Zinc smelting commenced in 1999 with a capacity of 7kt/a slab zinc. The smelter processed calcine produced on redundant equipment at the Bayi copper mine. The first fluid bed roaster was built at Mian Xian in 2000 and the tankhouse was expanded to provide a total capacity of 25kt/a slab zinc. Further expansions have taken the plant capacity to 330kt/a slab zinc. These included the building of a twin zinc smelter adjacent to the original in 2008.