Wednesday, 21 October 2009

Mine subsidence in Newcastle



That Newcastle City Council establishes a sunset working party to formulate recommendations on mitigating the impact of mine subsidence on the revitalisation of Newcastle CBD.

The working party should consist of relevant stakeholders and experts including but not limited to: Council staff, a representative from NSW Mine Subsidence Board, a representative from NSW Department of Premier and Cabinet, a representative from NSW Department of Planning, a representative from Property Council and interested Councillors.

Investigations should include:
  • Existing and alternative construction methods available
  • Existing and alternative funding arrangements, including both public and private sector models, and State and Federal funding
  • Existing legislation and possible amendments if necessary (eg for MSB to proactively address mine subsidence risk by releasing funds to partly pay for grouting)
  • Consistency regarding the time that an approved DA remains valid (eg MSB approvals are valid for 2 years whereas approvals under the Environmental Planning and Assessment Act 1979 are generally valid for 5 years)

The working party should report back to Council within 6 months with recommended methods and actions, consistent with the City Centre Plan, on which Council can either act directly and/or play an advocacy role to other spheres of government.


Mine subsidence has been identified as a key issue affecting the revitalisation of Newcastle CBD.

Newcastle is unique in the amount of old underground mine workings under our CBD. The early history of mine subsidence in NSW is dominated by references to Newcastle (see the History section on the MSB website For Newcastle to be revitalised, our history needs to be recognised and we need a unique solution.

The NSW Mine Subsidence Board (MSB) requires the ‘grouting’ or backfilling of old underground mine workings, up to 70 metres below ground of affected sites prior to redevelopment.

The issue has been raised in submissions to various planning studies including the Newcastle City Centre Plan and the Newcastle CBD Taskforce. The summaries of the Taskforce reports were provided at the Newcastle Panthers Club meeting listing Mine Subsidence as the highest priority.

Subsequent to the CBD Taskforce, the reports prepared by the Hunter Development Corporation completely fail to address the issue.

The MSB requirements mean that grouting usually extends well beyond the footprint of the site to be developed, under public space and adjacent sites. There is currently no mechanism for cost sharing back to the first site developed if an adjacent site is subsequently developed

Grouting is expensive, including a relatively large fixed mobilisation cost, regardless of the size of the site, just to get equipment on site and set up (before any costs for drilling and materials etc). Grouting costs add to unit costs, smaller sites generally incur much higher cost per unit.

The MSB collects levies from coal mines and uses the money as compensation for damage to buildings caused by mine subsidence.

Why can’t some of the money be used to work pro-actively to prevent mine subsidence in the Newcastle CBD given its unique nature? If this requires a change to the State legislation, then it should be changed.

The viability of both commercial and residential redevelopments in the Newcastle CBD is constrained by this issue. This leads to a reduction in housing stock at the lower end of the market within the CBD and a subsequent reduction in the socio-economic residential mix in CBD. This has flow on effects for pushing development away from our CBD, leading to transport issues across the city and ongoing issues relating to the derelict look of the CBD and the functioning of the retail sector in the CBD.

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