Explosives Safety & Handling Flashcards
7 cards from real CES practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Explosives Safety & Handling flashcards as text
What is the primary purpose of a 'blasting mat' during surface blasting operations?
Answer: To prevent fly-rock from projecting beyond the blast zone
Blasting mats are heavy woven steel or rubber covers placed over shot holes to suppress fly-rock and limit debris projection distance.
Under ATF regulations, what is the maximum quantity of explosive material that may be stored in a Type 3 magazine (portable/jobsite box)?
Answer: 100 lbs
A Type 3 portable magazine (day box) may store up to 100 pounds of explosive material when properly secured on the job site.
Which factor most directly controls the 'critical diameter' of an explosive?
Answer: The minimum charge diameter needed to sustain detonation
Critical diameter is the minimum diameter at which a specific explosive can sustain a stable detonation wave; charges smaller than this diameter will fail to propagate.
When an explosives vehicle is involved in a traffic accident, what is the FIRST action the driver should take if there is no fire?
Answer: Warn approaching traffic and notify emergency services and the employer
The driver must immediately warn other traffic, call emergency services, and notify the employer per DOT and ATF requirements without moving or unloading the cargo prematurely.
What does the term 'VOD' (velocity of detonation) indicate about an explosive?
Answer: The speed at which the detonation wave travels through the explosive column
VOD is the speed in feet or meters per second at which the detonation shock wave propagates through the explosive, indicating its energy release rate.
Which action is required before stemming a borehole that contains a primed explosive column?
Answer: Ensure the detonator leads are shunted and secured away from the hole collar
Shunting and securing detonator leads prevents stray current or accidental contact during the stemming process from triggering premature detonation.
Under MSHA regulations, what is the minimum permissible distance between a blasting operation and an unprotected individual during underground mining?
Answer: 500 feet
MSHA requires all persons not directly involved in the blast to be at least 500 feet from the blast site or behind adequate barricades in underground mining operations.