Ground Support Requirements in Coal Burst Prone Mines

As Australian coal mines progress deeper, the likelihood of coal burst increases in some areas; the current ground support system alone maybe inadequate for coal burst control in these limited areas. This project aims to assess the role and effects of a wide range of ground support elements and systems and determine the energy requirements for the Australian underground coal mines to minimise the damage caused by catastrophic dynamic failures (i.e., coal and rock burst) and enhance the safety of mine workers.

The report consists of seven chapters.

• Chapter 1 presents a general introduction of the international control experience of coal bursts, ground support systems and the associated dynamic test approaches, and the objectives and scope of this project.
• Chapter 2 identifies the ground support principles and considerations in burst-prone areas.
• Chapter 3 assesses the support capacities of various ground support elements in laboratory tests, including yielding rock bolts, mesh, mesh straps and integrated support systems.
• Chapter 4 utilises the ABAQUS/Explicit (finite element method) numerical modelling package to assess the support performance of ground support elements in dynamic loading conditions.
• Chapter 5 reviews the international best-practice ground support systems in burst-prone mines (coal and hard rock mining).
• Chapter 6 presents an improved coupled mathematical model to quantitatively assess the burst profile in supported and unsupported coal faces.
• Chapter 7 summarises the major conclusions drawn from each chapter of this report and provides recommendations for future studies.

The main approaches used in this project are a combination of literature review, site study and analytical and computational methods to assess the ground support capacities and demand in burst-prone conditions. The project allows the operators to assess the effective ground support techniques for coal burst control in Australian mining conditions.

This report comprehensively examined the ground support principles and requirements in burstprone conditions and assessed the support capacities of various yielding support elements (e.g., rockbolts, mesh) and ground support systems in laboratory tests. Numerical modelling was conducted to investigate the support performance of yielding support elements and integrated systems under dynamic loading conditions. A novel explicit coupled model was proposed to estimate the ejection velocity in coal faces considering the gas environment and support elements with given capacities.

Outcomes of this project showed that the quantification of the ground support requirements in a complex coal burst-prone environment and its selection is a major advancement over the current system which relies on semi-analytical and/or empirical support design methods that are established based on a large amount of qualified data and site-specific indices. The coal burst hazard profile with the selected ground support elements of various mine layouts, structural domains, gas environments and geological sequences can then be estimated on the basis of the quantitative outcomes.