore the explosion did not occur without warning. The appellant had warning of the symptoms which might lead to it. But the appellant continued its operations and did nothing to protect the respondent but allowed him to continue to work in ignorance of the danger. This provided evidence of negligence.

The foundation of this reasoning is that there was on this occasion a particular risk or danger of the occurrence of an explosion of material from the furnace, different from the normal risks involved in the operation of the furnace and that this particular risk was of such a character that no one should have been permitted to work at or near the furnace under pressure, until it was certain that the danger had been removed or, at least, it was such that the respondent should have been informed of the danger. But, in my opinion, there was nothing special or particular about this occasion to distinguish it from other occasions when tuyeres had been damaged in consequence of leakages and had been replaced. According to the evidence explosions had been quite infrequent. The appellant's witness Anderson said that it was known that the cooling of material near the tuyere was capable of leading to the burning of the end of the new tuyere. But he adopted the same procedure on this occasion as on others, taking what he described as a safety precaution. It is true that he could not be certain that this would necessarily remove the danger. But there is no basis for saying that he was aware on this occasion, rather than on any other similar occasion, of the existence of a particular danger. His evidence was that he had no reason to believe that the tuyere would burn out or blow out. In my opinion there is not any evidence relating to this particular occasion upon which the appellant could have been found liable, on account of some special knowledge possessed by it that there existed a risk which was greater than any that was present on other occasions.

I have had the advantage of reading the reasons for judgment jointly prepared by the Chief Justice and my brother Menzies, and the further reasons prepared by my brother Walsh. I am in agreement with those reasons and with the conclusion that there was no evidence of negligence on the part of the appellant company. I would accordingly allow the appeal.

Subject only to the observations which follow, I am in agreement with the reasons for judgment prepared by the Chief Justice and Menzies J. and with the reasons for judgment prepared by Walsh J.

I have not read the judgments of the Court of Appeal as attempting to enunciate a general rule of absolute or strict liability. Jacobs J.A. did say that the appellant's negligence lay in a system "which allowed the plaintiff to be in the vicinity" [of the furnace] "at all" but he had prefaced this remark with the following observations [1] :

The evidence of negligence lay in the system which allowed the plaintiff, without any safeguards, to be in the vicinity when the furnace did that thing which it was prone to do, namely, eject burning slag and coke over a wide area. The previous rare happenings on a less serious scale were sufficient to make the employer aware of the distinct possibility of an explosion of this kind but were hardly such that it could be said that the plaintiff would have appreciated that he had undertaken an employment which exposed him to such grave danger. 1. [1972] 2 N.S.W.L.R. 592, at p. 602.

The passage is complicated by his Honour's attempt to draw a distinction between the respondent's appreciation and the appellant's appreciation of the risk of an explosion in the furnace with a view to showing that such an occurrence was not an inherent risk of the employment. This distinction is not easy to accept because in this employment the respondent had seen explosions occur on seven (or several) previous occasions. On each occasion molten material had escaped from the furnace and "was flying around", to use the respondent's words.

However, once the passage is shorn of this complication it is evident that Jacobs J.A. was saying that on the evidence there was a negligent omission on the part of the appellant in that it adopted a system of work which placed the respondent in close proximity to the furnace without taking any protection (other than the supply of protective clothing) for the respondent's safety. His Honour thought that in the circumstances it was evident that some, albeit unspecified, precaution could have been taken by the appellant which would have avoided the risk of injury to the respondent. I cannot agree. The operations conducted by the appellant with the blast furnace were complex and technical. The feasibility of any particular precaution designed to protect the respondent from injury could not be determined in the absence of expert evidence identifying the precaution and, if it was a protective device in the nature of a shield or barrier, indicating how it could be installed in the vicinity of the furnace so as to protect the respondent, and at the same time allow the cycle of operations essential to the production of iron to continue on foot. Common knowledge and common sense alone could not bridge this gap.