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
What is the purpose of using electronic detonators (EDs) compared to pyrotechnic delay detonators?
Answer: EDs provide programmable, highly accurate delay times reducing scatter and misfires
Electronic detonators allow precise programmable delays with timing accuracy in the sub-millisecond range, dramatically reducing timing scatter compared to pyrotechnic delays.
What is 'controlled blasting' as used in highway construction and excavation near structures?
Answer: Techniques such as presplitting, smooth blasting, or cushion blasting to limit damage beyond the design perimeter
Controlled blasting techniques like presplitting and smooth blasting use closely spaced, lightly loaded perimeter holes to create a fracture plane that limits overbreak and damage.
Which instrument is used on a blast site to measure ground vibration levels at nearby structures?
Answer: Seismograph (seismometer)
A seismograph records peak particle velocity (PPV) and frequency of ground vibration, providing data to compare against regulatory limits and damage criteria.
What blast design parameter most directly controls the airblast overpressure generated at the surface?
Answer: Stemming length and confinement of the explosive charge
Adequate stemming length and confinement prevent explosive gases from venting rapidly to atmosphere, which is the primary source of airblast overpressure.
In a 'deck loading' blast hole configuration, what separates the explosive decks?
Answer: Air gaps or inert stemming decks between explosive charges
Deck loading separates explosive charges within a single hole using air decks or inert stemming to improve energy distribution and reduce overbreak.
What is 'flyrock' in surface blasting, and what is its primary cause?
Answer: Rock fragments propelled beyond the blast zone; caused by insufficient burden, inadequate stemming, or weak rock zones
Flyrock is uncontrolled rock projectile displacement caused by inadequate burden, short stemming, or geological anomalies that allow explosive gases to escape rapidly.