CES Blasting Operations & Techniques Flashcards
6 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 6 CES Blasting Operations & Techniques flashcards as text
Under ATF regulations, what is the required minimum distance for clearing personnel during a surface blast?
Answer: The perimeter must be cleared to a safe distance determined by the blaster-in-charge based on site conditions, flyrock potential, and applicable regulations
Federal regulations require the blaster-in-charge to establish a safe clearance distance based on charge weight, geometry, rock conditions, and flyrock potential rather than a single fixed distance.
What is the significance of 'scaled distance' in blast vibration management?
Answer: It is the ratio of distance to the square root of maximum charge weight per delay, used to predict ground vibration levels
Scaled distance (D/W^0.5) correlates blast distance and charge weight to predicted PPV, allowing blasters to limit vibration at sensitive locations.
What does 'maximum instantaneous charge' (MIC) or 'maximum charge per delay' mean in blast planning?
Answer: The maximum weight of explosives that detonates within any single 8-millisecond window, used to control vibration
MIC (maximum charge per delay) limits the explosive weight firing in any 8 ms window to control the peak particle velocity reaching nearby structures.
In quarry blasting, what does a 'block model' or 'geological face map' help the blaster determine?
Answer: The location of geological discontinuities such as voids, faults, and joints that affect blast design
Geological face mapping identifies structural features like joints, faults, and voids that affect explosive confinement, fragmentation, and flyrock risk.
What is the role of a 'perimeter hole' or 'line drilling' in contour blasting?
Answer: To define the final excavation limit and reduce overbreak beyond the design line
Line drilling creates a row of closely spaced, uncharged or lightly charged holes along the final excavation perimeter to guide fracture propagation and minimize overbreak.
Which ISEE (International Society of Explosives Engineers) document provides widely referenced blast vibration and airblast criteria for residential structures?
Answer: ISEE Blasters' Handbook — the blasting seismograph and vibration limits chapter
The ISEE Blasters' Handbook provides industry-standard vibration criteria, including frequency-based PPV limits and airblast limits used to protect residential structures.