List of top Mining Methods and Machinery Questions

A Bord and Pillar panel is developed at a depth of 250 m in a flat coal seam. The vertical stress gradient is 0.027 MPa/m. If the strength of a square pillar is 12.5 MPa, the extraction ratio of the pillar for a safety factor of 1.5, is____.(round off up to 2 decimals)

A mine worker weighing (W) 600 N lifts an object of 100 N as shown. The 50% body weight is applied downward through point A and a force FE is produced parallel to x axis by the contraction of erector spinae muscle during lifting. The lumber disc, L (shown by red box) acts as a smooth hinge and keeps the upper body in static equilibrium. Ignore all other forces in the body. The magnitude of the resultant of the reaction forces, in N at the lumber disc, is____.(round off up to 2 decimals)

For a continuous miner (CM) panel, the following data are given.
Data related to CM 
Dimension of a working face  : 5.0 m (width) x 3.0 m (height)
Web depth m : 0.6 
Time for one web cut up to full height, min :  9 
Data related to shuttle car
Bucket capacity of shuttle car, tonne : 10 
Fill factor : 0.9 
Number of cars : 2 
Cycle time of each car including loading, travel and unloading, min : 6 
Assume, unit weight of coal is 1.4 tonne/m3 and its swell factor is 1.2. Consider, 6 working hours per shift. 
The non-working time in min, in working hours per shuttle car to dispatch all coal cut by the CM, is____ (round off up to 2 decimals) 

In a development coal face, 12 holes are drilled and charged with explosive. Holes are initiated with electric delay detonators connected in series. The length of a detonator lead wire is 1.5 m. The length of the blasting cable is 120 m.
Data are as given: 
Resistance of each detonator : 1.48 Ω
Resistance of lead wire : 0.04 Ω/m
Resistance of one wire of the blasting cable : 0.009 Ω/m 
The total resistance of the circuit in , is____.(round off up to 2 decimals)

A 1.2 m diameter drum winding system is shown. One of the winding ropes will be replaced for the manwinding cage.

Consider the following:
1) A new rope is recapped once at least in every 6 months and a length of 2 m including existing capping is to be cut off from the rope before recapping.
2) The maximum life of a rope is 3.5 years and at least 2 rounds of rope should remain on the drum while the descending cage lands at the bottomost landing point.
3) No overwinding will take place during the maximum life of the new rope. 
Neglecting the impact of fleet angle on the length of the rope, the minimum length, in m, of new winding rope is ____.(round off up to 2 decimals)

A 35.0 kW motor transmits power to a pulley of 600 mm diameter, which rotates at 400 rpm to drive a flat belt. The tension in the tight side is 2.5 times of the slack side. Neglect all transmission losses. If the maximum allowable tension is 8.0 N per mm of belt width, then the minimum width of the belt in mm, is____.(round off up to 2 decimals)

A longitudinal section of a mined out stope block in a copper mine is shown by the shaded portion. For a uniform thickness of the stope block, the percentage of ore recovery, is____.(round off up to 2 decimals)

Data for a centrifugal pump discharging water from a sump to the surface are given.
Head, m : 180 
Discharge rate, m m³/hr : 320 
Operating hours per day for 270 days in a year : 14 
Operating hours per day for remaining 95 days : 20 
Overall efficiency of the pumping system  : 0.70 
Specific weight of mine water, kN/m³  : 10.20
The annual electrical power consumption in GWh, due to pumping operation, is____(round off up to 2 decimals)

A transportation system for carrying ore from stock pile to railway siding through an ore bin is shown. The time between failure of each conveyor belt follows an exponential distribution with mean time between failure of 700 hours. The system is considered to be a 'success' if ore transports from stock pile to siding by any combination of belts. The reliability of the system for 350 hours of continuous successful operation, is_____.(round off up to 2 decimals)

Data from two production faces of an open pit iron ore mine are given.

Item description	Face 1	Face 2
Maximum production capacity (tonne/day)	1600	2000
Fe (%)	63	58
Production cost of ores (in INR/tonne)	1500	1200

Ores from two different faces are blended and supplied with Fe grade not less than 60 %. Based on the demand, the combined production is limited to a maximum of 2500 tonne/day. If the selling price of blended iron ores is INR 4500 /tonne, the optimal production from two faces in tonne/day, for maximizing the profit, respectively are

The ore that is NOT used for commercial extraction of metal is

In an underground coal mine, two fatalities and three serious bodily injuries occurred during the year 2022. The average daily employment is 1100 and annual working days is 300. The severity index as per DGMS guideline for the mine is