Mining Engineering > GATE 2023 > Underground Coal Mining
Strength of a rectangular coal pillar in MPa is given by
where w, l(≥ w) and h are width, length and height of the pillar, respectively. The parameter S1 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 safety factors between one half-pillar and the original square pillar is [rounded off to 2 decimal places]
The ratio of safety factors between one half-pillar and the original square pillar is [rounded off to 2 decimal places]
Correct : 0.78
Similar Questions
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...
For a continuous miner (CM) panel, the following data are given. Data related to CM A Table:
Assume, unit weight of coal is 1.4 tonne/m3 and its swell facto...
'Critical subsidence has occurred on the surface due to mining of a flat longwall panel at a depth of 200 m. The width of the panel is 150 m. The maximum width...
Total Unique Visitors
Loading......