Introduction To Mining Engineering - Study Mode
[#356] A bucket wheel excavator with 20 buckets of capacity 0.5 m 3 each, rotates at 5 rev/min. The bucket fill factor is 80%. The excavator loads on to 1200 mm wide belt conveyor. The cross-section area (m 2 ) of the material on the belt is 0.1B 2 , where B is the belt width in m. The minimum speed of the belt in m/s to avoid spillage of material is
Correct Answer
(C) 4.63
[#357] An ore block of length 30m and height 20m having an average width of 1.5m with sharp boundary walls is mined with a minimum mining width of 2m. If the tonnage factors are 3 t/m 3 for ore, 2 t/m 3 for wall rock and average grade of ore is 10%, the diluted grade of ore mined in percent is
Correct Answer
(C) 8.18
[#358] In an overburden bench of an iron ore mine the following data were found: Height = 10m Burden = 4m Spacing = 3m Sub-grade drilling length = 1m Collar stemming length = 3m If the diameter of the explosive column is 150 mm and the specific gravity of explosive and that of rock are 0.9 and 2.4 respectively, the powder factor in te/kg will be
Correct Answer
(C) 2.26
[#359] Cut & Fill stoping can be done by
Correct Answer
(D) All of the above
[#360] A flat coal seam of thickness (t) 3m is excavated and broken roof rock has completely filled the space created due to extraction as shown in the figure. If the bulking factor of roof rock is 1.2. the caving height (H) in m is
Correct Answer
(A) 15