A coal burst occurred on 15 April, 2014 at the Austar Coal Mine, located west of Newcastle, NSW,Australia. The burst resulted in fatal injuries to two men working as part of the mining crew at the development face. At...A coal burst occurred on 15 April, 2014 at the Austar Coal Mine, located west of Newcastle, NSW,Australia. The burst resulted in fatal injuries to two men working as part of the mining crew at the development face. At the time, a continuous miner was being used to mine a longwall development gate road through heavily structured coal, at a depth of approximately 550 m. A number of pre-cursor bumps had occurred on previous shifts, emanating from the coal ribs of the roadway, in proximity to the coal face.This paper reviews the geological, geotechnical and mining conditions and circumstances leading up to the coal burst event; and presents and discusses the available evidence and possible interpretations relating to the geomechanical behaviour mechanisms that may have been critical factors in this incident. The paper also discusses some key technical and operational considerations of ground support systems and mining practices and strategies needed for operating in such conditions in the future.展开更多
University of New South Wales(UNSW Australia) had been involved in the study of premature failure of rock bolts in Australia coal mines from the initial identification of the problem in 1999. Rock bolt steel changes o...University of New South Wales(UNSW Australia) had been involved in the study of premature failure of rock bolts in Australia coal mines from the initial identification of the problem in 1999. Rock bolt steel changes over the last decade appear to have not reduced the incidence of failures. A broadened UNSW research project funded by the Australian Research Council(ARC) and Industry has targeted finding the environmental causes through extensive field and laboratory experiments. This paper describes the field studies conducted in underground coal mines,in particular attempts to measure the contribution to corrosion from groundwater,mineralogy and microbial activity. Various underground survey techniques were used to determine the extent of broken bolts,with the presence of both stress corrosion cracking(SCC) and localized deep pitting making no single technique suitable on their own.Groundwater found dripping from bolts across various coalfields in Australia were found to be not aggressive and known groundwater corrosivity classification systems did not correlate to where broken bolts were found. In-hole coupon bolts placed in roof strata containing claystone bands confirmed the clay as being a major contributor to corrosion. Microbes capable of contributing to steel corrosion were found to be present in groundwater,and culturing of the microbes taken from in-situ coupon bolts proved that the bacteria was present on the bolt surface. An ‘in-hole bolt corrosion coupon' development by the project may have multiple benefits of (1) helping quantify newly developed corrosivity classification systems,(2) providing an in-situ ground support corrosion monitoring tool,and (3) for testing possible corrosion protection solutions.展开更多
An underground coal mine located in New South Wales has a target coal seam located 160-180 m deep directly below a 16-20 m thick conglomerate unit that has been associated with significant periodic weighting events on...An underground coal mine located in New South Wales has a target coal seam located 160-180 m deep directly below a 16-20 m thick conglomerate unit that has been associated with significant periodic weighting events on the Iongwall face. As part of the investigations to better understand the causes of periodic weighting at the mine. inclinometers capable of measuring horizontal shear movements through the full section of the overburden strata were installed ahead of mining at two locations approximately 1 km apart above the centre of two iongwall panels. These inclinometers were monitored as the longwall approached each site. This paper presents the details of the installation, the results of the inclinometer monitoring at both sites, and the insights that these measurements provide for overburden behaviour about longwall panels. Horizontal shear movements were observed to develop on shear horizons that correlate closely across the two sites suggesting a mechanism that is consistent across a large area of the mine. Shear movements were observed to develop on a single horizon near the top of the conglomerate strata that was mobilised almost immediately after initial formation of the longwall goal at a distance of 425 m ahead of the longwall face.展开更多
Princeton Ocean Model is used to study the response of Jervis Bay, NSW, Australia, to the local wind and remote shelf coastal trapped wave (CTW) forcings in summer seasons when the water column is stratified by the wa...Princeton Ocean Model is used to study the response of Jervis Bay, NSW, Australia, to the local wind and remote shelf coastal trapped wave (CTW) forcings in summer seasons when the water column is stratified by the water temperature.The study has revealed that the response of bay to the wind forcing is the generation of the wind driven currents and the internal Kelvin waves (IKW). However, both temperature and flow sub-inertial oscillations in the bay are weaker than those from the observations and the correlation between the modeled and observed low frequency currents is low. In response to the forcing of CTWs on the adjacent shelf, IKWs are also established in the bay and amplitudes of sub-inertial oscillations of temperature and currents agree better with the observations. It can be concluded that sub-inertial baroclinic flows in the bay is dominantly forced by remote CTW on the shelf adjacent to Jervis Bay during thermally stratified summer seasons.展开更多
