Expert evidence concerning LHDs, relevant risks and systems of work
- In support of his case on liability, the plaintiff relied upon the report of Mr Cockbain dated 22 May 2017. It was not in dispute that Mr Cockbain was relevantly an expert in occupational health and safety and risk management matters. He holds a Master of Applied Science degree in safety management and a Graduate Diploma in Applied Science in occupational health and safety. He is also a Fellow of the Safety Institute of Australia and a Chartered Generalist OHS Professional as well as being a Companion Member of Engineers Australia and a Certified Practising Risk Manager. He has decades of experience in risk management.
- A significant part of Mr Cockbain's report amounted to submissions on the meaning and effect of various statutory provisions, regulations, standards or guidelines, on whether aspects of the equipment and system of work were safe and on whether the defendant had or had not complied with any relevant obligations or duties. This part was admitted as submission only and not as evidence. Further, where Mr Cockbain recounted what Whitehaven had or had not done and what had happened to Mr Davies, this was admitted only as the assumptions on which Mr Cockbain based any relevant expert opinions.
- At pars 92 to 94 of his report, Mr Cockbain identified, based on his assumptions, what he considered to be the relevant risks and appropriate measures to control those risks as follows:
"92. Based on the information provided to the writer there were a number of identifiable risks associated with the task being undertaken by the Plaintiff during the course of his employment:
• The provision of an engine compartment cover which could not be closed by the Plaintiff standing on ground level and which required the Plaintiff to work at height where there was a risk to the Plaintiff falling and suffering injury.
• The inadequate system of work which required the Plaintiff to ascend and descend the fixed steps on the rear of the LHD and stand on top of the LHD, which did not have any barriers or adequate hand holds to protect the Plaintiff from the risk of falling.
• The process by which the Defendant modified the LHD and failed to undertake any risk assessment to identify the hazards/risks created by the modification.
• The failure of the Defendant to undertake a risk assessment of the modified system of work which required the Plaintiff to ascend and descend the fixed steps on the rear of the LHD and stand on top of the LHD in order to lower the engine compartment cover.
• The requirement for the Plaintiff to undertake the work task in the absence of any further instruction or training in safety systems of work following the modification of the LHD.
• The failure of the Defendant to consult with the OEM prior to undertaking the modification work to identify if the engine compartment cover. [sic]
• the absence of any designated walkway or work platform from which the Plaintiff to [sic] close the engine compartment cover in order to eliminate risk of the Plaintiff suffering a slip and fall event.
93. The writer notes that, the access provided by the fixed steps on the rear of the LHD and the positioning of the Plaintiff on top of the LHD was not safe. In addition, once the Plaintiff was standing on top of the LHD there was a risk that he could fall and suffer injury which ultimately occurred.
94. The system of work adopted for the performance of the work task should have required to be Plaintiff to work from ground level or from a designated walkway/platform which would have ensured that the Plaintiff was not exposed to a risk of falling from height or suffering a slip and fall event when descending the rear steps on the LHD."
- Whitehaven relied on the report of Prof Hebblewhite dated 3 September 2017. It was not in dispute that Prof Hebblewhite had relevant expertise. He holds a Bachelor of Engineering (Mining) degree with first class honours and a Doctorate of Philosophy in mining engineering. Prof Hebblewhite is also a member of the Australasian Institute of Mining and Metallurgy and of the Australian Geomechanics Society, as well as a number of other professional memberships. He holds the Chair of Mining Engineering at the University of New South Wales and is also a consultant in mining engineering. Prior to joining the University of New South Wales in 1995, Prof Hebblewhite was a mining engineer and senior manager with ACIRL Ltd, involved in mine design, and research and consulting activities in all aspects of mining and coal production.
- Similarly to the approach adopted in relation to Mr Cockbain's report, to the extent that Prof Hebblewhite's report contained submissions and assumptions as to factual matters, they were admitted as such and not as evidence.
- Prof Hebblewhite noted in his report that, in relation to the diesel bay being wet and involving some diesel/oil on the ground:
"To some extent such conditions are going to be unavoidable in a temporary, underground diesel bay such as this. It is not practical or reasonable to expect pristine spill-free conditions in a temporary location (as opposed to a fixed workshop bay)."
