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:
- 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.
- 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.
- 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)
For a continuous miner (CM) panel, the following data are given.
| Parameter | Value |
|---|---|
| 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 (loading, travel, 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.
| Parameter | Value |
|---|---|
| Resistance of each detonator | |
| Resistance of lead wire | |
| Resistance of one wire of the blasting cable |
The total resistance of the circuit in Ω, is _____. (round off up to 2 decimals)
A rectangular face of 2.0 m x 2.5 m dimension is blasted with 20 kg explosive in a 1000 m long drive. One kilogram of explosive produces 2200 cm³ of nitrous fumes. The face is ventilated with a duct, located 10.0 m away from the face, to dilute the fumes. The quantity of air, in m³/s to be circulated for reducing the concentration of nitrous fumes to 5 ppm within a period of 5 minutes, is _____. (round off up to 2 decimals)
Use the relation,
,
where:
- ( t = ) time,
- ( V_m = ) volume of the tunnel over which the mixing of the gases produced at the face, and air delivered by the fan occurs,
- ( c = ) concentration at time ( t ),
- ( V = ) volume of tunnel,
- ( Q = ) quantity of air flow,
- ( q = ) total volume of nitrous fumes produced.
A circular tunnel is constructed at a depth of 100 m. The average unit weight of overburden rock is 27.0 kN/m³. If the tangential stress measured at point A located at the horizontal boundary of the tunnel as shown, is 5.0 MPa, the tangential stress at point B in MPa, 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 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)
In an open pit mine, the mineral inventory, prices, costs and capacities are given.
| Grade interval | Tonnage (in million tonne) |
|---|---|
| 0 < Cu% ≤ 0.3 | 0 |
| 0.3 < Cu% ≤ 0.4 | 5 |
| 0.4 < Cu% ≤ 0.5 | 5 |
| 0.5 < Cu% ≤ 0.6 | 5 |
| 0.6 < Cu% ≤ 0.7 | 5 |
| 0.7 < Cu% ≤ 0.8 | 5 |
| 0.8 < Cu% | 0 |
Concentrating cost : INR 3,200/tonne of ore milled Smelting & refinery cost : INR 10,000/tonne of copper metal Selling price : INR 6,50,000/tonne of copper metal Overall recovery : 100%
Maximum production capacity : 5 million tonne/annum
The mine is operating at 5 million tonne in a year. Considering mining capacity being the only constraint, Lanes’ algorithm (based on profit maximization) is used for determining mill cut-off grade. The total amount of copper produced in million tonne, in the life of the pit, is ______. (round off up to 2 decimals)