Q. Are there still working gold mines in the United States?

A. Today there are at least 100 major gold mines in operation. That's because of two things: first, in the 1980s the price of gold shot up to around $1,000 a troy ounce. It's not that high now, but it's still profitable. Secone, the mining industry found new ways to mine. It's called cyanide-heap leaching. Miners are able to go into old mines that were thought to be used up. They can dip up heaps of ore and pour cyanide over them. The cyanide attracts the gold as it trickles though and gathers at the bottom. Cyanide is extremely poisonous. Some of it has gotten into the ground-water near the mines. Mining is still regulated in large part by the federal 1872 Mining Law. That law allows anyone to put down stakes on federal land and take away the gold without paying the government anything for it. If you want to buy the land, you can get it for $5 per acre.