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High-performance TSD bits improve penetration rate
369A more efficient. Design of the ultrasonic device is analysed and reasons why oversize and undersize particles are not well fractured are discussed.
Drilling See also." 936262
936288 Drilling of deep large boreholes for ultimate storage of waste materials dangerous to the environment in salt (In German) Kolditz, H Gluekauf V129, N2, Feb ]993, P98-104 Disposal of high level radioactive waste in salt deposits is proposed in Germany. Dry drilling of boreholes for waste canister emplacement is envisaged. The development and testing of a drill rig capable of dry drilling 600mm diameter boreholes for this purpose is described.
936289 Double-headed equipment for drilling boreholes in caved debris On German) Wallussek, H; Vorhoff, W G~ckauf V129, N5, May 1993, P346-351 A double-headed drill bit, with an inner circular and an outer annular component, has been developed for use in unstable rock or caved waste. Boreholes up to 83m long have been drilled by the bit, with penetration rates of 0.5-0.7m/min. Tests at a waste dump have shown that a high pressure, high volume pump is necessary for adequate discharge of cuttings.
936290 Positioning of charges and quality of the blasted debris (In French) Heraud, H; Roy, Y P; BoiUat, P; Puntous, R Mines Carrieres V75, N2, Feb 1993, P26-29 Accuracy of drilling operations has a very significant influence on the performance of a blasting operation. Mapping of the real geometry and topography of the face is important and can be achieved with relative ease using laser-based EDM instruments. Drillholes must be located and oriented as planned. Several inclinometric and ultrasonic instruments are available to measure borehole alignment and borehole cameras can be used to monitor in-hole conditions. The consequences of deviation from planned layout are described.
936291 High-performance TSD bits improve penetration rate Cohen, J H; Maurer, W C; Westcott, P A Oil Gas J V91, N15, April 1993, P47-51 Laboratory tests to optimise the number, size, and orientation of cutters on thermally stable diamond (TSD) drill bits are described. 6 TSD bits, 2 roller cone bits, and a PDC bit were compared against rocks including granite, limestone, marble, and shale. Specific energies required to remove rock were examined. Effects of cutter orientation, cutter density, differential pressure, and rotational speed were examined. Optimum conditions for use of TSD bits are discussed.
936292 Multiphase hydrodynamic analysis of pneumatic transportation of drill cuttings in air drilling Adewumi, M A; Tian, S Powder Technol V75, N2, May 1993, P133-144 Air drilling has many applications in hydrocarbon extraction technologies. A wellbore hydrodynamics model is developed and used to analyse certain factors affecting air drilling operations, including cuttings size and size distribution, hole size change, attrition, and particle shape. A clear explanation of the clogging phenomenon is possible using results of the modelling. Areas requiring further work are defined.
936293 Automation of hard rock drilling machines Tuunanen, A Tunn Tunnlg V25, N5, May 1993, P51-52 Notable improvements in productivity of percussive hard rock drilling have been achieved through automation in the past decade. The basis of reduction in errors in collaring, alignment, deviation, hole depth, and hole diameter/cross section is briefly outlined. Future systems will show greater automation and greater integration into the overall mine planning and control system.
Crushing and grinding See also: 936103
936294 Effect of the adsorption of polymeric additives on the wet grinding of minerals. 2. Dispersion and fine grinding of concentrated solutions Velamakanni, B V; Fuerstenau, D W Powder Teehnol V75, N1, April 1993, Pl1-19 Success in ore beneficiation depends on liberating valuable minerals from the gangue. In wet grinding, the rheology of the slurry influences dynamics of the grinding mechanism within the mill and can affect grinding rate. The use of carboxylic polyelectrolyte additives to control slurry viscosity has been examined for grinding of hematite, dolomite, and quartz. The behaviour is seen to be system-specific, and certain conditions must be met before any benefit is gained.
936295 Effect of intensive grinding on the crystal structure of dolomite Kristof, E; Juhasz, A Z Powder Technol V75, N2, May 1993. P145-152 Mechanochemical changes during mechanical activation of solids can have significant effects on geological or geochemical phenomena. Dolomite and its constituent minerals have been subjected to grinding experiments of duration 5 minutes to l0 hours in a planetary mill. Structural changes resulting were examined using infrared spectroscopy, X ray diffraction, thermal analysis, and measurement of specific surface area and heats of solution. Only dolomite underwent considerable structural deformation, a 'loose' crystal structure developing due to the distortion of 'magnesite-type' lattice planes.
