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Aspects of rock pre-splitting
99A used in the d-'st,,n o( "he ext~enment~. Result~ determine that ~-"- subjected to ele,,ated temperatures are m~crofractured and dri!l more slov~l.x than do intact rocks. Hov, e,.er, the magnitude of the tempera:.ure has ,':.o significant effect on drtlling penetramm rates. Microcracks induced b> differenual thermal expansion o ( m m e r a l grains in rocks subjected to cie,,ated temperatures decrease drillability, as do macrocracks alread.,, present and or induced b.~ temperature-gradient thermal stresses Change in the compressi'.c ~a,,e ~docity. Brazil'.an tensile s~rength, and uniaxml compression strength of the rock. due to exposure to ele~ ated temperature, shov, ed no direct correlation with the change in penetranon rates. Auth...I.-{ refs.
wi',l increase ~,th t'cv,er. larger buttons on the bit for granite or sandstone, whereas for marble a greater number o( smaller buttons is desirable.
863171 Unique aspects of drilling and completing hot. dr,, rock geothermal wells Carden. R S; Nicholson. R W; Pe:titt. R A; Ro~le:.. J ( J Pet Engng [37..VS..~la~ I9,~'5. P.~'21-R34
Smoother and sat'er high~alls have been obtained at a ~,kest Virginia contour coal mine. where the I..S Bureau ot Mines conducted a series of delayed blasting experiments that ha,,e reduced o,.erbreak and the likelihood of rockfall. Dcscrlptior', o( achie',ing this reduced overbre:tk, by increasing the highwall hole delay' intervals so as to change the et'fecu'.c de!ay pattern geometry and the direction of burden mo,,ernent. ~s presented. The three test designs yielded highv, a!l impro'.ements over the nominal design with only occasionai exceptions because of geologic variations. To evaluate the re-,u',ts of blasting. terrestrial photogrammetry ,,,,as used to generate '.ertical profiles at regular intervals.
It ts concluded that deep directional drilling and completion operations can be accomplished ira ,.cry hot crystalline rt.)~",~ v, ith rnodifica'ions of presently axailable eqmpment and materials, and ~hat man',, improvements are needed m cost effecti'.eness and technical etIicienc,, of drilling and completion hardware. Fracturing operations ~ere conducted at Fenton Hill in November 1982. Massive ~olumes of fluid at high pressure had to be pumped to connect the tv, o wellbores; ~ork string operations ~ere difficult because of high drag in the holes; extreme changes in temperature of the fracturing string were hard to handle; corrosi,,e gases caused short-term equipment failure. Successful cemcntmg operations ~ere conducted under the most adxerse conditions with meticulous design. planning, and co-ordmatior: 863172 Effects of I~)re pressure and mud filtration on drilling rates in a permeable sandstone Black. A D; Dearing. H [.: DiBona. B G J Pet Technol l ' y . . V / t ) . Sept 19,Y5. P1671-16,~1 Dunng laboratory drilling tests in a permeable sandstone, changes in penetration rate ~ith bit ~eight and pressure drop across the filter cake ~ere examined. The relationship between penetration rate and filtration rate ~as determined. An attempt to correlate the drilling test results with standard API filtration properties was also made.
863173 Large diameter mine shaft construction using a rodless boring machine Raine, A G Alin Technol 1 6 - . . \ 7 " 5 . 31,zv lv,~5. P151-154 Four methods of drilling. \'-mole application, ra'se drilling. blind shaft drilling v, ith drill string and blind shaft drilling v, ith V-mole are described, each having its o,.vn relatixe merits and some disad;antages. The main ad,,antage of all is the standard and security of the excavation.
