Question

For highwall mining, web pillar design is governed mainly by

• A. Surface drainage
• B. Overburden thickness and coal strength
• C. Coal calorific value
• D. Conveyor speed

Hint:

Web pillar design in highwall mining is primarily controlled by \[ \boxed{ \text{Overburden load and coal strength}. } \]

Answer 1

The Correct Option is B

Step 1: Recall the purpose of web pillars. In highwall mining, web pillars support the overlying strata and maintain the stability of the entries.

Step 2: Identify the governing parameters. The required pillar dimensions mainly depend on \[ \boxed{ \text{Overburden thickness} \quad\text{and}\quad \text{Coal strength}. } \] These factors determine the load acting on the pillars and their load-bearing capacity. Hence, \[ \boxed{(B)} \] is the correct answer.