Inspection & Testing
Precious metals, base metals, battery minerals, the 3T ores, bulk ores and specialty minerals — inspected at source, sampled under supervision and tested by accredited laboratories, with results addressed to you, not the seller.
What most buyers never check
Tungsten is almost exactly as dense as gold — 19.25 g/cm³ against 19.32 — and costs a tiny fraction of the price. Under a thick gold skin it weighs right, measures right and reads as gold on the outside. The surface is real. The inside is not.
Before your next purchase, ask
Has anyone tested this gold below the surface, from a sample I saw taken?
If the only evidence is a surface reading, or a certificate for a sample nobody watched being cut, you do not yet know what you are paying for.
Nairank Global inspectors weigh and seal the lot in front of both parties, take samples from the body of the metal, and send them to an ISO/IEC 17025-accredited laboratory for fire assay, with the certificate issued in your name.
Laboratory testing
Copper concentrate, cobalt hydroxide and the 3T and battery-mineral ores are bought on their laboratory grade. Our laboratory specialists manage the work with independent laboratories accredited to ISO/IEC 17025, from sealed sample to certificate — and the certificate is addressed to you. Standards we work with.
Gold doré, refined gold, silver and the platinum group metals — tested on site to screen the lot, and assayed in the laboratory for the figure a sale is settled on.
Methods and standards: Fire assay (ISO 11426 for gold alloys); laboratories accredited to ISO/IEC 17025; LBMA Good Delivery listings confirmed with LBMA.
Copper, zinc and lead concentrates are paid on laboratory grade and dry weight, so representative sampling and moisture determination decide the money. Cathode is checked against its brand and specification.
Methods and standards: Concentrate sampling with reference to ISO 12743:2021; laboratory analysis under ISO/IEC 17025 accreditation; cathode against the contract specification (for example LME Grade A).
Cobalt, lithium and graphite — newer trades where buyers often have least history with the seller and where impurities can make a lot unusable for refining.
Methods and standards: Laboratory analysis under ISO/IEC 17025 accreditation; industry sampling and analysis procedures for cobalt hydroxide; responsible-sourcing checks with reference to the OECD Guidance.
Tantalum (coltan), tin (cassiterite) and tungsten (wolframite) — Great Lakes ores where traceability and the regional certificate matter as much as grade.
Methods and standards: OECD Due Diligence Guidance; ICGLR Regional Certification Mechanism certificates confirmed with the issuer; laboratory analysis under ISO/IEC 17025 accreditation.
Iron ore, manganese and chrome move in large tonnages, where the stockpile survey and the loading are where quantity and quality are lost.
Methods and standards: Bulk sampling and laboratory analysis under ISO/IEC 17025 accreditation, against the contract specification.
Rare earth concentrates and other specialist materials, where the value lies in specific elements and the analysis must be matched to them.
Methods and standards: Laboratory analysis under ISO/IEC 17025 accreditation; export authorisations confirmed with the issuing authority.
Gold and silver, platinum group metals, copper (concentrate, cathode, wire and scrap), zinc and lead concentrates, cobalt, lithium, graphite, coltan, tin, tungsten, iron ore, manganese, chrome and rare earth concentrates. For anything else, describe it in the request.
Copper concentrate is paid on laboratory grade and dry weight. If the sample does not represent the whole lot, the laboratory result — however accurate — moves money between buyer and seller. Sampling across the lot, with moisture taken at the time of weighing, is what makes the result fair.
By supervised sampling of the bagged lot, moisture determination, and laboratory analysis of cobalt content and the impurities refiners penalise, such as manganese, magnesium and copper — with the lot reconciled to its export documents.
On-site testing — handheld XRF, density, acid tests — screens a lot quickly. Laboratory testing on a representative, sealed sample produces the figures a contract is settled on. Concentrates and ores should always be settled on laboratory results.
Nairank Global’s laboratory specialists manage the work with independent laboratories accredited to ISO/IEC 17025 for the test required. Certificates are addressed to the client, not to the seller, and name the laboratory and method.
Field teams are based in Tanzania, Kenya, Uganda, Zambia, DR Congo, Ghana, Sierra Leone and travel to wherever in Africa the material is held — mines, stockyards, warehouses and ports.
No. Nairank Global is independent of buyers and sellers. Its fees are outcome-neutral: they are the same whether or not the transaction proceeds. We act for the client alone.
Related: gold testing, assay and inspection · copper sampling and laboratory testing · mine, warehouse and stockpile inspection · copper suppliers in Zambia · standards and quality
We return a scope, the sampling plan, the laboratory and a fee, usually within one working day.
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