Guinea’s authorities signed the first-ever “convention de base” (basic mining convention) for Nimba Mining Company (NMC SA) on 3 August 2026 in Conakry, one year after the company’s creation by presidential decree. NMC is wholly owned by Guinean state capital, no foreign or private stake. Officials describe it as the first mining convention in the country’s history to cover an entire value chain, from extraction to export, held by a company entirely owned by the state.
The convention sets the legal framework for the company’s operations, covering fiscal, customs, environmental and social obligations for both the state and the operator. NMC’s assets stem from the state’s takeover of the former GAC concession. Over its first year, the company restarted the Tinguilinta bauxite mine, a 92-kilometre rail corridor, and port infrastructure at Kamsar, and shipped its first bauxite in November 2025. NMC has also launched feasibility studies for a 1.2-million-tonne-a-year alumina refinery, aimed at processing more bauxite domestically rather than exporting it raw.
The signing ceremony was chaired by Djiba Diakité, the minister-director of the Presidency’s cabinet and chairman of the Simandou 2040 Strategic Committee. Guinea’s foreign minister called the day historic, framing the convention as the fulfilment of a long-standing goal to gain direct control over national mineral resources since independence.
Reading
The convention formalizes a shift Guinea’s government has been signaling since Simandou entered production: moving from a model where the state licenses foreign operators to one where a state-owned company holds the mine, the transport corridor and the export terminal outright. Bauxite is the test case, not iron ore. Guinea is already the world’s largest bauxite exporter, so the question this convention answers is not access to resources, but who captures the value along the chain, from mine to port to eventually refinery.
Implication
The refinery feasibility studies matter more than the mining convention itself for long-term revenue. Guinea currently exports almost all its bauxite raw; a domestic alumina refinery, even a modest 1.2-million-tonne one against annual bauxite exports above 100 million tonnes, would be a first step toward the local value addition the government has said it wants under Simandou 2040. Whether NMC can execute at the scale of established operators like SMB or CBG, which each ship well over 15 million tonnes a quarter, remains untested; a one-year-old state company running a single mine and a short rail line is a different proposition from an integrated multinational operation.
Projection
Worth tracking: the timeline and financing structure for the alumina refinery feasibility studies, since a firm construction decision would be the real signal of intent rather than a study announcement; NMC’s actual production and export volumes in its second year, to see whether it can scale beyond a symbolic first shipment; and whether this state-owned model is extended to other Guinean mining assets, which would mark a broader shift in how the country manages its resource sector alongside its existing foreign-operator agreements.