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Breakage properties of some materials in a laboratory ball mill
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rotation speed and low percussive power) which can be used for soft soils amd m e d i ~ hard rocks a r e ou~li~ed. L o r ~ r h o l e d e p t h s a~d b e t t e r bc~ehole stability can be achieved.
is used, an airgap of 3-4m is needed to cause detonation failure. With a water content of 3.~ per cent detonation failure occurs for an alrgap of l-l.Sm. Auth.
Blasting
Avail: The Four~ation, Box 32058, S-126 ii, Stockholm, Sweden
822243 BLASTING VIBRATION AND S T R U ~ DAMAGE Sen~ G S Civ EDging, Lordon, Sept 1981, IWI,2-I~6 Explains the l~nclples of damage caUsed by exploalve charges detonated w a r buildi~s. Facters i ~ l u e n c i ~ blast vibrations i~clude dip of the rock, rock type and fault planes.
8222~II. OPEN-PIT AND U~DE~ROb~D SLASTING TECHNIQUES Min
Eng,, VS3, NS, Aug 1981, PI215-1ZI 9
The geology of the material to be blasted is seen as ~ in determining blastl~g requirements. Rock fracture planes should also be considered when determi~img blast l~tterns a~i the rock fracturimg mechanism due to the explosives is described.
8222~ TRUE IN-SI~'J FRaCtUrING EXPERIMENT - FINAL RESULTS Parrish, R L; Stevens, A L; Turner, T F J Pet Technol, V33, NT, July 1981, P12~tT-l~3~ Describes an In-sltu oil shale r e t ~ t bed preparation experiment. An explosive slurry was displaced from wellbc~es into preformed horizontal h~ulic fractures ard then detonated. Results showed that fractnxri~ of the shale was induced by d e t o n a t i o n ~ was distributed randomly. Dislocation of t h e s h a l e was foumd not to be sufficient to increase porosity ard permeability. 8222~6 V ~ I C A L RETREAT MINING Scott, J D Proc 5th Rapid Excavation add Tunneling Conf~ence, San Francisco, 3-7 May 1981, V2, PII0~I125. Publ New York: AIME, 1981 Gives the Livi~ston strain energy eq~tion used in spherical charge blasting and outlines the field data required for its use in full scale operation. Explosives used ard their characteristics are given. Application of the technique is illustrated with brief case studies, at the Coleman, Levack, and McCreedy West mines. These applications include Primary Stops Minir~, Secondary M i n i ~ Against Fill, Mi~ing a Faulted Ore Zone ar~ Drop Raise Blasting. 822247 MEASUREMEN~ OF DETONATION STABILITY AND GAP TESTS FOR ANFO (IN SWINISH) Niklasson, B; Norberg, L Swedish Detonic Research Foundation report DS 1981 :ll, 1981, 24P This report reviews a field test at the I/gAB-mine in Malmberget where detonation stability amd gap test were measured in ANFO-loaded bcreholes with a diameter af 57ram. The motive behind the test was to find out if interru~tlon in the powerstrlng will cause detonation failure anl thereby increase the ,--~er of bootlegs or even misfired rou~s, when s e v e r a l r o u n d s a r e l o a d e d i n a d v a n c e . T e s t s
with various water contents in the explosive were made. The result inlicates, that when dry ANFO
Crushing and grinding 8222~8 BREAKAGE PROPERTIES OF SOME MATERIALS IN A LABCRAT(~Y BAIl MILL Austin, L G; Bagga, P; Celik, M Powder Technol, V28, 1981, P235-241 Crystalline quartz, ailicon carbide, 3 coals of different rank and a cement clir~er were studied in a small laboratory ball mill under s t a r ~ comditions. The first-order specific rates of ~reAIcA~e aIEl the c~m~tlative l~imary dau@hter fragment distributions were determined. Wet grinding was foumd to be faster than dry grindimg but the shape of the size distributions was the same. Two coals showed a slowing down of breakage rate at fins, dry grinds: anthracite showed an acceleration of grir~tim6 rate. The results of grl:~iing tests were fitted to the Pseudo-Kick, Pse~o-Rittinger and Bond's l~s. Bore's law was f o u ~ to provide the best fit.
8zs21~9 EREAKAGE
PARA~S OF SOME MATERIALS IN ROLL CRUSHERS Austin, L G; Van Orden, D; McWilliems, B Powder Technol, V28, 1981, P245-251
A model has been developed to describe the size distributions produced by fracture of material in a smooth roll crusher. The model aseu~s that each size breaks indeperdently of other sizes, that the breakage pattern depends on the relative size of particle to gap, and that the overall breakage pattern can be deduced from repeated fracture with a nc~nalised primary breakage distribution and by-pass of sizes through the gap without breakage. The descriptive perameters of primary breakage distribution and by-pass are given for 2 rocks (a rhyolite and a diabase) and
8 coals.
8z225o CRUSHING
CHARACTERISTICS Krogh, S R Powder Technol, V27, 1981, P171-181
Drop tests (impact tests) were carried out on several materials: quartz, anorthosite I dolo~te, quartzite, calcite ar~ Jasper, to determine their major ccmwinution functions. A crushimg body was dropped onto individual particles of the material from a certain height. The crushing probability function is defined as the strength distribution uf particles of a given size, the emergy function as the stretch of particles as a function of their size, amd the breakage function as the size distribution of the crushe~ material. Results are presented for the tests a~d each fur~ion is defined mthematically. The probability function is found to be i~dependent of particle size, ar~ the b r e a ~ e function to depe:~ on the material's crystal structure ar~ bor~Ing.
rotation speed and low percussive power) which can be used for soft soils amd m e d i ~ hard rocks a r e ou~li~ed. L o r ~ r h o l e d e p t h s a~d b e t t e r bc~ehole stability can be achieved.
is used, an airgap of 3-4m is needed to cause detonation failure. With a water content of 3.~ per cent detonation failure occurs for an alrgap of l-l.Sm. Auth.
