Design and Application of Blasting Parameters for …
In presplit blasting, rock fracturing is the product of the synergistic action of stress waves and detonation gas. The study found that the presence of empty holes between blast holes can improve tangential stress distribution and guide crack propagation. The characteristic zones of crack initiation, propagation, and interconnection were ...
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Crack Extension Characteristics of Deep Hole Pre-splitting Blasting …
The performance of presplit blasting deteriorates when the rock is at high in-situ stress. The experimental result that radial cracks induced by blasting tend to extend preferentially along the orientation of the principal stress was generally reproduced in numerical simulations (Li et al. 2021, 2024c; Yilmaz and Unlu 2013).
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Comparison of Blast-Induced Damage Between Presplit and Smooth Blasting
For the presplit blasting, the final damage of rock slope is mainly induced by presplit blasting itself. The spatial distribution characteristics of the final damage zone of two methods are compared. Two classes of damage zone could be found in smooth blasting excavation; one of them is the columnar high-degree damage zone around the slope ...
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Pre-split blasting design to reduce costs and improve safety …
Advances in controlled blasting look to improve blasting efficiency and reduce overbreak, with the end product a smooth, stable rock surface with high contour quality. To this …
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Directional presplit blasting in an innovative no-pillar …
Directional presplit blasting (DPB) technology for an innovative no-pillar mining approach is introduced. First, a mechanical model is established to analyze crack initiation and coalescence using the new technology. The explosion pressure formula containing tress concentration factor explains the relationship between the quantity of explosives ...
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Comparison of Blast-Induced Damage Between …
smooth blasting and presplit blasting excavation methods are widely used in the contour excavation of high rock slope. The excavation sequence of these two methods is illustrated in Fig. 2. (The ...
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Webinar Summary: Guidelines for Perimeter Control and Pre …
14. With regard to the perimeter control blasting seminar tomorrow, one of the determinants is the presence of water. Water can help the formation of a presplit but can adversely affect wall stability by inducing high hydraulic pressures from production blasting.
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Investigation on Rock Fracturing in Presplit …
When the presplit blasting is applied to rock excavation at a deep level, crack-forming difficulties are encountered due to the characteristics of high geo-stress. In this study, the influences of ...
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Precision Presplitting – Design Aspects
How To Effectively Calculate The Explosive Load For A Precision Presplit On 24-In. Spacing Along With The Stemming, Loading And Timing Of The Holes. By Anthony Konya and Dr. Calvin Konya This is the second in a three-part article about Precision Presplitting. –Ed. Precision Presplitting is a form of presplitting where the blast design is
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Precision Presplitting: The Basics
precision presplitting is being used in the blasting industry to increase safety and prevent overbreak in weaker rocks. By Anthony J. Konya and Calvin J. Konya This is the first in a two-part article about Precision Presplitting.
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Study of presplit blasting under high in-situ stress
Presplit blasting is found by Holmes at the ton Power Plant [9], later it was applied in the Niagara Power Project and reported by Paine et al. [10].In practice, presplit-holes are drilled along the excavation perimeter and are initiated simultaneously or with minimum delays at the beginning of the blasting sequence.
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Presplitting in Wet Ground – Techniques and Design …
• Hydraulic blasting has been explored in other areas such as small scale dimension cutting in quarries and oversize blasting • Water will also wedge into the radial fractures generated in the surrounding rock during detonation, amplifying fracture propagation • The use of water coupled blasting in an underground presplit application
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Pre-Split Techniques: A Review
Pre-splitting 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 …
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Experimental and numerical investigation on rock fracturing …
Controlled blasting, such as smoothwall and presplit blasting, is widely adopted in tunnel perimeter excavation and plays a significant role in reducing underbreak/overbreak and the extent of excavated damage zone, which controls the integrity and stability of excavated tunnel contour [1], [2], [3].In recent decades, tunnelling has extended into a deep level and as a …
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Effects of in-situ stress on rock cracking in presplit blasting
Semantic Scholar extracted view of "Effects of in-situ stress on rock cracking in presplit blasting" by Xu-dong Li et al. Skip to search form Skip to main content Skip to account menu. Semantic Scholar's Logo. Search 224,052,432 papers from all fields of science. Search ...
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Pre-split blasting design to reduce costs and improve safety …
the controlled blasting technique mostly used in surface mining, pre-split blasting, where reduced charges, decoupled and empty drills holes create fracture planes around the excavation mass, to ...