- As to the modification to the engine compartment cover of the LHD, he was of the view that this was a relatively simple change that would have been carried out in consultation with engineering staff at the mine. In his view, this equipment modification was appropriate, following a series of problems with the design provided by the original equipment manufacturer, or OEM, and there was no evidence to support the allegation that, in itself, the modification created unnecessary or additional risk of injury.
- Prof Hebblewhite observed that it was the "sub-task" of dismounting from the top of the LHD via the steps on the rear that led to the injury, not the refuelling task or the issue of working on top of the machine. He also explained the practice of using the "Take 5" process whereby employees assess a task, prior to commencing it, to ensure that the conditions and the task can be carried out safely. The procedure with using a Take 5 is that if there is an unnecessary or excessive risk identified, the person should not commence the task, but seek assistance from their supervisor.
- Mr Davies gave evidence, and I accept, that he did undertake a Take 5 not long before the incident on 2 June 2011. This including looking at the ladder at the rear of the LHD. [8]
- Prof Hebblewhite was of the view that if Mr Davies had maintained three points of contact firmly he would have been able to maintain stability even in the event of a foot slip. The circumstances which actually occurred indicated to Prof Hebblewhite that Mr Davies "was not descending in a correct and cautious manner".
- Prof Hebblewhite also noted that Mr Davies had received specific training in the Take 5 front-line individual risk assessment practice and referred to a copy of Mr Davies's own competency assessment with respect to Take 5, in part 3.5 of his report.
- More specifically, in relation to Mr Cockbain's report, Prof Hebblewhite commented as follows:
"• P 22, para 92 - Mr Cockbain is critical of a lack of handholds, and yet the fact that Mr Davies held onto a handhold with his left hand resulted in his shoulder injury. There is no evidence of lack of handholds. …
• P 22, para 94 - Mr Cockbain then commences discussion of suitable alternative safe work platforms that could have been provided to avoid the risk of working at height, and slipping and falling (see later discussion).
• P 23, Paras 97 - 99 - these sections discuss the need for adequate training and supervision. Once again, the principle of these points is agreed with. However, the evidence suggests that Mr Davies was adequately trained, including training for dealing with any unforeseen, or elevated hazards that he has not come across before. Regarding supervision, his supervising Deputy was working in the same panel as he was, and was available for him to consult, if his Take 5 assessment had identified any concerns.
• Pages 32 and 33 - three different alternative work platforms are offered by Mr Cockbain as suitable safe alternatives for accessing the LHD engine cover.… In consideration of these alternatives, a few simple observations raise serious questions about either their suitability and practicality, as well is their safety in terms of prevention of a similar accident.
All three still involve stairways that someone can fall from, especially if they are not descending in an appropriate, safe and cautious manner, as was the case with Mr Davies. The simplest of the three, this is a deck, involves a steep ladder access, with limited rails or handholds, that could just as easily have led to Mr Davies falling, through failure to place feet and hands correctly. The other two options are simply impractical, in terms of size and complexity, to fit in a temporary diesel bay located within a small cut-through space where multiple vehicles have to be able to access."
- In summary, Prof Hebblewhite was of the opinion that:
1. the modification to the LHD engine compartment cover, did not create an unnecessary or increased risk of injury nor was Mr Davies exposed to unnecessary injury provided he followed appropriate risk assessment procedures and acted with due caution and adherence to safe mining practices;
2. the task which Mr Davies was called upon to perform was not unsafe and he was able to undertake it in a safe manner, with appropriate recognition of his workplace environment; and
3. in addition to noting that the evidence did not support allegations in relation to failure to provide instruction, to heed complaints or to develop systems or plans, a transport management plan was in place and Mr Davies had been trained and assessed with respect to it.
- A conclave involving the two experts was convened on 3 October 2018 and a joint expert witness report was prepared dated 4 October 2018. It can be observed that, in general terms, the joint report reflected in large measure the differing views expressed by the two experts, which have been referred to in some detail above.
