I don't know Matt at all, The tailings at Endeavor may work,...

I don't know Matt at all,
The tailings at Endeavor may work, remember the early days also they trialed a lot of different chemicals also. But I am sure a lot is still in it if it is a simple water jets and pump it back through the circuits on a skeleton crew would make good money and easy money.
The higher grade stuff near the head frame will not be a simple open cut, it is on top of an open mine under it and all that ground has caved in before. I would assume safely the stopes under it are open and if it lets go while you have men working above it is game over. This will require careful planning. The ground will be locked up now not sure if they will be able to back fill under it but they defiantly won't be able to block mine it from below.
The ore body at the bottom is not economical I don't think, pretty sure it is only 8% Lead and zinc combined, if you mined it lean might be ok but wouldn't be worth it on its own right you spend $100mill to make $5mill.
100% there would be more ore bodies around, heaps of old holes and data available, just need a billion dollars to spend to find them.
I know about 30km further down the road drill results produced visible specs of gold in shallow samples maybe 20mtrs deep, wasn't enough for a viable deposit though.
Anyway good luck hope it does well but just remember integrity here is not the highest priority.