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Glossary of Terms (A-Z)
AIR BLAST
An airborne shock wave resulting from the detonation of explosives. May be caused by burden movement or the release of expanding gas into the air.
ANFO
A blasting agent consisting of ammonium nitrate prills and fuel oil.
BACK BREAK
Rock broken at the hole collar beyond the limits of the last row of holes. Also known as backshatter.
BENCH
The horizontal ledge in a quarry or mine face, along which holes are drilled vertically.
BLASTER-IN-CHARGE
A qualified and certified person in charge of a blasting operation.
BLASTING AGENT
Any mixture of fuel and oxidizer intended for blasting, not detonable by a No. 8 cap when unconfined (e.g., ANFO).
BLASTING MAT
A heavy mat made of wire rope, cable, or rubber used to cover a blast to hold down flyrock.
BLOCKHOLE
A hole drilled into a boulder (oversize rock) to allow placement of a small charge to break it.
BOOSTER
A high-energy explosive unit (like a cast primer) used for intensifying an explosive reaction and initiating insensitive blasting agents.
BOOTLEG
The portion of a borehole that remains intact after firing due to insufficient explosives at the toe.
BURDEN
The distance from an explosives charge to the nearest free face.
CAP SENSITIVITY
The sensitivity of an explosive to initiation by a standard blasting cap.
COUPLING
The degree to which an explosive charge fills the cross-sectional area of a borehole.
CRITICAL DIAMETER
The minimum diameter of an explosive charge at which a stable detonation can be maintained.
CUTOFF
A failure of the explosive column to detonate completely, often due to bridging or disruption of the detonating cord.
DECKING
Placing smaller, separate charges (decks) in the same borehole, separated by inert material like stemming, to distribute energy and reduce vibration.
DECOUPLING
The use of explosive cartridges with a diameter smaller than the borehole, creating an air gap that reduces blast pressure and vibration.
DEFLAGRATION
A rapid burning process, slower than the speed of sound, which is characteristic of low explosives like gunpowder.
DELAY BLASTING
The use of delay detonators to fire blastholes in a specific sequence with millisecond intervals.
DETONATING CORD
A flexible cord with a core of high explosive (usually PETN) used to initiate multiple charges.
DETONATION
A supersonic exothermic reaction that propagates through an explosive via a shock wave.
DYNAMITE
A high explosive mixture containing nitroglycerin, an oxidizer, and stabilizers.
EMULSION
An explosive material where droplets of oxidizer solution are suspended in a fuel oil phase, providing excellent water resistance.
FLYROCK
Rock propelled into the air from a blast, often caused by inadequate stemming, incorrect burden, or geological weaknesses.
FRAGMENTATION
The extent to which rock is broken into smaller pieces by a blast.
GROUND VIBRATION
The shaking of the ground caused by seismic waves from a blasting operation.
MAGAZINE
A specially designed building or facility for the safe storage of explosives.
MISFIRE
A charge or part of a charge that has failed to detonate as planned.
POWDER FACTOR
A measure of blasting efficiency, calculated as the weight of explosives used per unit volume or mass of rock broken (e.g., kg/m³ or kg/tonne).
PRIMER
An explosive unit (e.g., a cartridge with a detonator) used to initiate the main, less sensitive explosive charge.
SAFETY FUSE
A cord with a black powder core that burns at a controlled, known rate, used to initiate a non-electric blasting cap.
SCALED DISTANCE
A formula (R / Q^0.5) used to predict and compare ground vibration levels from blasts of different sizes at different distances.
SECONDARY BLASTING
The process of breaking oversized rock (boulders) after the primary blast, often done with blockholing or plaster shots.
SLURRY
A water-based explosive mixture, also known as a water gel.
SPACING
The distance between adjacent boreholes in the same row.
STEMMING
Inert material, like crushed stone, placed in a borehole on top of the explosive charge to confine the detonation gases.
SUBDRILLING
Drilling boreholes slightly deeper than the planned floor grade to ensure the rock breaks cleanly at the toe.
TOE
The unbroken rock left at the bottom of a bench after a blast, which is controlled by proper burden and subdrilling.
VELOCITY OF DETONATION (VOD)
The speed at which the detonation wave travels through an explosive column, measured in meters per second (m/s).
