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gold placer deposits

Gold in placer deposits - pubs.er.usgs.gov

Man most likely first obtained gold from placer deposits, more than 6,000 years ago. Placers account for more than two-thirds of the total world gold supply, and roughly half of that mined in the States of California, Alaska, Montana, and Idaho.Placer deposits result from weathering and release of gold from lode deposits, transportation of the gold, and concentration of the gold dominantly in ...

Major Gold Deposit Types and Exploration process

Major Gold Deposit Types and Exploration process N. N. Singh Indo Gold Mines Private Ltd, 68B Sect-9, HM; Udaipur, India 313001 [email protected] Gold occurs as primary commodity in a wide range of gold deposit types and settings. Three main clans of deposits are now broadly defined, each including a range of specific deposit types with common

Placer deposits | Journal of the Geological Society ...

Editorial note: A meeting on 'Placer deposits', convened by Dr D. G. Sutherland (Placer Analysis Ltd, Edinburgh) and Dr I. Reid (Birkbeck College, London) on behalf of the British Geomorphological Research Group and the Institution of Mining and Metallurgy was held at the Geological Society. Burlington House on 15 November 1984. Drs Ian Reid and Donald G. Sutherland have provided the ...

PLACER DEPOSITS Sub-committee Members - CIM

Gold has a high unit value, so that the amounts of gold in a cubic metre of gravel that is economic may be as low as 1 part per one hundred million. Gold distributions are often extremely erratic. The combination of these problems results in a situation where the sampling of …

Large Gold Deposit Types | ICMJs Prospecting and Mining ...

Witwatersrand (Paleo-placer) Deposits. There is still some small amount of debate among geologists as to the origin of the famous Witwatersrand gold deposits of South Africa, but most firmly believe these deposits reflect the remains of an ancient placer deposit.

What is Placer Gold and How do You Find it ...

Placer gold is a term that refers to gold found in a secondary deposit. Usually gold occurs in lode deposits. However, the weathering of the hard rock and action of rivers and even glaciers in some places have carried the fine gold nuggets and …

Placer Deposits – The Effects Of Glaciation – BC Gold ...

Placer Deposits – The Effects Of Glaciation. A major consideration is the effects of glaciation on the topography of British Columbia in general, and on placer deposits in particular. Moving ice has a tremendous eroding and carrying power and any placer deposit disturbed by moving ice is likely to be dispersed, with the gold mixed with the ...

Ancient placer gold deposits | SpringerLink

Individual ancient placer deposits like the Steyn/Basal placer in the Welkom goldfield of South Africa have produced in excess of 4500 t (metric tons) of gold from heavy mineral concentrates distributed over a palaeosurface area of 170 km 2 (Minter et al., 1986). This amounts to about 26 t of gold/km 2.

Quartz-Pebble-Conglomerate Gold Deposits

placer deposits. Quartz-pebble-conglomerate gold deposits represent some of the largest gold depositories in the world; in fact, the Witwatersrand Basin represents the largest resource of produced gold in the world (for example, Frimmel, 2002, 2008; Frimmel and …

GOLD PLACER DEPOSITS - Earth Sci

Residual placer deposits formed in the immediate vicinity of source rocks are usually not the most productive, although exceptions occur where veins supplying the gold were unusually rich. Reworking of gold-bearing materials by stream action leads …

Supergene gold mineralization from exploited placer ...

The occurrence of crystalline aggregates of gold and authigenic gold in the form of octahedral crystals or concentrations with a typical spongiform structure on the surface of rounded gold grains and nuggets in alluvial placer deposits indicates postdepositional remobilization of gold in the placer itself (Youngson and Craw, 1993, Hough et al ...

An Introduction to Placer Gold Mining - AZoM.com

An Introduction to Placer Gold Mining. The running water in a river can cause deposits of gold to form: in the riverbed, on the neighboring inundation plains or the banks of the river. These are known as gold placer deposits, and they have been mined for …

How does gold become concentrated in placer deposits?

Placer deposits are loose unconsolidated and semi-consolidated materials. It forms by surface weathering, erosion of the primary rocks, transportation and concentration of valuable minerals. Small deposits of gold, tin, diamond, monazite, zircon, rutile and ilmenite are common example.

Placer Gold Deposit and Mining Beneficiation - JXSC

Placer deposit is a significant source of gold, placer mining was the main method used in the early years of many gold rushes, like the California gold rush. Next, I will do a description of the following aspects: Go to the What is the placer gold, Types …

What Is Placer Gold And How Much Is It Worth?

Gold that is found in such sources, like black sand, crushed or eroded ore, is known as placer gold. It must be noted, however, that there are two different kinds of gold placer deposits. The first, shallow gold placers will generally be found within or nearby existing rivers and won't be …

Placer Deposit - Mineral, Types, Causes, Factors and Location

Minerals that form placer deposits include precious deposits like gold, platinum, copper, zircon and various gemstones apart from magnetite, ilmenite, chromite, cassiterite, rutile, and native monazite. Factors Influencing Placer Development. Placer development is activated by a combination of tectonic activity and oscillations in climate and ...

TRACE ELEMENT ANALYSIS OF PLACER GOLD SAMPLES …

The placer gold deposits were discovered in 1877. Numerous studies have described the Hillsboro mining district (Lindgren et al., 1910; Johnson, 1972; McLemore et al., 1999, 2000, Geedipally, et al., 2012). Jicarilla, New Mexico . The Jicarilla mining district is located approximately 30 mi

(PDF) Placer deposits - ResearchGate

Detrital gold particles in paleoplacer deposits develop recrystallised rims, with associated expulsion of Ag, leading to the formation of Ag-poor rims which have been recognised in most placer ...

Sampling and the Estimation of Gold in a Placer Deposit ...

The sampling and the estimation of the gold present and recoverable play a very important part in the history and development of all placer deposits. For this reason everyone interested in placer mining should know the best methods of working this class of mineral deposit. The purpose of this bulletin is to indicate and describe to the miner ...

Geology and Placer-Gold Deposits - USGS

deposits of specularite and sulfides, and small disseminations of pyrite have been precipitated from hydrothermal solutions. Some of the pyrite and specularite contains minor ( < 1 ppm) gold. Placer-gold deposits, clearly of local derivation, extend ramplike down …

IN ARIZONA GOLD PANNING ARIZONA GOLD PANNING …

of streams and rivers into alluvial deposits. Un­ derground, or buried placer deposits, recovered by driftmining, occur as the result of sediments or volcanic flows covering and preserving placer deposits. Gold Panning in Arizona 5 GOLD FACTS AND FIGURES Gold is a native element with the sym­ bol Au. It has a hardness of2.5 to 3 on the Mohs

The Witwatersrand Basin and Its Gold Deposits | SpringerLink

Hayward CL, Reimold WU, Gibson RL, Robb LJ (2005) Gold mineralization within the Witwatersrand basin, South Africa: evidence for a modified placer origin, and the role of the Vredefort impact event. In: MacDonald I, Boyce AJ, Butler IB, Herrington …

What is Placer Gold Mining? - Yukon - Charley Rivers ...

The word placer is thought to have come from Catalan and Spanish, meaning a shoal or sand bar. The word entered the American vocabulary during the 1848 California Gold Rush, and when gold was discovered in Alaska and the Canadian …

Prospecting Placer Gold Deposits

Placer Mining. General Geology of Placer-Gold Deposits. Characteristics of Placer Gold. Prospecting for placer gold, except perhaps in the case of buried placers, …