40 × 40 m centre to centre size of coal pillar in bord and pillar working, at a depth of 280 m has 4 m wide gallans. What area of roof does a pillar support according to tributary area.
A. 1600
B. 1296
C. 1120
D. 1936
E. 4480
Answer: Option A
This Question Belongs to Mining Engineering >> Mine Supports And Strata Control
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