MCL Exam MCQ 2026 - Part 03 (Ventilation, Gases & Safety) Extended
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30 objective questions on mine ventilation, gases (firedamp, etc.), and safety provisions from CMR 2017 & standard mining practices. Click "Show Answer" to check.
Q21. What is the primary purpose of ventilation in coal mines?
A) To supply oxygen and remove toxic gases
B) To cool the mine only
C) To transport coal
D) To support roof
Q22. As per CMR 2017, the minimum quantity of air per person in a working face should be at least?
A) 1 m³/min
B) 3 m³/min
C) 6 m³/min
D) 10 m³/min
Q23. Which instrument is used to measure the percentage of methane in mine air?
A) Anemometer
B) Methanometer / Flame Safety Lamp
C) Barometer
D) Hygrometer
Q24. The explosive limit of methane (firedamp) in air is?
A) 1-5%
B) 5-15%
C) 15-25%
D) Above 25%
Q25. In Degree III gassy mines, what action is required if methane exceeds 1.25% in the general body?
A) Continue normal work
B) Withdraw workmen and take precautions
C) Increase ventilation only
D) Stop electricity supply permanently
Q26. Carbon monoxide (white damp) is produced mainly due to?
A) Coal combustion / fire
B) Methane emission
C) Water inrush
D) Roof fall
Q27. The permissible limit of carbon monoxide in mine air as per DGMS/CMR is?
A) 0.005%
B) 0.01%
C) 0.05%
D) 0.1%
Q28. Who is responsible for conducting ventilation surveys in the mine?
A) Mining Sirdar
B) Overman
C) Manager / Ventilation Officer
D) Surveyor
Q29. In case of underground fire, the first action by Overman/Sirdar should be?
A) Fight the fire alone
B) Withdraw all persons to fresh air and inform Manager
C) Seal the area immediately
D) Continue blasting
Q30. The anemometer is used to measure?
A) Gas percentage
B) Air velocity / quantity
C) Temperature
D) Humidity
Q31. As per CMR 2017, the minimum oxygen percentage in mine air should not be less than?
A) 18%
B) 19%
C) 20%
D) 21%
Q32. The maximum permissible percentage of carbon dioxide in mine air as per CMR 2017 is?
A) 0.3%
B) 0.5%
C) 1.0%
D) 1.5%
Q33. In gassy mines (Degree III), methane emission rate exceeds how many cubic meters per tonne of coal produced?
A) 0.1 m³/t
B) 1 m³/t
C) 10 m³/t
D) 20 m³/t
Q34. Which instrument is used to measure the cooling power of air in mines?
A) Anemometer
B) Methanometer
C) Kata thermometer
D) Barometer
Q35. As per CMR 2017, inflammable gas (mainly methane) in the general body of air should not exceed?
A) 0.5%
B) 0.75%
C) 1.0%
D) 1.25%
Q36. If methane concentration reaches 1% at the working face in a gassy mine, what immediate action is typically required?
A) Continue work
B) Cut off electrical power supply
C) Withdraw all persons
D) Increase fan speed only
Q37. Black damp in mines primarily consists of?
A) Methane and air
B) Carbon monoxide
C) Carbon dioxide and nitrogen
D) Hydrogen sulphide
Q38. The main mechanical ventilator in a coal mine must be installed as per which regulation of CMR 2017?
A) Reg. 153
B) Reg. 154
C) Reg. 161
D) Reg. 166
Q39. In case of main fan stoppage underground, the primary safety action is?
A) Continue operations
B) Withdraw all persons immediately
C) Start auxiliary fan
D) Monitor gases only
Q40. Which gas is known as "stink damp" in coal mines?
A) Methane
B) Carbon monoxide
C) Hydrogen sulphide
D) Carbon dioxide
End of Extended Part 03 (Ventilation, Gases & Safety – 30 Questions). For Part 04 (e.g., Explosives, Blasting, Mining Machinery/HEMM, or General Awareness/Aptitude MCQs), or a set on specific CMR chapters — let me know the topic! Stay focused, practice daily, and best wishes for cracking the MCL 2026 CBT. You've got this! ⛑️🚀
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