How do you calculate blasting volume?
The volume of material to be blasted is calculated by the rock-volume formula, as follows: Volume = burden dimension x spacing dimension x (hole depth – subdrill length)/27, where • hole depth – subdrill length = bench height∗ and • burden dimension, spacing dimension, and bench height all are measured in feet.
How is blasting powder factor calculated?
Powder factor can be expressed as a quantity of rock broken by a unit weight of explosives. Since rock is usually measured in pounds, there are several possible combinations that can express the powder factor. Powder Factor = Tons of rock (or cubic yards) per pounds of explosive.
What is the formula of Blast ability?
Most of these studies have suggested that the parameter that best correlates with both the energy developed from the explosion and the stress suffered by the rock-mass and nearby structures is the vibration velocity or, more precisely, the peak particle velocity ppv, expressed according to the following equation:(1) …
How do you calculate burden spacing?
- 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.
What is the K factor in blasting?
K-factor – A scaling factor correlating the distance (D) and Net Explosive Weight (W) with a particular peak incident overpressure based on the Kingery-Bulmash relationship, as shown in Figure 1.
What is drilling and blasting method?
Drill and blast method is mostly used method for the excavation throughout the world. The method can be used in all types of rocks and the initial cost is lower than the mechanical method like TBM. This tunneling method involves the use of explosives. Drilling blast holes and loading them with explosives.
What is coupling ratio in blasting?
The ratio of the volume of explosive to the volume of the hole is known as the Coupling Ratio. As volume is proportional to the square of the diameter, a uniform continuous charge of half the diameter of the blasthole gives a coupling ratio of (0.5)2 × 100 = 25%.
What is the process of blasting?
Blasting, process of reducing a solid body, such as rock, to fragments by using an explosive. Conventional blasting operations include (1) drilling holes, (2) placing a charge and detonator in each hole, (3) detonating the charge, and (4) clearing away the broken material.
What is peak over pressure?
The maximum value of overpressure at a given location which is generally experienced at the instant the shock (or blast) wave reaches that location. Dictionary of Military and Associated Terms.
Which is the correct formula for rock blasting?
(Ref. ”The Modern Techniques of Rock Blasting” by Langefors-Kihlström). The formula can be rewritten as: K* = v Q 3/2 The constant k must be determined, preferably by test blasting.
How to calculate the size of a pocket blast?
Hole Diameter = D Burden = (20 to 40) × D Spacing = (1.1 to 1.4) × B (1.15 for even hole distribution in a staggered pattern) Subgrade = (8 to 12) × D Stemming length = (20 to 30) × D Stemming particle size = 0.1D Initiation Timing Rules of Thumb
What do you mean by distance per blast?
A term commonly applied for mining development and civil tunnelling. It is the distance by which the face of tunnel is progressed and may be described as distance per blast or distance per unit time (shift, day, week, or month). Pressure pulses in air (often not audible), which are generated by blasting.
How is the spacing between blast holes determined?
The distance between adjacent blastholes in a row, measured along the row. Spacing is nearly always larger than the burden. A blast designed to minimise forward movement and instead “stand up” the muckpile, usually for efficient digging with a face shovel.