Changes to development policy framework
Subsidence Advisory NSW recently completed a cyclical review of its development policy framework. The review was underpinned by critical research projects completed in recent years to inform subsidence risks caused by underground coal mining. An expert reference group was convened to provide input into the review.
The revised changes, which took effect on 5 April 2023, align with an increased understanding of potential mine subsidence risks obtained from the research projects. There are five key changes:
1. The surface development guidelines requirements have been updated, there are two additional guidelines - 1A and 3A, to be applied to properties in historical mine working areas to better regulate development in accordance with their applicable subsidence risk. Guideline 1A (PDF 839.06KB) provides complying development options for goaf consolidation risk (sites with a lower pothole risk due to previous collapse of shallow underground coal mine workings) and Guideline 3A (PDF 766.1KB) provides complying development options for low subsidence risk.
2. Subsidence Advisory approval is now required for all guideline 5 sites. Development that complies with guidelines 2, 3, 3A, 6 and 8 can be approved by the relevant council or a registered certifier as defined in the Environmental Planning and Assessment Act 1979. All other development requires approval by Subsidence Advisory. Please see further information on guidelines at the FAQ's below.
3. A designing for pothole subsidence brochure (PDF 276.11KB) has been developed to assist with information on appropriate engineering design measures for pothole subsidence risks. A further design guide has been added to the Merit Assessment Policy.
4. The exempt developments list (PDF 701.36KB) has been revised to align more closely with the exempt and complying development codes provided in the State Environmental Planning Policy. The list details all minor construction works that do not require approval from Subsidence Advisory NSW.
5. The Merit Assessment (PDF 2.26MB) and Subdivision Assessment (PDF 536.93KB) Policies have been revised to ensure that high risk development and proposed subdivisions are appropriately mitigated and designed.
Further information about each of these changes is outlined below.
Frequently asked questions
Subsidence Advisory NSW has set development guidelines to help property owners building within a mine subsidence district. The guidelines provide a streamlined approval process that allows complying development options, that are approved within seven days.
Subsidence Advisory’s guidelines include requirements related to the nature and class of any development on a property, the size, height and location of new structures, and the use of certain building materials and construction methods.
Different guidelines may apply to neighbouring properties within a district. This is because each property can have differing subsidence risks for example, one property is mined beneath while the neighbouring is not.
Details of the surface development guideline assigned to a property are available on the NSW Planning Portal’s ePlanning Spatial Viewer. Find out more here.
Note: Subsidence Advisory may assign a different guideline to a property over time due to subdivision, mitigation work such as grouting (filling of mine voids with cement based mix) or new information about subsidence risks.
Subsidence Advisory initiated a review of its surface development guidelines (guidelines) to reflect the findings of key research projects carried out to inform potential subsidence risks from underground coal mining and the ongoing improvement and availability of geospatial data and mapping capabilities. See revised guidelines that take effect from 5 April 2023:
Guideline 1A (PDF 839.06KB)
Guideline 2 (PDF 743.76KB)
Guideline 3 (PDF 758.5KB)
Guideline 3A (PDF 766.1KB)
Guideline 4 (PDF 776.29KB)
Guideline 5 (PDF 780.08KB)
Guideline 6 (PDF 755.44KB)
Guideline 8 (PDF 728.53KB)
As a result of the review, key improvements have been added to existing guidelines to ensure fit for purpose design on applicable sites. Two additional guidelines (1A and 3A) were formulated to be assigned to properties in historical mine working areas.
Guideline 1A was developed for properties in shallow goaf subsidence areas with a lower sinkhole risk. The guideline was created as a variation to Guideline 1 and provides lower cost complying development options including standard slab on ground design accounting for site specific ground conditions and building type. Key improvements for homeowners include the ability for development to be constructed as slab on ground providing substantial cost benefits. Slabs are to be designed to cater for minor pothole subsidence, ensuring continued safety.
Guideline 3A was developed for properties that have had previously extracted longwalls from coal mining with a low subsidence risk. The guideline provides homeowners with greater design flexibility and minimal restrictions whilst allowing for relevant ground movement.
Some properties will be reallocated a guideline to ensure potential subsidence risks are proactively managed. These changes are informed by the key research findings and will take effect on 5 April 2023 which will be reflected in the NSW Planning Portal’s ePlanning Spatial Viewer. Find out more here.
Subsidence Advisory recently completed its cyclical development policy framework review following policy implementation in 2017. The review considers the changes and advances in industry practice over the previous 5 year term.
The review found that there was opportunity to regulate development more efficiently for properties with certain subsidence risks. As a result, guidelines 1A and 3A were formulated.
The guidelines have been updated to ensure they remain up to date, to continue providing low-risk complying development options to property owners.
An expert reference group with representatives from government, the development and mining industries along with academics specialising in structural, geotechnical or mining engineering was convened to consider changes.
Councils and registered certifiers are authorised to approve development applications that comply with the following five guidelines without a requirement for referral to Subsidence Advisory.
• Guideline 2
• Guideline 3
• Guideline 3A
• Guideline 6
• Guideline 8
Subsidence Advisory’s approval is required for any development applications that do not comply with a property’s guideline, or applications for development on properties assigned Guidelines 1, 1A, 4, 5 or 7. Subsidence Advisory may approve a development application subject to conditions to better protect the proposed structure from potential subsidence damage.
You can now find out the development guideline for a property in a mine subsidence district online through the NSW Planning Portal’s ePlanning Spatial Viewer. Find out more here.