- In relation to part 6(a) of the joint report, it can be noted that, at the hearing, the Court was informed that Mr Cockbain had changed his view and now agreed with Prof Hebblewhite that the NSW Department of Primary Industries MDG 15 Guidelines for Mobile and Transportable Equipment for Use in Mines was a guideline and not intended to be a mandatory compliance document and accordingly did not require the development of a risk assessment in relation to the modifications to the engine covers of the LHD prior to 2 June 2011.
- Both witnesses accepted that if there was no assessment of risks in any form in relation to the modification of the engine compartment covers of the LHD, the absence of such an assessment posed an increased risk of injury to operators.
- Both experts also agreed that accessing the top of the LHD in wet and greasy conditions in a fuel bay underground, carried a greater risk of injury and that the controls in place included the handles and steps/rungs. As noted above, Mr Cockbain was of the view that those controls were not adequate, contrary to Prof Hebblewhite's opinion that they were adequate, provided the operator followed appropriate risk assessment procedures and acted with due caution and adherence to safe mining practices.
- Both experts also agreed that modification of the engine compartment cover resulted in Mr Davies being unable to perform the task of refuelling and rewatering at ground level and introduced the risk of falling from height, but Prof Hebblewhite was of the view that this risk only arose if there was no alternative safe means of access.
- Mr Cockbain was cross-examined jointly with Prof Hebblewhite. I formed the view that Mr Cockbain had a tendency at times to stray into arguing in support of, and avoid anything that might detract from, the plaintiff's case rather than answering the questions asked to the best of his ability as an independent expert. [9] It also appeared to me that there was little or no compelling reasoning to support Mr Cockbain's conclusions including those at pars 92 to 94 of his report. I found Prof Hebbelwhite to be more measured and responsive than Mr Cockbain and his expertise and experience, in mining engineering across all aspects of coal mining and production, was wider and more relevant than Mr Cockbain's which was focused upon occupational health and safety and risk management. Prof Hebblewhite's conclusions were, in my view, better supported by reasoning. For these reasons, while there was some agreement between these experts, where there was not, I prefer the evidence of Prof Hebblewhite. In particular, Prof Hebblewhite disagreed with some of Mr Cockbain's conclusion in pars 92 and 94 (and related paragraphs) and provided an explanation for his disagreement. I prefer the evidence of Prof Hebblewhite in these particular regards.
- Accepting Prof Hebblewhite's evidence and in light of the reasons above and the further comments set out below, my conclusions in relation to Mr Cockbain's evidence (generally at pars 92 to 94 of his report) are as follows:
1. I do not accept that the "system of work" was "inadequate" because the top of the LHD and the ladder or "fixed steps" at the rear did not have any barriers or adequate handholds. In cross-examination, Mr Cockbain was asked to explain why the ladder and handholds were not adequate. His explanation at T155.26-T158.20 and his subsequent comments on related topics did not, in my view, provide a convincing explanation of inadequacy nor was such an explanation given in his report. The rungs and the handgrips were secure. Mr Davies had already used them to mount the LHD without slipping and he was aware of the three points of contact rule. In cross-examination, Mr Cockbain acknowledged that requiring use of such a ladder would not be unusual (at T168.16-.28) as follows:
"KING: It's not unusual for an employer to call upon an experienced employee to use a ladder in those circumstances, is it, Mr Cockbain?
WITNESS COCKBAIN: Yes, on the basis that it's secured, it has sufficient scope for handgrip and footgrip and complies with the coefficient of fraction, then that wouldn't be the case [i.e. unusual].
KING: It's particularly so if the experienced employee is well aware of the significance of three points of contact, isn't it?
WITNESS COCKBAIN: That's one minor point, as, as you said previously, as long the handgrip and footgrip was sufficient and appropriate and enabled him to traverse safely, that may be the case, yes."
1. In my view, the absence of any further instruction or training in safety systems of work following the modification of the LHD did not create, or lead to an increase in, a relevant, non-theoretical risk. At par 134 of his report, Mr Cockbain himself noted that Mr Davies, given his length of time in the coal mining industry should have a "reasonable understanding … of the specific hazards and risks associated with the various work tasks involved in the industry". Mr Davies had been trained in and gave evidence of carrying out a Take 5 process just before the incident and was aware of appropriate safety measures such as maintaining three points of contact. Indeed, in oral submissions, counsel for Mr Davies acknowledged that:
"there is no doubt the plaintiff knew the three point of contact rule. We would never suggest otherwise, this man after all was a "competent person". He had been certified as such, he'd been trained well it would appear by the defendant, and he doesn't suggest he wasn't fully aware of that necessity."