863 ! 74 Some stamp test results for Lemunda sandstone, Ekeberg marble and Bohus granite
wijk, G Swedish Detonic Re.vearch Foundation report DS 19X4 9. 2S:II De{ /984. I / P In the stamp test. a flat ended carbide button is pressed again.,t a &amond saxon fiat rock surt,tce until fracture occurs. Fracture force and resultant crater dimensions are measured. Tests with ['our stamp radii ha,.e been carried out on three different rocks. Results indicate that. with button hits. drilling c(ficienc> ,
.4vail: The Foundation. Box 32058. S-126 II Stockholm. S~ eden
Blasting 863175 Longer dela) periods reduce rockfall hazard at contour mine Stachura. V J; Fletcher, L R Coal .Ilin V22. \'5. May 19,7'5, P32-36
863176 Aspects of rock pre-splitting Redpath. J Highways Transp 1:32. N12. Dec 19S5. PI5-I,¥ Presplitting ~as used to excavate rocks ,x-10m irt height and 300m long for the A82 trunk road in Scotland The predon:inant rock v, as quartz mica schist with an outcrop of fclsttc The site preparation, setting out. charging and resalts of this case stud..` are presented v, ith particular ret'crencc "o selection of drilling equipment and its correct use.
863177 Application of short-delay electric blasting in an up-dip stope Ozbay, M U l S ,4fr Inst Alin .~letall ~,~5. N7, ,luh 19X5. P2¢H-207 A series ot blasting experiments was carried out in an up-dip stope of a gold mine using short-period-delay elec:ric detonators. The main object of the investigation ,,,,as to sho,a the interactive effects of short-delay blasting. To quantify the blast results, data v, as collected on fragmentation, thro~, position of muckpile, and ground vibration. For comparative purposes. blasting parameters for conventional pyrotechnic sequential firing were also measured. The most relevant parts of the stud~ and the experimental results are described. The interacn~e effects of short-delay blasting are analysed, and some aspect.-, of the breaking mechanism are discussed.
863178 Seismic spectroscopy in fracture characterization Young. R P: Hill. J J: Bryan, I R: Middleton. R Q d gngng Geol ['18, .V4, 1985, P459--U'9 To define efficient blasting systems for open cast mining. microprocessor based instrumentation has been de~eloped to monitor rock, blast, exca~,ation and environmental factors Results indicate that fragmentation efficiency can be quantified in terms of seismic attenuation spectra and polar a n i s o f rop~ diagrams. Three dimensional spectra and polar plots are correlated ~ith three dimensional exca,,ation efficienc~ profiles, blast and ground vibration data in the optimis~,tion study. A case stud,,.' demonstrates the scope o( the data acquired and the multivariate statistical analys~s methods used.
1986 Pergamon Press Ltd. Reproduction not permitted
wi',l increase ~,th t'cv,er. larger buttons on the bit for granite or sandstone, whereas for marble a greater number o( smaller buttons is desirable.
863171 Unique aspects of drilling and completing hot. dr,, rock geothermal wells Carden. R S; Nicholson. R W; Pe:titt. R A; Ro~le:.. J ( J Pet Engng [37..VS..~la~ I9,~'5. P.~'21-R34
Smoother and sat'er high~alls have been obtained at a ~,kest Virginia contour coal mine. where the I..S Bureau ot Mines conducted a series of delayed blasting experiments that ha,,e reduced o,.erbreak and the likelihood of rockfall. Dcscrlptior', o( achie',ing this reduced overbre:tk, by increasing the highwall hole delay' intervals so as to change the et'fecu'.c de!ay pattern geometry and the direction of burden mo,,ernent. ~s presented. The three test designs yielded highv, a!l impro'.ements over the nominal design with only occasionai exceptions because of geologic variations. To evaluate the re-,u',ts of blasting. terrestrial photogrammetry ,,,,as used to generate '.ertical profiles at regular intervals.
