Mining for stability

A new  research project into mine wall stability will break ground both figuratively and literally.

Geotechnical and hydrogeological engineering researchers from Federation University will use techniques never-before applied to Victorian brown coal mines to gain a better understanding of factors surrounding mine stability.

The State Government announced the $2.2 million ‘Batter Stability Project’ on Monday which will begin immediately at the Yallourn mine and run until 2020.

Bore holes will be drilled at the mine where monitoring systems will be placed to test for things like stress distribution, material properties and ground water pressure.

Federation University’s Geotechnical and Hydrogeological Engineering Research Group senior research fellow Dr Ali Tolooiyan said the study would involve techniques never before used in Victorian brown coal mines like pressure meter testing, state-of-the-art computer simulation and advanced laboratory testing.

GHERG director Professor Rae Mackay said since establishing in 2011, the group’s work had been predominantly laboratory based and to be able to do detailed, field investigation was “major”.

“Over the last few years we’ve had a number of movements (in mines) that were not properly foreseen and some of the reasons for that is that material behaviour is changing over time in the coal system and ground conditions are changing over time, we need to understand what those changes are,” Professor Mackay said.

It is hoped the information gleaned from the research at Yallourn can be applied to the Valley’s other coal mines.

“A significant amount of data we generate will be transferrable, but there are differences,” Professor Mackay said.

“Knowledge about material behaviour and properties, and a lot of modelling will be transferrable, but specific numbers we generate will not be transferrable in their entirety. Additional studies will be required.”

The project follows recommendations by the independent mining Technical Review Board to study risk factors affecting batter stability in mines to make them safer.

The TRB was established by the government in 2008 in response to the 2007 Yallourn mine failure, where the Latrobe River collapsed through the mine’s northern batter wall.

In 2011 cracks appeared in the section of the Princes Freeway adjacent to the Hazelwood open cut, shutting the road for seven months; while in 2012 the Morwell River Diversion collapsed into the Yallourn open cut.

“We want to make sure that the learnings from this project will make sure we don’t have the occurrences that we’ve had happen up until now and that we have a future that is safe and secure, protecting people who work in the mines and the infrastructure that surrounds our mines and of course the environment,” Energy and Resources Minister Lily D’Ambrosio said on Monday.

Three GHERG staff and two PhD students will work on the project, with support from Yallourn personnel.