Introduction To Mining Engineering - Study Mode
[#161] The ratio of weight per unit volume of solid rock mass in the bench and weight per unit volume of loose rock mass after blasting or loosening is called
Correct Answer
(D) swell factor
[#162] It is the mining method in which masses, panels or block of ore are undercut to induce caving, permitting the broken ore to be drawn off below
Correct Answer
(B) block caving
[#163] Risk of premature collapse and over-ridding of pillars are maximum with
Correct Answer
(C) bord and pillar
[#164] Danger of air blast is maximum with
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(C) blasting gallery
[#165] In a coal mine the depth of working is 200 m from surface, width of galleries 3 m, height of galleries 3 m and distance of square pillars between centres of bords is 22.5 m. What is strength of the pillar
Correct Answer
(D) 139.97 kg/cm 2