GATE MN topic:mining PYQs & Answers — Page 26

Questions 251–260 of 650. Imported answers require independent review unless marked reviewed.

Topic practice 650 questionsPage 26 of 65

A thermal power station receives coal of calorific value 4000 kcal/kg and uses 700 tonnes of coal every day. Assuming 860 kcal is the heat equivalent of 1.0 kWh, for a thermal efficiency of 40% and electrical efficiency of 85% the power generation per day in MWh is _____.

[rounded off to 1 decimal place]

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A coal company has three mines which transport coal to four washeries. The daily production from each mine, the demand at each washery and unit transportation cost from each mine to each washery are given in table

Mine	W1	W2	W3	W4	Supply (tonnes/day)
M1	19	30	50	10	700
M2	70	30	40	60	900
M3	40	8	70	20	1800
Demand (tonnes/day)	500	800	700	1400

The cost of initial basic feasible solution using Vogel’s approximation method is _____.

[rounded off to 1 decimal place]

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A workship has four tasks and equal number of machines to perform the tasks. Each of the machines can perform only one of the four tasks. The estimated cost at each of the machines to complete each task is given in table

| MACHINE | T1 | T2 | T3 | T4 | |---|---:|---:|---:|---:|---:| | M1 | 10 | 40 | 60 | 30 | | M2 | 90 | 70 | 100 | 90 | | M3 | 40 | 50 | 110 | 70 | | M4 | 80 | 70 | 80 | 50 |

The total cost of optimal assignment is_____.

[rounded off to 1 decimal place]

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The time between consecutive accidents in days in an underground coal mine in a year are as follows

10, 15, 6, 18, 12, 14, 16, 9, 21, 15, 26, 18, 22, 25, 13

Assuming exponential distribution, the probability that there will be no accident over a 10-day period is _____.

[rounded off to 2 decimal places]

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A surface mine blast pattern has spacing 4 m and burden 3 m. The diameter of the drill hole is 110 mm. The drilling length is 8.8 m including subgrade of 10%. The bulk explosive density is 900 kg/m³.

If the powder factor is 2.5 m³/kg, the charge length in m is _____.

[rounded off to 2 decimal places]

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A mining company makes an initial investment of Rs 200 crore on a project.

The following data are available:

Production life : 3 years Year wise production after gestation period (Mtonne) : 1.0, 2.0, and 1.0 Stripping ratio : 1.5 m³/tonne Selling price of ore : Rs. 200 per tonne Ore mining cost : Rs. 500 per tonne Waste mining cost : Rs. 500 per m³ Discount rate : 10%

By ignoring any other cash-flows, if the NPV of the project becomes Rs. 5.367 crore, the gestation period of the project, in years is _____.

[rounded off to the nearest integer]

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A rock slope is intercepted by a joint plane at an angle 30° as shown in figure.

Diagram for Mining Engineering question 62

The following data are available

Unit weight of the rock : 20 kN/m³ Cohesion of joint : 30 kPa Friction angle of joint : 22°

The factor of safety of the rock slope to slide along the joint plane is _____.

[rounded off to 2 decimal places]

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A mine void of width 20 m, length 50 m and height 30 m is to be filled with mill tailings based cemented paste backfill (CPB). The CPB contains tailings:cement:water as 1.0:0.1:0.2 by weight. The specific gravity of tailings and cement are 2.8 and 2.4 respectively. Assuming 20% of the original volume of water is retained in the final backfill, the amount of cement in tonne required so as to fill the void completely is _____.

[rounded off to nearest integer]

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A fan installed in a line ventilation system circulates 30 m³/s of air to two districts A and B as shown in Figure below. It is desired to increase the quantity of air by 20% in the district B using a booster fan in it. Assuming that the main fan pressure is unchanged, the pressure of the booster fan, in Pa, is _____.

[rounded off to 2 decimal places]

Diagram for Mining Engineering question 64

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Data related to a water turbine pump with backward bladed impellers are given below:

Impeller diameter : 35 cm RPM : 1200 Angle of curvature of blade : 30° Radial velocity of discharge : 2 m/s Manometric efficiency : 0.8

The number of impellers required in the pump to lift water by a height 300 m is _____.

[rounded off to higher integer]

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GATE MN topic:mining PYQs

Question 56

Question 57

Question 58

Question 59

Question 60

Question 61

Question 62

Question 63

Question 64

Question 65