The Central Coast and the legacy of the Mother Lode

But there was another environmental hazard from unfettered mining with a link to the Central Coast: Mercury pollution of the Sierra streams.
Coarse gold- and silver-bearing ore was taken from the mine or hydraulic operation to a steam- or water-powered rock crusher and stamp mill. The ore was crushed to the consistency of gravel and then would slide down onto metal plates situated under the stamp battery where water would push it under a set of five or more stamps. The ore was pulverized into a fine sand.
The slurry mixture was pushed over a recovery table, a copper-sheeted table coated with mercury; the gold in the sand would stick to the mercury. The amalgamated gold and mercury mixture would be removed by straining it through a chamois and sent to a retort where the mercury would be boiled off and mostly recovered, leaving gold bullion.
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