Question

In bord and pillar mining, the main load-bearing elements are:

• A. Roof bolts
• B. Timber supports
• C. Pillars
• D. Side walls

Hint:

In bord and pillar mining, remember: {Pillars = main support, Roof bolts = secondary support}.

Answer 1

The Correct Option is C

Step 1: Understanding bord and pillar mining.
Bord and pillar mining is an underground coal mining method in which coal is extracted in a network of roadways (bords), leaving blocks of coal (pillars) to support the roof.
Step 2: Load distribution in underground mines.
The weight of the overlying strata is transferred to the remaining coal blocks. These coal blocks must be strong enough to support the roof and prevent collapse of the mine workings.
Step 3: Role of pillars.
Pillars act as the primary structural supports in bord and pillar mining. They carry the load of the overburden and maintain stability of the mine. Other supports like roof bolts or timber are only auxiliary supports.
Step 4: Analysis of the given options.
(A) Roof bolts: Provide additional roof stability but do not carry the main load.
(B) Timber supports: Used as temporary or secondary support only.
(C) Pillars: Correct — they are the main load-bearing elements.
(D) Side walls: Do not serve as primary load-bearing components.
Step 5: Conclusion.
In bord and pillar mining, the stability of the mine depends mainly on the strength of the pillars, which act as the primary load-bearing elements.