Guidance about inundation and inrush hazards

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On 31 March 2022, the Work Health and Safety (WHS) laws replaced the health and safety elements of the Mines Safety and Inspection laws. For information visit

All health and safety notifications, forms and guidance for mining and petroleum has moved to the WorkSafe website

What is an inundation or inrush hazard?

Liquid, gas or other substance can enter into the mining workplace with the potential to create an emergency situation and create a risk to health and safety of mine workers. Under high pressure, these substances can swiftly flow or release into or within a mine.

An inundation or inrush hazard may exist if any of the following are located in the vicinity of mining workplaces:

  • significant quantities of stored water, rainfall or other fluid material
  • rivers, lakes, the ocean or other natural water bodies
  • voids and geological structures in the rock that can hold water
  • any material that flows when wet
  • material that may be fluidised as a result of vibrations such as earthquakes, blasting or other means
  • flammable or toxic gases held under pressure in the rock
  • paste- or hydraulic-filled stopes and loose broken rocks in ore passes
  • water-filled old workings
  • unstable ground that has the potential for an airblast or windblast
  • water storage dams, tailings dams or waste dumps.


A high impact function (HIF) audit is available that looks at mine planning and design, operational considerations, quality assurance, monitoring and back analysis aspects for paste and hydraulic fill.

Frequently asked questions on self-auditing of mining activities - information sheet - 942 Kb

This information sheet outlines the frequently asked questions on self-auditing of mining activities.

Reporting an inrush

An inrush is a notifiable incident under section 78(3)(d) of the Mines Safety and Inspection Act 1994.

Refer to s. 78(3)(d) of the Mines Safety and Inspection Act 1994

Accident and incident reporting - guideline - 1632 Kb

Accident and incident reporting - guideline: This guideline will assist employers and employees at Western Australian mining operations to understand their reporting duties for accidents involving injury to persons and occurrences (notifiable incidents).

Hydraulic/paste fill incident or barricade failure occurrence - template - 252 Kb

This is a template for hydraulic/paste fill incident or barricade failure occurrence.

Accessing mine plans

Mine survey plans can be a key source of information for identifying inrush hazards from old water-filled underground workings.
The department is the custodian of Western Australian mine plans dating back to the late 1880s. This information may be useful when establishing the presence of historical workings or previous drilling in a location.

Related information

Below is the list of documents and links that you may find useful.

MSB No. 064: Safety issues associated with hydraulic backfill - 13 Kb

Mines Safety Bulletin No. 064: Safety issues associated with hydraulic backfill (31 July 2001)

MSB No. 055: Potential hazards associated with mine fill - 32 Kb

MSB No. 055: Potential hazards associated with mine fill (29 June 2000)

A Draft code of practice: Inundation and inrush hazard management was available from Safe Work Australia.