It is normal for the terms between miner and smelter to be...

It is normal for the terms between miner and smelter to be confidential. But as I said you can get pretty close to working it out if you are prepared to do some simple arithmetic. DS has mentioned it quite a few times coming pretty close. You should be able to find a You Tube of his last D&D presentation where he came very very close.

I will give you a clue - it’s not miles away from 80%.