Amalgam (chemistry) copper trough, which formed a thin coating of mercury on the exterior. The waste ore was then transferred down the trough, and gold in the waste amalgamated with the mercury. This coating would then be scraped off and refined by evaporation to get rid of the mercury, leaving behind somewhat high-purity gold. Mercury amalgamation was first used on silver ores with the development of the patio process in Mexico in 1557. There were also additional amalgamation processes that were created for processing silver ores, including pan amalgamation and the Washoe process. Gold amalgam has proved effective where gold fines ("flour
Dental amalgam controversy they contain Bis-phenol A (BPA) a chemical known to cause reproductive toxicity at high doses. In Canada, amalgam use is considered safe and effective. A 2005 position statement from the Canadian Dental Association (CDA) states that "current scientific evidence on the use of dental amalgam supports that amalgam is an effective and safe filling material that provides a long-lasting solution for a broad range of clinical situations. The CDA has established its position based on the current consensus of scientific and clinical experts and on recent extensive reviews of strong evidence by major North American and international organizations, which have