WEIGHT STRENGTH
A rating comparing the energy output of an explosive to a standard, usually ANFO (where ANFO = 100%).
AIR BLAST
An airborne shock wave resulting from the detonation of explosives. May be caused by burden movement or the release of expanding gas into the air.
ANFO
A blasting agent consisting of ammonium nitrate prills and fuel oil.
BACK BREAK
Rock broken at the hole collar beyond the limits of the last row of holes. Also known as backshatter.
BENCH
The horizontal ledge in a quarry or mine face, along which holes are drilled vertically.
BLASTER-IN-CHARGE
A qualified and certified person in charge of a blasting operation.
BLASTING AGENT
Any mixture of fuel and oxidizer intended for blasting, not detonable by a No. 8 cap when unconfined (e.g., ANFO).
BLASTING MAT
A heavy mat made of wire rope, cable, or rubber used to cover a blast to hold down flyrock.
BLOCKHOLE
A hole drilled into a boulder (oversize rock) to allow placement of a small charge to break it.
BOOSTER
A high-energy explosive unit (like a cast primer) used for intensifying an explosive reaction and initiating insensitive blasting agents.
BOOTLEG
The portion of a borehole that remains intact after firing due to insufficient explosives at the toe.
BURDEN
The distance from an explosives charge to the nearest free face.
CAP SENSITIVITY
The sensitivity of an explosive to initiation by a standard blasting cap.
COUPLING
The degree to which an explosive charge fills the cross-sectional area of a borehole.
CRITICAL DIAMETER
The minimum diameter of an explosive charge at which a stable detonation can be maintained.
CUTOFF
A failure of the explosive column to detonate completely, often due to bridging or disruption of the detonating cord.
DECKING
Placing smaller, separate charges (decks) in the same borehole, separated by inert material like stemming, to distribute energy and reduce vibration.
DECOUPLING
The use of explosive cartridges with a diameter smaller than the borehole, creating an air gap that reduces blast pressure and vibration.
DEFLAGRATION
A rapid burning process, slower than the speed of sound, which is characteristic of low explosives like gunpowder.
DELAY BLASTING
The use of delay detonators to fire blastholes in a specific sequence with millisecond intervals.
DETONATING CORD
A flexible cord with a core of high explosive (usually PETN) used to initiate multiple charges.
DETONATION
A supersonic exothermic reaction that propagates through an explosive via a shock wave.
DYNAMITE
A high explosive mixture containing nitroglycerin, an oxidizer, and stabilizers.
EMULSION
An explosive material where droplets of oxidizer solution are suspended in a fuel oil phase, providing excellent water resistance.
FLYROCK
Rock propelled into the air from a blast, often caused by inadequate stemming, incorrect burden, or geological weaknesses.
FRAGMENTATION
The extent to which rock is broken into smaller pieces by a blast.
GROUND VIBRATION
The shaking of the ground caused by seismic waves from a blasting operation.
MAGAZINE
A specially designed building or facility for the safe storage of explosives.
MISFIRE
A charge or part of a charge that has failed to detonate as planned.
POWDER FACTOR
A measure of blasting efficiency, calculated as the weight of explosives used per unit volume or mass of rock broken (e.g., kg/m³ or kg/tonne).
PRIMER
An explosive unit (e.g., a cartridge with a detonator) used to initiate the main, less sensitive explosive charge.
SAFETY FUSE
A cord with a black powder core that burns at a controlled, known rate, used to initiate a non-electric blasting cap.
SCALED DISTANCE
A formula (R / Q^0.5) used to predict and compare ground vibration levels from blasts of different sizes at different distances.
SECONDARY BLASTING
The process of breaking oversized rock (boulders) after the primary blast, often done with blockholing or plaster shots.
SLURRY
A water-based explosive mixture, also known as a water gel.
SPACING
The distance between adjacent boreholes in the same row.
STEMMING
Inert material, like crushed stone, placed in a borehole on top of the explosive charge to confine the detonation gases.
SUBDRILLING
Drilling boreholes slightly deeper than the planned floor grade to ensure the rock breaks cleanly at the toe.
TOE
The unbroken rock left at the bottom of a bench after a blast, which is controlled by proper burden and subdrilling.
