Dr. Andrew King – CSIRO geophysicist

Dr Andrew King: improving mine safety with microseismics

Dr Andrew King is a geophysicist using microseismics to 'listen' for rock movements and predict roof failure in mines.

• 10 January 2006 | Updated 14 October 2011

• Current activities
• The future

Dr Andrew King is a Project Scientist, geophysicist, with CSIRO Earth Science and Resource Engineering.

Dr King undertook his undergraduate studies at the University of Witwatersrand, Johannesburg, and was awarded a doctorate from Macquarie University, Sydney, New South Wales.

Current activities

Dr King is part of a team improving mine safety and design by using microseismic data to help predict rock movements and monitor mine roof stability.

The collapse of underground roadways in mines can kill or injure people, bury equipment and cause significant financial losses. However, fractures developing in the roadway roof before the collapse produce changes in seismic character and can be measured. This means that there is a chance of predicting, and preventing, these accidents.

Dr King and his team are 'listening for the cracks' and measuring them using sound waves passing through the rocks.

Their research is based on methods used in earthquake seismology. Using seismic waves arriving at an array of geophones (specially designed sensors that listen to seismic waves), the team try to determine the location, size and characteristics of the source. 

Laboratory experiments with samples of rock a few centimetres in size pick up seismic waves from grain-sized microfractures.

'The fractures start at random but then they begin to align and coalesce as the rock reaches the state where a sudden, large-scale failure occurs,' said Dr King. 'We see the same behaviour on a larger scale too.'

The team have worked with the Japan Coal Energy Center (JCOAL), a Japanese coal research organisation, to install receivers in a coal mine roof that was expected to collapse. They measured microseismic and ultrasonic frequencies, stress and displacement.

The team have found that the roadway roof vibrates at certain resonant frequencies, which change during the build-up to roof collapse.

The future

Future research and development will focus on the creation of real-time microseismic systems for use in long-wall coal mining.

'Ultimately we would like to develop microseismic systems that are cheap enough to be installed in every mine, and the knowledge and understanding to be able to predict roof-fall and other geotechnical problems reliably and early enough to prevent them from happening,' says Dr King.

Read more about CSIRO Earth Science and Resource Engineering.