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 one third to less than one half of the normal spacing used in production blast holes. It also
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)
6.2. Comparison of BlastInduced Damage between Presplit and Smooth Blasting of High Rock Slope by Hu et al. (2013) Advance of computers has allowed for more modeling techniques over the last decade. This is noted by the use of numerical modeling comparing the damages of presplit and smooth blasting for the study done by Hu et al.
Mar 24, 2015 · Comparison of BlastInduced Damage between Presplit and Smooth Blasting of High Rock Slope by Hu et al. (2013) Advance of computers has allowed for more modeling techniques over the last decade. This is noted by the use of numerical modeling comparing the damages of presplit and smooth blasting for the study done by Hu et al.
But, similar to presplit blasting, there is a small boring diameter limits blasting depth to 15 m (50 ft). Borehole traces are present for much of the boring length. It does not protect the slope from damage caused by production blasting and also do not perform well
Blasting is a daily practice on the mines and presplit is performed with decoupled charges, such as the In smooth wall blasting, the final row of holes contains a lighter than normal charge, possibly a smaller burden and is ignited after the main charge is completed in order to limit the
a presplit line was run along the back of the blast on the side closest to the structure. This served two purposes since it was a final wall blast it helped to create a smooth wall, and the crack produced from barrier against transmitting blast vibration towards the structures. Where R = dist. (m) Q = mass
Presplit blasting involves drilling a single row of holes along the back of the final excavation zone . 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 3.1. Line drilling
ABSTRACT Investigations by the authors during surface and underground excavations indied that the success of presplitting and smooth blasting was largely depended on the nature and orientation of joints and bedding planes in the rock mass. The pap
ORIGINAL PAPER Comparison of BlastInduced Damage Between Presplit and Smooth Blasting of High Rock Slope Yingguo Hu • Wenbo Lu • Ming Chen • Peng Yan •
The blasting parameters and hole spacing were optimized. Moreover, the study illustrated the dynamic evolution of the strain and the complex fracture network in a blasted rock mass under the synergistic action of dynamic and static loads. The findings are expected to provide guidance on deephole presplit blasting for breaking rocks. 2.
A better way to presplit. slopes that are close to the planned angle of the final pit wall and benches that are smooth and stable. Unfortunately at other mines, the opposite is a common experience presplit holes that take off in different directions, a lot of waste rock that has to be blasted and hauled away at great cost and uneven slope
normal blasting procedures. It was believed that the inability to presplit in a horizontal direction underground was a direct consequence of the static stress conditions. If the in situ stress is due primarily to the weight of the overburden, the vertical
Feb 19, 2017 · Blasting a presplit in Granite This video gives a brief look at the drilling of the presplit for the garage and the blast. The presplit was drilled 38mm diameter, 4m deep and loaded with 70
PRESPLIT BLASTING Presplit blasting is an effective technique for stabilizing the final wall in open pit metal mines. This technique is based on the phenomenon that the detonation shock wave is stopped and reflected at any free face. In presplit blasting, an intentional fracture is created at the excavation line prior to the detonation
Each type of blastingpresplit, smooth, and cushion blastinghas its own formula. Presplit Blasting. As discussed above, presplit blasting (or presplitting) is most often done before production blasting to create a secondary fracture plane that will protect the final slope face from damage in the main production blast.
Among the total damage, the blasting of the production hole is the main resource, followed by the smooth and buffering holes. 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.
A deviation of greater than 6 inches 152 mm from the desired plane or shear from AA 1
Postsplitting: As with Smooth Blasting, but the back holes are simultaneously initiated in a separate blast. In this paper the general principles behind these techniques will be described, the design and appliion of the techniques will be dealt with. 3.1 Line Drilling
Resolution of Some Common Problems Highway Blasting In • The first presplit blast caused the entire Smooth blasting minimizes the danger of displacing the rock mass until each successive portion has been fragmented during the planned blasting sequence.
These techniques are presplit blasting, smooth blasting, and cushion blasting. Presplit Blasting: Presplit blasting, or presplitting, is used before production blasting to protect the final rock face from damage caused by the production blasting. Presplitting creates a fracture plane along the final slope face, which prevents the radial cracks
Sep 14, 2013 · Among the total damage, the blasting of the production hole is the main resource, followed by the smooth and buffering holes. 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.
Feb 25, 2011 · WALL CONTROL BLASTING TECHNIQUES The best approach will be to initially design the presplit shot, using the airdeck approach, on the normal presplit
effects of smallscale structures could be controlled through lighter smooth blasting, whereas the impact of larger, more dominant, structures, prevailed even for very light smooth (for open pit operations) blasting. For the footwall, presplit blasting in inclined (70°)
blast presplit holes before production blast. Presplitting advantage. steeper cuts with less maintenance issues. uses small diameter holes at close spacing that are lightly loaded with distributed charges. Smooth blasting advantages. produces appealing, stable perimeter. Can be done years after initial excavation. Smooth blasting
blasting in underground mining operations, protect the safety of students, faculty, and staff, prevent overbreak, and to ensure the stability of openings and workings, four experimental control blasts, comprising of three smooth blasts and one presplit blast were conducted at the Orphan Boy Mine (an underground mine at Montana Tech).
smooth blasting presplit indiaecommerce. rock blasting presplitting earthstonegranites. Rock Blasting and Associated Damages Geoengineer. Summary of Surface Blasting and Damages with Analysis of Two Mitigation Techniques Presplit and Smooth. Get Price And Support Online Numerical modeling of presplitting controlled .