Coal Inspectorate | Bulletin | No.217 V 1 | 11 December 2023

Dozer operator risks their life by driving into a water body

What happened?

A bulldozer working on a coal floor in the Moranbah region has entered a body of water and walked through it towards the back of the pit. The bulldozer has walked off an edge created by the coal floor being excavated at two different levels, before water covered the floor of the pit (refer to Figure 1).  The investigation for this incident has now closed with a number of recommendations listed below.

How did it happen?

On the night shift prior to the incident, coal mine workers (CMWs) and their supervisors were dealing with water ingress into the working area. A body of water at the far end of the pit was held back by a solid coal rib.

The night shift operators took a first cut of approximately four metres in depth in front of the coal rib. As water entered the working area a decision was made to reduce the cut depth to three metres and continue to raise it in a sloped manner as the water level increased.

At the end of the night shift a bund was installed to delineate the areas affected by water and the areas still dry and available for mining. Before the day shift started, the edge created by the change in cut height was completely concealed by water.

The day shift dozer operator walked the bulldozer through the bund and entered the body of water. As the machine walked further towards the back of the pit it fell off the water covered edge that had been created by the night shift mining activities.

Key issues

The investigation identified that:

• knowledge at the coal mine of the Safety and Health Management System (SHMS) procedures for working around bodies of water and working in or on bodies of water was limited even though CMWs were recorded as having been trained in the material.
• the handover between shift supervision did not sufficiently cover the change in conditions and the new hazard created.
• the shift task documentation including the photographs used at the pre-shift meeting did not accurately reflect the conditions present in the pit including water levels and changes in the coal floor level.
• GPS units were not regularly programmed with locations of trenches, sumps, and other hazards.
• geofencing was not a control practiced at the mine for tasks of this risk profile.
• if mining was suspended and water pumps were installed the water hazard may have been able to be mitigated.

Recommendations

Site Senior Executives should:

• review the effectiveness of systems for dealing with different level cuts (including trenches and sumps) being created on the coal floor or in any other surface that may be presumed by coal mine workers to be level and flat.
• review the effectiveness of systems for dealing with bodies of water or other liquids at the mine, including planned storage such as trenches and sumps and unplanned events including water ingress to pits and working areas. Consideration should be given to:
  • section 93 of the Coal Mining Safety and Health Regulation 2017 (CMSHR) which deals with “working near a body of water or other liquid”.  This regulation is not intended to include working “in” bodies of water. There are different risk profiles for both situations which need to be individually controlled and managed effectively.
  • section 99 of the CMSHR outlines when it is appropriate to restrict access to parts of the mine. Section 99 should be considered when reviewing the effectiveness of section 93 procedures and controls.
  • section 146 of the CMSHR deals with trenches present at the mine. Section 146 should be considered when reviewing the effectiveness of section 93 procedures and controls.
• identify all operational areas containing edges with a vertical drop of one metre or more and adopt appropriate control measures as required by section 118 of the CMSHR.
• recognise in those control measures that edges of all heights present more risk when concealed by water and / or the angle, colour, and presentation of the ground.
• implement engineering systems that can assist identifying trenches, sumps and edges such as GPS-enabled mobile plant.
• implement geofencing capability on operational mobile plant and ensure it is used and updated appropriately.
• ensure operators are sufficiently trained in and complying with all SHMS requirements relating to edges, working near bodies of water, and working in or on bodies of water.

CMWs should:

• recognise that edges created by floors being cut at different levels are a hazard that need to be appropriately reported, controlled, and managed.
• be trained in and follow all standard operating procedures relating to edges, working near bodies of water, and working in or on bodies of water.
• if available, ensure GPS systems are functioning and have been updated to identify all trenches, sumps, edges, and other hazards present in the working area.
• conduct local area hazard management (SLAM / TAKE 5) as required by your mine’s risk management system. Be aware of changing environmental conditions including water and hazards that are created or discovered during the shift period and stop to reassess the risk.