The NSW Resources Regulator has published its findings and recommendations in a report into an incident in which a load haul dump (LHD) operator suffered serious head lacerations.
The then 24-year-old operator was driving in an underground roadway at Mannering Colliery, Doyalson, when a damaged roof support strap entered the open cab and hit the operator in the head. The incident occurred on 22 January 2016.
Details of the report:
At 1.40 pm on 22 January 2016, an operator was driving a load haul dump (LHD) vehicle in an underground roadway at Mannering Colliery when a damaged roof support strap entered the open cab and hit the operator in the head. The impact resulted in a serious laceration to the operator’s head. The laceration extended from near his left ear to his left eye. The injury resulted in his temporal artery being damaged.
The operator parked the LHD and applied pressure to the wound with his hand to stem the blood flow. He staggered about 120 m into the mine to get help. Other workers gave him first aid and evacuated him from the mine. The operator was transported to Wyong Hospital via ambulance and treated. The wound required 60 stitches.
The mine is on the southern side of Lake Macquarie in Doyalson NSW. The mine operator is LakeCoal Pty Ltd (LakeCoal). LakeCoal contracted LD Operations Pty Ltd (LD Operations) to provide labour and services to the mine for a project to build an underground link from the mine to the adjacent Chain Valley Colliery. Both LakeCoal and LD Operations are part of the LDO Group. The LDO Group is a group of companies that operates mines and provides services to the mining industry, predominantly in the Hunter region.
At the time of the incident, the mine was transitioning from being in a state of care and maintenance to recommencing operations. This involved the introduction of new personnel and plant to the mine. It was the operator’s first day on duty underground at this mine and it was also the first time a personnel transport vehicle identified as SMV003 was used in the underground roadways. This vehicle was 50 mm higher than other vehicles used at the mine.
The investigation identified that the roof support strap (W strap) was broken when SMV003 travelled the road into the mine and then out of the mine before the operator entered the mine in the LHD. SMV003 had made contact with the W strap, tore it in two and rotated one section to point in the direction of vehicles that were travelling
The mine is about 40 years old. An inspection of roof support and W straps identified signs of previous impacts and structural damage to roof support in the vicinity of the incident site. The mine also has areas of low roof and is prone to the level of the floor of the mine rising, which is known as floor heave. While on care and maintenance, the mine managed the risk of vehicles making contact with the roof by having minimal personnel in the mine in conjunction with the knowledge that the vehicles in the mine at the time had been used for years without incident. The mine also relied on daily inspections to identify hazards.
The mine was in care and maintenance and a transition period was in effect between the repeal of the Coal Mine Health and Safety Act 2002 and associated Regulations and the existing work health and safety legislation. The mine was not required to have an overall health and safety management plan. Instead, the mine relied on a combination of inherited management plans and the mine operator’s procedures from other mining operations.
The management plan for underground roadways identified the minimum height of the roadways but did not identify the maximum height of underground vehicles. The mine relied on an existing procedure used by LD Operations to induct new plant and machinery. It did not detail the maximum height of underground vehicles for the Mannering site. This resulted in mine personnel being required to develop a maximum height for new plant. The factors considered to establish a height limit for new plant was:
1. the height of the existing vehicles
2. the height limit for the men and materials drift (entrance tunnel to the underground roadway)
3. the minimum height of the underground roadways.
The development of the maximum height figure did not consider other dimensional differences between the existing underground vehicles and the new underground vehicle such as wheel base and overhangs, nor did it consider that the roadways were undulating.
The clearance between the existing personnel transport vehicle and the minimum roadway height was 150 mm. The clearance figure that was adopted for new personnel transport vehicle (SMV003) was 100 mm. This resulted in the loss of 33% of the roof clearance.
The operator and contractor undertook two separate risk assessments (WRACs) before the incident (May 2014 and November 2015) that identified hazards and additional controls. The additional controls that were identified in the May 2014 WRAC were not implemented due to a decision not to proceed with the link road project at that time. The additional controls that were identified in the November 2015 WRAC particular to this incident were to:
• conduct a roadway height audit and set barricades to height of existing fleet
• review introduction to site document and include the height of plant.
At the time of the incident, some height audits were conducted in relation to services such as pipes and cables around the pit bottom area due to this area having more vehicle movements. But the additional controls that were identified in the November 2015 WRAC were scheduled to be put in place by 20 February 2016. They had not been completed when the incident occurred.
After the incident, the mine undertook a roadway height audit by attaching two poles with a cross bar at the front and rear of the SMV003 set at the required height and barricaded areas that did not conform. The mine has also finalised its work health and safety management plan, which includes a principle hazard management plan for roads and other vehicle operating areas.
Mobile plant interactions with roof supports and other services in underground coal mines is a well-known risk to the mining industry. When operating or travelling in mobile plant, the consequences of being struck by, or hitting damaged roof supports or other metal structures can include serious injury or death. This incident highlights the importance of effective change management and risk management programs in relation to the operation of mobile plant in underground mines. The following recommendations are advanced to improve industry safety and in turn reduce the recurrence of similar incidents. When considering the recommendations, mine operators are reminded of their obligation to take a combination of measures to minimise the risk, if no single measure is sufficient for that purpose.
Mine operators should:
1. ensure the mine strata management plan encompasses procedures for inspecting the condition of roadways, strata support, reporting of damage and repair or replacement of strata support in a timely manner
2. ensure the mine change management plan makes provision for introducing new plant and equipment to site. Such provisions should include a detailed risk assessment and have regard to changes in plant size and dimensions and the likely consequences.
3. conduct frequent physical audits of mine roadways to ensure adequate clearances for plant to operate
4. identify low roof areas, rectify if possible, erect ‘low roof’ warning signs and where necessary prohibit entry to mobile plant
5. use fit-for-purpose plant and ensure operator cabins provide adequate protection for operators
6. provide adequate information and training to workers about the potential risks associated with operating mobile plant underground in site inductions and training resources.