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Explosives are energy and the efficient use of this energy is a major factor in keeping rock blasting costs under control High energy explosives enhance fragmentation which ultimately produces a positive effect on production costs The degree of fragmentation or movement obtained is directly related to the amount of operation This relationship is illustrated in Figure 8 7 117 explosive
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presplitting rock slopes for highways trid presplitting rock slopes for highways the presplitting method of producing a plane of split rock along the face of the slope prior to any primary drilling or blasting is described this sheared area from hole to hole along slope line may be formed for the entire …
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Blasting practices in the alborz tunnel As the characteristics of contour holes have a great influence on the results of blasting with respect to overbreak and underbreak the presplitting and smooth blasting methods of controlled blasting were
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In the blast design of rock wells or tunnels presplit and smooth blasting both need to drill a circle of small spacing boreholes along the designed contour line [ 14 ] as shown in Figure 1 a These boreholes are usually the same diameter as the main boreholes All peripheral holes are lightly loaded and decoupled with low powered explosives
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The present invention relates to a blasting method of rock by which blasting nuisances can be reduced and blasting efficiency increased The method utilizes a blasting mechanism comprising the steps of successively drilling a plurality of blasting holes on a upper free surface of a bench of rock with two free surface consisting of the upper free surface and a slant free surface extended from
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Controlled blasting is used to form a shear plane in rock at a certain slope by limiting the effects of blasting with presplitting cushion or trim blasting The purpose of controlled blasting is to construct stable rock cut slopes without damaging the rock face Production blasting is used to fracture rock in manageable sizes for excavation
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cross cut and presplitting blasting Entered by Ra91571 18 44 Jul 17 2024 Spanish to English translations [PRO] Tech/Engineering Spanish term or phrase Voladuras de recorte y precorte Blasting operations open cast mining Peter Spence Local time 02 06 cross cut and presplitting blasting Explanation Terms found on eurodicautom Note added at 2024 07 17 19 06 10 GMT cross
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To reduce gas disasters in low permeability and high gas coal seams and improve gas predrainage efficiency conventional deep hole presplitting blasting permeability increasing technology was refined and perfected The damage degree of coal and rock blasting was quantitatively evaluated by using the value range of the damage variable D
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This book is a unique supplement to contemporary scientific literature on rock blasting technology It encapsulates theoretical and practical aspects of drilling and blasting techniques used in both surface and subterranean excavations connected with civil as well as mining activities Case studies are presented to illustrate correlations between theoretical calculations and empirical findings
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View Notes Lecture 13 Drilling Blasting Rock from CFM 335 at Brigham Young University Blasting Rock Blast design Powder factor Vibration Trench rock Presplitting Production Mowbrays N
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In presplitting blasting the quality of hole stemming has a great in・Vence on the energy utiliza tion of explosive the hole wall pressure and the action dura tion especially that completely depends on the blasting quasistatic pressure to destroy the rock mass
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Bob Cummings of Saguaro GeoServices Inc discusses the development and implementation of aesthetic blasting and rock excavation techniques for highway cut slopes in sensitive and scenic infrastruc…
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Mechanism of roof presplitting in a nonpillar mining method with entry automatically retained and its influence on the strata behaviors PDF 。
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Presplitting Blasting the Roof Strata to Control Large Deformation in the Deep Mine Roadway Link/Page Citation Author s Chaowen Hu corresponding author [1 2] Xiaojie Yang [3] Ruifeng Huang [3] Xingen Ma corresponding author [3 4] 1 Introduction China s coal resources buried below 1000m are trillion tons accounting for 53% of the total coal resources [1 2] At present there
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Presplitting can be defined as a technique using lightly charged closely spaced holes to induce a fracture plane along a required design profile which isolates the rock to be blasted from the surrounding rock mass The holes are generally fired instantaneously well in advance of any blasting in the adjacent rock
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The findings are expected to provide guidance on deep hole presplit blasting for breaking rocks 2 Mechanism of Fracturing by Blasting After deep hole blasting of a rock mass the resulting stress near a blast hole exceeds the rock s dynamic compressive strength This combined with the high strain rate will create a crushed zone
