I referred a friend to an article in this months Atlantic about a "Superfund" (a designation of US government for really nasty pollution sites) and it mention "trailings"

Trailings (not in my M-W10th) are the bits of stuff, (rock) that aren't ore, and that are left at the mine site.

I tend to use slag for this stuff– but M-W10th says slag is a synonym for dross.

So:
Trailing rocks (not ore) left over from mining process. (Not listed at all in my M-W10th )

Slag waste material from refining ore

But in the case of coal– which doesn't need refining (but can be refined to coke) the slag and trailing are the same thing?

Dross left over material from refining ore.--

Are there other words? Do others on the east coast use slag– for trailings?
Is trailing the correct word-- or is slag? or is this a regionalism? What do you call them in Wales, Mav?

What do you Zilds and Ozzies call them?

Most of the mining on the east coast (US) is coal. And while most of it on the east coast is further south than NY, there is coal to be found in many parts of the Appalachians mountains. —right on up to Nova Scotia.

I have gone spelunking in old (colonial) iron mines– and the waste from these has always been called a slag heaps.


my other obsession