Subsidence prediction workshop

A SUBSIDENCE prediction workshop is being offered as part of this year’s Coal 2006, Coal Operators Conference at the University of Wollongong in July.
Subsidence prediction workshop Subsidence prediction workshop Subsidence prediction workshop Subsidence prediction workshop Subsidence prediction workshop


Staff Reporter

Organised by the mining group of the School of Civil, Mining and Environmental Engineering at Wollongong, the workshop will be presented by the University of Wollongong’s Dr Ross Seedsman and Walter Keilich.

“The expectations for accurate subsidence predictions are rapidly increasing and are now in excess of the capabilities of the standard design tools,” said Naj Aziz, Associate Professor in Mining Engineering.

“There is a growing gap between what subsidence engineers can predict and the requirements of many current consent conditions. This short course will review the state of the art in subsidence prediction with the aim of providing a basis on which to build a better understanding of the capabilities and limitations of the process.”

Topics to be covered include:

Geotechnical basis of subsidence

Subjects to be covered include the spanning and subsequent collapse of overburden strata, the deformation and failure of coal pillars, and the deformation of roof and floor rocks. There will be a discussion on the prediction of caving and fracturing heights.

The general shape of the subsidence bowl and the associated tilts and strains

The systematic deformations of the surface above extraction panels will be discussed, along with the range of deviations that are sometimes recorded (disordered subsidence). This session will also outline the various subsidence impacts that need to be considered.

The use of empirical prediction methods

The “Holla” method, published by the NSW Department of Minerals Resources, continues to form the basis of subsidence prediction in Australia. The strengths and weakness of this method will be investigated.

The use of the influence function method to visualise subsidence deformations

Influence function methods are now readily available and provide the ability to readily produce contour plans of vertical subsidence, tilts, curvatures and strains. Case studies of their application will be presented, and participants are encouraged to bring their own data set for analysis.

The place for numerical methods

The application of finite element and discrete element codes for subsidence prediction will be outlined.

Design of monitoring programs

Can surface surveys provide the basis for management of physical impacts? Is there a place for the observational method, or should monitoring be designed to validate predictions?

Further information is available at or email