CES CES Blasting Operations & Techniques 2

Question 1

What is the purpose of using electronic detonators (EDs) compared to pyrotechnic delay detonators?

Accepted Answer

EDs provide programmable, highly accurate delay times reducing scatter and misfires

Answer

Electronic detonators allow precise programmable delays with timing accuracy in the sub-millisecond range, dramatically reducing timing scatter compared to pyrotechnic delays.

Question 2

What is 'controlled blasting' as used in highway construction and excavation near structures?

Accepted Answer

Techniques such as presplitting, smooth blasting, or cushion blasting to limit damage beyond the design perimeter

Answer

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.

Question 3

Which instrument is used on a blast site to measure ground vibration levels at nearby structures?

Accepted Answer

Seismograph (seismometer)

Answer

A seismograph records peak particle velocity (PPV) and frequency of ground vibration, providing data to compare against regulatory limits and damage criteria.

Question 4

What blast design parameter most directly controls the airblast overpressure generated at the surface?

Accepted Answer

Stemming length and confinement of the explosive charge

Answer

Adequate stemming length and confinement prevent explosive gases from venting rapidly to atmosphere, which is the primary source of airblast overpressure.

Question 5

In a 'deck loading' blast hole configuration, what separates the explosive decks?

Accepted Answer

Air gaps or inert stemming decks between explosive charges

Answer

Deck loading separates explosive charges within a single hole using air decks or inert stemming to improve energy distribution and reduce overbreak.

(CES) Certified Explosives Specialist Practice Test

(CES) Certified Explosives Specialist Practice Test

CES CES Blasting Operations & Techniques 2