In-seam drilling technologies for underground coal mines

There are- several in-seam coal research projects currently under investigation by the Cooperative Research Centre for Mining Technology and Equipment (CMTE). The overall aim of the projects is to produce new technologies to enhance safety and the efficiency of in-seam gas drainage drilling. Results from high pressure waterjet rotary drilling trials indicate that by applying high pressure water to a rotary drill bit, the hole can be drilled to follow the planned trajectory very closely. Steerable drill bits for drilling long holes (\u3e 1 kID) have been produced and trialed. A flexible high speed drilling system provides a capacity for rapid in-seam drilling, particularly suited to cross panel drainage. Geophysical tools are being developed to provide a geological steering capability and a better understanding of potential gas outbursts zones

Combining modern assessment methods to improve understanding of longwall geomechanics

Ongoing, collaborative research between CSIRO\u27s Exploration and Mining and Strata Control Technology has resulted in a better understanding of rock failure mechanisms around longwall extraction. Failure has occurred further ahead of the retreating face than predicted by conventional longwall geomechanics theory. In some cases significant failure has been detected several hundred metres ahead of the face position with demonstrated influences of minor geological discontinuities. Shear, rather than tensile failure has been the predominant failure mechanism in the environments monitored. Validating technologies of microseismic monitoring and new face monitoring techniques have assisted the development of predictive 2D computational modelling tools. The demonstrated 3D consequences of failure has assisted in the ongoing direction of the project to further investigate these effects

O 1s excitation and ionization processes in the CO2 molecule studied via detection of low-energy fluorescence emission

Oxygen 1s excitation and ionization processes in the CO2 molecule have been studied with dispersed and non-dispersed fluorescence spectroscopy as well as with the vacuum ultraviolet (VUV) photon?photoion coincidence technique. The intensity of the neutral O emission line at 845 nm shows particular sensitivity to core-to-Rydberg excitations and core?valence double excitations, while shape resonances are suppressed. In contrast, the partial fluorescence yield in the wavelength window 300?650 nm and the excitation functions of selected O+ and C+ emission lines in the wavelength range 400?500 nm display all of the absorption features. The relative intensity of ionic emission in the visible range increases towards higher photon energies, which is attributed to O 1s shake-off photoionization. VUV photon?photoion coincidence spectra reveal major contributions from the C+ and O+ ions and a minor contribution from C2+. No conclusive changes in the intensity ratios among the different ions are observed above the O 1s threshold. The line shape of the VUV?O+ coincidence peak in the mass spectrum carries some information on the initial core excitatio

Determining the Cotnrols for Strata Gas and Oil Duistribution within Sandstone Reservoirs Overlying the Bulli Seam

The continuing and effective management of gas within the sandstones overlying the Bulli seam mines of BHP Billiton Illawarra Coal is required to ensure safe and productive mining operations. Recent surface exploration has also detected the presence of oil accumulations in these sandstones which have the potential to impact on future mining operations. Some of these hydrocarbons are located within the longwall relaxation zone of the overlying strata and, as a result, can migrate to the goaf and active workings subsequent to extraction. A number of new exploration techniques, which are in common use by the petroleum industry, have been adopted by Illawarra Coal in order to more accurately locate these zones and determine the potential impact on future mining. These techniques include: • Advanced analysis of downhole geophysics to determine the location and extent of strata gas horizons. • Specialist interpretation of 2D and 3D seismic to detect gas zones. • Modeling of multiple data-sets to determine controls on gas distribution and composition. • Detailed geological and chemical analysis of the oil-bearing horizons to gain a better understanding of the petroleum system and the controls to its distribution. • Geotechnical studies of the overlying strata to determine the extent and nature of post-mining strata relaxation in comparison with the location of the hydrocarbon zones. The results of these studies have formed the scientific basis for the development of more effective technologies to manage the impact and potential impact of strata oil and gas on the underground extraction of coal