Wanshan

WANSHAN (EN: Wanshan; RU: Ваньшань) is the group of the mercury deposits within China (the Guizhou, Hunan, and Sichuan provinces, and the Guangxi-Zhuang autonomous region).

Wanshan unites several tens of the deposits, including large and medium (How Tzy Pin, Sui Yin Chan, Ta Tun La, Fa Mu Pin, Mo Li Pin, and others), and many hundreds of the ore manifestations, which are concentrating themselves within the limits of the zone, which is encircling the ancient Tszyannan massif. The large part of them localizes itself within the thick (up to 3000 metres) stratum of the almost horizontally embedded sedimentary rocks of the Cambrian. There prevail the multi-tier conformal ribbon-shaped ore depositions with the large crystals of vermilion (often with the Se element). The depositions are controlled by the structures of the intraformational stratification, which are expressed by the packs of the banded dolomites. The enriched bulges are noted within the places of bendings, which have been complicated by the faults (the Sui Yin Chan deposit); there may be also found the steeply dipping veinous bodies (the Tszyaolin deposit), and the stockworks (the Bay Myao Tun deposit). As the consequence of the dissected karstic relief, the ore depositions within the upper horizons of the ore-hosting stratum are exposed on the precipitous slopes of the mountains-outliers, which fact facilitates their development with the usage of the adits. The ore bodies within the lower horizons are unsealed with the usage of the inclined shafts. The system of the development is room-and-pillar, with the irregular virgin rock pillars. The operation of the individual deposits was performed continuously, during several millennia: the total extraction of mercury before the start of the 20th century was several tens of thousands tonnes from the rich (more than 1% of Hg) and ordinary (0.1-0.2% of Hg) ores. During the 19th century, the annual production of mercury reached several hundred tonnes, and during the 1950-60-ies, it has increased significantly. The extraction of mercury is performed with the usage of sublimation, prevalently within the shaft furnaces.