Placer deposit

Soaps (English: placer ) denote the Geology and Mineral Deposits in the secondary mineral enrichments in sediments such as sand or gravel, where mineral-rich grains sorted in accordance with their specific weight by mechanical movements, concentrated and then have deposited. Deposits mineable concentrations of precious metals, heavy minerals or precious stones are called placer deposits.

Formation

Because of its resistance to weathering and high weight, the above -mentioned minerals are by flow conditions, eg caused by wind and water, concentrated in sediments and deposited. Here are differentiated by mode of formation:

• Residual soaps, which have formed in place by weathering of parent rock, in the example Gold or cassiterite transitions are. Often, only the soaps themselves of economic importance, while the subjacent mineralizations are not mineable.
• Eluvial soaps are concentrated in loose rubble on slopes and embankments below the parent rocks. Sometimes, these soaps are enriched in existing erosion sinks in so-called pockets. Also near upcoming chromite deposits often form soaps.
• Alluvial river soaps or soaps in flowing waters belonged in the past to the most important placer deposits. Despite the thousands of years of experience of mankind with such soaps the exact processes of enrichment are not yet fully understood today. It is a complex interplay of flow rate, sink rate, occurrence of turbulence, specific gravity and the hydraulic equivalence of the mineral grains. The most significant soaps formed during the shift from meandering river channels, which can be as "dead arms " later quite far from the river.
• Beach soaps are caused by tides, ocean currents and wave action.
• Marine soaps generally arise through the flooding of existing beach soaps in land cuts or raising the sea level.
• Aeolian soaps are blowouts of desert and coastal dunes by the wind.

Occurrence

The largest known gold soap is in the Witwatersrand in Johannesburg, South Africa - an Archean solidified uranium-bearing quartz conglomerate with a matrix of pyrite, sericite and quartz.

The gold deposits in the Klondike River in Yukon, Canada are the stuff of stories and movies. Also on the Rhine, Danube, Isar, Inn, Salzach, Eder, the Thuringian and Saxon Schwarza Göltzsch placer gold were exploited until about 100 to 150 years. Partial yield ducats were coined it for representation purposes (Rhine, Isar, Inn, Danube ). More recently ( 1930s, unsuccessful) and recently attempts have been made to win gold from gravel from quarry, as the gold concentration already increases fivefold in industrial screening and washing operations. A pilot plant is in Balaguer in Spain and the first attempts were successful. Was from a few gravel pits in the Upper Rhine Valley and recovered some gold as a by- product (Ref. 2).

An important example of residual soaps are the apatite soaps on carbonatites in Jacupiranga (Brazil), Sokli (Finland) and Sukulu (Uganda).

From Flusseifen where much of the global tin production from the soaps in Brazil and Malaysia.

Beach soaps are the diamond soaps on the coast of Namibia, the placer gold from Nome (Alaska), the uranium and thorium Monazitsande in India, Australia and Brazil, the titanium-containing rutile -zircon soaps in Australia, and the magnetite soaps in New Zealand.

A larger fossil heavy mineral soap ( ilmenite and zircon) in some decametres depth was in the 1990s discovered and investigated southwest of Cuxhaven. At a loss, it has not come.