Tin: Extraction

Divers, dredges and the tin sands of Bangka

Almost all tin comes from cassiterite, a tin oxide. It occurs in granite-related hard-rock lodes, as in Bolivia, Peru and southern China, and in placer deposits washed from them. On Indonesia's Bangka island, thousands of small pits and offshore barges dredge tin-bearing sand, with divers working the seabed on air hoses (Pitron). Cassiterite is dense, so it is separated by gravity rather than chemistry. The concentrate is smelted with carbon and refined into ingot. Tin is mostly a main product; only about 5% is a by-product of other metals.

Almost all tin comes from cassiterite, a dense tin oxide. It is mined either from hard-rock lodes linked to granite, as in China, Peru, Bolivia and Australia, or from alluvial and offshore placers washed out of those rocks, as in Indonesia, Myanmar and Brazil. Because cassiterite is heavy, it is concentrated by gravity rather than flotation. Concentrates are smelted with carbon and refined into ingot. A growing share of supply comes from recycling solder dross and scrap. About 5% of tin is a by-product of other metals; the rest is mined for itself.

Methods compared

How each method works

Ore from lode deposits is crushed and ground. Cassiterite is recovered with gravity equipment and sometimes flotation for fine particles. Sulphide minerals may be removed first. The concentrate goes to a smelter, often far away. Peru's San Rafael (Minsur), Bolivia's state mines, China's Yunnan districts and Australia's Renison are of this type.

Higher grades and stable output; deep mines are costly and slow to build.

Tin-bearing sand and gravel is dug or dredged, washed and passed over sluices and jigs to collect cassiterite. In Indonesia large dredges work alongside thousands of informal miners on land and on small offshore barges. In Myanmar's Wa region, small operators feed concentrate across the border to Chinese smelters.

Low capital and quick to start; output depends on informal labour, licensing and enforcement, and damages land and seabed.

Concentrate is reduced with coal or coke in reverberatory, electric or top-submerged lance furnaces, then refined by heat or electrolysis to remove iron, lead, copper and other impurities. China has the largest smelting base and imports concentrate from Myanmar, DR Congo and others.

Smelters earn treatment fees and control the refined market; they compete for scarce concentrate.

Solder dross, electronic scrap, tinplate scrap (detinning) and bronze scrap are remelted and refined. Belgian recycler Aurubis Beerse is among the top ten tin producers.

Supply rises with prices and scrap flows; dispersed uses such as chemicals cannot be recovered.

Share produced as a by-product

Who does it: global

Who does it: India

India has almost no tin mining or smelting: Chhattisgarh produced only about 26 t of concentrate and 5 t of metal in FY2022 (IBM). It imported 12,100 t of refined tin in 2023, almost all from Indonesia, and is the sixth-largest consumer; import duties on refined tin and concentrate were removed in July 2024 (ITA).