Combined, the three open-cut coal mines in Victoria’s Latrobe Valley are more than four times the size of Sydney Harbour.
- Plans to rehabilitate open-cut coal mines in Victoria are expected to be finalised this year
- Filling the largest of the three mines with water will take up to 30 years
- Local farmers are sceptical about a proposal to use the Latrobe River to fill the mines
“It’s very much about safety, stability. And it’s also a little bit about sustainability as well,” Professor Mackay said.
“We want to try and find a way that doesn’t actually cost us a lot of money or cost us a lot of effort to actually maintain these pits into the future.”The report looked at other water sources but found none were “of suitable quality, volume or comparative cost” to be feasible, but noted that could change in the future.
Filling them will take decadesThe rehabilitation of the mines entered the spotlight during the inquiry set up after the 2014 fire which burnt inside the Hazelwood mine for 45 days. It found the three mines had a combined volume “more than four times the volume of water in Sydney Harbour”. The Hazelwood mine closed in 2017 and 725 gigalitres is needed to fill it, which the report said would take 15 to 20 years without interruption. Hazelwood also naturally fills with water from under ground, which needs to be continually pumped to maintain its stability. The Yallourn mine, which is due to close in 2032, will need 725GL and take 20 to 25 years to fill, while the Loy Yang mine (closure in 2048) has a capacity of 1,420GL and will take 25 to 30 years to fill.
The Latrobe River is dryingThe state’s peak environment group, Environment Victoria, is concerned about the impact filling the mines will have on the river system. The Government’s report found flows into the Latrobe had dropped by 25 per cent since 1997, from 800GL to 600GL a year. It also found water availability would not be a problem until at least 2035, “after which water availability may become more limited”. Environment Victoria community organiser Laura Melville said she was concerned about the availability of water in the future.
“I think we’ve already seen the impacts of not having that much water in the Latrobe River system on the Gippsland Lakes and increased salinity in the lakes,” she said.
“And if we take even more water out of that system, who knows what the impacts will continue to be on that ecosystem?”According to the timelines contained in the report, the Loy Yang mine would be filled sometime between 2073 and 2078.
Plan needs review
“As we know, this season has been a very different season to previous ones in terms of climate, and we don’t have certainty of the climate going forward,” Dr Reeves said.
“So any plan in terms of water allocations needs to be evaluated constantly in terms of the quality of the water, the timing of the flows, what the downstream impacts are going to be, and any projections about fill rates and where that water is becoming available from, needs to be taken into consideration and re-evaluated.”She said the plan was for the lakes to be closed, meaning the water in the mines wouldn’t be able to flow downstream and would be unavailable for other uses such as firefighting or farming.
“It would require a higher level of management and maintenance to ensure that the quality of the water was high enough to be able to be released if it was needed, but I think that would be an aspiration that’s worth considering,” Dr Reeves said.
Irrigators would like more water
“Surely the electricity companies have money in their budgets to undertake this sort of process,” he said. “I’ve sort of heard whispers that it’s the cheapest option, that by just dumping water in there and then they can walk away.
“But for us, we need access to water and not just now, for the future, and if we are in a bit of a drying climate, we need to have greater access to more water.”The Government is due to release its final plan for the mines by the end of June.
What is mine rehabilitation?
According to the Department of Industry, Tourism and Resources, mine rehab (rehabilitation) is “the process used to repair the impacts of mining on the environment. Mine rehabilitation can also be referred to as coal mine rehabilitation, land rehabilitation, mine site rehabilitation or mine site restoration. The long-term objectives of rehabilitation can vary from simply converting an area to a safe and stable condition, to restoring the pre-mining conditions as closely as possible to support the future sustainability of the site”.
What are the different types of mine rehabilitation practices?
There are several types of mine rehabilitation practices including: - Hydrogeology - Flooding - Soil and capping material assessment - Water characterisation - Landform and cover design - Water management - Revegetation - Tailings storage facilities
Is my Progressive Rehabilitation and Closure Plan (PRCP) compliant?
Organisations carrying out mining activities in Queensland (QLD) are legally obligated to rehabilitate the land. A progressive rehabilitation and closure plan (PRC plan) is a critical element of the QLD Government’s Mined Land Rehabilitation Policy. When submitting a site-specific application for an Environmental Authority (EA) for a new mining activity relating to a mining lease, applicants are required to develop and submit a proposed PRC plan as part of their application. Download your free guide below to find out: https://www.decipher.com.au/MineRehabilitationGuideQLD
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- Speak to our team for a free demo of our mine rehabilitation tool, DecipherGreen
- See how our solutions help manage environmental, standard and approval requirements for mine rehabilitation here