Talk:Longwall mining

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Of the three footnotes in this piece only one works and that leads one to a lobby group (the Illinois Coal Association)--not the picture of nonpartisan information. There are "further reading" links to a book review that focuses on coal in Appalachia and stops at 1945 as well as an "educational" link to an Australian University that educates students on how to extract coal. Again, this presents a single side to this extremely controversial subject. Claiming immediate subsidence a benefit is as well an interesting take on this violently disruptive effect. This is not a neutral entry. This is not a quality entry. —The preceding unsigned comment was added by SADouglas (talk • contribs).

I can see that SADouglas is a little concerned by the neutrality of the article. I am not sure what the contention is because it hasn't been spelled out by him. The only obvious (and immediate) negative consequence of longwall mining is the issue of subsidence. The article does mention this, though I can see if it really gets someone's goat, they could add examples of instances of subsidence that has actually affected someone other than cattle and kangaroos. I think Muswellbrook might be an example though I am not 100% sure.

The cut and thrust of subsidence is that it's more or less necessary. The goaf will collapse. It can't be stopped without filling the ground with cement or whatnot. If I was a land owner affected, I'd prefer it to be immediately when the mine is still a going concern than in 25 years time when who knows who one should sue. In most cases, the property above coat extraction is compensated for. Definitely such compensation and mining methods are better than open-cut.

If it's such a huge issue, SADouglas, please add any relevant information on the topic. Boy do I feel silly for not signing that. Bilious 13:16, 26 October 2006 (UTC)

I read the article first and then the discussion, I did not notice that the article was biased in any way. It may have changed since SADouglas read it, though this is difficult to determine as there is no "timestamp". I am anti-coal mining and have a conflict of interest on this subject as BHP Billiton want to commencing test drilling on our property.--Yendor72 23:22, 9 December 2006 (UTC)

As ex mining engineer from area of the UK (North Staffordshire) which was the most intensively mined, with multiple seams over 200years of extraction, you are over concerned by the effects of subsidence. Damage to the surface is to an area at the edges of the longwall projected out at 35 degree, (making no allowance for the gradient of the strata) The damage is due to the surface at these points being subjected to a tensile stress. The bulk of the area undermined will drop uniformly and undamaged. The time scale for this event will be substantially less than 25 years, a couple of years would normally be enough for the effect to be observed, and that is from over 1000m below the surface.

Now you might be against mining for global warming but that's another argument!