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Second generation explosive emulsions
.308A 925271 Ocean Drilling Program - an overview Rabinowitz, P D; Harding. B W; Francis, T J G
925275 Investigation of heave and fragmentation related to explosive
Sci Drilling ~L~, N5. 1991. P261-269
Kristiansen, J; Kure, K: Vestre, J; Bergqvist, 1 Proc 3rd International Symposium on Rock Fragmentation by Blasting, Brisbane, 26-31 August 1990 P83-90. Publ Parkville: AusI,~[M, 1990
The purposes, scope, and participants of the ODP are outlined. The holes drilled to date, metres cored and core recovery, deepest penetration, and maximum water depth are reported. The shipboard and seabed hardware necessary to drill and core under these extreme conditions is illustrated.
925272 Environmentally safe water-bnsed alternative to oil muds Enright, D P; Dye, W M: Smith, F M
SPE Drilling Engng V7. N1. March 1992, P15-19 Need to minimise environmental pollution has placed restrictions on use of some oil based muds in the drilling industry. Water based fluids have achieved varying degrees of success to date. The interactions of the aqueous phase with the bit, drill assembly, and formation are the overriding parameters. Bit bailing is a common manifestation of fluid-formation interaction. Shale/water, bit/water, and shale/water/bit interactions are examined and a mechanism to describe the onset of bit bailing is developed. On the basis of this, a new copolymer/polypropylene glycol (COP/PPG) water-based mud is formulated. Properties are described and its field performance evaluated.
925273 Field application of the All-Oil drilling-fluid concept Fraser, S J SPE Drilling Engng V7. NI. March 1992, P20-24 Oil based muds have been used since the earliest days of rotary drilling but the all-oil concept suffered from problems of cost, flammability, intolerance to water, and, above all, difficulty in providing sound rheologic and filtration control without an emulsified aqueous base. A new oil-based fluid with low solids content has been developed recently. Viscosity can be routinely adjusted, it provides efficient hole cleaning, good suspension of weight material and bit solids, and can accommodate influxes of water-wet solids or free water. Its use with minimal formation damage at several sites is discussed.
Blasting See also: 925191, 925246, 925442
925274 Practical blast optimization and performance assessment Vassie, B; Bonneau, M
Quarry Manage March 1992, P21-27 The basics of blast theory as relevant to bench and crater blasting in quarries are outlined. Blast monitoring techniques are examined, in particular the use of high speed photography for qualitative and quantitative examination of blast performance. Computer based systems capable of very high rates of data capture may become of increasing importance. Velocity of detonation measurement and its importance to optimisation of blast design are discussed. Finally, the range of explosives of general use in quarrying and their particular attributes are described.
properties
Practical laboratory tests for comparison of explosives use materials with different properties from rock. Neither these nor theoretical estimations indicate possible heave or fragmentation. To overcome this, model tests were carried out using 0.5m cubes of concrete and rock containing 78gm charges of explosives of 22mm diameter. The blocks were fragmented inside a steel cylinder. Velocity of fragments was determined from time of arrival at the steel wall, size distribution by sieving. Explosive properties such as energy, gas, VOD and density were varied and influence on heave and fragmentation studied. Comparisons are made with results of full scale field tests. 925276 Borehole damage effect on stress waves Simha, K R Y
Proc 3rd International Symposium on Rock Fragmentation by Blasting, Brisbane, 26-3I August 1990 P91-92. Publ Parkville: AuslMM, 1990 A new analytical model for blasting design that accounts for effects of borehole damage on patterns of far-field stress waves in terms of compaction around the borehole is advanced. The main departure from previous formulations is in defining a measure for material damage in terms of this compaction. Explosion of a fully coupled spherical charge in an unbounded geological medium is analysed. Compaction is significant in the vicinity of the charge but not at large distances. Compaction explains the borehole expansion observed after a blast, This model explains the reduced frequency and increased damping observed in the field. 925277 Hollow microspheres - reliable sensitizers for water gel and emulsion explosives Smith, C G Proc 3rd International Symposium on Rock Fragmentation by Blasting, Brisbane, 26-31 August 1990 P93-95. Pub/Parkville: AuslMM, 1990 Water gel and emulsion explosives are both difficult to initiate without a sensitiser. Hollow microspheres, generally of glass, are used for this purpose. The choice of microphere grade and amount is dictated by field conditions and blasting practices. The sensitizing properties of microspheres, formulation guidelines, and quality control are discussed, and information provided on packaging, sampling, transferring, metering, mixing and pumping. 925278 Second generation explosive emulsions Wasson, D A; Reddick, D P Proc 3rd International Symposium on Rock Fragmentation by
Blasting, Brisbane, 26-31 August 1990 P97-99. Publ Parkville." AuslMM, 1990 Emulsion explosives have been available for about 10 years. The initial products were of low viscosity, absorbed water, had low shelf life, and were not very suitable for shock tube detonation. To overcome these problems, porous ammonium nitrate prill was added and a more stable emulsion developed.
