MNG 331 Final Exam Questions And Answers Graded A+ Guaranteed Pass.

Match the following event to its cause in the fragmentation process. - correct answer Fractures extend to free face → Gas Pressure Crushing and grinding in moving of muckpile → Secondary Fragmentation Crushing around the hole → Shock Wave Rotation of fragments → Momentum Who invented the blasting cap? - correct answer Alfred Nobel Who invented dynamite? - correct answer Alfred Nobel The purpose of explosives is to break rock so we can easily: - correct answer load, crush, haul, dig it What is the most efficient way to use explosives? - correct answer (Minimize energy expended on making: Air blast, ground vibrations, and flyrock, Maximize energy used to break rock to requirements) On average, how much explosives does the United States use every year? - correct answer 6 billion pounds The goals of the course include: - correct answer To be knowledgeable in the subject and be confident and able to design blasting shots. The course objectives include: - correct answer Obtain an understanding of explosives and explosive products, and the ability to apply this to the breakage of rock in an environmentally acceptable and safe manner. Are Explosives affected by freezing temperatures? - correct answer True Water gels and slurries contain: - correct answer Ammonium Nitrate (AN), Fuels The difference between detonation and deflagration is dictated primarily by which explosive property? - correct answer Sonic velocity of the explosive mixture. In wet holes, explosive density should be? - correct answer greater than 1, the hole should be dewatered, and a water resistant explosive should be used. Does Propagating ground reduce misfires. - correct answer No it does not Is it possible to get a blend density that is higher than the density of 100% emulsion? - correct answer Yes it is A moderate variation of the amount of fuel oil in ANFO will affect? - correct answer energy, production of fumes, sensitivity, and velocity. The relative bulk strength of an explosive is relative to? - correct answer ANFO. Which of the following is not an advantage of Gassed Emulsion? - correct answer Does not require special equipment to load. Permissible explosives are? - correct answer low flame, classified for use in coal mines, and used in underground operations that are classified "gassy." Black Powder is a? - correct answer DEFLAGRATING explosive product Which is the highest density explosives product? - correct answer Cast booster When considering fuel content in ANFO? - correct answer it is typically preferred to be overfueled rather than underfueled. Which explosive has the least water resistance? - correct answer ANFO Detonation velocity is dependant on: - correct answer Explosive type, Confinement, Charge diameter, and Priming Which of the following statements is incorrect regarding propagating ground? - correct answer Reduces mis-fires Which type of initiation system lingers as a player in the market due to permissibility? - correct answer Electric. If 10 blasting caps are wired in parallel and each blasting cap is 3 Ohms, - correct answer the total resistance of the circuit will be 0.3 Ohms. Are Electronic detonators accurate to 1 microsecond. - correct answer No they are not Non electric systems are safe to use in the presence of which of the following: - correct answer stray electricity Which initiation system is traditionally known to have cap scatter of at least +/- 5%? - correct answer Nonel Which type of initiation system is used most effectively for vibration control? - correct answer Programmable Electronic If 20 electric blasting caps are wired in series and the resistance of each cap is 2.5 Ohms, - correct answer the total resistance is 50 Ohms. The ALL FIRE current of a standard electric cap is 250 milliamps, and the NO FIRE current is 50 milliamps. - correct answer Nonel can be cut and spliced where? - correct answer Only on the lead line. Commercial detonating cord contains which of the following explosives? - correct answer PETN What primary explosive is typically used in commercial detonators currently being produced? - correct answer Lead Azide What is the safety factor of a blaster's multimeter when checking an electric blasting cap? - correct answer 10 Which of the following are correct about a safety fuse? - correct answer It is designed to burn at 40 seconds per foot, its burning rate varies with moisture content and age, and its burning rate varies with altitude. Nonel comprises a hollow tube with? - correct answer dusting of HMX and Aluminum. For bench blasting a 4 inch hole loaded with ANFO, the burden and spacing should be: - correct answer 8 x 12 ft If a large void is encountered during drilling, the hole should be loaded as follows: - correct answer Deck through the void with stemming, reprime above decking and continue loading Hard toe is caused by: - correct answer Too high a burden at the toe, insufficient energy at the bottom of the hole, bad drilling, mis-fires The most effective way to produce smaller rock is to - correct answer increase powder factor The most complete fragmentation occurs? - correct answer around the powder Oversize found in the middle of a muckpile is most likely a potential sign of? - correct answer a mis-fire The column density of a 3.5 inch hole loaded with bag ANFO is how many pounds per foot of hole? - correct answer 3.5 The jointing and bedding in a limestone ledge will? - correct answer determine the suitability for jetty stone, control face profile, determine the best blasting direction Primers should only be assembled? - correct answer at the time of use, not be tamped, not have cartridges above 4" in diameter be dropped on them in the blast hole A good starting place for powder factor in bench blasting is? - correct answer 0.5 lb/ton or 1 lb/yd3 Oversize will be a problem if the blast hole spacing is? - correct answer 2 to 3 times the joint spacing. For blasting massive rock, which is the most important rock strength? - correct answer Tensile Having a face height too low normally results in? - correct answer poor breakage, too small of powder factor, flyrock, stemming ejection Which post blast phenomenon is the key indicator of insufficient delay on the back row of a bench blast... - correct answer Hint... This is the one discussed in class. Several of these may be indicators, but only one is the "KEY" indicator. Think about the picture of a man walking in what seems to be a muckpile. Where is this muckpile? Rock from the blast on the bench behind Having too high of a face height can result in? - correct answer drilling inaccuracies, flyrock, and toe. For the use of delays in a blast, which of the following are correct? - correct answer Using delays reduces ground vibrations, there are optimum delay periods for minimum vibration, there are optimum delays for fragmentation. The fragmentation process includes? - correct answer dynamic shock wave fracturing the rock, tensile reflection at the free face, gas pressure induced radial fracturing, crushing and grinding caused by movement. Increasing degrees of freedom in blasting results in? - correct answer increased fragmentation. The rules of thumb for minimum delay period are: - correct answer 1 ms per foot of burden hole to hole (on same row), 3 ms per foot of burden row to row, and 3 ms per meter of burden hole to hole (on same row) Bench blasting is the most common form of blasting because: - correct answer It's easy to drill vertical holes, Free face to blast allows easy breakage, Low cost blasting. Under MSHA regulations, a vehicle carrying explosives must be: - correct answer maintained in good condition, equipped with sides higher than the explosive transported, equipped with a non-sparking cargo space, have dry chemical fire extinguishers, and be secured while parked with the brakes set, wheels chocked off, and the engine shut off. The person most likely to be injured during a blast is: - correct answer Blaster If a blast is delayed more than 72 hours, then.... - correct answer The operator shall notify the appropriate MSHA district office. Flyrock is caused by? - correct answer insufficient burden, mud seams and cavities, improper timing, stemming that doesn't hold well (all of the above.)