Talk:Placer mining

message: :In California, from 1853 to 1884, "hydraulicking" of placers removed an enormous amount of material from the goldfields, material that was carried downstream and raised the level of the Central Valley by some seven feet in some areas and settled in a huge layer at the bottom of San Francisco Bay. 
Interesting; the degree to which San Francisco Bay/Sacramento River estuary was filled in by this would be a useful figure.  What's piqued my interest is all that sediment on the bottom of San Francisco Bay; old mining techniques were very low-efficiency and there's a good chance there's a high percentage of gold in that "huge layer at the bottom of San Francisco Bay".  Reminds me of Dawson City, Yukon, a bit, where twenty years ago or so old tailings were used to pave the streets of a new subdivision.  The tailings turned out to have a higher concentration of gold than material being sluiced on Eldorado and All Gold Creeks, and the entire subdivision and the source for the gravels used wound up being staked and mined.  Many old tailings from gold workings have been re-excavated and re-worked, sometimes earning more than the original prospect (not that the original prospectors were always honest about how much they were pulling in).  Not that digging up the bottom of San Francisco Bay is a viable option, given latter-day environmental standards, and I'm not a miner; but it's interesting nonetheless.Skookum1 19:11, 13 November 2006 (UTC)
thread_title: Hmmmm....

message: Logic says in syllogism - if water flows down-hill over rock, then eventually, the precious metal or mineral will wash down to the valley. Further, if the matter (gold & mineral) is heavier than water, then force and gravity will distribute the matter. Force (water current) will push the matter down the path of least resistance. Gravity will attract that matter to the centre of the earth. Therefore, matter is washed from the hills to the centre and sides of the water-flow. Stream tests have shown that sediment will gather at the bend in the stream (water-flow) but (gold) accumulation, in the centre, is just Baer Law theory. Rodeney (talk) 14:35, 31 August 2008 (UTC)
replies: text: I presume you are quoting Emmons 1937 Gold Deposits of the World here. Please attribute your sources. Also, this is the talk page of the article - so are you proposing an addition or what? Vsmith (talk) 15:34, 31 August 2008 (UTC)
thread_title: Placer gold accumulation

message: I plan on filling out the sections on individual forms of placer mining and adding citations, since they are all currently very short and have none. Specifically, I would like to add information about the expected gold output from each method, along with where and when they are most commonly used. I would also like to contribute to the placer deposit section, which is currently very short with no citations.Finally, I would like to expand the history of placer mining section, primarily by adding citations since there currently aren't any. To find this information, I will begin with the following sources. I plan to begin work on these edits in the coming weeks, and to begin adding them to the actual article in late march.
International Correspondence Schools (Scranton, Pa.) and Collier Engineer Company (Scranton, Pa.). Placer Mining: A Hand-Book for Klondike and Other Miners and Prospectors, with Introductory Chapters regarding the Recent Gold Discoveries in the Yukon Valley, the Routes to the Gold Fields, Outfit Required, and Mining Regulations of Alaska and the Canadian Yukon; also, a Map of the Yukon Valley Embracing all the Information Obtainable from Reliable Sources Up to December 1st, 1897. Vol. no. 15911. Scranton, Pa: Colliery Engineer Company, 1897.
Basque, G. (1999). Methods of placer mining. Surrey, B.C: Heritage House.
Garnett, R. H. T.. (2015). Graphical representation of production results versus estimates in placer mining. Institution of Mining and Metallurgy. Transactions. Section B: Applied earth sciences. (124)3. p.175 - 190.
Ferguson, R. I.. (2015). Reconstructing a sediment pulse: Modeling the effect of placer mining on Fraser River, Canada. Journal of geophysical research. Earth surface. (120)7. p.1436 - 1454.
Kennedy, M. (2008). fraser river placer mining landscapes. BC Studies, (160), 35.
Nelson, A. D.. (2012). Placer mining along the Fraser River, British Columbia: The geomorphic impact. Geological Society of America bulletin. (124)7-8. p.1212 - 1228.
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There are many other methods.
In recent decades, pulsator machines have been very popular for small and medium sized placer mines. I don't have actual references, but a google search reveals several firms who want to sell you one.
Circa 1890 to 1970 "dredges" were used in larger mines, certainly for gold and tin, maybe other stuff. Maybe still in use somewhere? Initially steam powered, later diesel or electric.  There is already a wikipedia article. Said to be very thirsty for water.  — Preceding unsigned comment added by 110.145.147.110 (talk) 00:48, 26 November 2021 (UTC)
thread_title: Methods and Deposits additions

message: Can someone knowledgeble on the topic please add shaker table to the list of methods.   75.80.37.234 (talk) 09:50, 17 September 2021 (UTC)
thread_title:  Shaker Table