Blasting Manual
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THE BLASTER’S GUIDE
COMMON FORMULAS USED FOR BLAST DESIGN
BLAST DESIGN FORMULAS Absolute Bulk Strength (ABS) .................................................................................... Absolute Weight Strength (AWS) ................................................................................ Actual Scaled Distance ............................................................................................ Base-Charge Length ............................................................................................... Burden .................................................................................................................. Deck Stemming ......................................................................................................
8 8 8 8 9 9
-For Dry Holes -For Wet Holes
Face Height ........................................................................................................... 9 Hole-to-Hole Delay Time .......................................................................................... 9 Loading Density .................................................................................................... 10 Maximum Charge Weight per Delay .......................................................................... 10 Minimum Distance.................................................................................................. 10 Powder Factor ...................................................................................................... 10 -Volume of Rock Input -Weight of Rock Input
Pre-Splitting Formulas for Air-Decked Charges .......................................................... 11 -Spacing of Air-Decked Charges -Weight of Air-Decked Charges -Stemming Column Length
Pre-Splitting Formulas for De-Coupled Charges ......................................................... 11 -Linear Charge Weight -Spacing between Pre-Split Holes
Pressure Formula .................................................................................................. 11 Relative Weight Strength (RWS) ............................................................................... 12 Resistance Formulas ............................................................................................. 12 -For Paralle Circuits -For Series Circuits
Row-to-Row Delay Time ......................................................................................... 12 Stone Stemming Particle Size .................................................................................. 12 Spacing ............................................................................................................... 13 -Instant -Delayed
Sub-Drilling .......................................................................................................... “Supersonic” Face Velocity ..................................................................................... Top-Stemming Length ........................................................................................... Water Displacement .............................................................................................. Weight of Rock per Blast Hole ................................................................................. Vibration Level Prediction .......................................................................................
13 13 13 14 14 14
-Peak Particle Velocity Prediction -Site Specific Ground Transmission Constant
Volume of Rock per Blast Hole ................................................................................ 14
© 2 0 0 2 AU S T I N PO W DE R C O M P AN Y
7
THE BLASTER’S GUIDE
BLAST DESIGN FORMULAS HOW TO READ FORMULAS
FORMULA NAME
FORMULA VARIABLES and [UNITS]
Variables used in formula and required units in [brackets]. If input variables are not in required units, then you must use the unit conversion tables.
Absolute Bulk Strength (ABS)
ABS E � AWSE � dE
Base-Charge Length Formula
Eb �
�� 0.3
VARIABLES and [UNITS]
E b = Length of base charge of high density explosives [ft] B = Average burden [ft] J = Sub-drilling depth [ft]
Acutual Scaled Distance Formula
Actual Scaled Distance
VARIABLES and [UNITS]
ABS E = Absolute bulk strength of the explosive [cal/cc] AWS E = Absolute weight strength of the explosive [cal/g] d E = Density of the explosive [g/cm 3 ]
SD �
RBS E � 7 . 462
AWS E = Absolute weight strength of the explosive [cal/g] RBS E = Relative bulk strength of the explosive [ANFO = 100] d E = Density of the explosive [g/cm 3 ] © 2 0 0 2 AU S T I N PO W DE R C O M P AN Y
W
� D � W �� � � SD �
2
Minimum Distance
D � SD �
dE
VARIABLES and [UNITS]
D
Maximum Charge Weight per Delay
Absolute Weight Strength (AWS)
AWS E �
� 0.5 � � B � � J
W
VARIABLES and [UNITS]
SD = Scaled distance factor W = Charge weight per delay [ lb ] D = Distance [ft]
8
THE BLASTER’S GUIDE
BLAST DESIGN FORMULAS
Burden Formula Hole-to-Hole Delay Time Formula � � �d � B � De � ��2 � � e � � 1.5�� � � dr � �
D hth � � 0 � 5 � � S ms/ft
VARIABLES and [UNITS]
B = Burden [ft] de = Density of the explosives [g/cm 3 ] dr = Density of the rock [g/cm 3 ] De = Diameter of fully coupled explosive column [in]
VARIABLES and [UNITS]
Dhth = Delay time between holes in a row [ms] S = Spacing between holes in a row [ft]
Hole-to-Hole Delay Times to Improve Fragmentation
Deck Stemming Formula
For Dry Holes
Td � 0.5 � D
For Wet Holes
Td � 1.0 � D
VARIABLES and [UNITS]
Rock Type
ms/ft
Sands, Loams, Marls and Coals
1.8 - 2.1
Some Limestones, Rock Shale and some Shales
1.5 - 1.8
Compact Limestones and Marbles, some Granites and Basalts, Quartzite Rocks and some Gneisses and Gabbros
1.2 - 1.5
Diabase, Diabase Porphyrites, Compact Gneisses, and Mica Schists and Magnetites
0.9 - 1.2
Td = Minimum length of stone deck consisting of particles of size Ts [ft] D = Blast-hole diameter [in]
Face Height Formula
H�
5
10 � D
VARIABLES and [UNITS]
H = Face Height [ft]
Leading underground mining technology.
