Explosives and Blasting


Question Answer Notes
Excessive production of this extremely toxic gas presents as a reddish or orange cloud that forms above the blasting site. Nitrogen dioxide (NO2)  
In sequence, name three types of explosives used in the 3-Step Explosive Train: 1. Primary high explosive; 2. Secondary high explosive; 3. Main charge 1. Detonators; 2. Boosters; 3. Blasting agent A triggering sequence, also called an explosive train or a firing train, is a sequence of events that culminates in the detonation of explosives. The explosive triggering sequence or the explosive train essentially consists of an ‘initiator’, an ‘intermediary’ and the ‘high explosive’.
What potential hazard involves unintended material propelled from the blast area by the force of the explosion? Fly rock  
Other than toxic gases, name two potential hazards that should be identified during a post-blast inspection. Unstable ground; misfires  
True or false: Explosive material must be transported without undue delay to the storage or blast site. True Blast vehicles always have the right of way. Never pass. Blast vehicles when loaded have placards showing and often a red strobe running. Storage on blast vehicles are called “day boxes”. Once explosives have been loaded into day box it may never be left unattended and remain locked until actively unloading.
When not in use or being transported, detonators and explosives must be stored in what ATF-approved storage facility? A. Warehouse; B. Underground vault; C. Daybox; D. Magazine D. Magazine  
Which is not a characteristic of Ammonia Nitrate Fuel Oil (ANFO)? A. Relatively insensitive; B. Water-resistant; C. Low cost; D. Generates gases that help create and expand fractures that are critical to rock fragmentation B. Water-resistant ANFO is by far the most prevalent blasting agent used in mining. Because ANFO is not water-resistant, emulsions are used instead when water is present.
List in chronological order the safety procedures to follow when initiating a blast: A. Provide for blaster safety; B. Guard and block; C. Use blast warning signals; D. Clear and sweep 1. D. Clear and sweep; 2. B. Guard and block; 3. C. Use blast warning signals; 4. A. Provide for blaster safety  
True or false: A best practice after an underground blast is to “watch for visible smoke” and to re-enter the area after about “an hour of smoke time.” False  
Main facilities used to store explosive material underground must be located at least _____ feet from work places or shafts. 200  
Only this type of personnel are allowed access to a blast site. Authorized  
A post-blast inspection must be conducted to ensure that this health hazard has been effectively mitigated before personnel can re-enter the area. Toxic gases After blasting, the blasting crew shall wait at least 5 minutes before returning the point of blasting. For underground blasting, no one shall enter the place where primary blasting has been been done for at least 15 minutes.
Ample warning must be given to all persons to do this before a blast is initiated. Evacuate  
All surface explosive loading and handling activities must be suspended when this potential environmental hazard arises. Lightning  
A mine must do this to all access routes to the blast area to prevent the passage of persons or vehicles. Guard or barricade  
Smoking and use of open flames shall not be permitted within ____ feet of explosive material except with separated by permanent noncombustible barriers. 50  
What term refers to a bullet-resistant, theft-resistant, fire-resistant, weather-resistant, ventilated facility for the storage of explosives and detonators? Magazine  
What term refers to the complete or partial failure of explosive material to detonate as planned? Misfire  
What is the most common type of blasting agent use in mining due to its low cost and low shock sensitivity? Ammonia nitrate fuel oil (ANFO)  
Who fights explosives fires? A. Mine rescue; B. Local fire departments; C. MSHA; D. No one D. No one  
True or false: Bulk explosives and detonators must be transported separately unless in their own container and separated by 4″ of hardwood. True  
Which is not a cause of explosives-related fatalities? A. Electrocution; B. Post-blast gases; C. Unintentional detonation; D. Fly rock A. Electrocution  
Which of the following is the common duration and interval for conducting pre-blast warnings? A. One two-minute long siren three minutes before the blast; B. One two-minute log siren two hours before the blast; C. One one-minute long siren five minutes before the blast, and then one one-minute long siren one minute before the blast; D. Any of the above C. One one-minute long siren five minutes before the blast, and then one one-minute long siren one minute before the blast  
How do drill and blast procedures affect ground control? A. They create smaller rocks; B. They shift stresses in the rock from compression to tension; C. They create unsupported ground; D. All of the above C. They create unsupported ground  
What causes fly rock? A. Too much overburden; B. Light confinement in the blast hole; C. Optimum depth of blast hole and proper stemming; D. Incomplete detonation of the explosive B. Light confinement in the blast hole  
Which of these is commonly used as a main charge for blasting? A. TNT; B. Dynamite; C. Black powder; D. ANFO, water gels, and emulsions D. ANFO, water gels, and emulsions  
Which is the safest common detonation method? A. Safety fuse and blasting cap; B. Electric detonators; C. Non-electric detonators (Nonel); D. Computer controlled electronic detonators D. Computer controlled electronic detonators  
Explosives magazines must be: A. Ventilated; B. Placarded; C. Locked or attended; D. Covered with non-sparking material on the inside; E. All of the above E. All of the above  
Which two of the following are required for blasting to take place? A. Warning signals for blasting operations; B. Employees trained to recognize blasting hazards; C. Notification of MSHA prior to a blast A. Warning signals for blasting operations; B. Employees trained to recognize blasting hazards  
Which is not a precaution that must be taken prior to initiating a blast? A. Guard the area; B. Yell out; C. Sound a warning prior to the blast; D. Clear all personnel from the blast area B. Yell out  
ANFO and emulsions are types of: A. High explosives; B. Detonators; C. Blasting agents; D. Boosters C. Blasting agents  
What is the most common cause of fatalities related to explosives? A. Burns from explosives fires; B. Fly rock; C. Misfires; D. Improper guarding B. Fly rock  
True or false: Explosives and detonators must always be transported on separate vehicles. False  
True or false: There is one standard warning signal for blasting operations. False  
Is it advisable to attempt to put out an explosives fire quickly with a fire extinguisher? No  
Name two potential hazards when working around explosives. Toxic gases; misfires; lightning; premature detonation; fly rock; unauthorized access  
Which is a characteristic of blasting materials that helps identify them? A. Manufacturer labels; B. Brightly colored such as neon green or orange; C. Colored bright red only; D. Hazard labels B. Brightly colored such as neon green or orange  
At what intervals are warnings given prior to a blast? A. 5 minutes; B. 1 minute; C. Depends on the mine site; D. Both A and B C. Depends on the mine site  
True or false: The best method for fighting explosives fires is by using a water truck. False