What Is Slag?

There's no mineralogical definition of slag. It's just whatever the foundery guy doesn't want, right? In europe especially, they refer to mining tailings as slag. Tailings are stuff that comes out of the mine and is not does not make it to the yes. And so you pile t stuff up like if you're doing placer mining,. You take all the gravel and you run it through your sluice box...