CES Fundamentals & Core Principles 2 — Questions and Answers
Question 1: What term describes the minimum diameter at which a specific explosive will reliably detonate?
- Critical diameter (Correct answer)
- Sympathetic diameter
- Threshold diameter
- Detonation diameter
Correct answer: Critical diameter
Critical diameter is the minimum charge diameter below which a detonation wave cannot be sustained in a given explosive.
Question 2: Which property of an explosive indicates its ability to do work as measured by the volume of gas produced per unit mass?
- Brisance
- Power index
- Gas volume (Correct answer)
- Heat of explosion
Correct answer: Gas volume
Gas volume (moles of gas per kilogram) is a key measure of an explosive's work capacity, as expanding gases do the mechanical work.
Question 3: What is the primary purpose of a booster in an explosive train?
- To initiate the blasting cap
- To amplify the initiation signal to reliably detonate a less-sensitive main charge (Correct answer)
- To reduce the shock wave in surrounding rock
- To delay the detonation sequence
Correct answer: To amplify the initiation signal to reliably detonate a less-sensitive main charge
A booster bridges the gap between a relatively weak initiator and a less-sensitive main explosive charge by amplifying the detonation wave.
Question 4: The Trauzl lead block test is used to measure which explosive property?
- Detonation velocity
- Sensitivity to impact
- Strength (work capacity) (Correct answer)
- Water resistance
Correct answer: Strength (work capacity)
The Trauzl lead block test measures the volume expansion in a lead block caused by an explosive, providing a relative measure of strength.
Question 5: Which chemical compound is commonly used as a sensitizer in ANFO to increase its sensitivity and performance?
- Sodium nitrate
- Aluminum powder (Correct answer)
- Calcium carbonate
- Ammonium sulfate
Correct answer: Aluminum powder
Aluminum powder is added to ANFO to increase its energy output and sensitivity, producing aluminum oxide and additional heat.
Question 6: What does the term 'oxygen balance' refer to in explosive chemistry?
- The ratio of oxidizer to fuel in a mixture expressed as a percentage (Correct answer)
- The atmospheric oxygen required for surface detonation
- The post-blast oxygen level in the borehole
- The oxygen content of the rock being blasted
Correct answer: The ratio of oxidizer to fuel in a mixture expressed as a percentage
Oxygen balance is the percentage by weight of excess or deficient oxygen in an explosive after complete oxidation of all combustible elements.
Question 7: In explosives classification, what distinguishes a 'high explosive' from a 'low explosive'?
- High explosives require a blasting cap; low explosives do not
- High explosives deflagrate; low explosives detonate
- High explosives detonate supersonically; low explosives deflagrate subsonically (Correct answer)
- High explosives are only used underground; low explosives are used on surface
Correct answer: High explosives detonate supersonically; low explosives deflagrate subsonically
High explosives undergo detonation—a supersonic reaction wave—while low explosives deflagrate at subsonic speeds through rapid burning.
CES Fundamentals & Core Principles 2
What term describes the minimum diameter at which a specific explosive will reliably detonate?