Gold occurs in almost every districts in Chosen, and the deposits are genetically classified as: first, quartzose fissure filling deposits (majority of gold in Chosen comes from these deposits), secondly, metamorphic metasomatic deposits, and thirdly, igneous deposits. Generally, ores are associated with sulphides, such as pyrite, galena, sphalerite, pyrrhotite, arsenopyrite, chalcopyrite, bismuthnite and stibnite to a considerable amount; pyrite, galena and sphalerite are essential, pyrite being most predominant, and other sulphide minerals are accessory.
Amalgamation and cyaniding have been applied to the oxidized ores near the surface hitherto, and as the mine became deep the unaltered sulphides had to be worked, and sometimes such ores were not amenable to direct amalgamation and cyaniding. Therefore rich sulphide are was preliminarily hand-picked as much as possible, and then amalgamation and cyaniding were applied, being followed by tabling for recovering the fine sulphides together with gold from the amalgamation and cyaniding tails. But the extraction was very low. These sulphide concentrates were sold to the smelter.
Recently, flotation is applied to such ores; two systems are incorporated:
(1) Amalgamation and cyaniding in conjunction with flotation and tabling;
(2) Flotation in conjunction with tabling.
Ball-milling in stead of stamp-milling is also adopted and accordingly the extraction of gold is remarkably increased.
Gold ores in Chosen will be entirely concentrated by flotation in future.

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