Case Study Cost Reduction in Wall Control Blasting

configuration working on 2m flitches after blasting on 5m benches. Presplit blasts are carried out in advance of trim blasting. The 115mm diameter holes are drilled over two benches (10m), with the top bench drilled at the design wall angle and the bottom bench drilled 5 degrees steeper to allow for drill mast access. A range of charging techniques have been used depending on blasthole

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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 mechanisms utlized. Some of this was previously explained in the crack formation, but this can be defined further. Model

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Detagel™ Presplit - Orica

Detagel™ Presplit is cost effective. The purchase price of the product is the total product cost. No need to add cord, tape, couplers, makeup labor or additional accessories. Each case contains splicing ties for attaching string loads. Detagel™ Presplit can be easily loaded by one person. The inclusive nature of the product allows for ease of job cost estimation.

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Presplitting in Wet Ground – Techniques and Design

Presplitting in Open Cut Coal Mining 2 • Presplits are a blasting technic to aid in the creation of safe stable highwallsessential for open cut mining operations • The aim of a presplit is to create a fracture plane within the rock along what will be the future highwall • This discontinuity will then intercept the radial cracking and gas propagation from the main production blast

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Directional presplit blasting in an innovative no

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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ComparisonofPresplitandSmoothBlastingMethodsfor

blasting is always larger than that based on presplit blasting at the same distance and direction, whether main or pe-ripheral boreholes. In addition, PF from both main and peripheral boreholes based on smooth blasting decreases gradually with the increases of distances, but PF from main boreholes based on presplit blasting rstly decreases and

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Research Article Research on Effects of Blast Casting

Research on Effects of Blast Casting Vibration and Vibration Absorption of Presplitting Blasting in Open Cast Mine precondition for the formation of presplit face. us, the formula for calculating the blast hole spacing of presplit blasting can be obtained. Based on the analysis of the principles of vibration teste r and vibration pick-up in detecting blast vibrations, a detection scheme of

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FINAL WALL STABILITY IN METAL OPEN PIT MINES USING

In presplit blasting, an intentional fracture is created at the excavation line prior to the detonation of the main fragmentation load, in order to reflect the shock wave. In this method, a curtain of fracture is created by firing the lightly charged holes before the main or primary production blast holes. These holes are drilled in a row along the final excavation boundary. The lightly fired

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Summary of Surface Blasting with Comparison of Two

Compared smooth blasting with presplit blasting. For each case, there were production blasts, buffer blasts, and then either a smooth or presplit blast. High Rock Slopes in China – Smooth Blast. Damage is predominately a result of the first two production blasts, penetrating into the rock mass. Little columnar damage was noted around the final smooth blast hole . High Rock Slopes in China

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Deep-hole pre-split blasting mechanism and its

The blasting boreholes use continuous couple charging method in forward direction, once-charging and blasting with short delay. The trial uses the Class-2 coal mine permissible emulsion explosive, the explosive package dimension is: diameter×length=∅50 mm×580 mm, and a diameter of ∅63 mm PVC drivepipe has been used to put the explosive into the blasting hole. The charging coefficient is

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Precision Presplitting: The Basics - Rock Products

Generally, when one chooses to presplit the weak or heavily jointed with typical presplit blasting, the blasts are overloaded and the results can be poor. It makes no sense then to use these high powder loads, which leave the wall in bad condition with scattered half casts, bad backbreak and hanging boulders. This becomes a safety issue when loading and guarding must be put up to keep

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Drilling and blasting - Wikipedia

Drilling and blasting is the controlled use of explosives and other methods such as gas pressure blasting pyrotechnics, to break rock for excavation.It is practiced most often in mining, quarrying and civil engineering such as dam, tunnel or road construction.The result of rock blasting is often known as a rock cut.. Drilling and blasting currently utilizes many different varieties of

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Presplit | Definition of Presplit by Merriam-Webster

Presplit definition is - of, relating to, or occurring in the time before a split. How to use presplit in a sentence.

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Presplit - definition of presplit by The Free Dictionary

Let's look at another example, in the past, it was stated that when presplitting the collision of shock waves between boreholes is what would cause the presplit.This was put into the DuPont Blasting Handbook, which was then bought by the International Society of Explosive Engineers, and even in the 17th edition of the handbook, still exists today.

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D'Ambruoso Blasting Company

Experts in Blasting & Drilling Serving all of Connecticut since 1973. Now serving Massachusetts and Vermont Get a free project estimate. Honest, Reliable, and Fully Insured. D'Ambruoso Blasting is fully insured, bonded & licensed in the states of Connecticut, Massachusetts and Vermont. We are locally owned and operated and have been providing honest and reliable service for over 43 years. Read

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Chapter 8 BLAST DESIGN

Blasting vibrations and air blast concerns may have a direct influence on which blasting program the opera-tor may select. Because of such constraints, the blaster may need to impose limits on quantity of explosives per delay, which relates directly to hole sizes and depths. Borehole diameter and the depth of the hole must always be evaluated in any cost analysis including explo- sives

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Definition of presplitting - Mindat.org

Definition of presplitting. i. A smooth blasting method in which cracks for the final contour are created by blasting prior to the drilling of the rest of the holes for the blast pattern. Once the crack is made, it screens off the surroundings to some extent from ground vibrations in the main round. Ref: Langefors ii. See: controlled blasting. Click here to see list of references, authorities

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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) Burden = 1.25 x Spacing Fire as many holes as possible on

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20.0 BLASTING 20.1 Introduction - Maine.gov

Blasting operations will be restricted to daylight hours; NECEC Site Location of Development Application Blasting Central Maine Power Company 20-5 Burns & McDonnell 13. The blasting operation will be under the direction of a blasting foreman. The blaster and driller will be experienced in both drilling and blasting; 14. Drilling patterns will depend upon the depth of the rock and its condition

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Special Blasting Technique | Strength Of Materials

Special Blasting Technique. Trim and Pre Split Blasting. DRILL AND BLAST SECTION MINING SERVICES DEPARTMENT PT KALTIM PRIMA COAL Reasons for Pit Wall Damage Block Heaving Load Release. No Free Face Prevents Burden Movement. Shear Failure. Gas Driven Crack Extension. Compressive and Tensile Failure. Subdrill Damages Crests Areas Concern in Wall Control Blasting.

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