The Integrated Marine Observing System [IMOS] is an Australian national program for observing the oceans around Australia. As one of its important nodes, the New South Wales Integrated Marine Observing System (NSW-IM...The Integrated Marine Observing System [IMOS] is an Australian national program for observing the oceans around Australia. As one of its important nodes, the New South Wales Integrated Marine Observing System (NSW-IMOS] aims to provide more accurate descriptions of the East Australian Current [EAC]. The purpose of this paper is to evaluate the potential economic benefits from NSW-IMOS. Six related sectors which can potentially be among its main beneficiaries are considered: beach recreation, commercial fishing, recreational fishing, recreational boating, natural hazard predictions, and oil spill mitigation. The 1% constant percentage increase evaluation method is used to estimate the potential economic benefits to these six beneficiaries. By using this method, our study shows that the total potential economic benefit for these sectors is estimated to be $ 6.07 million per year. We consider that this is indicative but not conclusive in demonstrating some of the potential economic benefits that can be provided from information gathered by NSW-IMOS facilities. We conclude with further evaluative approaches that could be used to provide more accurate estimates of potential economic benefits.展开更多
Sowing time of wheat in south eastern Australia varies from autumn to early winter, depending on the seasonal 'break'. Wheat yields are often reduced by frost damage at flowering time and by heat-and/or water-stress...Sowing time of wheat in south eastern Australia varies from autumn to early winter, depending on the seasonal 'break'. Wheat yields are often reduced by frost damage at flowering time and by heat-and/or water-stress during grain filling. Selecting suitable varieties for specific sowing times is a complex decision farmers make because these varietal phenology and climate risks have to be assessed together. In order to help farmers make decisions, they need tools that simulate and analyse agronomically-suitable sowing dates (ASSD) for a given variety of wheat. The hypothesis underlining this study is the integration of a wheat phenology model with historical climate data is an effective approach to modelling the ASSD of current varieties used in the wheat growing areas of Southern NSW. The parameters of the wheat phenology model were based on data from five years of field experimentation across 15 sites. Data from four sites were used to examine varietal suitability in relation to sowing time and its associated risks of frost and heat damage. The optimum ASSD for any variety at 72 locations across Southern NSW was investigated. The results showed that there were substantial spatial variations in the ASSD across the target region. ASSD for a late maturing wheat genotype (EGA Gregory) can range from early March to late April, while the earliest acceptable sowing date for an early maturing spring wheat genotype (H46) can range from early to late May. The wide range of spatial variation in the earliest and latest sowing dates, as well as the varied length of sowing opportunities, highlighted the importance of being able to apply a modelling approach which can integrate information on crop phenology with climate risk for a given location. This approach would allow better decision-making on suitable varieties and sowing dates in order to minimise the risk of frost and heat damage affecting crop yield.展开更多
文摘A coal burst occurred on 15 April, 2014 at the Austar Coal Mine, located west of Newcastle, NSW,Australia. The burst resulted in fatal injuries to two men working as part of the mining crew at the development face. At the time, a continuous miner was being used to mine a longwall development gate road through heavily structured coal, at a depth of approximately 550 m. A number of pre-cursor bumps had occurred on previous shifts, emanating from the coal ribs of the roadway, in proximity to the coal face.This paper reviews the geological, geotechnical and mining conditions and circumstances leading up to the coal burst event; and presents and discusses the available evidence and possible interpretations relating to the geomechanical behaviour mechanisms that may have been critical factors in this incident. The paper also discusses some key technical and operational considerations of ground support systems and mining practices and strategies needed for operating in such conditions in the future.
基金the UNSW ARC funded project,these companies includeAnglo American Coal,BHP Billiton,Centennial Coal,Glencore,Jennmar Australia and Whitehaven Coal
文摘University of New South Wales(UNSW Australia) had been involved in the study of premature failure of rock bolts in Australia coal mines from the initial identification of the problem in 1999. Rock bolt steel changes over the last decade appear to have not reduced the incidence of failures. A broadened UNSW research project funded by the Australian Research Council(ARC) and Industry has targeted finding the environmental causes through extensive field and laboratory experiments. This paper describes the field studies conducted in underground coal mines,in particular attempts to measure the contribution to corrosion from groundwater,mineralogy and microbial activity. Various underground survey techniques were used to determine the extent of broken bolts,with the presence of both stress corrosion cracking(SCC) and localized deep pitting making no single technique suitable on their own.Groundwater found dripping from bolts across various coalfields in Australia were found to be not aggressive and known groundwater corrosivity classification systems did not correlate to where broken bolts were found. In-hole coupon bolts placed in roof strata containing claystone bands confirmed the clay as being a major contributor to corrosion. Microbes capable of contributing to steel corrosion were found to be present in groundwater,and culturing of the microbes taken from in-situ coupon bolts proved that the bacteria was present on the bolt surface. An ‘in-hole bolt corrosion coupon' development by the project may have multiple benefits of (1) helping quantify newly developed corrosivity classification systems,(2) providing an in-situ ground support corrosion monitoring tool,and (3) for testing possible corrosion protection solutions.
