NB Blasters Manual - Table of Contents

Attribution

This material was designed and prepared by Stephen McIsaac for his instruction of Blasting courses.

Permission was provided for use by his Estate.

37 years experience 1977 - 2014

Caveat

The facts stated here and the recommendations as to how to accomplish specific tasks with the use of explosives are based upon the best available information, field trials, and the experience of several highly trained and experienced explosives specialists. The reader should be aware that there is no means by which this or any other book can cover the equipment, explosives and techniques which will fit all of the circumstances and conditions which may be encountered in the field.

There is no express or implied guarantee that the methods described here will produce exactly what is needed or guarantee the safety of those who use the information contained in this book. As we state in the introduction, blasting is an inherently hazardous occupation; and should not be attempted by anyone who does not have the necessary knowledge and training.

This book is meant to be a guide, and only a guide, for individuals who have the training, knowledge and experience to understand what is stated, and to use that information in a safe, proper and intelligent manner. The authors of this manual can not accept responsibility for the results of its use.

Introduction

This manual has been written to provide a structured, understandable, illustrated course in the handling and use of explosives in both small and large blasting projects, to be undertaken by BLASTER'S. It is intended to also provide BLASTER'S who engage in specialized blasting with an understanding of the fundamentals and essentials of safe and efficient explosive usage.

To a large extent this manual is a compilation of data collected from many sources that has been organized into one volume. No originality is claimed for much of this material.

Before proceeding, you should know that no book is a "HOW TO DO IT" text for blasting. The use of explosives is hazardous and requires TRAINING as well as book knowledge. Before going out with manual in hand and explosives in a truck, some "hands on" training is a necessity.

It is impossible to place too much emphasis on the safety requirements in blasting. Anyone using explosives assumes the absolute responsibility, both moral and legal, for the results of their work. Explosives are like the label says, "DANGEROUS"! An incompetent or careless user of explosives is also dangerous. Put the two together and you have all the essentials for tragedy.

There is an excellent rule for dealing with explosives: "IF IN DOUBT, DON'T DO IT!"

In the field of blasting, experience seems to be the ultimate criteria for competence. How often have I heard someone say "OLD BOOM-BOOM WALTERS" is the best blaster around; he has 30 years experience. Or sometimes 20 years, if "BOOM-BOOM" is under 50 years old. What that has to do with anything is more than I have been able to fathom. Competence in anything does indeed take some practice. It also, and more importantly, takes technical knowledge. Technical knowledge does not necessarily come from experience. Because you have blasted 500 tree stumps does not mean that you are ready to blast a rock which has been found in someone's basement. You shouldn't take on dropping some smoke stack in the middle of an alleyway either.

This manual, then, is a guide, a help for those who already have proper hands on training and who know what they are about. The techniques are tested and reliable. They work under most circumstances, but neither this author nor anyone else can guarantee the results from their use. There are simply too many variables. Approach each blasting job as if someone else's life depends upon your ability and knowledge, because it DOES.

Chapter One: Explosives Products

Topic	Page
Chemistry and Physics of Explosives	2
Reactive Ingredients	2
Elements in Explosives	2
Oxygen-Balanced	2
Types of Explosives and Blasting Agents	5
High Explosives	5
Blasting Agents	5
Nitroglycerin-Based Explosives	5-7
Straight Nitroglycerin Dynamite	7
High-Density Ammonia Dynamite	7
Low-Density Ammonia Dynamite	7
Blasting Gelatin	7
Straight Gelatin	7
Ammonia Gelatin	8
Semigelatin	8
Nitrostarch Explosives	8
Ammonium Nitrate - Fuel Oil (ANFO)	8
Properties of Dry Blasting Agents	8
Coupling Ratio	9
ANFO Mixes	9
Specific Gravity and ANFO	10
Detonation Velocity of ANFO	10
Wet Holes	10
Purchased Forms of Dry Blasting Agents	11
Slurries, Water Gels, Emulsions	11
Composition of Slurries	11
Water Resistance of Slurry Type Products	11
Classification of Slurry Type Products	11
Efficiency	12
Sensitivity	12
Cartridged Products	12
Detonating Cord Downlines and Blasting Agent Slurries	12
Heavy ANFO	13
Primers and Boosters	13
Cast Primers	13
Primers and Borehole Size	13
Black Powder	14
Properties of Explosives	14
Strength	15
Detonation Velocity	16
Density	16
Water Resistance	16
Fume Class	17
Detonation Pressure	18
Borehole Pressure	18
Sensitivity	19
Sensitiveness	19
Explosive Selection Criteria	20
Charge Diameter Considerations	20-21
Cost of Drilling	21
Drilling and Fragmentation Difficulties	21
ANFO Water Resistance	22
Factors Influencing Toxic Fumes	22
ANFO Underground	23
Atmospheric Temperature	23
Propagating Ground	23
Dead Pressed ANFO or Slurry	24
Storage Considerations	24
Two-Compound Explosives	24
Sensitivity Considerations	24
Explosive Atmospheres	25

