Certification Examination Practice

FDNY E11 Blaster (Shaft and Tunnel) Certification Examination Practice Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What is the primary hazard associated with blasting in confined tunnel

spaces?

• Excessive humidity
• Noise exposure
• Over-pressure and flying debris
• Cold temperatures

Rationale: Confined spaces amplify blast pressure and debris projection,

increasing injury risk.

• When transporting explosives underground, which method is safest? 1 / 4

• In a metal toolbox
• In approved, non-sparking explosive containers
• In workers' backpacks
• Wrapped in plastic bags

Rationale: Approved containers prevent friction, impact, and sparks.

• The minimum safe distance between blasting caps and explosives during

storage is primarily to prevent:

• Moisture spread
• Temperature imbalance
• Accidental sympathetic detonation
• Light exposure

Rationale: Separating caps from charges prevents unintended initiation.

• Which initiation system is most commonly used in shaft blasting for

precision timing?

• Black powder fuses
• Manual electric sparkers
• Electric detonators with millisecond delays
• Match cord

Rationale: Millisecond delays improve fragmentation and reduce vibration.

• / 4

• Before charging blast holes in a wet tunnel, what must be checked?
• Hole temperature
• Rock color
• Presence of water requiring water-resistant explosives
• Diameter uniformity only

Rationale: Water can desensitize explosives unless water-resistant types

are used.

• During shaft sinking, the pattern selected for blasting is mainly designed

to:

• Create artistic fracture lines
• Maintain vertical advance and minimize overbreak
• Reduce dust only
• Increase noise control

Rationale: Controlling wall integrity and efficient advance is key.

• What is the purpose of the cut holes in tunnel blasting?
• Reduce airblast
• Create an initial void for rock movement
• Store leftover explosives
• Support ventilation pipes

Rationale: Cut holes create a relief cavity for the blast. 3 / 4

8. A misfire in underground blasting must first be:

• Ignored until shift change
• Immediately re-fired
• Identified, barricaded, and reported
• Flooded with water

Rationale: Securing the area prevents accidental triggering.

9. Ventilation after blasting is required to remove:

• Moisture
• Post-blast fumes (NOx and CO)
• Cold air pockets
• Lighting reflections

Rationale: Post-blast gases are toxic and must be cleared.

• What is the safest method for checking a blast hole depth?
• Inserting a metal rod
• Using bare hands
• Using a non-sparking measuring tape/line
• Pouring water into the hole

Rationale: Non-sparking tools reduce ignition risk.

• / 4