文摘An underground coal mine located in New South Wales has a target coal seam located 160-180 m deep directly below a 16-20 m thick conglomerate unit that has been associated with significant periodic weighting events on the Iongwall face. As part of the investigations to better understand the causes of periodic weighting at the mine. inclinometers capable of measuring horizontal shear movements through the full section of the overburden strata were installed ahead of mining at two locations approximately 1 km apart above the centre of two iongwall panels. These inclinometers were monitored as the longwall approached each site. This paper presents the details of the installation, the results of the inclinometer monitoring at both sites, and the insights that these measurements provide for overburden behaviour about longwall panels. Horizontal shear movements were observed to develop on shear horizons that correlate closely across the two sites suggesting a mechanism that is consistent across a large area of the mine. Shear movements were observed to develop on a single horizon near the top of the conglomerate strata that was mobilised almost immediately after initial formation of the longwall goal at a distance of 425 m ahead of the longwall face.
文摘Princeton Ocean Model is used to study the response of Jervis Bay, NSW, Australia, to the local wind and remote shelf coastal trapped wave (CTW) forcings in summer seasons when the water column is stratified by the water temperature.The study has revealed that the response of bay to the wind forcing is the generation of the wind driven currents and the internal Kelvin waves (IKW). However, both temperature and flow sub-inertial oscillations in the bay are weaker than those from the observations and the correlation between the modeled and observed low frequency currents is low. In response to the forcing of CTWs on the adjacent shelf, IKWs are also established in the bay and amplitudes of sub-inertial oscillations of temperature and currents agree better with the observations. It can be concluded that sub-inertial baroclinic flows in the bay is dominantly forced by remote CTW on the shelf adjacent to Jervis Bay during thermally stratified summer seasons.
文摘The Integrated Marine Observing System [IMOS] is an Australian national program for observing the oceans around Australia. As one of its important nodes, the New South Wales Integrated Marine Observing System (NSW-IMOS] aims to provide more accurate descriptions of the East Australian Current [EAC]. The purpose of this paper is to evaluate the potential economic benefits from NSW-IMOS. Six related sectors which can potentially be among its main beneficiaries are considered: beach recreation, commercial fishing, recreational fishing, recreational boating, natural hazard predictions, and oil spill mitigation. The 1% constant percentage increase evaluation method is used to estimate the potential economic benefits to these six beneficiaries. By using this method, our study shows that the total potential economic benefit for these sectors is estimated to be $ 6.07 million per year. We consider that this is indicative but not conclusive in demonstrating some of the potential economic benefits that can be provided from information gathered by NSW-IMOS facilities. We conclude with further evaluative approaches that could be used to provide more accurate estimates of potential economic benefits.
文摘Sowing time of wheat in south eastern Australia varies from autumn to early winter, depending on the seasonal 'break'. Wheat yields are often reduced by frost damage at flowering time and by heat-and/or water-stress during grain filling. Selecting suitable varieties for specific sowing times is a complex decision farmers make because these varietal phenology and climate risks have to be assessed together. In order to help farmers make decisions, they need tools that simulate and analyse agronomically-suitable sowing dates (ASSD) for a given variety of wheat. The hypothesis underlining this study is the integration of a wheat phenology model with historical climate data is an effective approach to modelling the ASSD of current varieties used in the wheat growing areas of Southern NSW. The parameters of the wheat phenology model were based on data from five years of field experimentation across 15 sites. Data from four sites were used to examine varietal suitability in relation to sowing time and its associated risks of frost and heat damage. The optimum ASSD for any variety at 72 locations across Southern NSW was investigated. The results showed that there were substantial spatial variations in the ASSD across the target region. ASSD for a late maturing wheat genotype (EGA Gregory) can range from early March to late April, while the earliest acceptable sowing date for an early maturing spring wheat genotype (H46) can range from early to late May. The wide range of spatial variation in the earliest and latest sowing dates, as well as the varied length of sowing opportunities, highlighted the importance of being able to apply a modelling approach which can integrate information on crop phenology with climate risk for a given location. This approach would allow better decision-making on suitable varieties and sowing dates in order to minimise the risk of frost and heat damage affecting crop yield.