Hacker News Reader

Comment by rwmj | Hacker News Reader

A lot of coal is strip-mined, which damages large amounts of land.

And let us not forget about towns like Centralia which had to be abandoned (by nearly all residents) due to an underground coal fire that has now been burning for 57 years.

https://www.history.com/news/mine-fire-burning-more-50-years...

https://en.wikipedia.org/wiki/Centralia_mine_fire

https://en.wikipedia.org/wiki/Centralia,_Pennsylvania

That had nothing to do with coal mining, per se, though. The spark was set off in a hole in the ground made by previous mining, yes, but it was an entirely-untapped coal vein that caught fire, and basically anything could have caught it on fire if it was ever exposed to surface air. (A meteorite impact, or earthquake fissure, or sinkhole collapse, could have made a similar crater and exposed the coal vein, for example.)

Centralia is more of a weird natural disaster. It's essentially a slow-motion, underground forest fire. And, like most forest fires, while usually a human with a match is the proximal cause, if the human wasn't there, nature would still have supplied a spark eventually.

Coal seam fires aren't particularly rare, and while they can occur "naturally", almost all of the thousand or so burning around the world at any given time (some for months, some for centuries) are explicitly linked to mining.

https://en.m.wikipedia.org/wiki/Coal-seam_fire

Sure, all the ones we know about today. It's a bit of an anthropic argument, though. We only know about the coal seams that have survived long enough for us to find them; and, almost universally, we've chosen to exploit the seams we've found. That leaves two questions unanswered:

• What would the statistical yearly probability of a coal-seam fire be for seams we find, check up on, but never mine? (We know of a few seams in protected areas, but I don't think we know of enough to have any statistical power. Also, the natural catching-fire rate might be, say, one per thousand years, which would be a bit like the pitch-drop experiment in its requirements, yet would still mean that coal seams catch fire pretty much "as soon as" they reach the surface, in geological time.)

• More interestingly: how many coal-seam fires have happened historically in the Earth's 4.2 billion years being around, that finished and burned out all the coal, and now there's just a cave there? Or ex-cave sedimentary layer, given that these caves tend to collapse? Can we tell when such a cave/layer was previously a coal seam? (I assume so, because soot, but can pressure-treated soot be differentiated from other kinds of naturally-occurring mineral striae?)

Hell, a lot of coal in Appalachia is extracted with mountaintop removal. They literally plow the tops of mountains into adjacent valleys.

It's not permanent though, the land is reclaimed after mining

Oh they rebuild those mountains?

Reply on news.ycombinator.com