© 1992 Pergamon Press Ltd. Reproduction not permitted
309A This has resulted in thickening, with improved ease of handling, reduction in detonation velocity, and higher energy. Cap sensitive emulsions for small diameter blasting, and chemically gassed and ¢rosslinked emulsions are now available.
925279 Fragmentation mechanics Persson, P A Proc 3rd International Symposium on Rock Fragmentation by Blasting, Brisbane, 26-31 August 1990 P101-108. Publ Parkville: AuslMM, 1990 Fragmentation of homogeneous materials is first examined, with experimental data from tests in plexiglas illustrated. Effects of rock mass structure are next investigated, including block model analysis. An analysis of ground vibration damage to buildings and remaining rock and of fragmentation is undertaken. Effects of explosives are finally assessed, including explosive strength and volume expansion work, packing density, and reaction kinetics.
925280 Experimental and computational investigation of the fundamental mechanisms of cratering Thorne, B J; Hommert, P J; Brown, B Proc 3rd International Symposium on Rock Fragmentation by Blasting, Brisbane, 26-31 August 1990 P117-124. Publ Parkville: AuslMM, 1990 A damage model to simulate dynamic fracture of brittle rock is under development at Sandia National Laboratory. It includes microcrack growth in tension and allows finite element solutions which remain stable at long times. Calculated fragmentation and crater profiles for granite obtained using the model are illustrated. Good agreement is found with field data.
925281 On the effect of dynamic fracture of rocks on the blasting Yalun, Y Proc 3rd International Symposium on Rock Fragmentation by Blasting, Brisbane, 26-31 August 1990 P125-127. Publ Parkville: AuslMM, 1990 Dynamic fracture properties of limestone, sandstone, and magnetite-quartzite rocks under impulsive loading were examined using a Hopkinson Split Pressure Bar apparatus. The dynamic stress strain curves obtained are compared to those from conventional triaxial tests. The relation between compressive strength and strain rate depends on rock type. This may be related to void content of the rock and its effect on attenuation of shock waves.
925282 Small-charge cone-fracture technique for rapid excavation Young, C; Dick, R D; Fourney, W L Proc 3rd International Symposium on Rock Fragmentation by Blasting, Brisbane, 26-31 August 1990 P129-135. Publ Parkville: AusIMM, 1990 An attempt to develop a pseudo-continuous excavation technique for hard rock is described. It is based on small charge blasting with a decoupled charge held in a shallow borehole by
a massive stemming bar. Detonation results in a penetrating cone fracture. Laboratory development using plexiglas and granite blocks and in-mine experiments are described. A drill rig which can take a mine gun holding the explosive on the end of the stemming bar is illustrated. Propellant charge is preferred to explosive. Blast design and layout are discussed.
