Any of you fans of GOLD RUSH tv show on Discovery will note that no mercury or arsenic is used to extract the gold. Which is all captured via mechanical processes, by agitation getting the heavier gold to settle downward.
I am sure there is no mercury or arsenic allowed in gold mining here. It is banned but not in the 3rd world
IIRC, they do use a lot of cyanide to recover gold from ore.
Your link is interesting. "Artisanal [Artisanal? Seriously?] gold miners combine mercury with gold-laden silt to form a hardened amalgam that has picked up most of the gold metal from the silt. The amalgam is later heated with blow torches or over an open flame to evaporate the mercury, leaving small gold pieces."
The Bamazon crew may have used this process as well. They certainly used the blow torch (looked like a welding torch). No mention made of mercury.
Most of the industrial hard rock mining here in CA used the cyanide process.