Mine subsidence is deformation and/or displacement of the ground and any surface or subsurface features caused by underground coal mining operations.
State-of-the-art subsidence information management
The Resources Regulator has completed the establishment of the Standardised Subsidence Information Management System (i.e. SSIMS), a state-of-the-art web-based subsidence information resource.
More about the web-based information management system
The System comprises a Data Submission Portal, a Subsidence Database and Subsidence Query Facilities.
The primary function of the Data Submission Portal is to ensure the mine operators’ compliance with clause 67(2)(d) of the Work Health and Safety (Mines and Petroleum Sites) Regulation 2014. This clause requires the mine operator of an underground coal mine to ensure that all subsidence monitoring data is provided to the regulator in the manner and form and at the times required by the regulator.
The overall objective of the Query Facilities in the SSIMS is to promote an improved risk-based approach to subsidence management.
By specifying relevant longwall design parameters, the users of the Query Facilities obtain quantifiable likelihood and its associated magnitude of a given subsidence parameter within a defined query range. This approach is new to conventional subsidence engineering. The quantifiable likelihood and its associated magnitude of a given subsidence parameter will lead to improvement to risk management, recovery of coal resources as well as risk-based regulation in relation to subsidence.
The Query Facilities of the SSIMS are supported by the state-of-the-art IT technologies and a substantial Database comprising more than 1.1 million subsidence data points collected from subsidence survey grids above more than 550 extracted longwalls across all Coalfields in NSW.
Regulation of mine subsidence
The NSW Government is committed to ensuring that the mining industry meets strict contemporary standards. The management of subsidence related to underground coal mining operations is a key focus of the government's regulatory oversight:
- Coal mining operations require development consent under the Environmental Planning and Assessment Act 1979. The environmental impacts of subsidence from these operations are assessed and approved under the Part 4 state significant development process. The views of the community and other government agencies are taken into account during the assessment process.
- Modern development consents are subject to conditions requiring submission to, and approval by, the Department of Planning and Environment (DPE) of an extraction plan which describes how subsidence impacts will be managed to meet the requirements of the development consent.
- The extraction plan is assessed by relevant agencies who provide advice to the DPE as to the adequacy of the plan.
- Extraction plans approved by DPE must then be implemented by the proponent as a requirement of both the development consent and mining lease.
One plan, joint regulators
From 1 July 2014, the department’s former subsidence management plan process was replaced by a consolidated extraction plan process. This provides for the joint regulation of mine subsidence under a single extraction plan.
- The DPE is responsible for compliance and enforcement of the extraction plan so far as it relates to the development consent.
- The NSW Resources Regulator is responsible for compliance and enforcement of the extraction plan so far as it relates to requirements under the Mining Act 1992 and relevant safety legislation. This role principally relates to workplace safety, public safety, rehabilitation and resource recovery requirements.
Rather than approving extraction plans, the NSW Resources Regulator advises the DPE in its approval process. The Regulator is also be able to direct or take other compliance actions to require mining lease holders to amend deficient plans. Any compliance actions undertaken by the NSW Resources Regulator is in the context of rehabilitation and safety legislative requirements only.
Guidelines and reference material
- Mining lease extraction plan condition The mining lease extraction plan condition replaced the former subsidence management plan condition on relevant underground coal mining leases from 1 July 2014. View the standard extraction plan condition on mining leases (PDF, 155.62 KB).
- Guidelines for the preparation of extraction plans / subsidence management plans The Extraction Plan Guideline prepared by the Department of Planning and Environment covers the regulatory requirements of both the DPE and the NSW Resources Regulator. This guideline provides further clarity as to the approval process and regulatory responsibilities of each agency. This guideline applies when preparing an extraction plan required for underground coal mining approved under the Environmental Planning & Assessment Act 1979. It also applies to subsidence management plans (SMP) or subsidence environmental management plans (SEMP), which are required under some older development consents and approvals. Within this guideline, the term ‘extraction plan’ also includes SMPs and SEMPs.
Notices of determination
For access to individual subsidence management plans, please contact the NSW Resources Regulator on 1300 814 609 or email@example.com
Exploration, geological and mining information, including subsidence management plans approved before 2020, can be accessed via the DIGS Database. More information on how to use DIGS.