MNG 331 Quizzes Verified And Accurate Questions And Answers Guaranteed Pass,

Why is the use of explosives important to our economy? - correct answer -Drilling & blasting is the least expensive way of breaking solid rock. -If it's hard rock, you have to use explosives to break it so you can economically mine it. -If we didn't have explosives, many raw materials would be very expensive. On average, how much explosives does the United States use every year? - correct answer 6 billion pounds What is the most efficient way to use explosives? - correct answer -Maximize energy used to break rock to requirements. -Minimize energy expended on making: Air blast, ground vibrations, and flyrock. Who invented the blasting cap? - correct answer Alfred Nobel Who invented dynamite? - correct answer Alfred Nobel 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. The purpose of explosives is to break rock so we can easily: - correct answer Dig It Load It Haul It Crush It The goals of the course include: - correct answer To be knowledgeable in the subject and be confident and able to design blasting shots Secondary Fragmentation - correct answer Crushing and grinding in moving of muckpile Gas Pressure - correct answer Fractures extend to free face Shock Wave - correct answer Crushing around the hole Rotation of fragments - correct answer Momentum What is optimum fragmentation? - correct answer It varies from operation to operation. Which of the following explosives has the least water resistance? - correct answer ANFO Which is the highest density explosives product? - correct answer Cast Booster The relative bulk strength of an explosive: - correct answer Is relative to ANFO In wet holes, which of the following apply? - correct answer -Explosive density should be greater than 1. -A water resistant explosive should be used. -The hole should be dewatered if possible. Explosives are not affected by freezing temperatures (T or F) - correct answer False Detonation velocity is dependent on: - correct answer -Explosive Type -Charge diameter -Confinement -Priming Permissible explosives are: - correct answer -Classified for use in coal mines -Used in underground operations that are classified "gassy" -Low flame Water gels and slurries contain: - correct answer -Ammonium Nitrate -Fuels A moderate variation of the amount of fuel oil in ANFO will affect: - correct answer -Energy -Sensitivity -Velocity -Production of fumes Which of the following statements is incorrect regarding propagating ground? -Negates the effect of delays -Causes high levels of vibrations -Can lead to dead pressing -Reduces mis-fires -Results in improper fragmentation - correct answer Reduces mis-fires The ALL FIRE current of a standard electric cap is _____, and the NO FIRE current is _____. - correct answer 250 milliamps, 50 milliamps 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 safety fuse? - correct answer -Its burning rate varies with altitude. -Its burning rate varies with moisture content and age. -It is designed to burn at 40 seconds per foot Non electric systems are safe to use in the presence of which of the following: - correct answer Stray electricity Nonel can be cut and spliced where? - correct answer Only on the lead line Nonel comprises which of the following: - correct answer A hollow tube with dusting of HMX and Aluminum Commercial detonating cord contains which of the following explosives? - correct answer PETN Electronic detonators are accurate to 1 microsecond. (T or F) - correct answer False If 20 electric blasting caps are wired in series and the resistance of each cap is 2.5 Ohms, the total resistance is _____ Ohms. - correct answer 20*2.5=50 If 10 blasting caps were wired and each blasting cap is 3 Ohms, the total resistance of the circuit will be _____ Ohms. - correct answer 3/10=0.3 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 The most complete fragmentation occurs - correct answer Around the powder Increasing degrees of freedom in blasting results in increased fragmentation (T or F) - correct answer True 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 A good starting place to powder factor in bench blasting is - correct answer 0.5 lb/ton The most effective way to produce smaller rock is to - correct answer Increase powder factor Having a face height too low normally results in - correct answer -Poor Breakage -Too small of powder factor -Flyrock -Stemming ejection Having a face height too high normally results in - correct answer -Poor breakage -Drilling inaccuracies -Flyrock -Toe For bench blasting a 4 inch hole loaded with ANFO, the burden and spacing should be - correct answer 8 x 12 ft 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 Primers should: -Only be assembled at time of use -Not be tamped -Not have cartridges above 4" in diameter be dropped on them in the blast hole - correct answer All of the above The jointing and bedding in a limestone ledge will: -Determine the suitability for jetty stone -Control face profile -Determine the best blasting direction - correct answer All of the above For blasting massive rock, which is the most important rock strength? - correct answer Tensile Oversize will be a problem if the blast hole spacing _____ times the joint spacing - correct answer 2 to 3 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 rules of thumb for minimum delay period are: - correct answer -1 ms per foot of burden hole to hole (same row) -3 ms per foot of burden row to row -3 ms per meter of burden hole to hole (on same row) 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 Oversize found in the middle of a muckpile is most likely a potential sign of - correct answer A misfire Which post blast phenomenon is the key indicator of insufficient delay on the back row of a bench blast? - correct answer Rock form the blast on the bench behind Hard toe is caused by: - correct answer -Too high a burden at the toe -Insufficient energy at the bottom of the hole -Bad drilling -Misfires If a blast is delayed more than 72 hours, then... - correct answer The operator shall notify the appropriate MSHA district office. Under combined MSHA and OSHA regulations, the drilling of holes next to holes being loaded or already loaded is only allowed at a distance farther than... - correct answer -50 ft -30 ft if a barrier is used Under MSHA regulations, "the area where explosive material is handled during loading included..." is defined as the... - correct answer Blast Site Under MSHA regulations, a vehicle carrying explosives must be: - correct answer -Main