Key questions from open days
In November 2017, the Latrobe Valley Regional Rehabilitation Strategy (LVRRS) Project Team hosted a series of open days across the Latrobe Valley to provide members of the local community with information about the project.
A number of questions were asked by attendees across the three days and this page provides answers to the more common questions.
All mine rehabilitation proposals, either from the mine operators or third parties, proposing a pit-lake or an alternative option, will be given due consideration.
While the LVRRS is testing the feasibility of the pit lake option only, in the event that a third party proposal is deemed to have merit or warrant further investigation, the Victorian Government may assist the proponent, in furthering the proposal.
In the event that a mine operator puts forward an alternative rehabilitation proposal, this would be considered through the appropriate regulatory processes.
The Hazelwood Mine Fire Inquiry concluded that in regard to the rehabilitation of the Latrobe Valley’s three brown coal mines "the pit lakes and the partial backfill below the water table options are currently the most viable" 1.
The Board of Inquiry did conclude that "there are many unresolved issues about how the lake option will be achieved" 2.
The LVRRS (being prepared as part of the Victorian Government’s response to the Inquiry’s findings) will test the feasibility of the pit lake rehabilitation scenario.
The scope of the project does not extend to options outside of the pit lake rehabilitation option. However, as per the above answer, alternative mine rehabilitation options and proposals will be given due consideration, through already established processes and procedures.
It is possible that a dry pit could deliver a safe and stable final rehabilitated landform, however this would require ongoing management, similar to what the mine operators currently undertake.
The costs of ongoing maintenance would be significant, and at this moment in time, the pit lake is seen as representing the most economically viable rehabilitation option to achieve a safe and stable final rehabilitated landform.
Filling the mine void (either fully or partially) with water exerts a force against the floor and batters of the mine which at a particular level will re-establish geotechnical stability conditions similar to those pre-mining.
The creation of pit lakes at the Latrobe Valley coal mines would require a large amount of water.
The regional water study for the LVRRS will assess how much water would be required to create and maintain the proposed pit lakes.
Based on the mine operator’s current workplans, the Hazelwood Mine Fire Inquiry made an initial estimate of the volumes of water required to create pit lakes, and although these numbers will change as the LVRRS progresses, this gives an indication of the magnitude of water required.
If filled to the top of the pit, it is estimated that each mine could require between 750 and 1,000 billion litres of water. In comparison, the combined capacity of the Latrobe’s Blue Rock, Moondarra and Narracan water storages is 245 billion litres. Sydney Harbour’s total capacity is 560 billion litres.
The Latrobe River system has finite water availability and significant demands from many different groups of water users, including towns, agriculture and industry, in addition to the water needed to maintain a healthy waterway and environment.
Victoria’s statutory water entitlement and planning framework manages these competing demands for water, and includes provisions to protect other water users’ entitlements and rights to water.
Accessing the water needed to create pit lakes will be very challenging, and it is too early to determine the feasibility of pit lakes in terms of water availability.
The LVRRS will determine the amount of water required to deliver a safe, stable and sustainable rehabilitation outcome, and then assess the options for accessing the water for rehabilitation within the water entitlement framework and in consideration of other water users and the environment.
The regional water study being undertaken as part of preparing the LVRRS is a comprehensive technical study of water-related issues and opportunities relevant to rehabilitation of the Latrobe Valley Coal mines in a regional context.
The study will assess a range of regional rehabilitation options with regard to the ability to achieve a stable final landform without impinging on other water users or resulting in unacceptable impacts on the environment, while enabling where feasible beneficial future uses of the mine sites and any pit lakes.
The final water quality of the proposed pit lakes is currently being investigated.
The regional water studies to be undertaken as part of the preparation of the LVRRS will assess:
- water availability and use of regional water resources, within Victoria’s statutory water entitlement and planning framework
- alternative sources of water to those currently available to the Latrobe Valley coal mines
- water quality impacts in the pit lakes, groundwater and off-site surface waters
- impacts on aquatic ecosystems and downstream users
- the scope of long-term regional groundwater monitoring requirements.
The studies will also consider possible impacts due to climate change and climate variability on water resources available.
The availability of water to rehabilitate the mines is currently being investigated.
All available water in the Latrobe Valley is fully allocated, shared between towns, agriculture, industry (including the power stations and coal mines) and the environment.
The LVRRS will determine the amount of water required to deliver a safe, stable and sustainable rehabilitation outcome and the availability of that water, within the context of Victoria’s clearly defined statutory water entitlement and planning framework.
Assessing the water quality of the proposed pit lakes is a key area of investigation for the LVRRS. This includes assessing any impacts that may occur due to the interaction of coal formations with water.
Is it too early to say whether any pit lake established as part of the rehabilitation of the Latrobe Valley’s brown coal mines would be publicly accessible, however the findings of the technical studies being undertaken as part of the LVRRS will inform this.
The mine sites are currently privately held and the potential for recreational uses will depend on, in addition to the findings of the technical studies, the post-rehabilitation landform, the owner’s intentions for possible post-mining uses and zoning in the future.
It is too early to say what kinds of activities may be able to be undertaken on the land surrounding the rehabilitated mine voids.
The kind of activities that would be able to be undertaken will depend on the findings of the geotechnical and hydrogeological studies being conducted as part of the LVRRS.
What is technically possible will inform the land use opportunities that will be possible on the rehabilitated sites.
It is too early to tell whether or not the final landforms will be transferred to the State.
The LVRRS is working to identify the most sustainable outcomes for rehabilitation. To ensure a sustainable outcome is achieved options regarding the long term management of the mine voids and pit lakes will need to be taken into consideration.
Government’s decision making regarding long term land ownership will be informed by the LVRRS and the most suitable land ownership arrangements to ensure the successful and sustainable rehabilitation of the mines.
Page last updated: 22 Oct 2019