VELOCITY OF DETONATION (VOD)
The speed at which the detonation wave travels through an explosive column, measured in meters per second (m/s).
WEIGHT STRENGTH
A rating comparing the energy output of an explosive to a standard, usually ANFO (where ANFO = 100%).
2. Quick One-Liners
- Burden: Distance from a charge to the nearest free face.
- Spacing: Distance between blastholes in the same row.
- Stemming: Inert material on top of a charge to confine gases.
- Powder Factor: A measure of explosive efficiency (kg of explosive per tonne of rock).
- ANFO: A mix of Ammonium Nitrate and Fuel Oil, used in dry holes.
- Emulsion: A water-resistant, pumpable explosive for wet conditions.
- Misfire: A charge that fails to detonate.
- Flyrock: Uncontrolled rock propelled through the air from a blast.
- PPV: Peak Particle Velocity, the key measure for ground vibration.
- Booster: A high-energy charge used to initiate insensitive blasting agents like ANFO.
- Detonation: A supersonic explosive reaction that creates a shock wave.
- Deflagration: A subsonic, rapid burning process (e.g., gunpowder).
- VOD: Velocity of Detonation, the speed of the explosive reaction wave.
- Burden: Distance from a charge to the nearest free face.
- Spacing: Distance between blastholes in the same row.
- Stemming: Inert material on top of a charge to confine gases.
- Powder Factor: A measure of explosive efficiency (kg of explosive per tonne of rock).
- ANFO: A mix of Ammonium Nitrate and Fuel Oil, used in dry holes.
- Emulsion: A water-resistant, pumpable explosive for wet conditions.
- Misfire: A charge that fails to detonate.
- Flyrock: Uncontrolled rock propelled through the air from a blast.
- PPV: Peak Particle Velocity, the key measure for ground vibration.
- Booster: A high-energy charge used to initiate insensitive blasting agents like ANFO.
- Detonation: A supersonic explosive reaction that creates a shock wave.
- Deflagration: A subsonic, rapid burning process (e.g., gunpowder).
- VOD: Velocity of Detonation, the speed of the explosive reaction wave.
3. Descriptive Q&A
Q1. Explain the key blast design parameters: Burden, Spacing, Stemming, and Powder Factor. ONLINEMININGEXAM
These four parameters are fundamental to any blast design:
- Burden (B): This is the most critical parameter. It is the distance from the explosive charge to the nearest free face (the rock surface that will move). If the burden is too large, the rock won't break properly, leading to a bootleg. If it's too small, it can cause violent flyrock and poor fragmentation.
- Spacing (S): This is the distance between adjacent blastholes in the same row. It is typically 1 to 1.8 times the burden. Proper spacing ensures that the fractures from adjacent holes connect, leading to uniform fragmentation.
- Stemming: This is the inert material (like crushed stone) placed in the top of the blasthole over the explosive column. Its purpose is to confine the high-pressure gases produced by the detonation, forcing the energy to break the rock mass instead of venting out of the hole, which would cause loud airblast and flyrock.
- Powder Factor (PF): This is a measure of blasting efficiency, defined as the amount of explosive used per unit of rock broken (e.g., kg per cubic meter or kg per tonne). A lower PF generally indicates a more efficient blast, but the optimal PF depends on the rock type and desired fragmentation.
Q2. Differentiate between Detonation and Deflagration with examples. ONLINEMININGEXAM
Detonation is a supersonic exothermic reaction that propagates through an explosive via a high-pressure shock wave. The reaction front moves faster than the speed of sound in the material. This process is extremely rapid and creates a shattering effect known as 'brisance'. This is characteristic of high explosives like TNT, PETN, and dynamite.
Deflagration is a subsonic combustion reaction that propagates through thermal conductivity, where hot material heats the next layer to ignition temperature. The reaction front is slower than the speed of sound. This process creates a pushing or heaving effect rather than a shattering one. This is characteristic of low explosives like gunpowder (black powder) and propellants.
Deflagration is a subsonic combustion reaction that propagates through thermal conductivity, where hot material heats the next layer to ignition temperature. The reaction front is slower than the speed of sound. This process creates a pushing or heaving effect rather than a shattering one. This is characteristic of low explosives like gunpowder (black powder) and propellants.
