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 _____.
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 _____.
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 _____.
The Mohr circle of stress of a dry porous rock is shown in the figure. If the rock is fully saturated with a pore pressure , then the Mohr circle takes the form of
Figure shown relates to the manufacture of roof bolts. With respect to the cost/revenue vs production level, match the appropriate trend line with corresponding description.
| Line | Item |
|---|---|
| (P). A | (1). Total cost |
| (R). B | (2). Indirect operating cost |
| (S). C | (3). Revenue |
The value of is
Production planning of a small quarry having 3 years of life is shown in the figure. The following information of revenue and cost data are available.
Selling price of ore = Rs. 1500/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]
Assume that COVID-19 growth rate of number of infections per day (c) in a certain population is represented by the following differential equation.
Where, t stands for time in days. Time taken for the number of infections per day to double, in days, is _____.
A 10 ml sample of wastewater is diluted with water having no BOD, to fill a 300 ml BOD bottle. The initial DO of the diluted waste water is 9.0 mg/l. If the BOD of the waste water sample is 60 mg/l, the final DO of the diluted waste water in mg/l, is
The straight line shown depicts the failure criterion of a rock type. The values of stress at points A and B are as shown. The safety factor at the points A and B respectively are