Rock Mechanics And Roof Supporting — Part 2 MCQs with Explanations

depth of cover is more is the correct answer to “Which of the following is not a contributory factor for the cause of the subsidence”. This question is standard in competitive examination syllabi for Rock Mechanics And Roof Supporting.

Equal to atmospheric pressure is the correct answer to “The pressure on a phreatic surface is”. This question is standard in competitive examination syllabi for Rock Mechanics And Roof Supporting.

thermistor is the correct answer to “It is an electrical resistance thermometer made from a semi-conductor having a large, negative temperature co-efficient useful to measure the rock temperature”. This question is standard in competitive examination syllabi for Rock Mechanics And Roof Supporting.

Director of Mines Safety is the correct answer to “Support plan of any underground mine shall be approved by”. This question is standard in competitive examination syllabi for Rock Mechanics And Roof Supporting.

one for every meter length of bar is the correct answer to “In order to maintain contact with the immediate roof, laggings are put with the cross-bars. The norms of putting such laggings is”. This question is standard in competitive examination syllabi for Rock Mechanics And Roof Supporting.

135 is the correct answer to “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/m 3 of the sample at the time of failure is”. This question is standard in competitive examination syllabi for Rock Mechanics And Roof Supporting.

51 is the correct answer to “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”. This question is standard in competitive examination syllabi for Rock Mechanics And Roof Supporting.

5000 kg/cm2 is the correct answer to “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”. This question is standard in competitive examination syllabi for Rock Mechanics And Roof Supporting.

Colliery manager is the correct answer to “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”. This question is standard in competitive examination syllabi for Rock Mechanics And Roof Supporting.

0.125 is the correct answer to “The specific gravity of gypsum mineral is 2.4. If the density of a gypsum core is 2100 kg/m 3 , the porosity of that core is”. This question is standard in competitive examination syllabi for Rock Mechanics And Roof Supporting.

good is the correct answer to “If a rock type has RMR value 70, then what will be its roof class”. This question is standard in competitive examination syllabi for Rock Mechanics And Roof Supporting.

3.20 is the correct answer to “The measurements of a site investigation are as follows: In = 9, Jr = 1.5, Ja = 2.0, Jw = 1.0. SRF = 2.5. The RQD values taken from five boreholes of the area are 94.2, 95.6, 99.4, 95.3 and 98.0 respectively. The rock mass quality index (Q) is”. This question is standard in competitive examination syllabi for Rock Mechanics And Roof Supporting.

supporting the roof is the correct answer to “The objective of such activity is to restrict displacements of the country rock to elastic orders of magnitude and to maintain as far as practicable the integrity of both the country rock and the unmined remnants within the ore body. Identify the mining activity”. This question is standard in competitive examination syllabi for Rock Mechanics And Roof Supporting.

2.60 ∗ 10-4 is the correct answer to “During uniaxial compressive testing of a rock specimen of diameter 54 mm and length 120 mm, the axial strain was found to be 6.5 × 10 -4 mm/mm. If the Poisson's ratio of the rock is 0.3, the volumetric strain of the rock specimen in mm/mm is”. This question is standard in competitive examination syllabi for Rock Mechanics And Roof Supporting.

42 is the correct answer to “From a series of tri-axial tests conducted on some sandstone specimens, the relationship between the major and the minor principal stresses in MPa is found to be σ 1 = 100 + 5 σ 3 . The angle of internal friction in degrees of that sandstone is”. This question is standard in competitive examination syllabi for Rock Mechanics And Roof Supporting.

15 is the correct answer to “The components of state of stress at a point in x - y plane are given as σ xx = 5 MPa, σ yy = 10MPA and $${\tau _{xy}}$$ = 2MPa. The sum of the principal stresses acting on the x - y plane in MPa is”. This question is standard in competitive examination syllabi for Rock Mechanics And Roof Supporting.