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Final Wall Stability in Metal Open Pit Mines …
Controlled Blasting Methods • Line blasting • Smooth blasting • Cushion blasting • Presplit blasting. Presplit Hole Design • As a general guide for the presplit holes, spacing can be 8 to 12 times of the hole diameter or about …
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Blasting and Explosives Quick Reference Guide 2010
Presplit blasting Spacing = Hole diameter x 12 Burden = 0.5 x production blast burden (B) Uncharged length at top = 10 x D Powder factor = 0.5kg per square metre of face Do not stem holes. Fire all holes on the same delay, or in groups of ≥ 5 holes Smooth Blasting Spacing = 15 x Hole diameter (hard rock) 20 x Hole diameter (soft rock)
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IOP Conference Series: Earth and Environmental Science …
Optimal Design of Presplit Blasting Network of Deep Concave Open-Pit Mine Slope with Heterogeneous Complex Rock Mass Yajun Chen1, Juanjuan Zhao1 2and De Cao 1 College of Mining Engineering and Geology, Xinjiang Institute of Engineering, Urumqi 830091, China 2 Beishan Open-Pit Coal Mine, Qitai County Changji Prefecture Xinjiang 831800 China
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(PDF) Design of Controlled Pre-Split Blasting in a …
Comparison of blast-induced damage between presplit and smooth blasting. of high rock slope. Rock Mechanics and Rock Engineering, 47(4), ...
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Optimizing Presplit Blasting for Environmental Control …
Presplit blasting has been adopted to protect final rock faces to ensure wall stability and protect structures against blast damage. According to Phifer et al. (2012), presplitting is an old but ...
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Understanding the connection between blasting and highwall stability
Presplit blasting is a technique that was initially developed during the Niagara power project [6]. The original intent was to reduce the amount of ground vibration that was created during blasting operations. However, it was also noted that rock breakage on one side of the fracture plane did not cause breakage on the other side—an obvious ...
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(PDF) Modified Presplit Blast Design and its
Presplit blasting helps in controlling the generation of fly rock, minimising the blast-induced ground vibrations and air overpressure. Min imizing the near field blast vibrations is one of the ...
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The Design of Pre-split Blasts
Effective pre-splitting is a key feature of wall control blasting. Most mining operations use historical designs or rules-of-thumb for designing pre-split blasts. If productivity and safety benefits are to be gained, these methods need to be improved in order to accurately predict pre-split performance. This will become more pertinent as overburden depths increase, placing more demands on the ...
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Presplitting Techniques and Design in Open Pit Mining: …
Presplitting is a widely used controlled blasting technique in open-pit mining, aimed at minimizing damage to the remaining rock formation and ensuring greater stability (Pomasoncco-Najarro et al ...
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Summary of Surface Blasting and Damages with …
Figure 5.3: Comparison between Presplit and Regular Blasting. Hoek (2007) Mechanics of Smooth and Presplit Blasting. In order to better understand how smooth and presplit blasting affect the final face, one needs to know the …
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Influence of Joint Conditions and Blast Design on Pre-split Blasting
Blasting is a major method of excavation in mining, civil construction and infrastructure projects. The integrity of the rockmass of the final wall after excavation is important for the stability and economics of the operation. Perimeter blasting achieves a planned surface of the rockmass. The pre-split is one such technique, deployed when there is no free face and, …
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FHWA
Holes used for presplit blasting are lightly loaded and range from 22.5 to 25 mm (7/8 to 1 in) in diameter. A heavier charge (2 to 3 times the normal load) is used at the bottom of the borehole to ensure shearing at the floor. A common charge density is approximately 0.45 kg per square meter (0.1 lbs per square foot) of face area in the main ...
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A Comprehensive Review of Traditional, Modern and …
Line drilling, trim blasting, buffer blasting, smooth wall blasting, air decking, and presplitting are the six controlled blasting methods that have been developed. In the mining, construction, and …
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Introduction to Types of Rock Blasting
Precision Presplit Blasting is a controlled blasting procedure that is used to produce a shear plane within a weak rock or one that is geologically complicated with the minimum amount of explosive and minimum overbreak. Used to produce a clean, relatively solid rock cut face where rock is weak, or rock has extensive geologic discontinuities such as closely spaced jointing.
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