A new study has emerged from the Minerals Research Institute of Western Australia (MRIWA) aiming to boost rock bolt safety in underground mines across the state.
Rock bolts are subjected to complex loading conditions in underground mines under axial and shear loads, as well as a combination of the two.
By testing and monitoring the rock bolts with fibre optic sensors, researchers aimed to develop improved support systems, preventing potential collapse.
The study used physical models to simulate the shearing in underground mines in order to study the effects of combined axial and shear loads on rock bolt reinforcement.
For their new design, researchers found the rock bolts should account for 80 per cent of the axial load. But in situations with a large shear, the load should be reduced to only 50 per cent.
For both conditions, if the displacement percentage is higher than 80 per cent then researchers said the rock bolt selection should be reconsidered.
It was concluded that optical instrumented rock bolts provide a high-resolution strain profile of the rock bolt installed in-situ.
Continuous improvement in the design of rock bolts and associated support system aims to improve safety outcomes in underground mining operations in WA.
Researchers used their findings to develop a new and improved rock bolt design for underground testing, as well as developing software which enables strain values to be monitored.
The software has the ability to display the 3D shape and deformation of the bolt, allowing for early intervention.
The project began in 2018 with a $1.2 million grant, with a $400,000 contribution from the MRIWA.
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