Q3. What is a misfire in blasting, and what are the essential safety procedures for handling one? ONLINEMININGEXAM
A misfire is a charge, or part of a charge, that has failed to detonate as intended after the initiation signal was sent.
Essential Safety Procedures (as per DGMS guidelines):
Essential Safety Procedures (as per DGMS guidelines):
- Waiting Period: All personnel must be withdrawn from the blast area, and no one is allowed to approach the misfired hole for a statutory waiting period, which is typically a minimum of 30 minutes.
- Securing the Area: The location of the misfire must be clearly marked and cordoned off to prevent accidental entry.
- Investigation: Only the certified and competent blaster-in-charge who prepared and attempted to fire the shot is permitted to investigate and handle the misfire.
- Handling: The blaster must follow strict, approved procedures to safely deal with the misfire, which may involve attempting to re-prime the hole or washing out the explosive. No drilling is permitted near a misfired hole until it has been made safe.
Q1. Explain the key blast design parameters: Burden, Spacing, Stemming, and Powder Factor. ONLINEMININGEXAM
These four parameters are fundamental to any blast design:
- Burden (B): This is the most critical parameter. It is the distance from the explosive charge to the nearest free face (the rock surface that will move). If the burden is too large, the rock won't break properly, leading to a bootleg. If it's too small, it can cause violent flyrock and poor fragmentation.
- Spacing (S): This is the distance between adjacent blastholes in the same row. It is typically 1 to 1.8 times the burden. Proper spacing ensures that the fractures from adjacent holes connect, leading to uniform fragmentation.
- Stemming: This is the inert material (like crushed stone) placed in the top of the blasthole over the explosive column. Its purpose is to confine the high-pressure gases produced by the detonation, forcing the energy to break the rock mass instead of venting out of the hole, which would cause loud airblast and flyrock.
- Powder Factor (PF): This is a measure of blasting efficiency, defined as the amount of explosive used per unit of rock broken (e.g., kg per cubic meter or kg per tonne). A lower PF generally indicates a more efficient blast, but the optimal PF depends on the rock type and desired fragmentation.
Q2. Differentiate between Detonation and Deflagration with examples. ONLINEMININGEXAM
Detonation is a supersonic exothermic reaction that propagates through an explosive via a high-pressure shock wave. The reaction front moves faster than the speed of sound in the material. This process is extremely rapid and creates a shattering effect known as 'brisance'. This is characteristic of high explosives like TNT, PETN, and dynamite.
Deflagration is a subsonic combustion reaction that propagates through thermal conductivity, where hot material heats the next layer to ignition temperature. The reaction front is slower than the speed of sound. This process creates a pushing or heaving effect rather than a shattering one. This is characteristic of low explosives like gunpowder (black powder) and propellants.
Deflagration is a subsonic combustion reaction that propagates through thermal conductivity, where hot material heats the next layer to ignition temperature. The reaction front is slower than the speed of sound. This process creates a pushing or heaving effect rather than a shattering one. This is characteristic of low explosives like gunpowder (black powder) and propellants.
Q3. What is a misfire in blasting, and what are the essential safety procedures for handling one? ONLINEMININGEXAM
A misfire is a charge, or part of a charge, that has failed to detonate as intended after the initiation signal was sent.
Essential Safety Procedures (as per DGMS guidelines):
Essential Safety Procedures (as per DGMS guidelines):
- Waiting Period: All personnel must be withdrawn from the blast area, and no one is allowed to approach the misfired hole for a statutory waiting period, which is typically a minimum of 30 minutes.
- Securing the Area: The location of the misfire must be clearly marked and cordoned off to prevent accidental entry.
- Investigation: Only the certified and competent blaster-in-charge who prepared and attempted to fire the shot is permitted to investigate and handle the misfire.
- Handling: The blaster must follow strict, approved procedures to safely deal with the misfire, which may involve attempting to re-prime the hole or washing out the explosive. No drilling is permitted near a misfired hole until it has been made safe.
