The logistics of transporting tonnes of raw materials to port from mining sites in remote parts of Guinea has been a major hurdle for prospective developers of the country's vast mineral wealth.

Portside sales of Rio Tinto's products at Chinese ports are currently sold via traders.

Company added that work to secure its Barragem Sul Superior tailings dam will be complete by December.

SL Mining has called for authorities to cancel the decision and threatened to "pursue all available remedies against the government."

Vale had also purchased access to the project data, but did not submit an offer, sources said.