Replying to Strange Science Question

As we all know we have been taking stuff our of earth forever, granted our tempo for doing so has increased over recent years with improved technology, increased demand etc... now I know in Utah there are some pretty decrepit looking mountains from a copper mine, and what with this oil spill and shit it got me thinking, what fills the spaces of what we take from the earth. I know in utah the mountains I was talking about are sort of collapsing in upon themselves, looking almost skeletal in comparison, so it seems that when taking things from mountains it makes them smaller, obvi... my question more likes in what happens when we take stuff from other areas, does it fill with gases or hot magma? I know this really isn't a forum for smart appropriate responses but whatever, just wondering if you had some thoughts on the issue