How it began
Zawar, or Jawar, is a mining township about 35 km from Udaipur in Rajasthan with ancient lead and zinc mines. Wikipedia reports archaeological evidence of zinc mining there at least as early as 750 BCE. For the distillation of metallic zinc, the Infinity Foundation's account states that the earliest dates come from a waste heap of the 12th century CE, and a study of the site describes large-scale zinc distillation technology from that century. Wikipedia credits the Bhil people who inhabited the region with devising the clay retorts used in the process.
How it works
The smelters used clay retorts with a cylinder about 10 cm in diameter and a narrow cylindrical pipe about 30 cm long at the other end. Zinc ore was placed with charcoal in the cylinder and the retort was sealed. About 36 retorts were set on a specially designed clay support and heated in a furnace to between 1,000 and 1,150 degrees Celsius. The zinc left the ore as a vapor, collected in the pipe, and cooled into liquid metal. One study estimates a yield of 300 to 400 grams of zinc per retort. Spent retorts were reused as building material.
Who pushed back
Zawar lost its importance with Chinese zinc exports and with the discovery of a new zinc distillation process in the 18th century. Political instability from invasions and several famines also affected mining. Because zinc had been mined for centuries, the ore lay ever deeper and became difficult to extract. Mining and smelting at Zawar ceased in 1812.
What changed first
Wikipedia describes Zawar as the first center in the world to produce zinc on an industrial scale. Zinc from Zawar was used to make brass and to mint coins, and it may have been exported. Silver was also mined there, and the town exported silver jewelry in the 13th century. Zawar is mentioned as a pilgrimage and mining center in a poem of 1461, and the late 16th century Ain-i-Akbari of Abul Fazal mentions zinc being mined there.
Where it stands today
After a Geological Survey of India report in 1942, the Indian government explored reopening the mines. In 1965 they were handed to Hindustan Zinc Limited, which has operated four mines extracting lead and zinc ores. The American Society of Metals designated the site an International Historical Landmark in 1988, and the Geological Survey of India has declared the Zawar lead-zinc mines a National Geological Monument.
