How do prospectors/miners figure out where to dig for ores, especially really deep mines?

Question

Seriously how the fuck do they know where the good stuff is going to be, especially back before ground penetrating radar?

In: Other

Answer 1

Telltale signs can sometimes exist at ground surface. Highly mineralized soil can leach out metals that prevent vegetation growth, so a miner could prospect those patches for what vein might exist at depth.