D = Blast-hole Diameter [in]
© 2 0 0 2 AU S T I N PO W DE R C O M P AN Y
9
THE BLASTER’S GUIDE
BLAST DESIGN FORMULAS
Loading Density Formula
2
d l � 0.3404 � De � d e
Minimum Distance Formula
D � SD �
W
VARIABLES and [UNITS]
VARIABLES and [UNITS]
d l = Explosives loading density [lb /ft] De = Diameter of explosives column [in] de = Density of explosives [g/cm 3 ]
SD = Scaled distance factor W = Charge weight per delay [lb] D = Distance [ft]
Powder Factor Formula Volume of Rock
PF �
We V
VARIABLES and [UNITS]
Loading a blast on an iron ore range.
PF = Powder factor [lb/yd 3 ] We = Total weight of explosives used in blast [lb] V = Total volume of rock generated in blast [yd3 ]
Maximum Charge Weight per Delay
� D � � � SD �
Weight of Rock
PF �
2
W �� VARIABLES and [UNITS]
SD = Scaled distance factor W = Charge weight per delay [ lb] D = Distance [ft]
© 2 0 0 2 AU S T I N PO W DE R C O M P AN Y
Wr We
VARIABLES and [UNITS]
PF = Powder factor [t/lb] Wr = Total weight of rock generated in blast [t] We = Total weight of explosives used in blast [lb]
10
THE BLASTER’S GUIDE
BLAST DESIGN FORMULAS
Pre-Splitting Formulas for Air-Decked Charges
Pre-Splitting Formulas for De-Coupled Charges Linear Charge Weight
Spacing of Air-Decked Charges
S
2
D Wl � 28
� �1 .5 � 2 .0 � � D VARIABLES and [UNITS]
VARIABLES and [UNITS]
S = Spacing between air-decked holes [ft] D = Diameter of blast-hole [in]
Wl = Linear charge weight for pre-splitting explosive [lb/ft] D = Diameter of blast-hole [in]
Spacing between Pre-Split Holes Weight of Air-Decked Charges
W
S�
� �0 .08 � 0 .12 � � S � Lh
D
2
2.8
VARIABLES and [UNITS] VARIABLES and [UNITS]
S = Spacing between pre-split holes [ft] D = Diameter of blast-hole [in]
W = Weight of air-deck charge [lb] S = Spacing between blast-holes [ft] Lh = Length of blast-hole [ft]
Pressure Formula Stemming Column Length
T � �1 .0 � 1 .2 � � D VARIABLES and [UNITS]
T = Stemming column length [ft] D = Diameter of blast-hole [in]
© 2 0 0 2 AU S T I N PO W DE R C O M P AN Y
2
P � 0.000000233 � VOD � d E VARIABLES and [UNITS]
P = Pressure [kbar] VOD = Velocity of detonation of explosive [ft/sec] d E = Density of explosive [g/cm 3 ]
11
THE BLASTER’S GUIDE
BLAST DESIGN FORMULAS
Relative Weight Strength (RWS) Row-to-Row Delay Time Formula RWS E �
AWS E 91,000
Drtr � � 2 � 15 � � B ms/ft
VARIABLES and [UNITS]
RWS E = Relative weight strength of the explosive [ANFO = 100] AWS E = Absolute weight strength of the explosive [cal/g]
VARIABLES and [UNITS]
D rtr = Delay time between consecutive rows [ms] B = Maximum burden in front of a row of holes [ft]
Effects of Various Row-to-Row Delays
Resistance Formulas
For Parallel Circuits 1 1 1 1 1 � � � � ... � Rtotal R1 R2 R3 Rn
Effects
ms/ft
Violent excessive air-blast and back-break
2
High pile close to face, moderate air-blast and back-break
2-3
Average pile height, average air-blast and back-break
3-4
Scattered pile with minimum back-break
4-6
For Series Circuits Rtotal � R1 � R2 � R3 � ... � Rn
Stone Stemming Particle Size Formula
VARIABLES and [UNITS]
Rtotal = Total resistance of the electrical circuit [ �] R1 ... R n = Resistance of individual blasting caps or circuit branches [ �]
