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Mining & ExplosivesMine Gases
Twenty flashcards on the gases a mine rescue team tests for: oxygen, carbon monoxide, methane, hydrogen sulfide and the damps.
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20 cards
- What is clean, dry air at sea level made of?
- 78 percent nitrogen and 21 percent oxygen; the remaining one percent is argon, carbon dioxide and traces of other gases.
- Which two atmosphere tests must every mine rescue team know, in any mine?
- How to test for oxygen deficiency and for carbon monoxide.
- What happens to you as oxygen drops to about 17 and then 15 percent?
- At about 17 percent you breathe faster and deeper; at 15 percent you get dizziness and headaches.
- How dangerous are 9 percent and 6 percent oxygen?
- At 9 percent you may lose consciousness; 6 percent or less is almost always fatal.
- What are the four main causes of oxygen deficiency in a mine?
- Poor ventilation, other gases displacing the oxygen, a fire or explosion consuming it, and workers using it up.
- At what height do you hold an oxygen detector, and why?
- At waist level, because oxygen is only slightly heavier than air.
- What is the explosive range of carbon monoxide in normal air?
- 12.5 to 74.2 percent; it is also highly toxic even at very low concentrations.
- Why is carbon monoxide so poisonous?
- It joins hemoglobin 200 to 300 times more readily than oxygen, so the blood can no longer carry oxygen.
- How little carbon monoxide can kill?
- As little as 500 ppm (0.05 percent) can kill in three hours; its effects build up over time.
- What does carbon monoxide above normal levels for a continued period tell the team?
- That there is definitely a fire somewhere in the mine.
- How does 5 percent carbon dioxide affect breathing, and where does the gas collect?
- It raises breathing 300 percent and makes it difficult; being heavy, CO2 gathers along the floor and in low places.
- How can you recognize nitrogen dioxide?
- It turns reddish-brown at higher concentrations and smells and tastes like blasting powder fumes.
- When can hydrogen explode, and where does it collect?
- From 4 to 74.2 percent, even with as little as 5 percent oxygen; being light, it collects in high places.
- Why is the rotten egg smell of hydrogen sulfide not a reliable warning?
- Continued exposure dulls your sense of smell; test for it with a detector held low, since it is heavy.
- What is the explosive range of methane?
- 5 to 15 percent when there is at least 12.1 percent oxygen; it is most explosive at 9.5 to 10 percent.
- Where does methane collect, and how do you test for it?
- In high places near the back of the mine, since it is light; hold the detector high.
- What are whitedamp and stinkdamp?
- Whitedamp is carbon monoxide and air (toxic); stinkdamp is hydrogen sulfide and air (toxic and possibly explosive).
- What is afterdamp?
- A mix of CO, CO2, methane, oxygen, nitrogen and hydrogen found after a fire or explosion: toxic, explosive and can lack oxygen.
- What is blackdamp?
- Carbon dioxide, nitrogen and air; it lacks oxygen and can cause suffocation.
- What is firedamp?
- Methane (5 to 15%) mixed with air; it can explode.
Official sources
Mine Safety and Health Administration (MSHA), U.S. Department of Labor
MSHA 3027: Mine Rescue Team Training (Metal and Nonmetal), instructor guide
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