When a well or mine is exhausted, is it collapsed, filled in, or abandoned?

Question

I'm kinda curious about what happens 2 a mine or a well once all or most of the resource is depleted. Do they collapse or implode it, fill it in w/ another material, or leave it alone? This also pertain 2 certain mines; I ain't sure about open-pit or strip mines. R safety & environmental issues major considerations in dealing w/ a exhausted mine or well?

Answer 1

pertty much all of the above...

Answer 2

Usually they are merely abandoned.  Many mines have an influx of water while in operation.  it is continuously pumped out.  If they abandoned the mine it will naturally fill with water.

I have NEVER heard of specifically imploding a mine.