Explosives and Blasting Techniques Quiz

Explosive Components and Types

• Blasting caps can be either electric or non-electric, used for initiation with instantaneous or delay methods.
• Detonating cord transmits energy from trunkline to primer in boreholes.
• Headache ball, a heavy weight dropped to fragment boulders, increases efficiency in rock fragmentation.
• Dynamite, created by Alfred Nobel, is a high explosive that often uses nitroglycerin as a sensitizer.
• Atmospheric disturbances can pose risks during blasting activities due to electrical activity.
• Water-in-oil emulsions are explosives containing oxidizers dissolved in water droplets with immiscible fuel.
• Explosives undergo rapid chemical reactions leading to gas pressure and heat release.

Properties and Behavior of Explosives

• High explosives produce significant gas and heat quickly when initiated.
• Low explosives, like gunpowder, ignite slower than sound waves and have different applications.
• Gelatinous explosives resist water and offer unique handling characteristics, while ANFO is popular for its cost-effectiveness.
• Blasting patterns influence efficiency and outcomes; staggered and square patterns dictate hole arrangements for optimal effects.

Blasting Techniques and Calculations

• Burden distance measures the gap between a blasthole and the nearest free face at detonation, typically at a 45-degree angle for accuracy.
• Insufficient burden leads to excess airblast and fly rock; excessive burden causes inadequate fragmentation and vibrations.
• For optimum blast performance, charge diameter must align proportionately with the blasthole diameter depending on loading methods.
• Conditions change the appropriate burden-to-charge-diameter ratio, influencing fragmentation quality and safety.

Drill Patterns and Methods

• Several drilling patterns are utilized based on excavation needs, including Square, Rectangular, and Staggered styles.
• Specific cut types, like Wedge and Pyramid Cuts, adapt to various rock formations and project dimensions for effective blasting.
• Controlled blasting techniques entail drilling closely spaced holes using decoupled charges for heightened accuracy during explosions.
• Core samples and explosives must be stored safely in designated structures to minimize risks during blasting operations.

Safety and Controls

• Protective measures such as stemming are vital to contain gas and dust during detonation, reducing accident likelihood.
• Regular monitoring and adjustments are necessary to account for variables like rock density, moisture content, and blasting technique.
• Failure to detonate or misfiring requires strict protocols to manage and mitigate risks connected to unexploded charges.

Summary of Drill Hole Patterns

• Specific number of holes is determined for different tunnel sizes, increasing effectiveness and efficiency:
  • 3m by 3m: 31 holes
  • 2.7m by 2.7m: 28 holes
  • 2.5m by 2.5m: 24 holes
  • 2m by 2m: 11 holes
• Wedge and fan cuts suit various rock conditions, enhancing the efficacy of each blast.

Test your knowledge on various blasting caps, detonating cords, and explosives used in demolition and construction. This quiz covers the definitions and uses of electric and non-electric blasting systems, as well as the types of explosives created by pioneers like Alfred Nobel. Perfect for students studying engineering or safety regulations in construction.