How can mining create a sinkhole?

1 Answer
Mar 7, 2016

Answer:

Underground coal and potash mines that were not too deep can sometimes produce sink holes in the overlying ground.

Explanation:

Mines that use "room and pillar" mining methods are susceptible to the collapse of the overlying strata which then causes a sinkhole at the surface.

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The eastern U.S. coal states are prone to this kind of collapse and you can even buy insurance against this happening! Many of these are "legacy" coal mines from decades to hundreds of years ago that were never abandoned properly.

http://www.greenpeace.org/usa/why-were-thinking-about-coal-on-world-water-day/ image source here

Sinkholes can also occur when underground mining lowers the water table, causing the overlying strata to collapse - see last pic from Mongolia.