The design mismatch
Regional certification mechanisms in the Great Lakes were built around minerals that move in sacks and containers, where tagging at the pit and reconciliation at the border is workable. Gold is dense, high value and easily concealed, and a year's artisanal output from a district fits in a briefcase.
Where the schemes still bite
Certification retains force at the buyer end. Refiners on international good-delivery lists apply their own due diligence, and losing accreditation is commercially fatal. The practical chain of custody is therefore enforced by London and Zurich, not by the border post.
Implication for Ugandan operators
Producers who intend to sell into accredited channels should build documentation to the standard those refiners audit against, and should assume that standard tightens rather than relaxes. Operators selling into unaccredited channels are accepting a discount whether or not it appears in the contract.