Blasting
Dr. Kadri Dagdelen
Surface Mine Design
Surface Mine Design
Blasting Principles
Surface Mine Design
Surface Mine Design
Surface Mine Design
Surface Mine Design
Blasting Terminology
Face Bench Top Plan ViewEnergy Force Vector Distribution
Blasting Terminology
Blasting Terminology
Holes too close together!Blasting Terminology
Spacing just right!Blasting Terminology
Staggered rows with proper spacing and timing help energy distribution within the rock mass!
Surface Mine Design
Hole spacing with respect to joints
Bench Top Face
Un-broken Ground Segments
Surface Mine Design
Hole spacing with respect to joints
Face Un-broken Ground Segments Un-broken Ground Segments Bench Top
Surface Mine Design
Fragmentation vs. Hole Diameter
Surface Mine Design
Bench Heights as a function of Hole
Diameter
Bench Height (Meters) Not Recommended Not Recommended RecommendedSurface Mine Design
Bench Heights as a function of Hole
Diameter
Bench Height (feet)
1.5” 2” 2.5” 3” 3.5” 4” 4.5” 5” 5.5” 6” 6.5” 1” 7” 10’ 20’ 30’ 40’ 50’ 60’ 70’ 90’ 80’ 100’ 110’ Not Recommended Not Recommended Recommended
Surface Mine Design
Surface Mine Design
Group Approach to Achieving
Optimum Blast Performance
Surface Mine Design
The Three Keys to Achieving Optimum
Explosive Performance
Surface Mine Design
Geological Effects on Blast Performance Physical Rock Properties
Physical Rock Properties
Compressive Strength Tensile Strength
Poisson’s Ratio Young’s Modulus Density
Surface Mine Design
Geological Effects on Blast Performance Typical Rock Properties
Surface Mine Design
Geological Effects on Blast Performance Rock Structure
Surface Mine Design
Geological Effects on Blast Performance Rock Structure
Surface Mine Design
Geological Effects on Blast Performance Rock Structure
Surface Mine Design
Geological Effects on Blast Performance Rock Structure
Surface Mine Design
Geological Effects on Blast Performance Rock Structure
Surface Mine Design
Geological Effects on Blast Performance Rock Structure
Surface Mine Design
Geological Effects on Blast Performance Rock Structure
Surface Mine Design
Geological Effects on Blast Performance Rock Structure
Surface Mine Design
Geological Effects on Blast Performance Rock Structure
Surface Mine Design
Rock Fragmentation by Blasting Basic Rock Breakage Theory
Surface Mine Design
Rock Fragmentation by Blasting Breakage Process
1. Explosive detonates and expands 1000 times its original volume. 2. High gas pressures crush the rock in compression for 2 to 3 times
charge diameters.
3. Stress within the rock causes tensile failure for 20 to 30 charge diameters.
4. Gas expands into existing and newly formed cracks. 5. Cracks are extended.
6. Rockmass is displaced along the path of least resistance. 7. Gas pressure vents and the muckpile is formed by gravity.
Surface Mine Design
Efficient Blast Design Blast Parameters
1. Bench height. 2. Charge diameter. 3. Burden.
4. Burden stiffness ratio. 5. Spacing.
6. Pattern layout. 7. Subdrilling. 8. Stemming. 9. Decking.
Surface Mine Design Bench Height vs. Hole Diameter
Efficient Blast Design Blast Parameters
Surface Mine Design
Decoupling
Efficient Blast Design Blast Parameters
Surface Mine Design
Loading Density
Efficient Blast Design Blast Parameters
Surface Mine Design
Burden Orientation
Efficient Blast Design Blast Parameters
Surface Mine Design
Stiffness Ratio
Efficient Blast Design Blast Parameters
Surface Mine Design
Efficient Blast Design Blast Parameters
Surface Mine Design
Spacing Orientation
Efficient Blast Design Blast Parameters
Surface Mine Design
Reduced Spacing for Ore Control Efficient Blast Design
Surface Mine Design
Pattern Configurations Efficient Blast Design
Surface Mine Design
Relationship Between Burden and Desired Displacement Efficient Blast Design
Surface Mine Design
Pattern Layout and Energy Distribution
Efficient Blast Design Blast Parameters
Surface Mine Design
Influence of Dipping Structures on Subdrill Efficient Blast Design
Surface Mine Design
Stemming Confinement Factors for ANFO (Relative Bulk Strength 1.0) Efficient Blast Design
Surface Mine Design
Stemming Confinement Factors for HANFO (Relative Bulk Strength 1.0) Efficient Blast Design
Surface Mine Design
Decking
Efficient Blast Design Blast Parameters
Surface Mine Design
Angle Drilling Considerations
1. Advantages.
a) Better energy distribution
b) Reduced overbreak
c) Better floor control
d) Improved highwall stability
e) Increased initial trajectory
2. Disadvantages.
a) Requires attention
b) Drill orientation to the free face must be at 90°
c) Shorter bit life
d) Greater hole deviation
Surface Mine Design
Angle Drilling Considerations Drilling 30°-angled Blastholes
Surface Mine Design
Angle Drilling Considerations Face Angles vs. Slope
Surface Mine Design
Surface Mine Design
Surface Mine Design
Surface Mine Design
Surface Mine Design
Surface Mine Design
Ground Vibration
Surface Mine Design
Ground Vibration Elastic Waves
The blast energy beyond the crater zone takes the form of elastic ground vibrations:
P wave – Compressional wave – 6000-20000 ft/sec S wave – Shear wave – 3/5 the velocity of the P wave
R waves – Surface waves – lowest frequency and greatest displacement.
The speed of the vibration waves through the ground is known as the wave propagation velocity.
Surface Mine Design
Ground Vibration Wave Propagation
Surface Mine Design
Ground Vibration Vibration Time History
Surface Mine Design
Ground Vibration
Components of ground vibration
Amplitude
It can represent velocity, acceleration, or displacement. Typically represents velocity.
Velocity
The speed the particles are moving back and forth.
The maximum rate that the particles are moving is known as peak particle velocity (PPV) and it is recorded in in/sec.
Surface Mine Design
Ground Vibration
Relationship Between Velocity, Frequency, Acceleration, and Displacement
Surface Mine Design
Ground Vibration
Surface Mine Design
Ground Vibration
Frequency considerations
Resonant or natural frequency
According to its physical characteristics any structure will vibrate at a natural frequency (3-18 Hz).
The maximum response of a building to ground
vibrations occurs when the frequency of the ground motion matches the natural frequency of the building.
Geological modification of vibration frequency Blast induced modification of vibration frequency
Surface Mine Design
Ground Vibration
Surface Mine Design
Office of Surface Mining Vibration Regulations for Surface Coal Mining
Surface Mine Design
Surface Mine Design
Ground Vibration
Surface Mine Design
Ground Vibration
Surface Mine Design
Ground Vibration
Surface Mine Design
Ground Vibration
Limit vibrations using scaled distance
0 – 300 ft away: minimum allowable SD is 50
301 – 5000 ft away: minimum allowable SD is 55 Over 5000 ft away: minimum allowable SD is 65
Surface Mine Design
Expected Vibration Based on Scaled
Distance
Surface Mine Design
Peak Particle Velocity Prediction
Formula
Surface Mine Design
Surface Mine Design
Surface Mine Design