Ts �
D 12 � 20
VARIABLES and [UNITS]
T s = Clean crushed stone stemming particle size [in] D = Blast-hole diameter [in]
Bulk trucks preparing for another day on the job. © 2 0 0 2 AU S T I N PO W DE R C O M P AN Y
12
THE BLASTER’S GUIDE
BLAST DESIGN FORMULAS
Sub-Drilling Formula Spacing Formulas J � � 0.2 � 0.5 � � B If: VARIABLES and [UNITS]
B = Burden [ft] J = Sub-drilling [ft]
H �4 B
If:
Instant
S � 2.0 � B
S�
Delayed
S � 1.4 � B
S�
H <4 B
H � (2 � B ) 3 H � (7 � B ) 8
VARIABLES and [UNITS]
H = Face height [ft] B = Burden [ft] S = Blast-hole spacing [ft]
Top Stemming Length Formula Industry’s leading Detonating Cord
T � � 0 .7 � 1 .3 � � B "Supersonic" Face Velocity Formula
D min �
S
VARIABLES and [UNITS]
B = Burden [ft] T = Top stemming length [ft]
1.127
VARIABLES and [UNITS]
D min = In order to avoid air-blast from "supersonic" lateral face velocity, the delay between holes must be more than Dmin [ms] S = Spacing between blast holes [ft]
© 2 0 0 2 AU S T I N PO W DE R C O M P AN Y
13
THE BLASTER’S GUIDE
BLAST DESIGN FORMULAS
Water Displacement Formula
C
�
Lw
Lc
� Dc � �� D � h�
Vibration Level Predictation Formulas Peak Particle Velocity Prediction
2
1 � �� VARIABLES and [UNITS]
PPV � K � SD
- 1.6
VARIABLES and [UNITS]
C = Number of explosives cartridges required to rise above standing water L w = Length of the standing water column [ft] L c = Length of one explosives cartridge [ft] D c = Diameter of explosives cartridges [in] D h = Diameter of blast-hole [in]
PPV = Peak particle velocity [in/s] K = Ground transmission constant [K=160 if no other seismic data is available] SD = Scaled distance factor
Site Specific Ground Transmission Constant 1.6 K � PPV � SD
VARIABLES and [UNITS]
K = Ground transmission constant PPV = Peak particle velocity [in/s] SD = Scaled distance factor
HEET Truck on display at an open house in 2001
Weight of Rock per Blast Hole Formula
W � V � dr VARIABLES and [UNITS]
W = Weight of rock generated per blast-hole [t] V = Bank volume of rock generated per blast-hole [yd 3 ] d r = Bank density of rock [t/yd 3 ]
© 2 0 0 2 AU S T I N PO W DE R C O M P AN Y
Volume of Rock per Blast Hole Formula
V�
B� S� H 27
VARIABLES and [UNITS]
V = Bank volume of rock per blast-hole [yd 3 ] B = Burden [ft] S = Spacing [ft] H = Face height [ft]
14
COMMON FORMULAS USED FOR BLAST DESIGN
BLAST DESIGN FORMULAS Absolute Bulk Strength (ABS) .................................................................................... Absolute Weight Strength (AWS) ................................................................................ Actual Scaled Distance ............................................................................................ Base-Charge Length ............................................................................................... Burden .................................................................................................................. Deck Stemming ......................................................................................................
