This is one of the tools used to crush the raw ore into something that could be used to chemically extract the gold from the other materials. A variety of methods were employed to do this, some including arsenic and mercury that had polluted Northern California ever since.
Someday, we’ll find a way to have the fish be born with warning labels stating: “Don’t eat me if you’ve already eaten two fish before me this week. I’ve been drinking so much mercury for so long you could use my oils for a thermometer, OK?”
Location: Empire Mine in Nevada County, California