CES Assessment & Evaluation Techniques 2 — Questions and Answers
Question 1: When conducting a post-blast evaluation, which indicator most reliably confirms complete detonation of an explosive charge?
- Presence of a blast crater matching calculated dimensions (Correct answer)
- Complete absence of fume color after detonation
- Recovery of intact detonator hardware
- Audible report matching the expected decibel level
Correct answer: Presence of a blast crater matching calculated dimensions
A blast crater matching the predicted size and shape is the most reliable physical indicator of complete detonation and proper energy release.
Question 2: Which standardized test is used to assess the sensitivity of an explosive to friction stimuli?
- BAM friction test (Correct answer)
- Card gap test
- Bureau of Mines impact test
- Trauzl lead block test
Correct answer: BAM friction test
The BAM (Bundesanstalt für Materialforschung) friction test is the internationally recognized standard for evaluating friction sensitivity of explosive materials.
Question 3: A CES technician evaluates a site where misfires occurred repeatedly. What is the FIRST step in the evaluation process?
- Establish a safe perimeter and account for all personnel (Correct answer)
- Inspect the blasting machine output voltage
- Review the blasting log for charge weight discrepancies
- Collect unexploded explosive samples for testing
Correct answer: Establish a safe perimeter and account for all personnel
Safety is always the primary step; establishing a perimeter and accounting for all personnel prevents casualties during a misfire evaluation.
Question 4: The Trauzl lead block expansion test is used to measure which explosive property?
- Brisance relative to TNT
- Total work capacity (energy output) (Correct answer)
- Detonation velocity
- Sensitivity to electrostatic discharge
Correct answer: Total work capacity (energy output)
The Trauzl test measures the total work capacity of an explosive by quantifying the expansion of a cavity in a lead block after detonation.
Question 5: During blasting operations assessment, ground vibration monitoring results are typically expressed in which unit?
- Pounds per square inch (PSI)
- Peak particle velocity (PPV) in inches per second (Correct answer)
- Decibels (dB)
- Hertz (Hz)
Correct answer: Peak particle velocity (PPV) in inches per second
Ground vibration from blasting is standardized and reported as Peak Particle Velocity (PPV) in inches per second, the unit used in regulatory compliance evaluation.
Question 6: Which technique is most appropriate for evaluating the effectiveness of controlled demolition in an urban environment?
- High-speed videography combined with seismic monitoring (Correct answer)
- Thermal imaging only
- Acoustic emission analysis
- Visual inspection at a 100-foot standoff
Correct answer: High-speed videography combined with seismic monitoring
High-speed videography captures structural collapse sequence while seismic monitoring verifies compliance with vibration limits, providing a comprehensive evaluation.
Question 7: When evaluating a new explosive formulation for quarry use, which parameter is assessed by the underwater explosion test?
- Detonation pressure and impulse (Correct answer)
- Minimum burning temperature
- Deflagration-to-detonation transition time
- Electrostatic sensitivity threshold
Correct answer: Detonation pressure and impulse
The underwater explosion test measures detonation pressure and shock impulse by analyzing the pressure wave transmitted through water, giving a precise energy output evaluation.
CES Assessment & Evaluation Techniques 2
When conducting a post-blast evaluation, which indicator most reliably confirms complete detonation of an explosive charge?