If you are preparing for GATE Mining, the DGMS exams or the Mining Sirdar test, you already know that safety questions carry real weight. Ventilation, gases, rescue work and basic safety rules show up again and again, and a few quick revision rounds can easily win you a handful of marks.
This is Part 02 of our Mining Safety MCQ series. It has 15 practice questions (Q16 to Q30). Try each one on your own first, then tap Show Answer to check yourself and read the short explanation. If you haven't solved the earlier questions yet, start with Mining Safety MCQ Part 01.
Mining Safety MCQs: Ventilation, Gases and Rescue (Q16 to Q30)
16. What is the permissible limit of carbon monoxide (CO) in mine air?
A. 25 ppm
B. 50 ppm
C. 100 ppm
D. 200 ppm
Show Answer
Answer: B. 50 ppm
CO is colourless and odourless, so it gives no warning. The limit of 50 ppm is the figure normally followed in Indian mining exams.
17. Which gas is mainly responsible for explosions in underground coal mines?
A. Carbon dioxide
B. Methane
C. Nitrogen
D. Oxygen
Show Answer
Answer: B. Methane
Methane (firedamp) turns explosive when it mixes with air in the range of roughly 5 to 15 percent.
18. What is the main job of an auxiliary fan in a mine?
A. To improve lighting
B. To supply air to, or exhaust air from, dead-end headings
C. To mix gases
D. To run machinery
Show Answer
Answer: B. To supply air to, or exhaust air from, dead-end headings
The main fan cannot reach blind headings on its own, so auxiliary fans take over there.
19. Which instrument is mainly used to detect methane in mines?
A. Hygrometer
B. Flame safety lamp
C. Methanometer
D. Oxygen meter
Show Answer
Answer: C. Methanometer
A flame safety lamp can indicate firedamp, but the methanometer is the instrument built to measure methane percentage.
20. What is the minimum quantity of air required per person employed in an Indian mine?
A. 2 m³/min
B. 3.5 m³/min
C. 6 m³/min
D. 10 m³/min
Show Answer
Answer: C. 6 m³/min
Indian regulations ask for at least 6 cubic metres of fresh air per minute for every person employed below ground.
21. How often must mine rescue team members go through refresher training?
A. Once a year
B. Every 3 months
C. Every 6 months
D. Every 2 years
Show Answer
Answer: C. Every 6 months
Rescue work depends on practice, so team members are expected to refresh their skills at regular intervals.
22. Which gas is lighter than air and tends to collect near the roof?
A. Methane
B. CO2
C. SO2
D. H2S
Show Answer
Answer: A. Methane
Methane is much lighter than air, so it layers along the roof. CO2, SO2 and H2S are all heavier and settle near the floor.
23. The flame of a flame safety lamp elongates in the presence of:
A. Oxygen
B. Blackdamp
C. Firedamp
D. Moist air
Show Answer
Answer: C. Firedamp
In firedamp the flame lengthens and a pale blue cap appears above it. In blackdamp the flame simply dims and goes out.
24. What is the standard duration of a self-contained self-rescuer (SCSR)?
A. 15 min
B. 30 min
C. 45 min
D. 60 min
Show Answer
Answer: B. 30 min
A self-rescuer gives you enough breathing time to get out of a smoke- or gas-filled area.
25. In Indian coal mines, what is the minimum incombustible content required in stone dust?
A. 25%
B. 40%
C. 60%
D. 80%
Show Answer
Answer: D. 80%
Stone dust is spread to dilute coal dust and stop an explosion from travelling, so it must be mostly incombustible material.
26. What does "balanced ventilation" mean?
A. Equal intake and return air
B. Air circulation without fans
C. Balancing of ventilation stoppings
D. Natural ventilation
Show Answer
Answer: A. Equal intake and return air
The quantity of air going in matches the quantity coming out, so the system stays steady.
27. Why is CO dangerous in mines?
A. It causes explosions
B. It combines with haemoglobin
C. It reduces the oxygen-carrying capacity of blood
D. Both B and C
Show Answer
Answer: D. Both B and C
CO binds to haemoglobin far more strongly than oxygen does, so the blood can no longer carry enough oxygen to the body.
28. What does a "return airway" in a mine mean?
A. The route for fresh intake air
B. A passage that carries used or contaminated air out
C. A rescue escape way
D. A ventilation stopping
Show Answer
Answer: B. A passage that carries used or contaminated air out
Air that has already swept through the working area leaves the mine through the return airway.
29. Rescue stations are required within roughly what radius of a coalfield's mines?
A. 8 km
B. 15 km
C. 25 km
D. 40 km
Show Answer
Answer: C. 25 km
The idea is simple: help must be able to reach a mine quickly when something goes wrong.
30. What is the first step when a mine accident occurs?
A. Report immediately to the mine manager
B. Restart production
C. Call family members
D. Wait for the supervisor to arrive
Show Answer
Answer: A. Report immediately to the mine manager
Quick reporting starts the rescue and emergency response. Waiting around only costs time.
Quick Revision Points
- Methane is lighter than air and collects at the roof. CO2, SO2 and H2S are heavier and collect near the floor.
- CO is dangerous because it binds with haemoglobin and starves the body of oxygen.
- A methanometer measures methane, while a flame safety lamp only gives a rough warning.
- Stone dusting needs at least 80% incombustible matter.
- In any accident, report first and act fast.
That wraps up Part 02. Keep practising a few questions every day and these facts will start sticking on their own. Share this post with your study group, and leave a comment with your score.
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