Mines located at American Bar, Middle Fork of the American River, Placer County, CA around Oct. 20th 1857. Breakout of charges for refining ore at 10 tons per day at $13 per ton. 9 pages on folded blue lined paper. The Aurora Gold & Silver Mining Co. approves use of J.A. Bartoler's (? ) mill amalgamating patent for use by the Bay State Quartz Mill Company of American River. Also that they provide J. Chambers or agent with enough quartz from their ledges to process 10 tons per day. The Aurora Gold & Silver Co. was located on the west side or the Sierras. The mill was located at American Bar on the American River and was considered one of the advanced and efficient at the time. It was the first introduced new methods of amalgamating and saving gold. Previously used processes were crude. The innovations made at the Bay State Mill was the adoption of the [x=#8220/]Chambers' Process," introduced by Judge Chambers, late of the banking house of Page, Bacon & Co. In this the quartz after being crushed under the stamps was ground still finer by mill-stones, then through amalgamating pans, with chemicals and quicksilver. The chemicals used were a secret to the inventor, and a large royalty was demanded for the use of the process, as it was patented. Much more information! State:California City:American Bar Date:1857 Provenance: