A dense, suffocating mixture of unbreathable gases, primarily carbon dioxide and nitrogen, that accumulates in unventilated or abandoned underground workings. Because it is heavier than air, it pools in sumps, dips, and low spots, displacing oxygen and causing rapid asphyxiation without any warning smell or color.
Heard on the job
Keep the crew out of the old south heading until the fans clear the chokedamp.
Insider tip
Historically, miners tested for this hazard by lowering a flame into a shaft; if the flame went out, the air was chokedamp.
Also heard as
- blackdamp