4. Multiple-Choice Quiz
Score: 0 / 40
Q1. An airborne shock wave resulting from a blast is known as: ONLINEMININGEXAM
Q2. What does ANFO, a common blasting agent, consist of? ONLINEMININGEXAM
Q3. The distance from an explosive charge to the nearest free face is called: ONLINEMININGEXAM
Q4. A heavy mat made of wire rope used to control flyrock is a: ONLINEMININGEXAM
Q5. The portion of a borehole that remains intact after firing is known as a: ONLINEMININGEXAM
Q6. The minimum diameter at which an explosive can sustain a stable detonation is its: ONLINEMININGEXAM
Q7. What is the purpose of decking a charge in a borehole? ONLINEMININGEXAM
Q8. A rapid burning process slower than the speed of sound is called: ONLINEMININGEXAM
Q9. What is the primary purpose of stemming? ONLINEMININGEXAM
Q10. Uncontrolled rock propelled into the air from a blast is called: ONLINEMININGEXAM
Q11. A charge that fails to detonate as planned is a: ONLINEMININGEXAM
Q12. What does the Powder Factor measure? ONLINEMININGEXAM
Q13. What is a primer used for in a blasting operation? ONLINEMININGEXAM
Q14. The distance between adjacent boreholes in the same row is known as: ONLINEMININGEXAM
Q15. Drilling deeper than the planned floor grade to eliminate the toe is called: ONLINEMININGEXAM
Q16. What does VOD stand for? ONLINEMININGEXAM
Q17. Which explosive type is known for its excellent water resistance? ONLINEMININGEXAM
Q18. A high-energy explosive unit used to initiate insensitive blasting agents like ANFO is a: ONLINEMININGEXAM
Q19. The process of breaking oversized rock after the primary blast is known as: ONLINEMININGEXAM
Q20. What is a blasting galvanometer used for? ONLINEMININGEXAM
Q21. The term for a supersonic exothermic reaction propagating via a shock wave is: ONLINEMININGEXAM
Q22. Inadequate stemming or incorrect burden is a common cause of: ONLINEMININGEXAM
Q23. Which facility is used for the safe storage of explosives? ONLINEMININGEXAM
Q24. A flexible cord with a core of PETN is known as: ONLINEMININGEXAM
Q25. The use of explosive cartridges smaller than the borehole diameter is a technique called: ONLINEMININGEXAM
Q26. What is the purpose of a blasting log or register? ONLINEMININGEXAM
Q27. A non-electric initiation system that uses a hollow tube is commonly known as: ONLINEMININGEXAM
Q28. What does 'Weight Strength' of an explosive refer to? ONLINEMININGEXAM
Q29. The mouth or opening of a borehole is called the: ONLINEMININGEXAM
Q30. What is a 'bootleg' in the context of blasting? ONLINEMININGEXAM
Q31. The process of breaking rock without significant movement or displacement is called: ONLINEMININGEXAM
Q32. A 'hangfire' is an event where an explosive: ONLINEMININGEXAM
Q33. Which term describes an explosive's tendency to absorb moisture from the air? ONLINEMININGEXAM
Q34. The pile of broken rock after a blast is called the: ONLINEMININGEXAM
Q35. What is the purpose of a pre-blast survey? ONLINEMININGEXAM
Q36. The ratio of the volume of broken material to its original in-situ volume is the: ONLINEMININGEXAM
Q37. An explosive with high 'brisance' would be good for: ONLINEMININGEXAM
Q38. The material lying above the rock that needs to be blasted is called: ONLINEMININGEXAM
Q39. What is a 'primer' in a blasting circuit? ONLINEMININGEXAM
Q40. The term 'face' in an excavation context refers to: ONLINEMININGEXAM
5. Frequently Asked Questions
What is an air blast in blasting?
An air blast is an airborne shock wave caused by detonation of explosives, often from burden movement or the unconfined release of expanding gases.
What is the American Table of Distance?
It specifies safe explosives storage distances from roads, railways, and buildings.
What is ammonium nitrate (AN) used for?
AN is the most common oxidizer in explosives and blasting agents.
What does ANFO stand for?
ANFO = Ammonium Nitrate Fuel Oil, a common blasting agent.
What are approved explosives?
Explosives tested and approved by regulatory authorities such as DGMS and CIMFR.
What is an approved magazine?
A licensed facility designed for safe storage of explosives.
What is back break in blasting?
Unwanted rock breakage beyond the last row of holes, also called backshatter.
What does BATF stand for?
Bureau of Alcohol, Tobacco, and Firearms, a U.S. body regulating explosives.
What is bedding in rock mechanics?
Layers of sedimentary rock separated by planes of weakness.
What is a bench in mining?
A horizontal ledge in a mine face used for drilling and blasting.
What is meant by a blast area?
The area affected by flying debris and concussion from a blast.
Who is the blaster-in-charge?
The qualified person authorized to conduct blasting operations.
What is a blasting agent?
A fuel–oxidizer mixture not detonable by a No. 8 blasting cap when unconfined.
What is a blasthole?
A drilled hole in rock where explosives are placed.
Why are blasting mats used?
To control flyrock and debris during a blast.
What is a blasting galvanometer?
A device for measuring resistance in an electric blasting circuit.
What is a blockhole?
A hole drilled in a boulder for small charges to break it.
What is a booster?
A high-energy explosive unit used to enhance detonation.
What is a bootleg in blasting?
The portion of borehole left unbroken due to incomplete blast.
What is bouldering in blasting?
Surface blasting of large rocks with small charges, sometimes called adobe shot.
What is a bridgewire?
A fine wire in electric blasting caps that ignites the charge.
What is bridging?
Loss of explosive column continuity due to improper placement or foreign matter.
What is burden in blasting?
The distance between the blasthole charge and the nearest free face.
What is bus wire used for?
Uninsulated copper wire used in blasting circuits.
What is cap sensitivity?
The ability of an explosive to be initiated by a blasting cap.
What is a cast primer?
A cast explosive block used to initiate blasting agents.
What are centers in drilling?
Spacing between adjacent blastholes.
What is critical diameter?
The smallest diameter at which an explosive can maintain detonation.
What is cutoff in blasting?
Failure of detonation due to bridging or disruption in the initiation system.
What is cushion blasting?
Controlled blasting technique to shear rock along neat lines.
What is decoupling?
Using cartridges smaller than the borehole diameter to reduce energy transfer.
What is deflagration?
A slow burning process (<3000 fps) that produces gas but not true detonation.
What is delay blasting?
Using detonators with delays to fire charges sequentially.
What is density in explosives?
Weight of explosive per unit volume, usually in g/cm³.
What is detonating cord?
Flexible cord containing high explosives used to initiate charges.
What is detonation?
Rapid propagation of shock wave with chemical reaction in explosives.
What is a detonator?
Device (electric, non-electric, or electronic) that initiates explosives.
What is dynamite?
A high explosive made from nitroglycerin, nitrates, and stabilizers.
What is emulsion explosive?
Explosive containing oxidizer in water droplets emulsified with fuel.
What is flyrock?
Rocks ejected into the air due to poor blast design or weakness zones.
What is fragmentation in blasting?
Degree to which rock is broken into smaller pieces.
What is gap sensitivity?
Distance across which detonation can propagate between charges.
What is ground vibration?
Seismic shaking of ground caused by blasting.
What is a misfire?
Failure of a charge or part of charge to detonate.
What is powder factor?
Amount of rock broken per unit of explosive used.
What is a primer in blasting?
An explosive cartridge containing a detonator to initiate the main charge.
What is specific gravity in blasting materials?
Density of material compared to water (water = 1.0).
What is weight strength?
Explosive strength rating compared with nitroglycerin or ANFO (ANFO = 100%).
What is an air blast in blasting?
An air blast is an airborne shock wave caused by detonation of explosives, often from burden movement or the unconfined release of expanding gases.
What is the American Table of Distance?
It specifies safe explosives storage distances from roads, railways, and buildings.
What is ammonium nitrate (AN) used for?
AN is the most common oxidizer in explosives and blasting agents.
What does ANFO stand for?
ANFO = Ammonium Nitrate Fuel Oil, a common blasting agent.
What are approved explosives?
Explosives tested and approved by regulatory authorities such as DGMS and CIMFR.
What is an approved magazine?
A licensed facility designed for safe storage of explosives.
What is back break in blasting?
Unwanted rock breakage beyond the last row of holes, also called backshatter.
What does BATF stand for?