925283 Effects induced on the stability of rock slopes by presplitting methods (In French) Heraud, H; Siffre, Y Proc 6th International Congress International Association of Engineering Geology, Amsterdam, 6-10 August 1990 V3, P2199-2203. Publ Rotterdam: A A Balkema, 1990 A comparison is made between the use of high gas energy gel explosives and high shock energy explosives for slope presplitring. Results from full scale field projects and from pilot slopes are discussed. The splitting process is analysed according to dynamic and quasi-static theories and by finite element analysis for an idealised isotropic elastic rock mass. The advantages of the gel explosive are illustrated.
925284 Use of explosives in rocklmrst control techniques Rorke, A J; Brummer, R K Proc 2nd International Symposium on Rockbursts and Seismicity in Mines, Minneapolis, 8-10 June 1988 P377-385. Publ Rotterdam: A A Balkema, 1990 Blasting is a practical method for destressing or preconditioning rock masses in order to control the rockbursts which occur in the vicinity of advancing stope faces. Location of charge relative to the rock mass, blast layout, and partitioning of explosive energy between gas energy and shock energy all influence the destressing. Numerical modelling is used to predict energy partitioning of various explosives under different conditions of confinement. Choice of explosive and blast design are discussed.
Crushing and grinding 925285 Study of 0/2mm sands produced in rotary floor crusher (In French) Blot, G Bull Liaison Lab Ponts Chaussees N176, Nov-Dec 1991, P4356 A study has been made of 0/2mm sands produced from limestone, gabbro, granite, quartzite, and gneiss rocks and alluvial deposits using a rotary floor crusher and a gyrating cone crusher. The quantity of 0/2mm output varies inversely with feed size, but is not influenced by recycling. Only for gabbro was rotary speed related to 0/2mm output. Softer rocks produced more 0/80 micron fines in the rotary floor crusher, for harder rocks this occurred in the cone crusher. The floor crusher produces the more rounded and shorter grains. Brittle rocks give shorter grains with the cone crusher, the converse is true for firmer rocks. Sands from the floor crusher have a markedly lower flow coefficient.
© 1992 Pergamon Press Ltd. Reproduction not permitted RMMS 29/5--I
925275 Investigation of heave and fragmentation related to explosive
Sci Drilling ~L~, N5. 1991. P261-269
Kristiansen, J; Kure, K: Vestre, J; Bergqvist, 1 Proc 3rd International Symposium on Rock Fragmentation by Blasting, Brisbane, 26-31 August 1990 P83-90. Publ Parkville: AusI,~[M, 1990
The purposes, scope, and participants of the ODP are outlined. The holes drilled to date, metres cored and core recovery, deepest penetration, and maximum water depth are reported. The shipboard and seabed hardware necessary to drill and core under these extreme conditions is illustrated.
925272 Environmentally safe water-bnsed alternative to oil muds Enright, D P; Dye, W M: Smith, F M
SPE Drilling Engng V7. N1. March 1992, P15-19 Need to minimise environmental pollution has placed restrictions on use of some oil based muds in the drilling industry. Water based fluids have achieved varying degrees of success to date. The interactions of the aqueous phase with the bit, drill assembly, and formation are the overriding parameters. Bit bailing is a common manifestation of fluid-formation interaction. Shale/water, bit/water, and shale/water/bit interactions are examined and a mechanism to describe the onset of bit bailing is developed. On the basis of this, a new copolymer/polypropylene glycol (COP/PPG) water-based mud is formulated. Properties are described and its field performance evaluated.
925273 Field application of the All-Oil drilling-fluid concept Fraser, S J SPE Drilling Engng V7. NI. March 1992, P20-24 Oil based muds have been used since the earliest days of rotary drilling but the all-oil concept suffered from problems of cost, flammability, intolerance to water, and, above all, difficulty in providing sound rheologic and filtration control without an emulsified aqueous base. A new oil-based fluid with low solids content has been developed recently. Viscosity can be routinely adjusted, it provides efficient hole cleaning, good suspension of weight material and bit solids, and can accommodate influxes of water-wet solids or free water. Its use with minimal formation damage at several sites is discussed.
