Tin exploration is the search for cassiterite (tin oxide) in and around highly evolved granites, and in the river, beach and offshore gravels that concentrate it once those granites erode. Hard-rock tin sits in greisens, sheeted veins, pegmatites and skarns close to granite contacts. Placer tin sits downstream. The two call for different tools, but both start with finding the right granite.

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Supply is concentrated and has been volatile. The USGS tin summary estimates world mine production at about 290,000 tonnes in 2025, with China and Indonesia together producing almost half. Output from Burma and Bolivia fell sharply in a single year. That is why smelters and governments pay attention to new tin sources, and why explorers keep returning to the tin provinces of Central Africa, Australia, South America and Southeast Asia.

“About 80% of the world’s identified tin resources are in placer deposits, according to the USGS.”

How tin deposits form: granites, greisens and placers

The USGS critical-minerals chapter on tin (Professional Paper 1802-S) sums up the geology in two numbers. Only about 20% of the world’s identified tin resources are primary hard-rock veins or lodes, which almost always occur with silicic, peraluminous granites. About 80% are unconsolidated secondary or placer deposits in riverbeds, valleys and on the sea floor. The largest concentration of placers is the Southeast Asian tin belt, running from China through Thailand, Burma and Malaysia to the Indonesian islands. For the same placer and hard-rock prospecting logic applied to gold, see our gold prospecting guide.

Why placers dominate

Cassiterite is heavy and chemically inactive. The USGS gives its specific gravity as 6.8 to 7.1, so running water carries away lighter material and leaves the cassiterite behind. Weathering over a lode forms residual placers, gravity moves the heavy grains downslope into eluvial placers, and streams build the richest deposits by reworking both. Beach sands can hold tin too, as in the offshore deposits mined in Indonesia and Thailand. In 2012, placers accounted for about 70% of world cassiterite concentrate output, the USGS chapter notes.

What makes a granite a “tin granite”

Not every granite carries tin. The USGS describes tin-bearing intrusions as highly differentiated, peraluminous porphyritic granites. Early work in Cornwall, Brittany and the Erzgebirge found tin deposits confined to a zone less than 500 m from the granite contact, preferentially in the apical parts of granites and in individual granite bodies rising out of larger batholiths. The ore sits in rocks rich in quartz, tourmaline and fluorine-bearing minerals formed by alteration of the host, the greisens.

In northern Nigeria, the USGS cites work showing that highly evolved biotite granites are genetically and spatially related to tin mineralisation. That is the logic behind tin exploration in northern Nigeria’s granite provinces and others like them: identify the most evolved granite phase, then look at its roof and margins.

Tin exploration methods that work

The USGS chapter notes that tin prospecting was historically done by panning, drilling, trenching and assaying, and that geophysical and geochemical surveys have since been used to cover large areas quickly, isolating the ground where drilling will be most effective. A modern tin exploration programme uses all of them, in order.

1. Map the granites. Government geology, magnetics and radiometrics, plus satellite imagery, separate granite phases and outline cupolas and contacts.
2. Rank them with geochemistry. The USGS lists barium, lithium, niobium, potassium, rubidium and zirconium as the most reliable chemical indicators of ore-forming processes and tin-bearing potential.
3. Pan the drainages. Heavy-mineral concentrates from streams show whether cassiterite is shedding from a catchment, and where the train stops.
4. Soil and rock sampling. Grids over the granite roof and margins outline greisen and vein zones.
5. Geophysics on targets. IP and magnetics help in skarn and sulfide-bearing systems; ground-penetrating radar and resistivity can map gravel thickness over placers.
6. Drill and bulk-sample. Diamond and RC holes for lodes; auger, sonic or large-diameter holes and pits for placers.

Radiometrics and tin granites

Potassium is one of the indicator elements the USGS lists for tin-bearing granites, and it can be measured from the air. Radiometric surveys record potassium, uranium and thorium in roughly the top 30 cm of the ground, which helps separate granite phases before anyone walks the ground. In Australia, national radiometric and magnetic grids make this a cheap first step.

Placer tin exploration: sampling gravels properly

Placer tin exploration looks simple and is easy to get wrong. Cassiterite settles to the base of a gravel, into bedrock cracks and behind obstacles, so a sample that stops short of bedrock can miss most of the tin. Pan samples show presence; they cannot give a reliable grade. A proper programme maps the old channels and terraces first, then drills or pits on lines across them to bedrock, logs gravel thickness and overburden, and processes bulk samples through a small gravity plant to measure grade per cubic metre or per tonne.

