The send one fellow in nonburning oiled cloth to detonate small pockets. Sometimes they died

Believe it or not they ventilated mines with fires. It likely started as a way to view what they were mining, but they noticed that the fires created an air current within their mine that drew fresh air in and the hot noxious air was pushed out. Later civilizations also had this same realization. The Greeks had ventilation shafts powered by fire heat. Romans, being engineers, figured out how to use manpower (ie slaves) and plam fronds to waft air along the ventilation shafts. Still mining was a dangerous business and many miners died from various gas poisonings.

For much of history we used simple wax candles for light in the mine. They were dim, but in pitch darkness they were more than adequate. Luckily candles really don't consume that much oxygen, much less than a human would. So there really wasn't any indications that candles were a risk.

Old mining tunnels were certainly a nightmare. But they did know how to ventilate them. They would sometimes dig a vertical shaft connected to a tunnel and set a fire in it. The fire would draw air in, and send smoke up. They could configure it so that it drew air from the working face, and sent it up and out.

Mines didn't have torches, they had small lamps. It was dark and hellish. Miners had short lives.

Mining engineer here,

Mining was the single most dangerous job in the world till about 1950. Old mines would use the change in temperatures combined with tunnels designed to encourage natural ventilation. A fire could be started that would "draw in air" and a smoke shaft would be built.

In 2022 we use 2000 hp fans to keep things cool/ clean air. Some extremely deep mines I have been to legit use the largest air-conditioning system the world has to keep the temp at a cool 120F its so hot 5000ft underground

Look at this graph of deaths each year in USA mining

https://www.minesafetycenter.com/mine-fatalities-progress/

Feel free to ask any other mining questions

1. Ancient mines weren't very deep.
2. They used whatever lighting they had to see: oil lamps, torches, etc.
3. They did their best with ventilation shafts.
4. It was a nightmare.

There are some great books on this and the ancient side of the development is a good start but things got really cool when industrial extraction got started properly.

The ventilation shafts of old stayed but then extensive systems of flaps operated by actual children took hold. Still, that was not what limited depth of mines. The desire to get clean burning coal eventually forced people to deal with large amounts of water that would seep down. The first steam engines were primarily designed not to move the coal, but for the more challenging subject of removing water from mines.

Also the canari was for finding noxious gases. The presence of flammable gasses was detected by having people walk into a mine with a long pole sporting a candle at the front. These goal was to burn the so called fire-damp before the rest of the workers were at risk.

All in all mining has always been a crazy world, Coal by Barbara Freese is a wild book to read if you’re interested in this world at all.

A nice trick is to light a fire in a mine level above the working one, the fire updraft and fumes do escape from a vertical shaft purposely built on top of it, the updraft sucks air form the levels below.

You need to arrange it with doors so you can force the fire to suck from the area you like and the outside air to be sucked in the level you want.

But that’s a method doable even at Stone Age tech.

Idk if gas pockets were common, as, ancient digging was superficial and by the time you get the tech to dig further down I imagine they got the tech to protect themselves. In between these two era they just died. I mean, there’s plenty of mine horror accounts from the 1700-1900. The whole industrial era was a gigantic trial and error thing. I remember industrial ventilation devices like hand operated, animal operated, and later steam operated air pumps, and acetilene lamps made “flash proof” to an extent. Problem is, if you get to a gas pocket, even if it doesn’t ignite, you are still really dead. There is no way to replace that much gas with fresh air in time. Having a bird that dies earlier than you is a good warning system, but to escape you have to climb a lot and climbing with little oxygen is not an endeavor that is famous for its success rate. To conclude, early ventilation systems were more about getting enough air to breathe and evacuate the lamps fumes.

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