1. I do not accept that a walkway or work platform, of the type suggested by Mr Cockbain, "would eliminate risk of the Plaintiff suffering a slip and fall event". Photographs of options for a "walkway/platform" were provided later in his report at par 144. These included a scissor deck or lift and portable platforms. Each proposed walkway or platform involved ascending and descending from a height by a ladder or steps. As a result, none of them would eliminate the risk of falling or slipping. That risk would remain, especially in an underground diesel bay in a colliery. Further, judging from those photographs, it did not appear that Mr Cockbain's description of them as "simple" and "portable" was necessarily correct, especially if they had to be deployed or utilised in an underground diesel bay on every occasion when an LHD had to be refuelled or rewatered in that bay.
- Mr Cockbain's conclusions that were said to flow from that evidence, for example in pars 145 of his report, should not be accepted for the same reasons. I also do not accept that the preventative measures referred to in par 146 were "reasonable" and "could and should have been implemented by" Whitehaven or that they would have eliminated the risk or were necessary to provide adequate safeguards.
- These conclusions concerning Mr Cockbain's evidence are based, in part, upon Prof Hebblewhite's. In particular, in respect of any increased risk because of the absence of a formal risk assessment and refuelling and rewatering in an underground diesel bay, I accept Prof Hebbelwhite's evidence to the effect that, in relation to the relevant sub-task of descending from the LHD, the ladder and handholds were adequate control measures, provided the operator followed appropriate risk assessment procedures and acted with due caution and adherence to safe mining practices. Thus, if a formal risk assessment had been carried out, it would not have required the implementation of any other control measures. I find that Mr Davies had received appropriate training of this nature and did carry out a Take 5 process prior to refuelling and mounting the rear of the LHD. I also accept Prof Hepplewhite's evidence that the alternative structures proposed by Mr Cockbain for accessing the top of the LHD either involved a steep ladder access, with limited rails or handholds, or were "simply impractical, in terms of size and complexity, to fit in a temporary diesel bay located within a small cut-through space where multiple vehicles have to be able to access" and would not, in any event, have eliminated the risk of falling or slipping.
- In cross-examination, [10] Prof Hebblewhite agreed that it was undesirable for a person to be required to work on top of a machine such as an LHD, if it was not necessary, and it had only become necessary in the present case because of the modification to the engine compartment covers. He also agreed that the risk of injury was magnified when the refuelling or rewatering was done underground because of the wet and greasy nature of diesel bays but he remained of the view the steps or rungs and the handholds, used with appropriate caution, were adequate control measures. He also noted that if the operator assessed that the task could not be performed safely, he had a responsibility to get instruction from his supervisor. Nonetheless, Prof Hebblewhite did acknowledge that when working underground it could be difficult to maintain a tight grip and be careful with footholds but was of the view that the issue remained whether the controls available to manage any increased risk were adequate in the circumstances.
- In summary but without attempting to be exhaustive, I find that as a result of the modification to the engine compartment cover, an operator such as Mr Davies was required to go to the top of the LHD to close the cover after refuelling at the underground diesel bay and that there was a risk of falling or slipping while he descended from the top of the LHD, which was the risk that was relevant in the present case. In addition, I accept that the failure of Whitehaven to undertake a formal risk assessment of that modified system of work may have led to an increase in risk, in a theoretical sense. But, if a risk assessment had been carried out, I am satisfied that, consistently with Prof Hebblewhite's evidence, any hazard arising out of the need to descend from the top of the LHD would have been assessed as reasonably and appropriately managed by the provision of the ladder and handholds on the rear of the LHD and appropriate training for, and safety checking processes and safe working practices to be carried out by, the operator in question. Mr Davies's evidence establishes that he was appropriately trained, knew of and implemented the relevant safe working practices and did carry out the appropriate safety checking process in the present case. I also find that the alternate equipment or structures proposed by Mr Cockbain to access the top of the LHD would not have eliminated the risk of slip or fall and were not reasonably practicable in the circumstances.