Offshore and beach placers add their own logistics, but the principle is the same: measure the volume of gravel, the depth to the base, and the grade of the whole gravel column, not just the richest layer. The USGS notes that most placer tin is mined by open pit or dredging, so the exploration data also has to support a mining method that can move that gravel economically.

Hard-rock tin: drilling greisens and veins

Greisens and sheeted veins sit in the roof and flanks of the granite, so drill holes are planned from a model of the granite contact. Many tin systems carry tungsten, molybdenum or sulfides as well, and some carry tin in stannite, a sulfide that behaves differently in processing. Core drilling gives the vein orientations and alteration detail needed to link surface anomalies to the granite cupola. Assays should cover tin and the likely by-products, because in some deposits the by-products change the economics.

Common mistakes in tin exploration

• Drilling a tin anomaly without mapping the granite, so the hole misses the cupola that controls the system.
• Trusting pan grades for placers instead of bulk samples to bedrock.
• Assaying for tin only in pegmatites and greisens, and missing tantalum, niobium, lithium or tungsten.
• Skipping mineralogy, so tin locked in silicates or stannite is counted as recoverable cassiterite.
• Ignoring glacial transport in northern terrains, where the East Kemptville discovery shows till can bury a deposit completely.

Where the world’s tin comes from

China mined about 71,000 tonnes of tin in 2025 and Indonesia about 61,000, according to the USGS. Peru (33,000), Brazil (28,000) and Congo (Kinshasa) (27,000) followed. Bolivia fell from 21,200 tonnes in 2024 to about 15,000, and Burma from about 20,000 to 12,000. Australia produced about 12,000 tonnes and Rwanda about 4,600. The United States has not mined tin since 1993 or smelted it since 1989.

The USGS describes world resources, principally in western Africa, Southeast Asia, Australia, Bolivia, Brazil, Indonesia and Russia, as extensive enough to sustain recent production rates well into the future if developed. The constraint is development, not geology: many tin districts have small, scattered deposits, artisanal mining and limited drilling.

Prices and demand

The USGS estimated the 2025 average LME cash price for refined tin at 1,500 US cents per pound, up 10% on 2024, and the New York dealer price at 1,600 cents, up 13%. In the United States, tin went into chemicals (25%), tinplate (16%), alloys (12%), solder (11%), babbitt, brass, bronze and tinning (7%), bar tin (2%) and other uses (27%). Solder for electronics is the use most tin exploration pitches mention, but the spread is wider than that.

Tin exploration in Australia, Central and East Africa, and Canada

Australia

Australia produced about 12,000 tonnes of tin in 2025 and holds reserves of about 570,000 tonnes, according to the USGS. The USGS tin chapter notes that eastern Australia, in the Tasmanides, has been a significant tin producer with a variety of deposit types. National magnetic and radiometric coverage and state geological survey data make Australian tin exploration strong at the desktop stage: evolved granite phases and their roof zones can be picked out before any fieldwork.

Central Africa: Congo (Kinshasa) and Rwanda

Congo (Kinshasa) produced about 27,000 tonnes in 2025 and Rwanda about 4,600, by the USGS estimate. The USGS also reports that in May 2025 a US tin company signed a letter of intent with a Rwandan tin miner to secure feed for a planned smelting and refining facility in Virginia. Central African tin exploration faces two practical conditions: much of the ground has artisanal workings, and all output falls under supply-chain due-diligence rules, covered below.

East Africa and Nigeria

The Tanzania High Commission’s minerals outlook notes tin occurring in granitic intrusions, without giving reserve figures. Nigeria produced about 3,500 tonnes in 2025. For licensing, see our Tanzania mining cadastre guide and our Nigeria Mining Cadastre Office guide.

Canada

Canada does not appear as a tin producer in the USGS table, but it has a classic tin discovery story. The USGS chapter describes how the East Kemptville deposit in Nova Scotia, completely buried under several metres of till, was found by a glacial till survey, with the discovery hole placed on the highest tin-in-till value. The Kidd Creek mine in Ontario has also long produced tin as a byproduct, from stannite. The chapter’s own summary is that tin exploration is “relatively simple” because the metal is invariably tied to evolved granites or their downstream placers. It also notes that in pegmatitic settings tin is associated with beryllium, boron, lithium, niobium-tantalum, tungsten and the rare-earth elements, so a tin anomaly in a pegmatite field is often worth assaying for the whole suite.

Planning a first tin exploration season

A first season on a tin licence should answer three questions: which granite phase is the tin granite, which drainages are shedding cassiterite, and whether the tin is in hard rock, in placers or both. A practical order of work looks like this.

