Explosives and Blasting Techniques Quiz
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Explosives and Blasting Techniques Quiz

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@KindlyEmerald1312

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Questions and Answers

Which type of blasting cap is designed to be triggered electrically?

  • Delay blasting cap
  • Non-electric instantaneous blasting cap
  • Mechanical blasting cap
  • Electric blasting cap (correct)

    • What is the primary purpose of a headache ball in blasting operations?

  • To break large boulders into smaller fragments. (correct)
  • To initiate a blasting cap.
  • To create a controlled explosion.
  • To measure the depth of boreholes.

    • What explosive is identified primarily by containing nitroglycerin or similar oils?

  • Dynamite (correct)
  • Ammonium nitrate
  • Blasting agents
  • Black powder

    • Which phenomenon presents a hazard during blasting activities due to electrical activity?

    <p>Atmospheric disturbance</p> Signup and view all the answers

    What type of explosive is characterized by its gelatinous consistency?

    <p>All of the above</p> Signup and view all the answers

    What kind of rock surface allows for expansion upon fragmentation?

    <p>Free face</p> Signup and view all the answers

    What term is used for rock propelled through the air as a result of a blast?

    <p>Fly rock</p> Signup and view all the answers

    What describes the process of breaking rock with or without the movement of the broken pieces?

    <p>Fragmentation</p> Signup and view all the answers

    What is blasting powder primarily composed of?

    <p>Potassium or sodium nitrate, charcoal, and sulfur</p> Signup and view all the answers

    What is the primary purpose of a cordlike fuse?

    <p>To light a series of safety fuses in sequence</p> Signup and view all the answers

    What defines a slow explosive?

    <p>A reaction slower than the speed of sound</p> Signup and view all the answers

    What is an overbreak control method used for?

    <p>To minimize rock damage around the excavation perimeter</p> Signup and view all the answers

    What is a common characteristic of a charge that has failed to fire?

    <p>It still contains the intended explosives</p> Signup and view all the answers

    Which of the following best describes the function of a coating placed over a shot?

    <p>To contain flying materials and debris</p> Signup and view all the answers

    What role does a building for storing explosives play?

    <p>It is designed to safely contain explosive materials</p> Signup and view all the answers

    Which component is often used as a sensitizer in dynamites?

    <p>Nitroglycerin</p> Signup and view all the answers

    What is the purpose of a staggered drilling pattern?

    <p>To fire holes of one row before those in the next row</p> Signup and view all the answers

    Which of the following statements about burden distance is true?

    <p>An insufficient burden can lead to excessive airblast</p> Signup and view all the answers

    What is the relationship between charge diameter and burden when using ANFO?

    <p>Burden is approximately 25 times the charge diameter in typical rock</p> Signup and view all the answers

    What happens if the burden is too large?

    <p>It leads to inadequate fragmentation and excessive vibrations</p> Signup and view all the answers

    How should the first row of blast holes for a second round be prepared?

    <p>They should be staked out before the first round is fired</p> Signup and view all the answers

    What is subdrilling primarily used for?

    <p>To avoid hard toe below the floor level</p> Signup and view all the answers

    In which conditions does the desired burden approach 40 times the charge diameter?

    <p>When using denser slurries or dynamites in low density formations</p> Signup and view all the answers

    What is the typical range for the burden-to-charge-diameter ratio?

    <p>20 to 40</p> Signup and view all the answers

    What is the purpose of a core of potassium nitrate black powder in blasting?

    <p>To promote greater ease in initiation of detonation.</p> Signup and view all the answers

    What does the term 'burden' refer to in blasting operations?

    <p>The distance between the bottom of a hole and the vertical free face of a bench.</p> Signup and view all the answers

    What is the number of holes drilled in a 3 m by 3 m tunnel?

    <p>31 holes</p> Signup and view all the answers

    Which of the following best describes a pressure pulse in the context of blasting?

    <p>A wave that propagates at supersonic velocity.</p> Signup and view all the answers

    Which blasting pattern is characterized by having equal burdens and spacing?

    <p>Square pattern</p> Signup and view all the answers

    What is the function of a firing device that burns with a flash?

    <p>To initiate the detonation of explosives.</p> Signup and view all the answers

    What cut is used for blasting hard rock mass and has horizontal and vertical axes symmetries?

    <p>Pyramid Cut</p> Signup and view all the answers

    What does controlled blasting involve?

    <p>Drilling closely spaced holes loaded with decoupled charges.</p> Signup and view all the answers

    What term describes the aqueous solution of ammonium nitrate that is sensitized with a fuel?

    <p>Ammonium nitrate slurry.</p> Signup and view all the answers

    Which cut involves drilling a series of holes closely spaced at right angles to the face?

    <p>Burn Cut</p> Signup and view all the answers

    What is the primary use of the Fan Cut in blasting operations?

    <p>In narrow drives with only one machine</p> Signup and view all the answers

    What is the purpose of stemming in a blasthole?

    <p>To confine the gaseous products of detonation.</p> Signup and view all the answers

    What does the term 'decoupled charge' refer to in blasting techniques?

    <p>Isolating parts of the blast to control timing.</p> Signup and view all the answers

    How many holes are typically drilled for a 2.5 m by 2.5 m breasthole?

    <p>24 holes</p> Signup and view all the answers

    In a rectangular blasting pattern, how does the spacing compare to the burden?

    <p>Spacing is larger than burden</p> Signup and view all the answers

    What is the defining feature of the Coromant Cut in drilling?

    <p>Drilling uncharged holes at the center and outer cuts</p> Signup and view all the answers

    Study Notes

    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.

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    Blasting Reviewer.docx

    Description

    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.

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