Blasting See also: 925191, 925246, 925442
925274 Practical blast optimization and performance assessment Vassie, B; Bonneau, M
Quarry Manage March 1992, P21-27 The basics of blast theory as relevant to bench and crater blasting in quarries are outlined. Blast monitoring techniques are examined, in particular the use of high speed photography for qualitative and quantitative examination of blast performance. Computer based systems capable of very high rates of data capture may become of increasing importance. Velocity of detonation measurement and its importance to optimisation of blast design are discussed. Finally, the range of explosives of general use in quarrying and their particular attributes are described.
properties
Practical laboratory tests for comparison of explosives use materials with different properties from rock. Neither these nor theoretical estimations indicate possible heave or fragmentation. To overcome this, model tests were carried out using 0.5m cubes of concrete and rock containing 78gm charges of explosives of 22mm diameter. The blocks were fragmented inside a steel cylinder. Velocity of fragments was determined from time of arrival at the steel wall, size distribution by sieving. Explosive properties such as energy, gas, VOD and density were varied and influence on heave and fragmentation studied. Comparisons are made with results of full scale field tests. 925276 Borehole damage effect on stress waves Simha, K R Y
Proc 3rd International Symposium on Rock Fragmentation by Blasting, Brisbane, 26-3I August 1990 P91-92. Publ Parkville: AuslMM, 1990 A new analytical model for blasting design that accounts for effects of borehole damage on patterns of far-field stress waves in terms of compaction around the borehole is advanced. The main departure from previous formulations is in defining a measure for material damage in terms of this compaction. Explosion of a fully coupled spherical charge in an unbounded geological medium is analysed. Compaction is significant in the vicinity of the charge but not at large distances. Compaction explains the borehole expansion observed after a blast, This model explains the reduced frequency and increased damping observed in the field. 925277 Hollow microspheres - reliable sensitizers for water gel and emulsion explosives Smith, C G Proc 3rd International Symposium on Rock Fragmentation by Blasting, Brisbane, 26-31 August 1990 P93-95. Pub/Parkville: AuslMM, 1990 Water gel and emulsion explosives are both difficult to initiate without a sensitiser. Hollow microspheres, generally of glass, are used for this purpose. The choice of microphere grade and amount is dictated by field conditions and blasting practices. The sensitizing properties of microspheres, formulation guidelines, and quality control are discussed, and information provided on packaging, sampling, transferring, metering, mixing and pumping. 925278 Second generation explosive emulsions Wasson, D A; Reddick, D P Proc 3rd International Symposium on Rock Fragmentation by
Blasting, Brisbane, 26-31 August 1990 P97-99. Publ Parkville." AuslMM, 1990 Emulsion explosives have been available for about 10 years. The initial products were of low viscosity, absorbed water, had low shelf life, and were not very suitable for shock tube detonation. To overcome these problems, porous ammonium nitrate prill was added and a more stable emulsion developed.
© 1992 Pergamon Press Ltd. Reproduction not permitted
309A This has resulted in thickening, with improved ease of handling, reduction in detonation velocity, and higher energy. Cap sensitive emulsions for small diameter blasting, and chemically gassed and ¢rosslinked emulsions are now available.
925279 Fragmentation mechanics Persson, P A Proc 3rd International Symposium on Rock Fragmentation by Blasting, Brisbane, 26-31 August 1990 P101-108. Publ Parkville: AuslMM, 1990 Fragmentation of homogeneous materials is first examined, with experimental data from tests in plexiglas illustrated. Effects of rock mass structure are next investigated, including block model analysis. An analysis of ground vibration damage to buildings and remaining rock and of fragmentation is undertaken. Effects of explosives are finally assessed, including explosive strength and volume expansion work, packing density, and reaction kinetics.