Chapter Two: Initiation and Priming

Topic	Page
Initiation Systems	26
Three Parts of an Initiation System	26
Types of Initial Energy Source	26
Distribution Networks	26
Delay Series	27
Instantaneous Detonator	27
Delay Detonators	27
Slow Delays	27
Millisecond Delays	27
Iron Leg Wires	28
Electric Initiation	28
Initiation Mechanism of an Electric Blasting Cap	28
Electric Blasting Cap Leg Wires	28
Magnadet	30
Series Circuit	30
Connecting Wire	30
The Firing Line	30
Parallel Series Circuit	31
Parallel Circuit	32
Resistance of a Series Circuit	33
Circuit Calculation of a Straight Parallel Circuit	34
Storage and Dry Cell Batteries	34
Capacitor Discharge (CD) Machine	35
Operation of Capacitor Discharge Machines	35
Sequential Blasting Machine	35
Powerline Blasting	35
Blasting Circuits Must be Checked	36
Checking Resistance of the Circuit	37
Checking Connecting Wires	37
Testing for a Break in the Firing Line	37
Current Leakage	37
Static Electricity	38
Electrical Storms	38
Radio Frequency Energy Hazard	38
Powerlines	38
Advantages of Electric Blasting	39
Exploding Bridge Wire	39
Detonating Cord Initiation	39
Detonation and Detonation Velocity	39
Trunklines	39
Cord Strengths Less Than 25 Grains Per Foot	40
Downlines	41
Millisecond Delays	41
Axial Initiation When Using Cap-Sensitive Explosives	41
Surface Delay Connectors	42
Surface Delay and Cutoffs	42
Detonating Rate of Detonating Cord	43
When Detonation Cord Downlines are Used	43
Primaline Primadet	44
Combination Surface and In-Hole Delays	44
Delay Cast Primers	44
Primary Advantages of Detonating Cord Initiation Systems	44
Safety Precaution	45
Cap-and-Fuse Initiation	45
Detonator Used in Cap and Fuse System	45
Assembly of Cap and Fuse	45
Burning Rate of Safety Fuse	46
Lighting Mechanism for Cap and Fuse	46
Ignitacord Connector	46
Water Deterioration	47
When Using Ignitacord or Quarry Cord	47
Fuse Lighting	47
To Avoid Misfires	47
Timing of Holes	47
Disadvantages of Cap and Fuse	47
Advantages of Cap and Fuse	48
Shock Tube Initiation	48
Shock Tube Initiation System	48
Noiseless Lead-in Line Detonation	49
Initiation of Noiseless Lead-in Line	49
Cutting and Splicing	49
Shock Tube and Detonation Cord Trunkline	49
Connect Shock Tube Trunkline Delay Unit	49
Initiating the System	49
Underground Initiation	50
Pneumatic Loading	50
Advantages of the Shock Tube System	50
Priming	50
Effect of Cord on Blasting Agents	50
Large Diameter Blastholes	51
Transient Detonation Velocity	51
Large-Diameter Slurry Columns	51
Delay Cast Primers	52
Primer Makeup	52
Outside Primer Makeup Facility	52
For Small Diameter Holes	52
Procedure for Safety Fuse	52
Attaching Detonating Cord to Small-Diameter Primer Cartridge	53
General Consideration	53
Bench Blasting, Bulk Loaded Products, and Subdrilling	53
Large Diameter Blastholes	53
Deck Charges	54
Multiple Priming as a Safety Factor	54
Detonation Sequence of Multiple Delayed Decks	54
Axial Priming	54

Chapter Three: Blasthole Loading

Topic	Page
Blasthole Loading	55
Electrical Storms	55
Checking the Blasthole	55
Before Loading Blastholes	55
Obstructed Boreholes	55
Redrilling	55
Checking Holes for Water	56
Voids in the Blasthole	56
Plugging a Blasthole	56
Hotholes	56
General Loading Procedures	57
Check Rise of Powder Column	57
Charge Coupling	57
Stemming	57
Wet Boreholes	58
Small-Diameter Blastholes	58
Loading Small-Diameter Blastholes	58
Cartridged Products	58
Pneumatic Systems for Water Gel Cartridges	58
Bulk Dry Blasting Agents	59
Pneumatic Loading of ANFO	59
Pressure Vessel Type ANFO Loader	59
Venturi-Type ANFO Loader	60
Small-Diameter Holes, Soft Formations, and High-Pressure Ejector Loader	60
Static Electricity and Pneumatic Loaders	60
General Recommendations	60
Pneumatic Loading and Wet Holes	60
Bulk Slurries	61
Large-Diameter Blastholes	61
Blasthole Diameters Larger Than 4 Inches	61
Packaged ANFO Products	61
Packaged Slurry Products	61
Bulk Dry Blasting Agents	61
Bulk Loading Systems for ANFO	61
Auger Loading of ANFO	62
Pneumatic Loading of ANFO	62
Hand Pouring ANFO	62
Bulk Slurries	62
Onsite Slurry Mixing	62
Hand Pouring of Slurry	62