Blasting
Avail: The Four~ation, Box 32058, S-126 ii, Stockholm, Sweden
822243 BLASTING VIBRATION AND S T R U ~ DAMAGE Sen~ G S Civ EDging, Lordon, Sept 1981, IWI,2-I~6 Explains the l~nclples of damage caUsed by exploalve charges detonated w a r buildi~s. Facters i ~ l u e n c i ~ blast vibrations i~clude dip of the rock, rock type and fault planes.
8222~II. OPEN-PIT AND U~DE~ROb~D SLASTING TECHNIQUES Min
Eng,, VS3, NS, Aug 1981, PI215-1ZI 9
The geology of the material to be blasted is seen as ~ in determining blastl~g requirements. Rock fracture planes should also be considered when determi~img blast l~tterns a~i the rock fracturimg mechanism due to the explosives is described.
8222~ TRUE IN-SI~'J FRaCtUrING EXPERIMENT - FINAL RESULTS Parrish, R L; Stevens, A L; Turner, T F J Pet Technol, V33, NT, July 1981, P12~tT-l~3~ Describes an In-sltu oil shale r e t ~ t bed preparation experiment. An explosive slurry was displaced from wellbc~es into preformed horizontal h~ulic fractures ard then detonated. Results showed that fractnxri~ of the shale was induced by d e t o n a t i o n ~ was distributed randomly. Dislocation of t h e s h a l e was foumd not to be sufficient to increase porosity ard permeability. 8222~6 V ~ I C A L RETREAT MINING Scott, J D Proc 5th Rapid Excavation add Tunneling Conf~ence, San Francisco, 3-7 May 1981, V2, PII0~I125. Publ New York: AIME, 1981 Gives the Livi~ston strain energy eq~tion used in spherical charge blasting and outlines the field data required for its use in full scale operation. Explosives used ard their characteristics are given. Application of the technique is illustrated with brief case studies, at the Coleman, Levack, and McCreedy West mines. These applications include Primary Stops Minir~, Secondary M i n i ~ Against Fill, Mi~ing a Faulted Ore Zone ar~ Drop Raise Blasting. 822247 MEASUREMEN~ OF DETONATION STABILITY AND GAP TESTS FOR ANFO (IN SWINISH) Niklasson, B; Norberg, L Swedish Detonic Research Foundation report DS 1981 :ll, 1981, 24P This report reviews a field test at the I/gAB-mine in Malmberget where detonation stability amd gap test were measured in ANFO-loaded bcreholes with a diameter af 57ram. The motive behind the test was to find out if interru~tlon in the powerstrlng will cause detonation failure anl thereby increase the ,--~er of bootlegs or even misfired rou~s, when s e v e r a l r o u n d s a r e l o a d e d i n a d v a n c e . T e s t s
with various water contents in the explosive were made. The result inlicates, that when dry ANFO
Crushing and grinding 8222~8 BREAKAGE PROPERTIES OF SOME MATERIALS IN A LABCRAT(~Y BAIl MILL Austin, L G; Bagga, P; Celik, M Powder Technol, V28, 1981, P235-241 Crystalline quartz, ailicon carbide, 3 coals of different rank and a cement clir~er were studied in a small laboratory ball mill under s t a r ~ comditions. The first-order specific rates of ~reAIcA~e aIEl the c~m~tlative l~imary dau@hter fragment distributions were determined. Wet grinding was foumd to be faster than dry grindimg but the shape of the size distributions was the same. Two coals showed a slowing down of breakage rate at fins, dry grinds: anthracite showed an acceleration of grir~tim6 rate. The results of grl:~iing tests were fitted to the Pseudo-Kick, Pse~o-Rittinger and Bond's l~s. Bore's law was f o u ~ to provide the best fit.
8zs21~9 EREAKAGE
PARA~S OF SOME MATERIALS IN ROLL CRUSHERS Austin, L G; Van Orden, D; McWilliems, B Powder Technol, V28, 1981, P245-251
A model has been developed to describe the size distributions produced by fracture of material in a smooth roll crusher. The model aseu~s that each size breaks indeperdently of other sizes, that the breakage pattern depends on the relative size of particle to gap, and that the overall breakage pattern can be deduced from repeated fracture with a nc~nalised primary breakage distribution and by-pass of sizes through the gap without breakage. The descriptive perameters of primary breakage distribution and by-pass are given for 2 rocks (a rhyolite and a diabase) and
8 coals.
8z225o CRUSHING
CHARACTERISTICS Krogh, S R Powder Technol, V27, 1981, P171-181
Drop tests (impact tests) were carried out on several materials: quartz, anorthosite I dolo~te, quartzite, calcite ar~ Jasper, to determine their major ccmwinution functions. A crushimg body was dropped onto individual particles of the material from a certain height. The crushing probability function is defined as the strength distribution uf particles of a given size, the emergy function as the stretch of particles as a function of their size, amd the breakage function as the size distribution of the crushe~ material. Results are presented for the tests a~d each fur~ion is defined mthematically. The probability function is found to be i~dependent of particle size, ar~ the b r e a ~ e function to depe:~ on the material's crystal structure ar~ bor~Ing.