Question

Which one of the following openings is a type of decline in underground mines?

• A. Crosscut
• B. Winze
• C. Spiral tunnel
• D. Drift

Hint:

In mining terminology:
- Horizontal openings = Drift or Crosscut
- Vertical openings = Shaft or Winze
- Inclined openings = Decline (including spiral tunnel)

Answer 1

The Correct Option is C

Step 1: Understanding mine openings.
In underground mining, several types of openings are made:
- Drift: A horizontal passage driven along the vein.
- Crosscut: A horizontal opening driven across the vein or ore body.
- Winze: A vertical or steeply inclined shaft that connects two levels, sunk downward.
- Decline/Spiral tunnel: An inclined passage driven downward at an angle, often spiral in shape, to connect the surface with ore bodies at depth.
Step 2: Identifying the decline.
A decline is specifically an inclined tunnel:
- It is not vertical like a Winze.
- It is not horizontal like a Drift or Crosscut.
- It is inclined, and the Spiral tunnel is the correct type of decline used for gradual descent of men, materials, and machinery.
\[ \therefore \text{The correct type of decline is the Spiral tunnel.} \] \[ \boxed{\text{Spiral tunnel (Option C)}} \]