At one time, canaries were carried into coal mines as an early warning system for the presence of poisonous gases. Since canaries are very small, they would die before humans could be affected.
they are found in mines, they die if they breathe toxic gases and if the canaries die it is time to get out of the mine. (usualy coal mine)
They were actually 2 canaries that die when the air goes bad alerting human workers to the threat
A coal mine is typically referred to as a coal mine.
to mine coal...
How did they used to coal mine
The Hurriers job was to whear a harnest and pull coal in a coal mine from one part of the coal mine to another.
The Davy lamp helped canaries because it was a safety lamp used in coal mines to detect the presence of dangerous gases like carbon monoxide. Canaries are sensitive to these gases, so if the bird showed signs of distress or illness, miners would know to evacuate the mine to avoid danger.
It is a Miner they go in Mines to mine out coal
The steam engine needs coal, the coal comes from the coal mine
To get coal.
I'm not sure the question here. The phrase of a "canary in a coal mine" refers to an early warning of disaster.Note link added from Wikipedia:By analogy, the term climate canary is used to refer to a species that is affected by an environmental danger prior to other species, thus serving as an early warning system for the other species with regard to the danger.[3]Apparently, the phrase "two canaries ..." was used in the film, Inconvenient Truths, in identifying two early warnings of Global Warming.
There is 2 shafts in a coal mine.