A thermal power plant has an agreement with three mines M1, M2 and M3 to receive ‘Grade 1’ coal, in the proportion of 60%, 25% and 15%, respectively. The probabilities that a wagon supplied coal to the plant containing below ‘Grade 1’ from mines M1, M2 and M3 are 0.02, 0.03 and 0.04, respectively. On a random check, a sample wagon is found to carry below ‘Grade 1’ coal. The probability that the wagon belongs to mine M1, is _____. (round off up to 2 decimals)
Polluted air with particulate matters of diameter 50 µm enter with a horizontal velocity of 1.0 m/s at a height of 0.5 m from the bottom of a dry settling chamber. The density of the particle is 2000 kg/m³ and dynamic viscosity of the air is 1.8 × 10⁻⁵ kg/m-s. Assume streamline flow and the density of air is negligible as compared to particles and uniform horizontal velocity of 1.0 m/s of gas and particles within the chamber. Considering particle settling follows Stoke’s law, the minimum length in m, of the chamber required for settling of the particle at its bottom, is _____. (round off up to 2 decimals)
In a tacheometry survey, the readings observed are given.
| Instrument Station | Staff Station | Bearing of line of sight | Vertical angle | Staff readings (m) |
|---|---|---|---|---|
| P | A | 145° | +8° | 1.2, 1.7, 2.2 |
| B | 205° | +3° | 0.8, 1.2, 1.6 |
The additive and multiplying constants of the instrument are 0 and 100, respectively. The length of the line AB in m, is _____. (round off up to 2 decimals)
The data obtained from an air sample analysis of an old working in a coal mine are given.
O₂ 17.15%, CO₂ 3.40%, CH₄ 2.20%, and N₂ 77.25%.
Considering atmospheric air contains O₂ 20.95%, CO₂ 0.03%, and N₂ 79.02%, the percentage of blackdamp in the old working, is _____. (round off up to 2 decimals)
The root of the function, in the interval [0, 1] using bisection method after two iterations, is _____. (round off up to 2 decimals)
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)
Match the method of mining with orebody geometry, orebody strength and type of supports.
| Geometry | Strength | Support | Method |
|---|---|---|---|
| P. Tabular & Moderately Steep | L. Strong | X. Unsupported | 1. Cut and Fill |
| Q. Tabular & Flat | M. Moderate | Y. Artificially Supported | 2. Block Caving |
| R. Massive and Steep | N. Weak | Supported | 3. Room and Pillar |
Water is pumped from a mine sump at the rate of 300 m³/hr to an inverted conical water tank, as shown. The rate of rise in water level in m/min, at the instant water level reaches at 5 m height from bottom of the tank, 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 for a centrifugal pump discharging water from a sump to the surface are given.
| Parameter | Value |
|---|---|
| Head, m | 180 |
| Discharge rate, m(^3)/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/m(^3) | 10.20 |
The annual electrical power consumption in GWh, due to pumping operation, is _____. (round off up to 2 decimals)