In-Person PETS Final Exam - Petr Explosives Group.com

What is the maximum temperature allowed for blasting?

100 C

150 C

100 F

150 F

What is a misfire?

The charge failed to detonate after initiation

Fly rock occurred during blasting

You had to stop blasting due to bad weather

What is powder factor?

Specific amount of explosives used for blasting

Specific amount of explosives needed to break rock

A main charge with a detonator is known as a

Detonation train

Primer

DDT

High explosive

You can store high explosives and low explosives together

True

False

You must have at least 1 year of blasting experience to obtain a Colorado Type I Permit

Always true

Always false

It depends on the classification

What is the difference between blast site and blast area?

They are the same thing

The blast area is the area of the blast within the influence of flying rock missiles, gases, vibration, and concussion

The blast site is the area where explosive material is handled during blasting operations, including a distance of 50 feet in all directions from explosive charges

Both B and C are correct

If your explosive catches fire, you should

Put it out with water

Put it out with a fire extinguisher

Put it out by smothering the fire

Any of the above

None of the above

Emulsions and water-based explosives are the same thing

True

False

The detonation velocity of shock tube is approximately

18,000 feet/second

1,800 feet/second

6,500 feet/second

65,000 feet/second

When do you need to use a booster in your initiation system?

When your main charge is detonator sensitive

When your main charge is not detonator sensitive

When you want more power from your main charge

When you want less power from your main charge

What is the difference between a blast wave and a detonation wave?

They are the same thing

Blast wave is propagation outside of the explosive charge

Blast wave is propagation within the explosive charge

Detonation wave is propagation outside the explosive charge

What does DDT stand for?

Detonation to deflagration transition

Dynamic detonation train

Distributed detonation transition

Deflagration to detonation transition

What is a detonator?

A device or small sensitive charge used to detonate low explosives

A device or small sensitive charge used to detonate high explosives

A device or small sensitive charge used to initiate safety fuse

All of the above

What is a pull wire igniter used for?

Initiate safety fuse

Initiate a blasting cap

Initiate detonating cord

Initiate shock tube

All of the above

What is particle velocity?

The speed at which particles of fly rock leave the blast area

A measure of the intensity of the ground vibration

The speed at which air particles in the shock wave move

The speed at which the explosive chemical reaction proceeds

What is a detonation?

A loud explosion

Combustion of a substance which is initiated suddenly and propagates extremely rapidly

An explosive reaction that moves through the material at a velocity greater than the speed of sound in the material

None of the above

What is deflagration?

A loud explosion

Combustion of a substance which is initiated suddenly and propagates extremely rapidly

An explosive reaction that moves through the material at a velocity greater than the speed of sound in the material

None of the above

What is combustion?

The process of burning

The process of deflagration

The process of detonation

All of the above

How does shock tube work?

HMX/aluminum burns down the length of the tube

HMX/aluminum deflagrates down the length of the tube

A HMX/aluminum dust explosion down the length of the tube

HMX/aluminum propagates an electric current down the length of the tube

The explosive power comes from the ______ group in explosive compounds

Nitro (NO2)

Oxygen (O2)

Carbon monoxide (CO)

Nitrogen oxides (NOx)

Emulsions are more stable at higher temperatures

True

False

Blasting caps are:

High explosives

Low explosives

Blasting agents

None of the above

All explosives require oxygen from the air to detonate

True

False

Air voids (micro-balloons) are important for non-molecular explosives

True

False

Orange fumes mean

An oxygen-rich reaction resulting in NOx fumes

An oxygen-deficient reaction resulting in carbon monoxide (CO) fumes

An oxygen-balanced reaction

None of the above

For det cord, grain size will affect detonation velocity

True

False

Which explosive type(s) can be used directly in wet holes?

ANFO

Water gels/slurries

All of the above

None of the above

What is an advantage of using a non-electric initiation system over electric?

Non-electric systems will not disturb the explosive column

Non-electric systems are insensitive to lightning

Non-electric systems are insensitive to static electricity

All of the above

The numbers identifying various types of detonating cord refer to the number of grains of ______ that are contained within a linear _______ of cord.

Cord; inch

Explosive; foot

Explosive; pound

Black powder; foot

Explosives in a day box can be left unattended

True

False

Only if the day box is locked

Only if the day box is at a secured site

For the ATF, the minimum age to be an employee possessor is

16

18

21

There is no age minimum

What is true about a cut-off?

When detonating cord downlines are used, detonation of the cord in the blast-hole proceeds from the top down.

When the detonation of the cord may have an undesirable effect on the column charge as it proceeds downward, and the stemming may be loosened

When the hole is cut off by (burden) movement caused by detonation of an earlier hole the powder in the lower portion of the hole will not detonate.

The State of Colorado and the ATF must both inspect and approve a new explosive magazine

True

False

Only the ATF conducts magazine inspections; the State of Colorado does not have this authority

Only the State of Colorado conducts magazine inspections, the ATF does not have this authority

The ATF regulates the use of explosives across the United States

True

False

Only true for states that do not have their own regulations

You must have at least 1 year of blasting experience to be an ATF employee possessor

True

False

It depends on the classification

How should you handle a misfire?

The blaster shall provide proper safeguards for excluding all unauthorized persons from the danger zone if a misfire is found.

No other work shall be done except the necessary to remove the hazard of the misfire and only those employees necessary to do the work shall remain in the danger zone.

Explosives shall not be extracted from a hole that has misfired unless it is impossible or hazardous to detonate any unexploded explosive materials by insertion of an additional primer

If there are any misfires while using fuse detonators and safety fuse, all employees shall remain away from the charge for at least one hour. Misfires shall be handled under the direction of the person in charge of the blasting. All fuses shall be carefully traced, and a search made for the unexploded charges

All of the above

When can you use matches or other sources of fire or flame?

Anytime if you have a fire extinguisher a maximum of 15 feet away

When explosives are being handled or used

When you are 50 feet away or more from the blast site

When you are ready to blast

All of the above

A misfire referes to:

Any remaining blast hole or portion of a blast hole which contains damaged signal tube, electric detonator wires, detonating cord, or safety fuse

Any remaining portions of a charged blast hole (i.e. "cutoff" or "bootleg") which is suspected to contain explosives

Any unexploded charge or suspected unexploded charge

Any situation where a safety fuse has been used and the number of "shots" counted is less than the number of blast holes fired

Any situation where there is reason to suspect that explosive charges have failed to explode

All of the above

What instrument is used to measure resistance in a blasting circuit?

Ohmmeter

Battery charger

Galvanometer

Multimeter

Lighting, static electricity, and radiofrequencies are forms of _______ that are very hazardous.

Extraneous electricity

Flyrock

Airblast

Blast waves

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