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Stamp Mill

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The ore was crushed into powder using a stamp mill. The stamp mill did the heavy crushing work using a belt-driven shaft. The five-stamp mill on the left did the bulk of the processing, while the small, single-stamp mill on the right was used to process sample batches of ore to see how much gold they contained. The evaluation process was called an assay report. The large five-stamp mill was made in San Francisco and shipped to Julian. As delivered, the mill did not include the heavy frame timbers or any assistance with assembly. The price in today's dollars was $4,000,000. After the ore was crushed into powder, it was further processed using mercury and cyanide to separate the gold from the non-valuable elements. Mining wasn't a job for dummies or the lazy.