Mining Engineering
GATE MN purpose:exam-prep PYQs
Build your understanding with focused practice from past exam papers.
Questions 371–380 of 650. Imported answers require independent review unless marked reviewed.
Question 36
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In order to check whether iron ore is supplied to the specification of 62% Fe, a steel company has conducted a hypothesis test with the null hypothesis as H₀: μFe = 62% and alternative hypothesis Ha: μFe < 62%. A random sample of 5 observations reveal the following grade values of the lot, 58%, 56%, 60%, 64%, 62%. The t-test statistic for the hypothesis is
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Production plan of a small quarry having 3 years of life is shown in the figure.
The following information of revenue and cost data are available. Ore: 3.0 million tonne each year; waste: 5.0 million m³ in the 1st year, 5.5 million m³ in the 2nd year, and 5.0 million m³ in the 3rd year. Selling price of ore = Rs. 150/tonne. Ore mining cost = Rs. 500/tonne. Waste mining cost = Rs. 500/m³. Initial capital = Rs. 1000 million. Discount rate = 10%. By neglecting depreciation, salvage value and corporate tax, the NPV of the mining project, in million Rs., is ______. [round off to 2 decimal places]
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A triangular distributed load is applied on top of a beam as shown in the figure.
The value of maximum bending moment in kN-m is ______. [round off to 2 decimal places]
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For a dumpy level, the bubble tube has sensitivity of 40″ for one division. While taking a staff reading at a distance of 60 m, the bubble is out of centre by 2 divisions. The error in staff reading in mm is ______. [round off to one decimal place]
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On an old plan of scale 1:100, leasehold area of a mine is now measured as 802 cm² using a planimeter. The plan is found to have shrunk, such that the original line of 10 cm is now measured as 9.8 cm on the plan. True lease hold mine area, in m², is ______. [round off to the nearest integer]
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CO is released from a point source on a level ground at a rate of 25 g/s. The average wind speed is 5 m/s. The dispersion coefficients are 150 m and 200 m in horizontal and vertical directions, respectively, at a receiver station located on the ground along the downwind direction. Assuming the plume follows Gaussian dispersion model, the concentration of CO, in μg/m³, at the station is ______. [round off to 2 decimal places]
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Assume that COVID-19 growth rate of number of infections per day (c) in a certain population is represented by the following differential equation.
Here, t stands for time in days. Time taken for the number of infections per day to double, in days, is ______. [round off to the nearest integer]
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Ore is hoisted from 620 m depth using a single skip of 7 tonne pay load. The skip winding system has constant acceleration/deceleration of 1 m/s² and a constant speed of 10 m/s. The skip loading time and unloading time are 120 s and 60 s, respectively. Considering the overall utilization of the skip as 70 %, the maximum daily capacity of the winding system, in tonne, is ______. [round off to the nearest integer]
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In an analysis of fragmented blast muck, the mean fragment size is found to be 60 cm with uniformity index of 1.25. Considering Rosin-Ramler equation, the cumulative mass fraction, in percent, to pass the grizzly screen size of 100 cm is ______. [round off to 2 decimal places]
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A single-acting reciprocating ram pump, while running at 120 rpm, delivers water at a rate of 10 litres per second. Considering the ram diameter is 150 mm and stroke length is 300 mm, the volumetric efficiency of the pump, in percent is ______. [round off to one decimal place]
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