Question

The shape of the pillar in flat and moderately inclined seams for adoption of shuttle car and locomotive is

• A. Rhombus
• B. Circular
• C. Square
• D. Rectangle

Hint:

Think about driving a car.
It's much easier and faster to navigate a gentle curve or an intersection at an angle greater than 90 degrees than it is to make a sharp 90-degree turn.
The same principle applies to large mining machinery.
Rhombus-shaped pillars facilitate this smoother traffic flow.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
The question asks for the preferred shape of coal pillars in a room-and-pillar mining system that uses trackless mobile equipment like shuttle cars.

Step 2: Detailed Explanation:
In traditional room-and-pillar mining, pillars were often square or rectangular.
This layout creates sharp, 90-degree turns at intersections.
While this is manageable for conveyor belts or rail-bound systems, it is inefficient and hazardous for large, rubber-tired vehicles like shuttle cars and load-haul-dump (LHD) machines.
These vehicles have a large turning radius and navigating sharp right-angle turns is slow, difficult, and can cause collisions.
To improve the efficiency and safety of these trackless mining systems, pillars are often developed in a

rhombus or diamond shape.
This creates intersections where the turns are obtuse (greater than 90 degrees), allowing for smoother, faster, and safer maneuvering of the equipment.
Circular pillars are sometimes used but are much more difficult to create and are not standard for this purpose.

Step 3: Final Answer:
The preferred shape of pillars for shuttle car and locomotive haulage is a rhombus.
This corresponds to option (A).