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(concentrate), a fraction of heavy minerals obtained by flushing unconsolidated natural deposits and artificially crushed rock or mineral formations. A schlich includes grains of minerals that are resistant to physical and chemical weathering and that have a density of more than 3,000 kg/m3, for example, gold, platinum, cinnabar, cassiterite, scheelite, magnetite, zircon, and diamond.
Schlich samples are taken systematically from alluvial and diluvial deposits in the course of prospecting for placer and primary deposits of useful minerals. Schlich sampling is also used in the exploration and development of placer deposits. During the process of concentrating sands from placer deposits of gold, platinum, and other metals, what is called gray schlich, containing a significant amount of foreign minerals, is obtained first and then black schlich, which is richer in valuable metals. Schlich concentrating installations or factories, concentrating tables, and separators of various designs are used to extract valuable minerals from schlich on an industrial scale.
A. M. BORSUK