Simple fact, Mercury does not dissolve gold. It amalgamates with certain metals making them easier to collect in one mass rather than having tiny bits all over the place. Mercury use has very little to do with gold mining or recovery today. Repeat: I said it's used very little- not that it is never used. Its much easier and more economical to just use aqua regia to get the gold away from the base metals. Gold recovery from electronics is done in semi- laboratory conditions and the gold is refined using the same conditions which are a far cry from some guy in the hills digging up dirt and spilling his waste into a mountain stream. Modern refiners shun Hg. It's hard to clean up the waste to acceptable levels. That's a big deal nowadays. No one wants to poison the environment. Acid based extraction techniques are much cleaner,easier and more environmentally friendly. Just like everything else- it comes down to profits and it's just more profitable to use acids instead of Mercury. Hell it's even more profitable to use cyanide to extract the gold. I know a little bit about this stuff- AMA?