Chain of Custody

Chain of custody in conflict minerals refers to the documented sequence of entities — from mine to smelter/refiner to downstream manufacturer — through which a mineral passes, with records at each transfer point establishing provenance and responsible sourcing status. A robust chain of custody allows downstream companies to trace whether minerals originated from conflict-affected areas and whether each transfer point exercised responsible sourcing practices.

OECD Due Diligence Guidance, Third Edition (2016), Step 4 and Annex II; Regulation (EU) 2017/821, Articles 4–7; Dodd-Frank Section 1502.

Chain of custody is particularly challenging for 3TG minerals because they are fungible — ore from multiple sources is often commingled at processing and smelting stages. The smelter/refiner is the ‘pinch point’ of the supply chain where RMAP audits concentrate because it is the last point where ore origin can be verified before the mineral is transformed into a metal that cannot be traced back to its source.

A tin mineral chain of custody: mine in DRC → artisanal miner collective → regional trader → export house → smelter in Malaysia (RMAP-conformant) → downstream manufacturer in Europe. Each transfer is documented. The RMAP audit at the smelter verifies that the ore entering the smelter was sourced from responsible origins.