Question

Abnormal change in barometric pressure in mine workings indicates

• A. Spontaneous heating in mines
• B. Accumulation of gasses in workings
• C. Leakage of gasses from goaf areas towards workings
• D. Increase in overall resistance of the mine

Hint:

Think of the goaf as a balloon filled with gas inside the mine.
If you lower the pressure outside the balloon (a drop in barometric pressure), the balloon will expand and push gas out.
This is a critical concept for mine gas management and safety.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
We need to understand the effect of changes in atmospheric barometric pressure on the conditions within an underground mine.

Step 2: Detailed Explanation:
Underground mines contain large, sealed-off, unventilated areas, particularly old workings known as the "goaf".
These goaf areas often act as large reservoirs for mine gases like methane (firedamp) or blackdamp.
The air and gas mixture trapped in the goaf is at a certain pressure, which is influenced by the atmospheric pressure on the surface.
- When the surface

barometric pressure drops, the external pressure on the goaf decreases.
This allows the higher-pressure gas inside the goaf to expand and "breathe out" or

leak through cracks and seals into the active, ventilated mine workings.
This can lead to a sudden and dangerous increase in the concentration of flammable or asphyxiating gases in the air that miners are breathing.
- Conversely, when the barometric pressure rises, fresh air is forced into the goaf areas.
This phenomenon is known as "barometric breathing" of the goaf.
Therefore, an abnormal change (especially a fall) in barometric pressure is a strong indicator of potential gas leakage from goaf areas.

Step 3: Final Answer:
An abnormal change in barometric pressure indicates leakage of gasses from goaf areas towards workings.
This corresponds to option (C).