Rock Mechanics and Roof Supporting MCQs Questions & Answers

41.
Which of the following is not a contributory factor for the cause of the subsidence?

A. stowing is not done

B. depth of cover is more

C. friable nature of superincumbent rock

D. void is not supported effectively

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42.
The pressure on a phreatic surface is

A. Less than atmospheric pressure

B. Greater than atmospheric pressure

C. Equal to atmospheric pressure

D. Independent of atmospheric pressure

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43.
It is an electrical resistance thermometer made from a semi-conductor having a large, negative temperature co-efficient useful to measure the rock temperature

A. calibrator

B. thermistor

C. micro-seismic monitor

D. geophone

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44.
Support plan of any underground mine shall be approved by

A. Colliery Manager

B. Safety Officer

C. Director (Technical)

D. Director of Mines Safety

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45.
In order to maintain contact with the immediate roof, laggings are put with the cross-bars. The norms of putting such laggings is

A. one for every meter length of bar

B. three for every meter length of bar

C. five for every meter length of bar

D. no such stipulation

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46.
The uni-axial compressive strength and modulus of elasticity of a rock sample are 90 MPa and 30 GPa respectively. The stored strain energy per unit volume in kN.m/m³ of the sample at the time of failure is

A. 1.5

B. 140

C. 270

D. 135

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47.
The ratio of uniaxial compressive strength to uniaxial tensile strength of a sandstone specimen is 8 : 1. The theoretical, value of angle of internal friction of the specimen in degree is

A. 51

B. 41

C. 32

D. 7

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48.
In a point load test on 50 mm diameter core specimen. rupture was observed at a load of 5000 kg. The uni-axial compressive strength of the specimen was

A. 3800 kg/cm²

B. 4000 kg/cm²

C. 4800 kg/cm²

D. 5000 kg/cm²

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49.
After every round of blasting, support of roof and sides shall be tested at places within the zone of influence of blasting. Who decides this zone?

A. Overman

B. Asst manager (blasting)

C. Colliery manager

D. Agent

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50.
The specific gravity of gypsum mineral is 2.4. If the density of a gypsum core is 2100 kg/m³, the porosity of that core is

A. 0.062

B. 0.125

C. 0.5

D. 0.875

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Rock Mechanics and Roof Supporting MCQs Questions & Answers | Mining Engineering

41. Which of the following is not a contributory factor for the cause of the subsidence?

Answer & Solution

42. The pressure on a phreatic surface is

Answer & Solution

43. It is an electrical resistance thermometer made from a semi-conductor having a large, negative temperature co-efficient useful to measure the rock temperature

Answer & Solution

44. Support plan of any underground mine shall be approved by

Answer & Solution

45. In order to maintain contact with the immediate roof, laggings are put with the cross-bars. The norms of putting such laggings is

Answer & Solution

46. The uni-axial compressive strength and modulus of elasticity of a rock sample are 90 MPa and 30 GPa respectively. The stored strain energy per unit volume in kN.m/m3 of the sample at the time of failure is

Answer & Solution

47. The ratio of uniaxial compressive strength to uniaxial tensile strength of a sandstone specimen is 8 : 1. The theoretical, value of angle of internal friction of the specimen in degree is

Answer & Solution

48. In a point load test on 50 mm diameter core specimen. rupture was observed at a load of 5000 kg. The uni-axial compressive strength of the specimen was

Answer & Solution

49. After every round of blasting, support of roof and sides shall be tested at places within the zone of influence of blasting. Who decides this zone?

Answer & Solution

50. The specific gravity of gypsum mineral is 2.4. If the density of a gypsum core is 2100 kg/m3, the porosity of that core is

Answer & Solution

41.
Which of the following is not a contributory factor for the cause of the subsidence?

42.
The pressure on a phreatic surface is

43.
It is an electrical resistance thermometer made from a semi-conductor having a large, negative temperature co-efficient useful to measure the rock temperature

44.
Support plan of any underground mine shall be approved by

45.
In order to maintain contact with the immediate roof, laggings are put with the cross-bars. The norms of putting such laggings is

46.
The uni-axial compressive strength and modulus of elasticity of a rock sample are 90 MPa and 30 GPa respectively. The stored strain energy per unit volume in kN.m/m³ of the sample at the time of failure is

47.
The ratio of uniaxial compressive strength to uniaxial tensile strength of a sandstone specimen is 8 : 1. The theoretical, value of angle of internal friction of the specimen in degree is

48.
In a point load test on 50 mm diameter core specimen. rupture was observed at a load of 5000 kg. The uni-axial compressive strength of the specimen was

49.
After every round of blasting, support of roof and sides shall be tested at places within the zone of influence of blasting. Who decides this zone?

50.
The specific gravity of gypsum mineral is 2.4. If the density of a gypsum core is 2100 kg/m³, the porosity of that core is