Question

Which gas is mainly responsible for explosions in coal mines?

• A. Carbon monoxide
• B. Carbon dioxide
• C. Methane
• D. Hydrogen sulphide

Hint:

Methane explosions are prevented by proper mine ventilation and continuous gas monitoring.

Answer 1

The Correct Option is C

The question pertains to identifying which gas is mainly responsible for explosions in coal mines. This is an important aspect of mine safety and involves understanding the properties of gases found in the mining environment.

Let's analyze each option:

1. Carbon Monoxide (CO): Although carbon monoxide is a toxic gas and poses a serious health threat in mines, it is not typically the primary cause of explosions. Its role is more related to suffocation and poisoning.
2. Carbon Dioxide (CO₂): This gas is generally not explosive. It is heavier than air and can displace oxygen, leading to suffocation, but does not ignite or explode under typical mining conditions.
3. Methane (CH₄): Methane is a highly flammable gas commonly found in coal mines, known as "firedamp." It is the primary culprit behind mining explosions when it accumulates to a concentration of 5% to 15% in air and comes into contact with a heat or spark source, leading to an explosion.
4. Hydrogen Sulphide (H₂S): This gas is known for its toxicity and rotten egg smell but is not usually associated with explosions in coal mines.

Therefore, the gas mainly responsible for explosions in coal mines is Methane (CH₄).

Conclusion: The correct answer is Methane, as it is the most common and potent explosive hazard in coal mines, often forming explosive mixtures with air.

Answer 2

Step 1: Understanding mine gases.
Coal mines contain various gases known as mine gases, such as methane, carbon monoxide, carbon dioxide, and hydrogen sulphide. Some of these gases are toxic, while others are explosive in nature.
Step 2: Properties of methane.
Methane is a colourless, odourless, and highly inflammable gas released naturally from coal seams. When mixed with air in certain proportions (about 5%–15%), it forms an explosive mixture.
Step 3: Cause of explosions in coal mines.
If methane accumulates due to poor ventilation and comes in contact with an ignition source such as sparks or open flames, it can cause violent explosions. Therefore, methane is considered the most dangerous explosive gas in coal mines.
Step 4: Analysis of the given options.
(A) Carbon monoxide: Highly poisonous but not primarily explosive.
(B) Carbon dioxide: An asphyxiant gas, not explosive.
(C) Methane: Correct — it is the main cause of explosions in coal mines.
(D) Hydrogen sulphide: Toxic gas but not the main cause of mine explosions.
Step 5: Conclusion.
The gas mainly responsible for explosions in coal mines is methane.