Old mine from the WW2 era. 
Old mine tailings. Acid generating mine tailings.
The importance of controlling erosion. The orange layer is already oxidized and most of the metals have already leached. The grey layer is unoxidized and has a higher metal content. When the grey comes to the surface the tailings oxidize and the metals are released into the environment.
New mines, just like this old one, create tailings that must be disposed of and managed. One of the biggest differences is that new mines are MUCH much much BIGGER. I think mining can be done responsibly to reduce environmental impacts and limit long-term cumulative effects. But the easiest way to reduce the impacts from mining is to buy less stuff. Everything comes from the field, the mine or the oil rig.