925280 Experimental and computational investigation of the fundamental mechanisms of cratering Thorne, B J; Hommert, P J; Brown, B Proc 3rd International Symposium on Rock Fragmentation by Blasting, Brisbane, 26-31 August 1990 P117-124. Publ Parkville: AuslMM, 1990 A damage model to simulate dynamic fracture of brittle rock is under development at Sandia National Laboratory. It includes microcrack growth in tension and allows finite element solutions which remain stable at long times. Calculated fragmentation and crater profiles for granite obtained using the model are illustrated. Good agreement is found with field data.
925281 On the effect of dynamic fracture of rocks on the blasting Yalun, Y Proc 3rd International Symposium on Rock Fragmentation by Blasting, Brisbane, 26-31 August 1990 P125-127. Publ Parkville: AuslMM, 1990 Dynamic fracture properties of limestone, sandstone, and magnetite-quartzite rocks under impulsive loading were examined using a Hopkinson Split Pressure Bar apparatus. The dynamic stress strain curves obtained are compared to those from conventional triaxial tests. The relation between compressive strength and strain rate depends on rock type. This may be related to void content of the rock and its effect on attenuation of shock waves.
925282 Small-charge cone-fracture technique for rapid excavation Young, C; Dick, R D; Fourney, W L Proc 3rd International Symposium on Rock Fragmentation by Blasting, Brisbane, 26-31 August 1990 P129-135. Publ Parkville: AusIMM, 1990 An attempt to develop a pseudo-continuous excavation technique for hard rock is described. It is based on small charge blasting with a decoupled charge held in a shallow borehole by
a massive stemming bar. Detonation results in a penetrating cone fracture. Laboratory development using plexiglas and granite blocks and in-mine experiments are described. A drill rig which can take a mine gun holding the explosive on the end of the stemming bar is illustrated. Propellant charge is preferred to explosive. Blast design and layout are discussed.
925283 Effects induced on the stability of rock slopes by presplitting methods (In French) Heraud, H; Siffre, Y Proc 6th International Congress International Association of Engineering Geology, Amsterdam, 6-10 August 1990 V3, P2199-2203. Publ Rotterdam: A A Balkema, 1990 A comparison is made between the use of high gas energy gel explosives and high shock energy explosives for slope presplitring. Results from full scale field projects and from pilot slopes are discussed. The splitting process is analysed according to dynamic and quasi-static theories and by finite element analysis for an idealised isotropic elastic rock mass. The advantages of the gel explosive are illustrated.
925284 Use of explosives in rocklmrst control techniques Rorke, A J; Brummer, R K Proc 2nd International Symposium on Rockbursts and Seismicity in Mines, Minneapolis, 8-10 June 1988 P377-385. Publ Rotterdam: A A Balkema, 1990 Blasting is a practical method for destressing or preconditioning rock masses in order to control the rockbursts which occur in the vicinity of advancing stope faces. Location of charge relative to the rock mass, blast layout, and partitioning of explosive energy between gas energy and shock energy all influence the destressing. Numerical modelling is used to predict energy partitioning of various explosives under different conditions of confinement. Choice of explosive and blast design are discussed.
Crushing and grinding 925285 Study of 0/2mm sands produced in rotary floor crusher (In French) Blot, G Bull Liaison Lab Ponts Chaussees N176, Nov-Dec 1991, P4356 A study has been made of 0/2mm sands produced from limestone, gabbro, granite, quartzite, and gneiss rocks and alluvial deposits using a rotary floor crusher and a gyrating cone crusher. The quantity of 0/2mm output varies inversely with feed size, but is not influenced by recycling. Only for gabbro was rotary speed related to 0/2mm output. Softer rocks produced more 0/80 micron fines in the rotary floor crusher, for harder rocks this occurred in the cone crusher. The floor crusher produces the more rounded and shorter grains. Brittle rocks give shorter grains with the cone crusher, the converse is true for firmer rocks. Sands from the floor crusher have a markedly lower flow coefficient.
© 1992 Pergamon Press Ltd. Reproduction not permitted RMMS 29/5--I