Chapter Four: Blast Design

Topic	Page
Introduction to Blast Design	63
Blast Design Is Not a Precise Science	63
Major Principles of Blast Design	63
Properties and Geology of the Rock Mass	63
Keys to Characterizing the Rock Mass	63
Drilling Information	64
Rock Density	64
Rock Hardness	64
Voids and Incompetent Zones	64
Improving Fragmentation in Voids and Zones of Weakness	65
Rise of the Powder Column	65
Alternate Zones of Competent and Incompetent Rock	65
Jointing Can Effect	65
Perimeter Holes	65
Bedding Can Affect	66
Pronounced Bedding Plane	66
Dipping Beds	66-67
Surface Blasting	67
First Consideration of any Blast Design	67
Large Diameter Blastholes	68
Four-Hole Pattern (20-Inch Diameter Holes)	68
400-Holes Pattern (2-inch Diameter Holes)	68
Geologic Structures	68
Collar Distance and Environmental Problems	69
Controlled Ground Vibrations	69
Selection of Blasthole Size	70
Three Commonly Used Drill Patterns	70
Square or Rectangular Drill Patterns	70
Burden	71
When Figuring the Burden	72
Charge Diameter	73
Burden Flexing and Rock Fragmentation	74
Subdrilling and Priming	74
Excessive Subdrilling	74
Collar Distance	74
Deck Charges	75
Public Relations and Collar Distance	75
Spacing	75
Too Wide a Spacing	75
Firing Holes in a Row on the Same Delay Period	75
Millisecond Delays and Spacing	75
Hole Depth-To-Burden Ratio	76
Bench Height	77
Long Slender Charges	78
Reasons to Use Millisecond Delays	78
Optimum Delay Intervals for Bench Blasting	78
In-Hole Delays	79
Delayed Decks	79
Delay Accuracy	79
General Formulas to Determine the Powder or Load Factor	80
Calculation of the Load Factor	80
Factors Contributing to a Lower Powder Factor	80
Secondary Blasting	81
Four Techniques for Secondary Fragmentation	81
Initiation Systems for Secondary Blasts	82
Safety Precautions for Secondary Blast	82
Controlled Blasting Techniques	82
Four Controlled Blasting Techniques	82
Line Drilling	82
Further Protection of the Final Perimeter	83
Conditions for Using Line Drilling	83
Presplitting	83
General Recommendations and Precautions for Presplitting	83
Smooth Blasting	84
An Alternative to Smooth Blasting	84
Some Advantages to Smooth Blasting	84
Cushion Blasting	85
Advantages of Cushion Blasting	85
Ditch Blasting	85
Preparation	85
Methods of Ditching	87
Single Line Method	87
Cross Section Method	88
Post Hole Method	89
Relief Method	89
Pond Blasting	91
Loading the Explosives	92
Stump Blasting	93
Estimating the Charge	94
Locating the Charge	95
Loading the Charge	95
Boulder Blasting	95
Blockhole Method	96
Mudcap Method	97
Snakehole Method	97
Ice Blasting	97
Blasting Old Foundations	100
Demolition Bridges/Piers	101
Trenching	102
Well Shooting	103

Chapter Five: Environmental Effects of Blasting

Topic	Page
Introduction to Environmental Effects of Blasting	104
Four Environmental Effects of Blasting	104
Flyrock	104
Preblast Survey	104
Blasting Records	104
Blasting Record	105
Blasting Reports	106
Causes of Flyrock	107
Alleviation of Flyrock	107
Protection Against Injury and Damage From Flyrock	108
Ground Vibrations	108
Excessive Ground Vibrations	108
Delays and Vibrations	109
Geology and Vibrations	109
Overconfinement	110
Millisecond Delay Timing	110
Vibration Damage Levels	110
Complaints About Vibrations	111
Measuring Ground Vibrations	111
Operator-Attended Instruments	111
When Accelerations Larger Than 0.3g are Expected	112
Seismograph Records	112
Scaled Distance Equation	112
Techniques to Reduce Ground Vibrations	113
Airblast	113
Causes of Airblast	114
Airblast Levels	114
Airblast and Blasting Complaints	114
Measuring Airblast	115
Advantages of Airblast Recording	115
Techniques to Reduce Airblast	115
Public Reaction to Airblast	116
Dusts and Gases	116

