slgwv's photos with the keyword: amalgamation

For mixing mercury(!) with the ore to dissolve out the gold and silver as an amalgam--a mercury alloy. The mercury is later distilled off to leave the precious metal. Simple--but there are a few hazards!

Note the stamp mills at the head of the tables. The crushed ore would spill across these tables, which contained pools of mercury that would trap the large gold fragments. The fines would wash on through to be cyanided in vats beyond. Bodie still used amalgamation as the first processing step, evidently thinking it was cost-effective for the big pieces. They no longer had to worry about overcrushing the ore, too. When amalgamation alone was used, the finest pieces of gold washed on through and were lost, so you didn't want to pulverize the ore _too_ much. However, with cyanide, the finer the pieces, the quicker they dissolved! So the more crushing, the better. (That's not a bug, it's a feature!) The woman on the left is our guide in her Edwardian-era garb.