Mining Engineering
2023 · Paper 1
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Complete GATE MN 2023 Paper 1 overview, original pages and practice · Timed previous-paper practice
Questions 61–63 of 65. Imported answers require review unless explicitly marked reviewed.
Question 61
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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.
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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