It ts concluded that deep directional drilling and completion operations can be accomplished ira ,.cry hot crystalline rt.)~",~ v, ith rnodifica'ions of presently axailable eqmpment and materials, and ~hat man',, improvements are needed m cost effecti'.eness and technical etIicienc,, of drilling and completion hardware. Fracturing operations ~ere conducted at Fenton Hill in November 1982. Massive ~olumes of fluid at high pressure had to be pumped to connect the tv, o wellbores; ~ork string operations ~ere difficult because of high drag in the holes; extreme changes in temperature of the fracturing string were hard to handle; corrosi,,e gases caused short-term equipment failure. Successful cemcntmg operations ~ere conducted under the most adxerse conditions with meticulous design. planning, and co-ordmatior: 863172 Effects of I~)re pressure and mud filtration on drilling rates in a permeable sandstone Black. A D; Dearing. H [.: DiBona. B G J Pet Technol l ' y . . V / t ) . Sept 19,Y5. P1671-16,~1 Dunng laboratory drilling tests in a permeable sandstone, changes in penetration rate ~ith bit ~eight and pressure drop across the filter cake ~ere examined. The relationship between penetration rate and filtration rate ~as determined. An attempt to correlate the drilling test results with standard API filtration properties was also made.
863173 Large diameter mine shaft construction using a rodless boring machine Raine, A G Alin Technol 1 6 - . . \ 7 " 5 . 31,zv lv,~5. P151-154 Four methods of drilling. \'-mole application, ra'se drilling. blind shaft drilling v, ith drill string and blind shaft drilling v, ith V-mole are described, each having its o,.vn relatixe merits and some disad;antages. The main ad,,antage of all is the standard and security of the excavation.
863 ! 74 Some stamp test results for Lemunda sandstone, Ekeberg marble and Bohus granite
wijk, G Swedish Detonic Re.vearch Foundation report DS 19X4 9. 2S:II De{ /984. I / P In the stamp test. a flat ended carbide button is pressed again.,t a &amond saxon fiat rock surt,tce until fracture occurs. Fracture force and resultant crater dimensions are measured. Tests with ['our stamp radii ha,.e been carried out on three different rocks. Results indicate that. with button hits. drilling c(ficienc> ,
.4vail: The Foundation. Box 32058. S-126 II Stockholm. S~ eden
Blasting 863175 Longer dela) periods reduce rockfall hazard at contour mine Stachura. V J; Fletcher, L R Coal .Ilin V22. \'5. May 19,7'5, P32-36
863176 Aspects of rock pre-splitting Redpath. J Highways Transp 1:32. N12. Dec 19S5. PI5-I,¥ Presplitting ~as used to excavate rocks ,x-10m irt height and 300m long for the A82 trunk road in Scotland The predon:inant rock v, as quartz mica schist with an outcrop of fclsttc The site preparation, setting out. charging and resalts of this case stud..` are presented v, ith particular ret'crencc "o selection of drilling equipment and its correct use.
863177 Application of short-delay electric blasting in an up-dip stope Ozbay, M U l S ,4fr Inst Alin .~letall ~,~5. N7, ,luh 19X5. P2¢H-207 A series ot blasting experiments was carried out in an up-dip stope of a gold mine using short-period-delay elec:ric detonators. The main object of the investigation ,,,,as to sho,a the interactive effects of short-delay blasting. To quantify the blast results, data v, as collected on fragmentation, thro~, position of muckpile, and ground vibration. For comparative purposes. blasting parameters for conventional pyrotechnic sequential firing were also measured. The most relevant parts of the stud~ and the experimental results are described. The interacn~e effects of short-delay blasting are analysed, and some aspect.-, of the breaking mechanism are discussed.
863178 Seismic spectroscopy in fracture characterization Young. R P: Hill. J J: Bryan, I R: Middleton. R Q d gngng Geol ['18, .V4, 1985, P459--U'9 To define efficient blasting systems for open cast mining. microprocessor based instrumentation has been de~eloped to monitor rock, blast, exca~,ation and environmental factors Results indicate that fragmentation efficiency can be quantified in terms of seismic attenuation spectra and polar a n i s o f rop~ diagrams. Three dimensional spectra and polar plots are correlated ~ith three dimensional exca,,ation efficienc~ profiles, blast and ground vibration data in the optimis~,tion study. A case stud,,.' demonstrates the scope o( the data acquired and the multivariate statistical analys~s methods used.
1986 Pergamon Press Ltd. Reproduction not permitted