8 8 8 8 9 9
-For Dry Holes -For Wet Holes
Face Height ........................................................................................................... 9 Hole-to-Hole Delay Time .......................................................................................... 9 Loading Density .................................................................................................... 10 Maximum Charge Weight per Delay .......................................................................... 10 Minimum Distance.................................................................................................. 10 Powder Factor ...................................................................................................... 10 -Volume of Rock Input -Weight of Rock Input
Pre-Splitting Formulas for Air-Decked Charges .......................................................... 11 -Spacing of Air-Decked Charges -Weight of Air-Decked Charges -Stemming Column Length
Pre-Splitting Formulas for De-Coupled Charges ......................................................... 11 -Linear Charge Weight -Spacing between Pre-Split Holes
Pressure Formula .................................................................................................. 11 Relative Weight Strength (RWS) ............................................................................... 12 Resistance Formulas ............................................................................................. 12 -For Paralle Circuits -For Series Circuits
Row-to-Row Delay Time ......................................................................................... 12 Stone Stemming Particle Size .................................................................................. 12 Spacing ............................................................................................................... 13 -Instant -Delayed
Sub-Drilling .......................................................................................................... “Supersonic” Face Velocity ..................................................................................... Top-Stemming Length ........................................................................................... Water Displacement .............................................................................................. Weight of Rock per Blast Hole ................................................................................. Vibration Level Prediction .......................................................................................
13 13 13 14 14 14
-Peak Particle Velocity Prediction -Site Specific Ground Transmission Constant
Volume of Rock per Blast Hole ................................................................................ 14
© 2 0 0 2 AU S T I N PO W DE R C O M P AN Y
7
THE BLASTER’S GUIDE
BLAST DESIGN FORMULAS HOW TO READ FORMULAS
FORMULA NAME
FORMULA VARIABLES and [UNITS]
Variables used in formula and required units in [brackets]. If input variables are not in required units, then you must use the unit conversion tables.
Absolute Bulk Strength (ABS)
ABS E � AWSE � dE
Base-Charge Length Formula
Eb �
�� 0.3
VARIABLES and [UNITS]
E b = Length of base charge of high density explosives [ft] B = Average burden [ft] J = Sub-drilling depth [ft]
Acutual Scaled Distance Formula
Actual Scaled Distance
VARIABLES and [UNITS]
ABS E = Absolute bulk strength of the explosive [cal/cc] AWS E = Absolute weight strength of the explosive [cal/g] d E = Density of the explosive [g/cm 3 ]
SD �
RBS E � 7 . 462
AWS E = Absolute weight strength of the explosive [cal/g] RBS E = Relative bulk strength of the explosive [ANFO = 100] d E = Density of the explosive [g/cm 3 ] © 2 0 0 2 AU S T I N PO W DE R C O M P AN Y
W
� D � W �� � � SD �
2
Minimum Distance
D � SD �
dE
VARIABLES and [UNITS]
D
Maximum Charge Weight per Delay
Absolute Weight Strength (AWS)
AWS E �
� 0.5 � � B � � J
W
VARIABLES and [UNITS]
SD = Scaled distance factor W = Charge weight per delay [ lb ] D = Distance [ft]
8
THE BLASTER’S GUIDE
BLAST DESIGN FORMULAS
Burden Formula Hole-to-Hole Delay Time Formula � � �d � B � De � ��2 � � e � � 1.5�� � � dr � �
D hth � � 0 � 5 � � S ms/ft
VARIABLES and [UNITS]
B = Burden [ft] de = Density of the explosives [g/cm 3 ] dr = Density of the rock [g/cm 3 ] De = Diameter of fully coupled explosive column [in]
VARIABLES and [UNITS]
Dhth = Delay time between holes in a row [ms] S = Spacing between holes in a row [ft]
Hole-to-Hole Delay Times to Improve Fragmentation
Deck Stemming Formula
For Dry Holes
Td � 0.5 � D
For Wet Holes
Td � 1.0 � D
VARIABLES and [UNITS]
Rock Type
ms/ft
Sands, Loams, Marls and Coals
1.8 - 2.1
Some Limestones, Rock Shale and some Shales
1.5 - 1.8
Compact Limestones and Marbles, some Granites and Basalts, Quartzite Rocks and some Gneisses and Gabbros
1.2 - 1.5
Diabase, Diabase Porphyrites, Compact Gneisses, and Mica Schists and Magnetites
0.9 - 1.2
Td = Minimum length of stone deck consisting of particles of size Ts [ft] D = Blast-hole diameter [in]
Face Height Formula
H�
5
10 � D
VARIABLES and [UNITS]
H = Face Height [ft]
Leading underground mining technology.
