Here's a really interesting documentary film about a group of Meth-head scrap metal gatherers who scrounge active impact areas in the SE U.S. It's 1 1/2 hours long but pretty good.
https://www.youtube.com/watch?v=I4pFat3VTkI&feature=youtu.be
https://www.youtube.com/watch?v=I4pFat3VTkI&feature=youtu.be