1. Before the field: compile government geology, magnetics and radiometrics, old workings and any artisanal sites, and map granite contacts and drainages from imagery and elevation data.
2. Week one: pan every drainage that leaves the granite and send heavy-mineral concentrates for assay and mineral counts.
3. Weeks two to four: rock-chip and soil lines over the granite roof and the sector the pan results point to, analysed for tin plus the USGS indicator elements.
4. End of season: rank targets, decide between hard-rock drilling and placer pitting, and plan metallurgical test samples.

Budget for mineralogy early. A handful of samples examined for cassiterite versus tin in silicates or stannite can save a whole drilling season aimed at tin that will never report to a concentrate.

Tin exploration companies and conflict-mineral rules

Tin exploration companies range from juniors drilling hard-rock greisen and vein targets in Australia and Europe to groups developing placer and hard-rock tin in Central Africa and South America. Whatever the size, two things shape how they work.

Supply-chain due diligence

Tin is one of the four minerals named in the EU Conflict Minerals Regulation, alongside tantalum, tungsten and gold. Its requirements began to apply on 1 January 2021 and require EU importers to source these minerals responsibly, with due-diligence schemes assessed against methodology developed by the OECD. For a tin explorer, that means land access, labour conditions and chain of custody records will be examined by any future buyer, so they should be kept from the first sample.

What to look for in a tin explorer’s disclosures

• Deposit type stated clearly: hard-rock lode, pegmatite or placer, because each has different mining costs and recoveries.
• Grade as % Sn with mineralogy, not just a total tin assay.
• Metallurgical recovery from test work, and the concentrate grade achieved.
• For placers: gravel volume, depth to bedrock and grade per cubic metre or tonne from bulk samples, not from pan samples alone.
• By-products: tungsten, tantalum, niobium or lithium assays where the geology suggests them.
• Due diligence: which supply-chain scheme the project will use, and how artisanal miners on the ground are dealt with.

Tin exploration terms in plain English

Cassiterite

Tin oxide (SnO2), the main ore mineral of tin. Heavy, dark and hard-wearing, so it concentrates in gravels.

Greisen

Granite or wall rock altered to quartz, mica and fluorine-bearing minerals by late fluids, often carrying cassiterite.

Cupola

A dome-shaped high point on the roof of a granite, where tin-bearing fluids tend to collect.

Eluvial placer

Weathered debris that has moved only a short way downslope from its source, still close to the primary deposit.

Stannite

A copper-iron-tin sulfide. Some mines recover tin from it as a byproduct, as Kidd Creek in Canada has.

How satellite screening fits tin exploration

Satellites suit the first stage of tin exploration well. Granite phases, their contacts and roof zones, the structures that feed greisens and veins, and the drainages, terraces and old channels that hold placer gravels can all be mapped from imagery and elevation data over a whole licence. Our satellite-based mineral detection analyses multispectral and hyperspectral data over your boundary to flag target zones, alteration halos, faults and fractures. Tantalum and niobium, which often occur with tin in pegmatites, are on our published list of detectable materials. To check coverage for a tin (cassiterite) target on your licence, ask us through the mining query form what a granite, structure and drainage screen can add for your cassiterite target.

• Input: coordinates, KML/KMZ or a polygon, plus country and target mineral.
• Output: high-potential zones, prospectivity heatmaps, estimated location and depth ranges, geological interpretation, PDF and GIS files.
• Time and cost: 5–20 business days; early-exploration timelines cut from months to days and costs lowered by up to 80–85%.
• Premium+: TargetMax™ drilling-angle recommendations and 3D subsurface models of vein structures.

We have scanned 100,000+ hectares for 20+ mineral types across 25+ countries. Draw your licence on mining.farmonaut.com (Map Your Mining Site), or see a sample of satellite-driven 3D mineral prospectivity mapping. For the wider exploration process, see our mineral exploration guide.

Frequently asked questions

Reviewed September 2026 against the USGS Mineral Commodity Summaries 2026 tin chapter, USGS Professional Paper 1802-S on tin deposits, Geoscience Australia’s radiometrics page, the European Commission’s page on the Conflict Minerals Regulation and the Tanzania High Commission’s minerals outlook.

Production, price and reserve figures are USGS estimates revised every February; check the latest edition. The calculator is a screen that ignores treatment charges, penalties and costs. Nothing here is investment advice. Satellite targets are exploration targets, not mineral resources, and need sampling and drilling to confirm.