Bureau of Alcohol, Tobacco, and Firearms, a U.S. body regulating explosives.
What is bedding in rock mechanics?
Layers of sedimentary rock separated by planes of weakness.
What is a bench in mining?
A horizontal ledge in a mine face used for drilling and blasting.
What is meant by a blast area?
The area affected by flying debris and concussion from a blast.
Who is the blaster-in-charge?
The qualified person authorized to conduct blasting operations.
What is a blasting agent?
A fuel–oxidizer mixture not detonable by a No. 8 blasting cap when unconfined.
What is a blasthole?
A drilled hole in rock where explosives are placed.
Why are blasting mats used?
To control flyrock and debris during a blast.
What is a blasting galvanometer?
A device for measuring resistance in an electric blasting circuit.
What is a blockhole?
A hole drilled in a boulder for small charges to break it.
What is a booster?
A high-energy explosive unit used to enhance detonation.
What is a bootleg in blasting?
The portion of borehole left unbroken due to incomplete blast.
What is bouldering in blasting?
Surface blasting of large rocks with small charges, sometimes called adobe shot.
What is a bridgewire?
A fine wire in electric blasting caps that ignites the charge.
What is bridging?
Loss of explosive column continuity due to improper placement or foreign matter.
What is burden in blasting?
The distance between the blasthole charge and the nearest free face.
What is bus wire used for?
Uninsulated copper wire used in blasting circuits.
What is cap sensitivity?
The ability of an explosive to be initiated by a blasting cap.
What is a cast primer?
A cast explosive block used to initiate blasting agents.
What are centers in drilling?
Spacing between adjacent blastholes.
What is critical diameter?
The smallest diameter at which an explosive can maintain detonation.
What is cutoff in blasting?
Failure of detonation due to bridging or disruption in the initiation system.
What is cushion blasting?
Controlled blasting technique to shear rock along neat lines.
What is decoupling?
Using cartridges smaller than the borehole diameter to reduce energy transfer.
What is deflagration?
A slow burning process (<3000 fps) that produces gas but not true detonation.
What is delay blasting?
Using detonators with delays to fire charges sequentially.
What is density in explosives?
Weight of explosive per unit volume, usually in g/cm³.
What is detonating cord?
Flexible cord containing high explosives used to initiate charges.
What is detonation?
Rapid propagation of shock wave with chemical reaction in explosives.
What is a detonator?
Device (electric, non-electric, or electronic) that initiates explosives.
What is dynamite?
A high explosive made from nitroglycerin, nitrates, and stabilizers.
What is emulsion explosive?
Explosive containing oxidizer in water droplets emulsified with fuel.
What is flyrock?
Rocks ejected into the air due to poor blast design or weakness zones.
What is fragmentation in blasting?
Degree to which rock is broken into smaller pieces.
What is gap sensitivity?
Distance across which detonation can propagate between charges.
What is ground vibration?
Seismic shaking of ground caused by blasting.
What is a misfire?
Failure of a charge or part of charge to detonate.
What is powder factor?
Amount of rock broken per unit of explosive used.
What is a primer in blasting?
An explosive cartridge containing a detonator to initiate the main charge.
What is specific gravity in blasting materials?
Density of material compared to water (water = 1.0).
What is weight strength?
Explosive strength rating compared with nitroglycerin or ANFO (ANFO = 100%).
🔹 Internal Linking Suggestions
CMR 2017 – Chapter 3: Examinations & Certificates
Read More 🔗Inspectors & Mine Officials – CMR 2017
Read More 🔗Bench & Dump Failures in Opencast Mines
Read More 🔗Water Hazards in Underground & Opencast Mines
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Mastering blasting terminology is essential for DGMS success. Blasting plays a critical role in coal and metalliferous mining, and every candidate appearing for the DGMS First Class Manager Exam, Second Class Manager Exam, Overman, Sirdar, or Surveyor Exam must be familiar with these technical terms. Examiners often test your knowledge of concepts like specific gravity, burden, stemming, powder factor, detonation velocity, ANFO, permissible explosives, and misfire handling. This glossary by OnlineMiningExam.com covers the A to Z of excavation and blasting terms, aligned with DGMS regulations, making it your trusted companion for DGMS exam preparation.