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1 ROCK BLASTING FOR MINING by Prof A Balasubramanian Centre for Advanced Studies in Earth Science University of Mysore Mysore 6 83 83 The idea is to minimize or eliminate overbreak from the primary blast and to produce a smooth rock wall Presplitting will add a large drilling cost to an operation Borehole Diameters Normally the diameter of a borehole is limited by the capabilities of
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Through presplitting blasting the roadway hard rock layer the stress propagation path is cut off and the surrounding rock stress environment of the roadway is improved to achieve the purpose of controlling the deformation of the roadway caused by stress Through theoretical analysis it is determined that the depth of the presplitting blasthole is 17 m and the angle with the vertical
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Drilling and blasting is the controlled use of explosives and other methods such as gas pressure blasting pyrotechnics to break rock for is practiced most often in mining quarrying and civil engineering such as dam tunnel or road result of rock blasting is often known as a rock Drilling and blasting currently utilizes many different varieties of
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presplitting before blasting and excavating the interior portion of the specified cross section at any location The Department may allow blasting for fall benches and haul roads prior to presplitting when blasting is a sufficient distance from the final slope and results are satisfactory to the Engineercertain leeway should be given to the blasting contractor in the shaft sinking
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Presplitting uses reduced blasthole spacing diameter and explosive charges The initiation of blasting in the presplit blastholes precedes the initiation of the adjacent production blasthole explosives by a delay The delay decouples the final excavated rock face from the excavation and prevents energy from production blasts from propagating to and damaging the final cut face 2 Trim
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Presplit blasting involves drilling a single row of holes along the back of the final excavation zone [3] Unlike smooth wall blasting the presplit holes are fired on the first delay of the production blast The presplit technique is the most commonly used controlled blasting technique for surface operations 3 Methods Line drilling
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PRESPLITTING ROCK IN THE PRESENCE OF A STATIC STRESS FIELD gravel An electric blasting cap is used to initiate a detonating fuse trunk line which ties the branch of each hole together Presplitting is useful where cleanJ smooth rock walls are a requisite The method has been used extensively and successfully for road cuts Get Price
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Before blasting arrange for a preblast condition survey of nearby buildings structures or utilities within 500 feet of the blast or that could be at risk from blasting damage Provide the Engineer a listing of all properties surveyed and any owners denying entry or failing to respond Notify the Engineer and occupants of buildings at risk at least 24 hours before blasting
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Presplitting is a controlled blasting method implemented in the Aitik mine to minimize the backbreak by creating a crack between the presplit holes before blasting the production blast The presplit height is 30m and sets of the presplit holes are blasted simultaneously with short delay times between the sets The full production blasts are blasted in two rounds with a height of 15m each
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Rock Cut Perimeter Blasting Best Management Practices Phase I Research Report 2024 07 Author Vilem Petr Eduardo Lozano Erika Nieczkoski Paul S Chinowsky Keywords Geotechnical safety blasting aesthetics explosives rockslides slope stabilization half casts blast design presplitting
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Controlled blasting techniques are used to control overbreak and to aid in the stability of the remaining rock formation The less competent the rock mass itself is the more care has to be taken in avoiding damage Presplitting is one of the most common methods which is used in many open pit mining and surface blast design
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One of the goals to understanding rock blasting better is to limit the extent of damage in the remaining rock mass The two techniques investigated are presplitting and smooth blasting For this two case studies will be looked at The Ekati Mine and the Excavation of High Rock Slopes in China Mechanics of a Blast
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RI 6843 Presplitting Rock In The Presence Of A Static Stress Field 1966 new Go to Product Center Rock Blasting and Explosives Engineering Chapter 9 Rock Blasting and Explosives Engineering Chapter 9 Explosives for smooth Blasting and presplitting rve name Manufacturer Cartridge size Linear charge Go to Product Center
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The impact of joint frequency and relative joint orientation to the presplit have been examined in medium strong overburden rock from 6 pits of a large open cut coal mine in Central Queensland Australia The results of this study have shown for this rock type that there is a significant decrease in the presplit quality with increased joint frequencies and that presplit quality decreases with
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