Analysis and management of outbursts: with particular reference to the Bulli coal seam

The Bulli Coal Seam, located in the Illawarra Coalfield of New South Wales, Australia has a long and varied history of sudden outbursts. From available information this problem has resulted in twelve (12) fatalities over the last one hundred and five (105) years, with over four hundred (400) separate outburst incidents being identified. These incidents vary in severity and intensity from the discharge of 1 to 2 tonnes of coal, with a slight increase in gas emission, to the discharge of 200 to 400 tonnes of coal some 6,000 m3 of gas being liberated and large items of mining equipment being pushed 1 to 2 metres down the roadway. Knowledge and experience gained in studying overseas experiences in the management of outbursts is of great benefit. When incorporated with the research and understanding developed in local conditions there is the potential to enhance mine safety and allow valuable coal resources to be mined. The analysis of mining techniques along with the review of specialised methods to predict and prevent outbursts are of major importance, with the ultimate barrier being to protect mine workers if and when an outburst type incident does occur. The primary aim underlying this thesis is to outline the various issues that relate to understanding the causal mechanisms that contribute to outbursts, how they impact upon mining operations in the Bulli coal seam and ultimately to identify strategies, procedures and processes to manage the outburst risk. The methodology adopted was to identify the factors that contribute to outbursts throughout the world but more specifically focus upon the Bulli coal seam, especially in respect of current techniques used to manage the outburst risk and ensure safe working conditions for mine workers. To achieve these aims the following strategy was utilised: Identify the characteristics that define and or determine an outburst Review the nature and occurrence of outburst incidents throughout the world Review in detail the factors associated with Bulli seam outbursts focusing on; \u3e Bulli seam geology \u3e Outburst characteristics \u3e Review of fatal outburst incidents for Bulli seam mines Consider mechanisms to predict, prevent and provide protection from outbursts Detailed review of current outburst management strategies Undertake case studies of outburst management plans for three indicative mines For modern day mining operations excessive risk associated with outbursts, is considered as unacceptable. The challenge therefore is to fully understand the outburst phenomena, the various techniques and technologies which can be utilised to predict, prevent and control outbursts and develop robust management systems which guarantee the safety of mine workers. Anything less is considered unacceptable. This thesis is mainly concerned with the development, application and specific implementation of outburst management plans for mines operating in the Bulli coal seam. The outcome of this approach to the management of outbursts, has dramatically reduced the number of outbursts incidents for Bulli Seam mines and thereby enhanced mine safety