Xikuangshan mine in Lengshuijiang, Hunan, China, contains the world's largest deposit of antimony. It is unique in that there is a large deposit of stibnite (Sb2S3) in a layer of Devonian limestone.
There are three mineral beds which are between 2.5 and 8 m thick which are folded in an anticline that plunges to the south-west. The total mineralised area of the mine has a surface extent of 14 km2.
There are two different units at the mine, the northern one produces mixed oxide and sulfide such as stibiconite (Sb3O6(OH)) and the southern one produces stibnite. Ore is concentrated and refined on site in a refinery with a capacity of 10,000 tonnes of antimony per year.
In 1981, reserves at the Xikuangshan deposit amounted to 10,000,000 tonnes of ore that contained 2 to 3 percent antimony (200-300,000 tonnes of antimony), at the time geologists thought that there may be more in the area. By 2002 the estimated size of the deposit was 2,110,000 tonnes of pure antimony.
According to en.wikipedia