In May, we took our second graders on a field trip to the copper mine since we study rocks and minerals. It was pretty cool and I decided I should take my own kids there. So, a week ago, I headed up there with some friends. They had a couple of weeks where it was free (usually it costs $5 per car) and it was very busy. I think I would have preferred it if we'd gone when it was less busy and we just paid the $5, but it was still fun. You parked and then rode a bus up to the actual "pit" ... the largest open air mine in the world... and to the visitors center. I'd told the girls before we left that the tires on the trucks they use to haul dirt, copper, rock, etc. were bigger than them...bigger than me. They didn't believe me, until they saw them. They are HUGE!
They show a 20 minute film that talks about how the mine was discovered, how they process the rock to get the copper (and silver and gold) out of the rock, and what they have done to be as environmentally friendly as possible. It's a little bit propaganda-ish at points, but also has some interesting facts and information in it.
The visitors center shows samples of different minerals found in mines around the world, displays miniatures of the different trucks and equipment they use to mine, contains a series of relief maps of what the area looked like in 1905 (before mining)and then how it changed over the years and has a few displays that show all the things we use daily that require copper as well as other minerals. Another fun, free (or nearly free if you pay the $5 per car entrance fee) educational activity. :)