What Is Tin
Concentrate?
Tin concentrate is the beneficiated, high-Sn-content intermediate product produced by separating the mineral cassiterite (SnO₂) from the surrounding gangue rock through a precision gravity concentration process. Cassiterite — with a specific gravity of 6.8–7.1 g/cm³ against silicate gangue at 2.65 g/cm³ — is ideally suited to jigging, spiral, and shaking-table separation techniques. The resulting concentrate, typically graded at 40–72% Sn, is the universal feedstock for tin smelters producing refined tin metal, tin chemicals, and tin alloys.
Known historically as Stannum (hence the chemical symbol Sn), tin holds the distinction of being one of the first metals worked by humans — its alloying with copper to produce bronze defined an entire epoch of human civilisation. Today, tin's unique combination of low toxicity, excellent wettability, high corrosion resistance, and low melting point makes it irreplaceable across electronics (solder), food packaging (tinplate), and industrial chemistry (tin chemicals), with growing demand in the energy transition through tin-based perovskite solar cells and solid-state battery electrolytes.
United Metals sources cassiterite from both primary hard rock deposits (lode tin in granitic pegmatites) and alluvial placers (secondary accumulations in river gravels and floodplains) in Tanzania and Sierra Leone. The alluvial origin typically yields higher-grade cassiterite with fewer penalty elements, while hard rock ore provides a more consistent bulk supply. Both deposit types are processed through integrated gravity beneficiation circuits producing concentrate to GB/T 200424-2006 standard.
Two Deposit Types.
Two African Jurisdictions.
United Metals operates across primary hard rock and alluvial placer deposit types — each with distinct geology, mining methods, and concentrate chemistry — across Tanzania and Sierra Leone.
Mining is by open-cut and underground selective methods, targeting cassiterite-mineralised veins. Ore is crushed and ground to P80 300 µm before entering the gravity circuit. Hard rock ore typically grades 0.3–1.5% Sn in-situ, upgrading to 40–60% Sn concentrate through a multi-stage gravity circuit. Tanzania is positioning itself as a growing East African tin producer, with ongoing exploration expanding the resource base.
Sierra Leone's alluvial deposits are mined by hydraulic, dredging, and excavator methods. The coarser, pre-concentrated nature of alluvial cassiterite means processing requires less aggressive grinding, and the concentrate typically grades 60–74% Sn with lower associated sulphides — reducing smelter penalty deductions and increasing net payable value per tonne.