Chapter Six: Blasting Safety

Topic	Page
Precautions Before Loading	118
Blast Area Prior to Loading	118
Primer Safety	118
Making Primers	118
Large Cartridges as Primers	119
Connecting Detonating Cord to a Primer Cartridge	119
Borehole Loading	119
Electrical Storms	119
Explosive Column Buildup	119
Loading Small-Diameter Cartridges	120
Loading Large-Diameter Blastholes	120
Extraneous Electricity and Pneumatic Loading	120
Hooking Up the Shot	120
Crew Size	120
Blasting Electrically	121
After Hooking Up Electric Circuits	121
Firing Electric Blasts	121
Firing With Detonating Cord	121
Firing With Cap-and-Fuse	122
General Precautions	122
Shot Firing	122
Just Prior to Blasting	122
Guarding	122
Warning Persons of an Impending Blast	123
Precautions for Shot Firer	123
Contact Between the Shot Firer and The Guards	123
General Procedure When Shot Firing	123
Blasting at Night at Surface Mines	123
Postshot Safety	124
Flyrock	124
Reentering the Blast Site	124
Disposing of Misfires	124
Removing a Misfired Charge	124
Refiring a Misfired Charge	124
Drilling and Shooting a Hole Adjacent to a Misfire	125

Chapter Seven: Accident Prevention

Topic	Page
Accident Prevention	126
Premature Firing of Electrical Blast	126
Stray Current	126
Galvanic Action	127
Static Electricity	127
Radio Frequency Energy	129
Extraneous Electrical Energy From Transmission Lines	130
Blasting Near Transmission Lines	130
Drilling Into Explosive	131
Unsafe Loading Practices	132
Delaying Too Long at the Face	132
Inadequate Guarding	133
Taking Insufficient Cover	133
Returning Too Soon After Blasting	134
Insufficient Ventilation After Blasting	134
Handling of Misfires	135
Accidental Initiation by Flame, Spark, etc.	136
Lightning	137

Chapter Eight: Handling and Destruction of Explosives

Topic	Page
Handling and Destruction of Explosives	138
Handling Explosives	138
Burning Explosives	138
Destroying Different Products	139
Recommended Methods of Destruction	139
Burying Explosives	139
Tips	140
References	156
Notes	160
Annexes	A

Acknowledgements and References

Apollo Artworks, Bob Collette, Graphic design (Cover & Scanning)
Ash, R.L., The Mechanics of Rock Breakage, Pit and Quarry, 1963
Atlas Powder Co., Handbook of Electric Blasting, 1976
Atlas Powder Co., Pneumatic Loading of Nitro-Carbo-Nitrates
Chironis, N.P., New Blasting Machine Permits Custom-Programmed Blast Patterns, Coal Age, 1974
CIL, Blasting Ditches, Stumps, Boulders & Ponds
Condon, J.L. and J.J. Snodgrass, Effects of Primer Type and Borehole Diameter on AN-FO Detonation Velocities, 1974
Damon, G.H. et al., Safety Recommendations for Ammonium Nitrate-Based Blasting Agents, BuMines IC 8746, 1977
D'Andrea, D.V. and L.A. Fletcher, Safeguarding of Blast-Affected Areas, 1984
Dick, R.A., Explosives and Borehole Loading, SME Mining Engineers, 1973
Dick, R.A., Factors in Selecting and Applying Commercial Explosives and Blasting Agents, BuMines IC 8405, 1968
Dick, R.A., New Nonelectric Explosive Initiation Systems, Pit & Quarry, 1976
E.I. duPont de Nemours & Co., Blaster's Handbook, 16th ed., 1978
Ensign Bickford Co., Primacord Detonating Cord, 1963
Fletcher, L.R. and D.V. D'Andrea, A Study of Misfires in Mining, 1985
Hagan, T.N., Optimum Priming for Ammonium Nitrate Fuel-Oil Type Explosives, 1974
Institute of Makers of Explosives, Safety Guide for the Prevention of Radio Frequency Radiation Hazards, Pub. No. 20, 1978
Institute of Makers of Explosives, The American Table of Distances, Pub. No. 2, 1977
Langefors, U. and N.A. Kihlstrom, The Modern Technique of Rock Blasting, John Wiley & Sons, 1963
Monsanto Co., AN-FO Manual, 1972
National Fire Protection Association, Manufacture, Transportation, Storage, Sale, Possession and Use of Explosive Materials, Pub. No. 3, 1980
U.S. Bureau of Mines, various publications

This document is the property of Maritime Blasting Services Ltd., Moncton, NB