Fred, the earth "breathes". There are cracks in the earth that air can get into, and they also carry CO2 meters, among other things, so they know if it is safe to enter a particular area.

The air in the mine is generally good unless there is black damp present...think of air as a fluid it will find its way down . It can be bad bit that's what the safety lamps are for and we also carry CSE sr-100 self contained self rescuers that supply one hour of oxygen if needed.

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I like deep dark wet holes...in the ground that is.

Or, listen to what that guy said. ^ You said it better than I could.

Thank you sir.

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I like deep dark wet holes...in the ground that is.

You are most welcome.

I'm used to getting blasted for almost every post on some other mine forum.

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I like deep dark wet holes...in the ground that is.

Fred, generally in the winter is the safest time to go. Cold air is more dense and wants to sink, so it will push into mines and create natural ventilation all on its own. Warmer air rises, so if the opening you enter through is lower than subsidence holes, outcrops, air shafts, second openings or escape ways ect, it will push the warmer mine air out there pulling any bad gas with it. This is usually the case but we still have encountered bad sir in certain mines even in the winter for several factors. Biggest one is the ventilation system in these mines is broken now. The mines are partially flooded and have some collapses. This doesn't allow the mine to ventilate as it was designed and can trap pockets of bad air, hence the importance of the safety lamps, or o2 meters and self rescuers.

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Come over to the Dark Side....... We have Cookies!

........ dave, look at that picture again.

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This ain't longwall... this is long hole!