Three major geotechnical issues for underground coal mines are structure, stress and gas. The significant downtime that occurs due to unpredicted faulting and associated poor ground conditions, high stress and high gas levels are ongoing challenges to the industry's productivity.

While many underground mines develop sophisticated models of seam structure and faulting patterns, the controls on mine-scale fault distribution and severity are still poorly understood and therefore difficult to predict.

Usually, these models are developed independently from adjoining sites that often experience similar ground conditions.

An ambitious Australian Coal Association Research Program (ACARP), launched in January this year, aims to bring together data from mine sites and government departments to quilt together a 3D structural model of the Moranbah-German Creek Coal Measures in the Bowen Basin.

The project will combine and cross-reference various forms of data including drill holes, 3D seismic, gravity and aeromagnetic surveys. To date 52,000 drill holes have been acquired from mine site database and loaded onto a common database for manipulation.

The project is being undertaken by CSIRO's exploration and mining division, under the leadership of Dr Joan Esterle, group leader for the CSIRO Coal Mine Geology Group.

Esterle says that by combining and sharing datasets, mines can achieve a better visibility of individual features, trends and scales of zones of faulting.

The model will improve the ability of companies to assess and rank structural disturbances and will assist mines moving from open cut to underground, by improving their ability to assess areas of low structural complexity.

"Many of the structural features manifested in the sedimentary coal measures can be tracked back to basement dislocations and subsequent reactivation throughout deposition, but few have pursued these relationships due to the difficulties of acquiring and integrating large and disparate regional data sets with mine scale information," Esterle said.

The project has the support of the coal industry, including BHP, North Goonyella Coal, MIM, Anglo American, CapCoal, and Kestrel Coal, which are providing invaluable data, ideas, in-kind support and finance. The Queensland Department of Mines and Energy is providing access to regional data, open file information and in-kind support. Australian mining software houses and local consultants are also providing key assistance.

In the first stage, a regional structural framework will be established from publicly available data (maps, seismic lines, aeromagnetic and gravity surveys, previous regional studies) to examine the basement control on the basin fill, and later deformation.

In the second stage, the mine site databases will be acquired, validated and integrated for modelling of coal seam structure. Esterle said data would specifically exclude any sensitive quality or production information.

Stage 3 of the project will focus on gas modelling, conditional simulations of the faults and defining domains of consistent geological complexity. GeoGAS Systems and the WH Bryan Mining Research Centre at University of Queensland are involved in this stage of the project.

The output will be a fully three-dimensional computer model containing seam thickness, major horizons and available geophysical surveys that can be viewed via the internet using tools developed by CSIRO, or viewed using current industry mine modelling software.

The total project cost is $429,338 of which $196,609 is ACARP funded for a duration of 18 months. Industry cash contributions of $150,000 have also been raised.

"The project is novel in that it is the first time data sharing at this scale has been implemented. When you start to drill into the copious amounts of info located at mine sites then you can start to refine models and see patterns emerging in the data."

By reducing the uncertainty of ground conditions, this project can also lead to significant improvements in safety and performance through pro-active mine planning.

"Preemptive design based on geology is what we're trying to push," Esterle said.