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Safety alert issued after exploration drill rig contacts overhead powerline

The following article is a news item provided for the benefit of the Workplace Health and Safety profession. Its content does not necessarily reflect the views of the Australian Institute of Health & Safety.
Date: 
Sunday, 17 July, 2022 - 12:30
Category: 
Policy & legislation
Location: 
Victoria

WorkSafe Victoria recently issued a safety alert about the importance of managing the risks associated with electrical energy while conducting surface mining and exploration activities.

The alert was issued following an incident involving an air core exploration drill rig which was being set up to drill a hole located within a farmer’s paddock.

The operator had lowered the stabilising jack legs and was in the process of raising the mast when the winching cable contacted a 12.7kV Single-Wire Earth Return (SWER) overhead powerline.

The SWER line was approximately 7 metres above ground level, and the drill operator received a shock and immediately retreated from the rig at which point the overhead line was observed.

The operator then approached the rig and activated the rig’s hydraulic levers with a shovel to lower the mast, and the operator was taken to the hospital for observation and later released uninjured.

The SWER powerline and associated infrastructure were not marked on locality maps provided by asset owners or within government authority databases. The line’s power poles were several hundred metres away and were not readily visible from the incident location.

Extreme caution should be taken after contacting SWER powerlines, as they may automatically re-energise up to three times before remaining permanently ‘tripped out’, according to the alert, which said there are a number of recommended ways to control risks:

To reduce the risk of contact with electrical energy, mine and exploration operators should:

  • Identify all potential hazards during risk assessments and assess the adequacy and benefits of existing control measures.
  • Consider additional control measures, such as:
    • Implement (eg retrofit) protective indication alarms to detect overhead high voltage electricity sources coupled with optional motion-stop technology.
    • Introduce secondary levels (eg supervisors and/or managers) of pre-task inspection and oversight to improve the capacity to identify and recognise potential hazards.
    • Marking overhead powerlines in accordance with Australia Standard AS 3891-2 as a visual warning.
  • Include a broad range of expertise and personnel when developing risk assessment teams to ensure all aspects of risk are considered.
  • Ensure employees are adequately and regularly trained in identifying hazards and assessing risk.
  • Ensure employees are adequately and regularly trained in the measures used for managing and controlling the risk associated with electrical energy (eg electrically energised plant should be isolated/barricaded, and employee access/contact prevented).
  • Ensure employees are aware electrically energised plant can only be accessed by qualified and certified electrical professionals (eg authorised power distributors).