D = Blast-hole Diameter [in]
© 2 0 0 2 AU S T I N PO W DE R C O M P AN Y
9
THE BLASTER’S GUIDE
BLAST DESIGN FORMULAS
Loading Density Formula
2
d l � 0.3404 � De � d e
Minimum Distance Formula
D � SD �
W
VARIABLES and [UNITS]
VARIABLES and [UNITS]
d l = Explosives loading density [lb /ft] De = Diameter of explosives column [in] de = Density of explosives [g/cm 3 ]
SD = Scaled distance factor W = Charge weight per delay [lb] D = Distance [ft]
Powder Factor Formula Volume of Rock
PF �
We V
VARIABLES and [UNITS]
Loading a blast on an iron ore range.
PF = Powder factor [lb/yd 3 ] We = Total weight of explosives used in blast [lb] V = Total volume of rock generated in blast [yd3 ]
Maximum Charge Weight per Delay
� D � � � SD �
Weight of Rock
PF �
2
W �� VARIABLES and [UNITS]
SD = Scaled distance factor W = Charge weight per delay [ lb] D = Distance [ft]
© 2 0 0 2 AU S T I N PO W DE R C O M P AN Y
Wr We
VARIABLES and [UNITS]
PF = Powder factor [t/lb] Wr = Total weight of rock generated in blast [t] We = Total weight of explosives used in blast [lb]
10
THE BLASTER’S GUIDE
BLAST DESIGN FORMULAS
Pre-Splitting Formulas for Air-Decked Charges
Pre-Splitting Formulas for De-Coupled Charges Linear Charge Weight
Spacing of Air-Decked Charges
S
2
D Wl � 28
� �1 .5 � 2 .0 � � D VARIABLES and [UNITS]
VARIABLES and [UNITS]
S = Spacing between air-decked holes [ft] D = Diameter of blast-hole [in]
Wl = Linear charge weight for pre-splitting explosive [lb/ft] D = Diameter of blast-hole [in]
Spacing between Pre-Split Holes Weight of Air-Decked Charges
W
S�
� �0 .08 � 0 .12 � � S � Lh
D
2
2.8
VARIABLES and [UNITS] VARIABLES and [UNITS]
S = Spacing between pre-split holes [ft] D = Diameter of blast-hole [in]
W = Weight of air-deck charge [lb] S = Spacing between blast-holes [ft] Lh = Length of blast-hole [ft]
Pressure Formula Stemming Column Length
T � �1 .0 � 1 .2 � � D VARIABLES and [UNITS]
T = Stemming column length [ft] D = Diameter of blast-hole [in]
© 2 0 0 2 AU S T I N PO W DE R C O M P AN Y
2
P � 0.000000233 � VOD � d E VARIABLES and [UNITS]
P = Pressure [kbar] VOD = Velocity of detonation of explosive [ft/sec] d E = Density of explosive [g/cm 3 ]
11
THE BLASTER’S GUIDE
BLAST DESIGN FORMULAS
Relative Weight Strength (RWS) Row-to-Row Delay Time Formula RWS E �
AWS E 91,000
Drtr � � 2 � 15 � � B ms/ft
VARIABLES and [UNITS]
RWS E = Relative weight strength of the explosive [ANFO = 100] AWS E = Absolute weight strength of the explosive [cal/g]
VARIABLES and [UNITS]
D rtr = Delay time between consecutive rows [ms] B = Maximum burden in front of a row of holes [ft]
Effects of Various Row-to-Row Delays
Resistance Formulas
For Parallel Circuits 1 1 1 1 1 � � � � ... � Rtotal R1 R2 R3 Rn
Effects
ms/ft
Violent excessive air-blast and back-break
