Mining Engineering
GATE MN Ground Control PYQs
Build your understanding with focused practice from past exam papers.
How to practice Ground Control
Attempt a question, record the concept and assumptions, then check the available answer. Rework mistakes after revising the relevant concepts. Topic tags can overlap; review the question context.
Questions 1–10 of 25. Imported answers require independent review unless marked reviewed.
Question 24
Open questionMNMCQ1 markNeeds review
The ideal load – deformation characteristic curve of a hydraulic prop is
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 49
Open questionMNNAT2 marksNeeds review
A plug dam is to be constructed in a mine gallery of size 3.5 m × 2.5 m. The interfacial shear strength between the surrounding rock and plug dam is 1.0 MPa. The minimum thickness of the dam, in m, to withstand a water pressure of 10.0 MPa, is _____________. (rounded off to two decimal places)
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Open questionMNMCQ2 marksNeeds review
A ground reaction curve (GRC) of a 3 m radius unlined circular tunnel is shown in the figure. The tunnel is supported by 300 mm thick shotcrete lining. The uniaxial compressive strength (
), modulus of elasticity (
) and Poisson’s ratio (
) of shotcrete material are 20 MPa, 15 GPa and 0.25 respectively. The maximum capacity (
) of the lining and its stiffness (
) are given as
where
= radius of the unlined tunnel and
= thickness of the lining.If the lining is constructed after 5 mm radial deformation, the support reaction is best represented by the line
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 49
Open questionMNNAT2 marksNeeds review
A mine void of dimension 100.0 m x 2.0 m x 1.2 m is to be filled in 3 hours by hydraulic stowing. The sand to slurry ratio is 0.4. If the hydraulic fill factor is 0.9, the hourly consumption of water for the operation, in m^3, is____ (rounded off to 2 decimal places).
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Open questionMNNAT2 marksNeeds review
In a bord and pillar panel, a square pillar of size 35 m × 35 m (centre to centre) is extracted to form four equal square-shaped stooks as shown. The width of each gallery and crosscut is 5 m. The height of the working seam is 3 m. The reduction in safety factor after pillar splitting by using Bieniawski’s pillar strength formula, in %, is____ (rounded off to 2 decimal places)
Bieniawski’s pillar strength formula,
; where,
= strength of 0.9 m^3 of coal block,
= pillar width and
= mining height
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 39
Open questionMNMCQ2 marksNeeds review
The roof convergence data for 30 days at a monitoring station in a coal mine gallery is given.
Day | Convergence reading (mm) |
|---|---|
0 | 0 |
5 | 4.7 |
10 | 11.3 |
16 | 19.6 |
22 | 28.8 |
30 | 34.8 |
The management decides on a Trigger Action Response Plan (TARP) if the following two premises occur simultaneously.
Premise 1: Rate of convergence exceeds 1.5 mm/day between two consecutive measurements.
Premise 2: Rate of cumulative increase in convergence exceeds 1.0 mm/day.
Identify the day on which TARP is enforced in that gallery.
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 53
Open questionMNNAT2 marksNeeds review
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)
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 37
Open questionMNMCQ2 marksNeeds review
A tunnel of diameter 8 m is to be driven in a rock mass having quality index, Q of 1.0. Assume the excavation support ratio (ESR) of the tunnel is 1.0. The support requirement of the tunnel wall using fibre reinforced shotcrete (based on the chart prepared by Grimstad and Barton, 1993) is
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Open questionMNNAT2 marksNeeds review
Strength of a rectangular coal pillar in MPa is given by
where
,
(
) and
are width, length and height of the pillar, respectively. The parameter
is constant.A 30 m square pillar is split into two halves as shown in the figure. The height of the pillar is 3 m. The ratio of safe factors between one half-pillar and the original square pillar is _____.
[rounded off to 2 decimal places]
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Open questionMNNAT2 marksNeeds review
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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