Each development guideline includes details of the assessment authority for proposed development that complies with the guideline on the property. Depending on the area, this may be council/ a registered certifier or Subsidence Advisory.
Development applications that exceed the assigned development guideline for the property are assessed on merit under the following policies.
Developments are assessed in accordance with Subsidence Advisory's Merit Assessment Policy (PDF 2.26MB).
Subdivisions are assessed in accordance with Subsidence Advisory's Subdivision Policy (PDF 536.93KB).
Merit based determinations are provided within 40 calendar days of receipt unless additional information is requested by Subsidence Advisory to progress the application, or if the application is an integrated referral and alternate timeframes apply.
Subsidence Advisory may request further investigations or place construction conditions on the development to help protect the proposed structure from damage should subsidence occur.
If you are planning a large or significant development, you should contact Subsidence Advisory on (02) 4908 4300 during the preliminary planning stages of the project, prior to having detailed plans drawn.
Subsidence Advisory can provide advice and guidance on likely construction conditions or subsidence mitigation measures.
No. Councils and registered certifiers are only able to assess applications for complying development on guidelines 2,3, 3A,6 and 8. If an application does not comply with these guidelines or is for any of the remaining guidelines, the application must be referred to Subsidence Advisory (or applied directly by the applicant to Subsidence Advisory) for assessment.
Subsidence Advisory will assess applications that do not comply with the assigned guideline on merit in accordance with its policies and may place conditions on the proposed development to help protect it from subsidence damage.
Merit based applications are generally processed within 40 days. However, in some instances where additional studies are required the assessment process can take longer.
If your development application requires assessment by Subsidence Advisory, you can lodge through Subsidence Advisory’s online portal or as an Integrated Development through Council.
You can log in to Subsidence Advisory’s portal using your Service NSW account details. If you do not have a Service NSW account, you will need to create one. There is no cost to register for a Service NSW account.
No. Subsidence Advisory continues to aim to process development applications that comply with the applicable guideline within seven calendar days. Development on certain properties that complies with the property’s development guideline can be assessed by the relevant council or a registered certifier without requiring a separate assessment by Subsidence Advisory.
Subsidence Advisory will continue to assess development applications outside of the guidelines as well as all development on properties assigned Guidelines 1, 1A, 4, 5 and 7. Large scale developments will continue to be assessed by Subsidence Advisory on merit.
Generally, merit based applications are processed within 40 days. However, in some instances where additional studies are required the assessment process can take longer.
Not necessarily. Subsidence Advisory is retaining assessment of all development on properties assigned Guidelines 1, 1A, 4, 5 and 7.
Properties assigned Guideline 7 do not have specific construction guidelines applied, rather Subsidence Advisory considers all proposed developments on these properties on application. There are many reasons why a property may be assigned Guideline 7, including:
- Insufficient information known about mining beneath property
- Property only partially mined beneath
- Subsidence risks necessitate engineering assessment.
There are many different types of subsidence impacts. Subsidence Advisory may be retaining assessment of all development on your property as the type of potential subsidence in the area requires technical input.
Yes. The development guideline assigned to a property may change as a result of further information about potential for subsidence. Subsidence Advisory may make changes to the existing guideline or assign a different guideline to a property over time due to subdivision, mitigation work such as grouting, or new information about subsidence risks.
For example, a large property that is partially mined beneath may be subdivided resulting in the creation of new lots that are not impacted by underground mining. In this instance, Subsidence Advisory may apply a different guideline with no restrictions to those new lots that are not mined beneath.
Updates to guidelines are reflected on the NSW Planning Portal’s ePlanning Spatial Viewer as they occur. Find out more here.
If you require any assistance, please contact our office on 02 4908 4300, our office hours are 8:30am – 4:30pm Mon-Fri.
In most cases, a property’s updated development guideline will be very similar to the previous guideline. To ensure any development works are not disrupted, a 6-month grace period (ending on 5 October 2023) will be allowed for property owners who have commenced planning of a development application under their previous guideline or commenced approval processes.
If this applies to you, please note there are no steps required from you. The grace period will be applied to all the relevant properties in Subsidence Advisory’s database.
If you have any questions about how the changes to development guidelines impact proposed development, please contact Subsidence Advisory on (02) 4908 4300 to speak with one of our technical officers. Please note that existing approvals that have been previously issued will continue to be upheld for their approval timeframe.
Based on key research projects and policy improvements, updates to conditions of approval have been made in historical and active mining areas as well as other changes. Please refer to Subsidence Advisory’s Merit and Subdivision Assessment policies.
The Subdivision Assessment Policy has been updated to ensure that the assessment of proposed subdivisions in active mining areas is consistent with the applicable mine subsidence risk based on coal mining license or lease types and the land zoning applied by the NSW Department of Planning and Environment.
All subdivision proposals will continue to be assessed by Subsidence Advisory. Subdivision applications can be lodged through Subsidence Advisory’s online portal.
Please note Subsidence Advisory NSW surface development guidelines do not apply to subdivisions.
The Lot and Deposited Plan (DP) number for your property can be found on your Council rates notice or contract of sale. You can also find it by searching your address on the NSW Planning Portal’s ePlanning Spatial Viewer. Find out more here.
No. Mine Subsidence Districts are reviewed separately.
Under Section 24 of the Coal Mine Subsidence Compensation Act 2017, Subsidence Advisory may exempt specified work from requiring approval subject to conditions.