2
High pile close to face, moderate air-blast and back-break
2-3
Average pile height, average air-blast and back-break
3-4
Scattered pile with minimum back-break
4-6
For Series Circuits Rtotal � R1 � R2 � R3 � ... � Rn
Stone Stemming Particle Size Formula
VARIABLES and [UNITS]
Rtotal = Total resistance of the electrical circuit [ �] R1 ... R n = Resistance of individual blasting caps or circuit branches [ �]
Ts �
D 12 � 20
VARIABLES and [UNITS]
T s = Clean crushed stone stemming particle size [in] D = Blast-hole diameter [in]
Bulk trucks preparing for another day on the job. © 2 0 0 2 AU S T I N PO W DE R C O M P AN Y
12
THE BLASTER’S GUIDE
BLAST DESIGN FORMULAS
Sub-Drilling Formula Spacing Formulas J � � 0.2 � 0.5 � � B If: VARIABLES and [UNITS]
B = Burden [ft] J = Sub-drilling [ft]
H �4 B
If:
Instant
S � 2.0 � B
S�
Delayed
S � 1.4 � B
S�
H <4 B
H � (2 � B ) 3 H � (7 � B ) 8
VARIABLES and [UNITS]
H = Face height [ft] B = Burden [ft] S = Blast-hole spacing [ft]
Top Stemming Length Formula Industry’s leading Detonating Cord
T � � 0 .7 � 1 .3 � � B "Supersonic" Face Velocity Formula
D min �
S
VARIABLES and [UNITS]
B = Burden [ft] T = Top stemming length [ft]
1.127
VARIABLES and [UNITS]
D min = In order to avoid air-blast from "supersonic" lateral face velocity, the delay between holes must be more than Dmin [ms] S = Spacing between blast holes [ft]
© 2 0 0 2 AU S T I N PO W DE R C O M P AN Y
13
THE BLASTER’S GUIDE
BLAST DESIGN FORMULAS
Water Displacement Formula
C
�
Lw
Lc
� Dc � �� D � h�
Vibration Level Predictation Formulas Peak Particle Velocity Prediction
2
1 � �� VARIABLES and [UNITS]
PPV � K � SD
- 1.6
VARIABLES and [UNITS]
C = Number of explosives cartridges required to rise above standing water L w = Length of the standing water column [ft] L c = Length of one explosives cartridge [ft] D c = Diameter of explosives cartridges [in] D h = Diameter of blast-hole [in]
PPV = Peak particle velocity [in/s] K = Ground transmission constant [K=160 if no other seismic data is available] SD = Scaled distance factor
Site Specific Ground Transmission Constant 1.6 K � PPV � SD
VARIABLES and [UNITS]
K = Ground transmission constant PPV = Peak particle velocity [in/s] SD = Scaled distance factor
HEET Truck on display at an open house in 2001
Weight of Rock per Blast Hole Formula
W � V � dr VARIABLES and [UNITS]
W = Weight of rock generated per blast-hole [t] V = Bank volume of rock generated per blast-hole [yd 3 ] d r = Bank density of rock [t/yd 3 ]
© 2 0 0 2 AU S T I N PO W DE R C O M P AN Y
Volume of Rock per Blast Hole Formula
V�
B� S� H 27
VARIABLES and [UNITS]
V = Bank volume of rock per blast-hole [yd 3 ] B = Burden [ft] S = Spacing [ft] H = Face height [ft]
14
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