Evaluation of the Chinese Outburst Assessment Methodology and Its Applicability to Australian Low Permeability Coal Seams

Australian coal mines use gas content as the primary index for assessing outburst propensity and risks, with gas composition, coal types and the presence of structures taken into consideration. This approach has been effective in preventing fatal outbursts over the years. However, as mining operations gradually extend into deeper regions, the decreasing permeability may introduce new challenges in outburst risk management.

To ensure effective management of outburst risks in low permeability coal seams, it is beneficial to gain a thorough understanding of the specific challenges associated with this seam condition and explore additional measures that can be adapted to Australian mines to enhance outburst risk control strategies.  

China has several hundreds of outburst-prone coal mines, where coal seams are mostly of low permeability, ranging from 0.0001 to 0.1 mD. In managing this large number of outburst prone mines, China uses a comprehensive outburst risk assessment methodology that employs multiple risk indices and different processes for outburst risk assessment.

This project performed a thorough evaluation of the Chinese outburst risk assessment methodology and its applicability to Australian low permeability coal seams. The main work involved:

• Collecting and collating data and information related to outburst management in China
• Reviewing Chinese coal seam conditions and outburst mechanisms
• Evaluating Chinese outburst risk assessment system, including indices, testing methods and applications.  Outburst prevention methods, such as enhanced pre-drainage and condition change monitoring techniques, were also reviewed.
• A comparative review of Australian coal seam conditions, outburst mechanisms, risk assessment methods, and prevention measures.
• Laboratory testing of Chinese outburst-propensity indices of Australian coal samples using the apparatus acquired from China.
• Numerical modelling investigation into the effect of various parameters on outburst propensity of low permeability coal seams.
• Analysis of the potential adaptation of Chinese methodology in Australian low permeability coal seams.

The project's key findings are:

• Seam conditions and outburst mechanisms in China;
• Outburst risk assessment processes in China;
• Outburst prevention methods used in China;
• Geophysical monitoring techniques for detecting structures and outburst warning signs;
• A comparative review of Australian seam conditions and outburst risk assessment methodology;
• Laboratory tests of Chinese outburst propensity indices on Australian coal samples;
• Numerical assessment of outburst sensitivity of various parameters to Australian coal;
• Numerical assessment of coal seam permeability measured in China;
• Applicability analysis of the Chinese methods in Australian low permeability coal seams.