Last week Mantle said it was continuing with its mission to assess the continuity and prospectivity of metallurgical black coal under the Latrobe Valley, but it will keep one eye on the potential of developing a solar-powered, pumped, hydro-electric generation project utilising existing disused brown coal open cuts connected to underground storage created by the black coal mining it aims to undertake.

Coming just days after Genex Energy launched an $8 million initial public offer to study a 300 megawatt pumped hydroelectric peaking power project at the abandoned Kidston gold mine in Queensland, Mantle says it wants to do something similar in Victoria.

Although Mantle says it will take decades for its plan to fly.

Mantle, which was recently granted EL5336, EL5338, EL5428 and EL5429 to allow it to continue its black coal studies outside the existing EL5337 and EL5210, , says there could a role for it in the Victorian State Government plans to move away from low-rank brown coals for power generation.

First Mantle wants to develop and extract an underground coking, PCI and high-grade thermal coal operation, before helping Victoria transition from brown coal mining to sustainable renewable energy production.

It says once the coals have been mined down to a depth between 500-1000m, concrete lining could be used to the seal the underground reservoir walls to prevent leakage, with the voids then hydraulically linked to surface dams via high efficiency, reversible hydro-generators and pumps.

Solar generation would be used to pump water from the underground reservoirs to the surface dams while that same water is used to generate hydro-electric power at night or during short high-demand peak periods when such an operation could be very profitable.

Unlike Genex’s plan Mantle believes off-grid solar power can be used, although it admits it will need partners for the technical innovation, underground mining and hydroelectric construction aspects of the long term project.

Mantle says that could happen by 2050, after the coal is extracted – a move unlikely to win it too many friends given green groups say all the coal already defined already needs to stay in the ground to avoid catastrophic global warming.

Mantle says the Gippsland coal basin becomes shallower towards the southern and western margins of the basin, possibly providing an economic entry point to underground workings targeting better quality coal once considered to be uneconomic.

The mined higher grade, higher valued black coal could be exported for steelmaking, combined into a less polluting power station fuel while still using the latest technology to convert the abundant and more volatile existing brown coal resources into less polluting fuels, synthesised industrial products and fertilisers for agriculture.

Infrastructure costs for the renewable energy systems would be paid for by the sale and export of the metallurgical coal.

Mantle is exploring around the Thorpdale region where black coal extraction dates back to the late 1800s.

It says cleaner coal can be a transition fuel while the world transitions to alternative energy sources.

Mantle has also announced it has given up any plans to look for CSG in its areas as a result of community concerns.