User:PatJardine/sandbox

I have selected the article "Placer mining" for my assignment along with my partner, Jessicanajera. 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.

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.

note: potentially add a section within methods for "hushing", a method used most often in the Roman Empire involving diverting large volumes of water towards an ore deposit to break it apart, or hydraulic mining which involves shooting high pressure water at a deposit to break it apart and was used during the early California gold rush. main article already exists for both, but not sure if they are considered a form of placer mining

note 2: potentially find sources for the sections that already exist since they have very few if any.

note 3: potentially add a section on "winnowing", where original Spanish miners used a blanket to throw gold rich dirt in the air so wind would blow the dirt away. from

Gold Panning

The simplest technique to extract gold from placer ore is panning. This technique has been dated back to at least the Roman Empire . In panning, some mined ore is placed in a large metal or plastic pan, combined with a generous amount of water, and agitated so that the gold particles, being of higher density than the other material, settle to the bottom of the pan. The lighter gangue material such as sand, mud and gravel are then washed over the side of the pan, leaving the gold behind. Once a placer deposit is located by gold panning, the miner usually shifts to equipment that can treat volumes of sand and gravel more quickly and efficiently. Gold panning was commonly used on its own during the California gold rush, however it is now rarely used for profit since even an expert gold prospector can only process approximately one cubic yard of material for every 10 hours of work.

Rocker

rocker box (or "cradle") is capable of greater volume than a gold pan, '''however it's production is still limited when compared to other methods of placer mining. It is only capable of processing about 3 or 4 yards of gravel a day .''' it is more portable and requires less infrastructure than a sluice box, being fed not by a sluice but by hand. The box sits on rockers, which when rocked separates out the gold, and the practice was referred to as "rocking the golden baby". A typical rocker box is approximately 42 inches long, 16 inches wide and 12 inches long with a removable tray towards the top, where gold is placed[5]. The rocker was commonly used throughout North America during the early gold rush, but it's popularity diminished as other methods that could handle a larger volume became more common .

Sluice box

The same principle may be employed on a larger scale by constructing a short sluice box, with barriers along the bottom called riffles to trap the heavier gold particles as water washes them and the other material along the box. This method better suits excavation with shovels or similar implements to feed ore into the device. Sluice boxes can be as short as a few feet, or more than ten feet (a common term for one that is over six feet +/- is a "Long Tom"). '''While they are capable of handling a larger volume of material than simpler methods such as the rocker box or gold panning, this can come at the cost of efficiency, since conventional sluice boxes have been found to recover only about 40% of the gold that they process. The sluice box was used extensively during the California gold rush for larger scale operations. When streams became increasingly depleted, the grizzly and undercurrent variants of the sluice box were developed. The grizzly is a set of parallel bars placed at a 45 degree angle over the main sluice box, which filter out larger material. The undercurrent variety includes additional, auxiliary sluice boxes where material is initially filtered. It then travels through a trough into the primary sluice box where it is filtered again. Both the grizzly and undercurrent are designed to increase efficiency, and were often used in combination .'''

Dry Washing

Sluicing is only effective in areas where there is a sufficient water supply, and is impractical in arid areas. Alternative methods developed that used the blowing of air to separate out gold from sand. '''One of the more common methods of dry washing is the Mexican dry wash. This method involves placing gravel on a riffle board with a bellows placed underneath it. The bellows is then used to blow air through the board in order to remove the lighter material from the heavier gold. . The amount of gravel that can be processed using the Mexican dry wash technique varies from 1 1/2 to 4 cubic yards per day, and can be processed at a maximum efficiency of 80%. . Another form of dry washing is "winnowing". This method was most commonly used by Spanish miner in America, and only requires a blanket and a box with a screen on the bottom. The material is first filtered through the box so only the finer material is place onto the blanket. The material on the blanket is then flung into the air so that any breeze can blow away the lighter material and leave the gold behind. While this method is extremely simple and requires very few materials, it is also slow and inefficient .'''

Dredging

Large-scale sifting of placer gold from large volumes of alluvial deposits can be done by use of mechanical dredges. These dredges were originally very large boats capable of processing massive amounts of material, however as the gold has become increasing depleted in the most easily accessible areas, smaller and more maneuverable dredges have become much more common '''. These smaller dredges commonly operate by sucking water and gravel up through long hoses using a pump, where the gold can then be separated using more traditional methods such as a sluice box.'''