CES Fundamentals & Core Principles 3 — Questions and Answers
Question 1: What is the Von Neumann spike in the context of detonation physics?
- The peak pressure immediately behind the shock front before chemical reaction completes (Correct answer)
- The spike in temperature at the borehole collar
- The pressure wave reflected from a free face
- The residual pressure after gas venting
Correct answer: The peak pressure immediately behind the shock front before chemical reaction completes
The Von Neumann spike is the extremely high pressure spike at the leading shock front of a detonation, just ahead of the reaction zone.
Question 2: Which regulatory agency primarily governs the manufacture, storage, and transportation of commercial explosives in the United States?
- EPA
- ATF (Correct answer)
- OSHA
- DOT only
Correct answer: ATF
The Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) has primary jurisdiction over licensing, storage, and record-keeping for commercial explosives under 18 U.S.C. Chapter 40.
Question 3: What is meant by the 'sympathetic detonation' of an explosive?
- Detonation caused by heat from a nearby fire
- Detonation triggered by the shock wave from an adjacent detonating charge (Correct answer)
- Detonation caused by static electricity
- Detonation triggered by mechanical impact
Correct answer: Detonation triggered by the shock wave from an adjacent detonating charge
Sympathetic detonation occurs when the shock wave from one detonating explosive initiates an adjacent explosive without direct contact.
Question 4: What is the purpose of stemming in a blasting operation?
- To prevent the explosive from absorbing water
- To confine the explosive gases and increase energy coupling to the rock (Correct answer)
- To reduce the amount of explosive required per hole
- To prevent misfires in wet conditions
Correct answer: To confine the explosive gases and increase energy coupling to the rock
Stemming confines the detonation gases within the borehole, improving energy transfer to the surrounding rock and reducing airblast.
Question 5: Which factor most directly determines the stand-off distance required between an explosive magazine and inhabited buildings?
- The type of initiator used
- The maximum quantity-distance (Q-D) tables based on net explosive weight (Correct answer)
- The local zoning ordinance
- The humidity level at the site
Correct answer: The maximum quantity-distance (Q-D) tables based on net explosive weight
Quantity-distance (Q-D) tables correlate the net explosive weight (NEW) stored to required separation distances from structures and public areas.
Question 6: What term describes the phenomenon where an explosive fails to detonate completely, leaving unreacted material in the borehole?
- Hangfire
- Misfire
- Cutoff
- Partial detonation (Correct answer)
Correct answer: Partial detonation
Partial detonation refers to incomplete reaction of the explosive column, often leaving cap-sensitive unreacted material that poses a serious hazard.
Question 7: In the context of explosives, what does the term 'dead pressing' refer to?
- Pressing explosive into a mold under high pressure to increase density until it becomes insensitive to detonation (Correct answer)
- Pressing a detonator into the explosive
- Using hydraulic pressure to pack ANFO into a borehole
- A manual tamping method for primer placement
Correct answer: Pressing explosive into a mold under high pressure to increase density until it becomes insensitive to detonation
Dead pressing occurs when an explosive is compressed to a density high enough that it becomes insensitive to normal initiation, a risk with cap-sensitive cartridged explosives.
CES Fundamentals & Core Principles 3
What is the Von Neumann spike in the context of detonation physics?