Guinea's junta has given bauxite mining companies 10 days to present a timeline for the construction of alumina refineries, extending an end of May deadline the companies did not meet, it said in a statement on Friday.
Africa's biggest producer of the aluminium ore has been seeking to channel its mineral wealth into economic development and has pressured companies to build local facilities to refine bauxite into higher value alumina.
"As of today, it has been noted that none of the companies has complied," said the statement, a readout from a June 9 cabinet meeting.
The companies affected by the refinery ultimatum include Guinea's top two bauxite producers Societe Miniere de Boke (SMB) and Compagnie des Bauxite de Guinee (CBG). Neither company immediately responded to a request for comment.
Guinea only has one alumina refinery so far, the Friguia refinery owned by Russian aluminium giant Rusal, which also operates two bauxite mines in the country.
Analysts say there are hurdles to refining in-country.
"Refinery projects in Guinea only benefit from their bauxite, as all the other raw material needs, such as energy and caustic soda, need to be imported," Anthony Everiss, senior consultant at commodity research house CRU, said in a recent note.
CRU estimated that six companies have alumina refinery plans in Guinea, for a total planned capacity of 11-million tonnes a year. Most of these plans are at an early stage, according to CRU.
Guinea is also looking to set a reference price for bauxite, according to the government statement, which did not detail how this would work in practice.
The interim president is concerned about bauxite miners in Guinea setting different prices for the ore, the statement said, and expects a draft decree on the issue by next Friday.
Guinea exported 81.1-million tonnes of bauxite in 2021, according to mines ministry statistics. China imports around half of its bauxite from the West African country.
The government also said that partners in the Simandou iron-ore mine would meet the president on Friday to finalise a joint venture between Rio Tinto and Chinese-backed consortium Winning Consortium Simandou.
Rio Tinto declined to comment on the meeting, and WCS did not reply to a request for comment.
Guinea has grown increasingly impatient with the companies that control the giant Simandou deposit, which has not been developed since Rio was first granted an exploration licence for it 25 years ago.