© 1993 Pergamon Press Ltd. Reproduction not permitted
Drilling See also." 936262
936288 Drilling of deep large boreholes for ultimate storage of waste materials dangerous to the environment in salt (In German) Kolditz, H Gluekauf V129, N2, Feb ]993, P98-104 Disposal of high level radioactive waste in salt deposits is proposed in Germany. Dry drilling of boreholes for waste canister emplacement is envisaged. The development and testing of a drill rig capable of dry drilling 600mm diameter boreholes for this purpose is described.
936289 Double-headed equipment for drilling boreholes in caved debris On German) Wallussek, H; Vorhoff, W G~ckauf V129, N5, May 1993, P346-351 A double-headed drill bit, with an inner circular and an outer annular component, has been developed for use in unstable rock or caved waste. Boreholes up to 83m long have been drilled by the bit, with penetration rates of 0.5-0.7m/min. Tests at a waste dump have shown that a high pressure, high volume pump is necessary for adequate discharge of cuttings.
936290 Positioning of charges and quality of the blasted debris (In French) Heraud, H; Roy, Y P; BoiUat, P; Puntous, R Mines Carrieres V75, N2, Feb 1993, P26-29 Accuracy of drilling operations has a very significant influence on the performance of a blasting operation. Mapping of the real geometry and topography of the face is important and can be achieved with relative ease using laser-based EDM instruments. Drillholes must be located and oriented as planned. Several inclinometric and ultrasonic instruments are available to measure borehole alignment and borehole cameras can be used to monitor in-hole conditions. The consequences of deviation from planned layout are described.
936291 High-performance TSD bits improve penetration rate Cohen, J H; Maurer, W C; Westcott, P A Oil Gas J V91, N15, April 1993, P47-51 Laboratory tests to optimise the number, size, and orientation of cutters on thermally stable diamond (TSD) drill bits are described. 6 TSD bits, 2 roller cone bits, and a PDC bit were compared against rocks including granite, limestone, marble, and shale. Specific energies required to remove rock were examined. Effects of cutter orientation, cutter density, differential pressure, and rotational speed were examined. Optimum conditions for use of TSD bits are discussed.
936292 Multiphase hydrodynamic analysis of pneumatic transportation of drill cuttings in air drilling Adewumi, M A; Tian, S Powder Technol V75, N2, May 1993, P133-144 Air drilling has many applications in hydrocarbon extraction technologies. A wellbore hydrodynamics model is developed and used to analyse certain factors affecting air drilling operations, including cuttings size and size distribution, hole size change, attrition, and particle shape. A clear explanation of the clogging phenomenon is possible using results of the modelling. Areas requiring further work are defined.
936293 Automation of hard rock drilling machines Tuunanen, A Tunn Tunnlg V25, N5, May 1993, P51-52 Notable improvements in productivity of percussive hard rock drilling have been achieved through automation in the past decade. The basis of reduction in errors in collaring, alignment, deviation, hole depth, and hole diameter/cross section is briefly outlined. Future systems will show greater automation and greater integration into the overall mine planning and control system.
Crushing and grinding See also: 936103
936294 Effect of the adsorption of polymeric additives on the wet grinding of minerals. 2. Dispersion and fine grinding of concentrated solutions Velamakanni, B V; Fuerstenau, D W Powder Teehnol V75, N1, April 1993, Pl1-19 Success in ore beneficiation depends on liberating valuable minerals from the gangue. In wet grinding, the rheology of the slurry influences dynamics of the grinding mechanism within the mill and can affect grinding rate. The use of carboxylic polyelectrolyte additives to control slurry viscosity has been examined for grinding of hematite, dolomite, and quartz. The behaviour is seen to be system-specific, and certain conditions must be met before any benefit is gained.
936295 Effect of intensive grinding on the crystal structure of dolomite Kristof, E; Juhasz, A Z Powder Technol V75, N2, May 1993. P145-152 Mechanochemical changes during mechanical activation of solids can have significant effects on geological or geochemical phenomena. Dolomite and its constituent minerals have been subjected to grinding experiments of duration 5 minutes to l0 hours in a planetary mill. Structural changes resulting were examined using infrared spectroscopy, X ray diffraction, thermal analysis, and measurement of specific surface area and heats of solution. Only dolomite underwent considerable structural deformation, a 'loose' crystal structure developing due to the distortion of 'magnesite-type' lattice planes.
© 1993 Pergamon Press Ltd. Reproduction not permitted