The use of nitric to clean concentrates and clean mercury that has broken up in a pan is also from experience, my own, while placer mining in BC. It does not dissolve the pan, nor the mercury. If you want it do that I suggest you add more heat and time, and more concentrated acid. In fact much gold in concentrates will not amalgamate at all until you use some kind of acid to clean the gold, and and the sulphides. A lot of miners use vinegar and treated the con overnite. They did use chamois as well, and magnets to clean cons of black sand and mercury. If you get a solid amalgam ball, the chamois works well. With liquid mercury it does no good and you do have to collect liquid mercury. As far as using copper amalgamation pans, I don't know. There is no mention of it, but I cannot rule it out. It was a technique used widely in gold mills. The most common substance to clean the copper amalgamation plates before using them, from the literature from Kokomo Colorado, from 1895, -- was nitric acid. In fact dirty or oxidized copper will not take to mercury and it should be cleaned or scraped shiny. In fact when you use mercury in a pan on a con, the mercury does break up and go all over the place and is hard to collect. Add some nitric to the pan, and voila! it collects into a single ball in few shakes. Often brillian gold coloured. Fascinating.
There is a method to get the gold from the amalgam with the nitric acid alone and aluminum. That technique was more than likely not used by the miners.
The Peruvian Indians used to use three salts to make aqua regia to dissolve the gold in their concentrates in 1400 before Pizarro. These three salts are nitre, iron aluminum sulphate and sodium chloride. Boil them in water and they will make a mixture of nitric and HCl. I have done it and dissolved gold. The HCL captures the nitric and it will not gasify. It works.
In 1850 you could buy aqua fortis or nitric and HCl to dissolve gold from any drugstore. I am sure a miner could buy it too. Both Lye and aqua regia were used as tests for gold since medieval times.
The CIBC, the largest bank in Canada used to use their Yukon experience in their advertising showing a picture of their bank in a tent in Dawson city. There were citizens competing with that too and some made good money loaning money to miners, accumulating all sorts of claims. Read Pierre Berton's book on the Klondike.
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