Subsidence engineering

As described in the Work Health and Safety (Mines and Petroleum Sites) Regulation 2022:

“subsidence means the deformation or displacement of a part of the ground surface or subsurface strata caused by the extraction of minerals.”

Such deformation or displacement has potential to cause hazardous conditions, which must be controlled to ensure, so far as is reasonably practicable, that the health and safety of workers and other people is not put at risk from subsidence. 

The Resources Regulator is responsible for regulatory oversight under WHS laws of mining activities that cause subsidence, particularly underground coal mining operations.  There are specific provisions relating to subsidence in the Work Health and Safety (Mines and Petroleum Sites) Regulation 2022.

Under the Regulation the operators of underground coal mines are required to monitor subsidence and submit the data to the Regulator in the approved way and form and the times required by the Regulator which can be done via the NSW Resources portal. The Regulator may also direct the monitoring of subsidence at other mines to ensure compliance with work health safety laws. For more information on subsidence monitoring requirements please contact subsidence.monitoring@dpird.nsw.gov.au.

In addition to the above, the Regulator also engages with mine operators and provides guidance to assist in meeting their obligations and undertakes compliance and enforcement activities in relation to subsidence under work health and safety laws.

The Regulator may also provide advice to other government agencies, mine operators and other relevant stakeholders in dealing with subsidence issues, for example, input into the planning approval processes for mining operations under the Environmental Assessment and Planning Act 1979. 

The Regulator has published comprehensive guidance on the management of subsidence risks (PDF, 406.92 KB) to meet the obligations of work health and safety law including examples of best practice. This guidance may also be applied more generally to the management of subsidence risks, for example in relation to planning approvals.