Much like the larger Simandou deposit, Mount Nimba have yet to start commercial production due to political instability in Guinea in past years and questions over the preferred route to ship the iron ore to market.

Shares in ArcelorMittal (NYSE:MT), the world’s No.1 steelmaker, were up 2.25% to $15.91 on late trade Monday on reports the company was close to becoming the buyer for BHP Billiton’s (ASX:BHP) stake in a major Guinean iron-ore deposit.

According to The Wall Street Journal, the steel giant is in "deep, deep discussions" with BHP, in a deal potentially worth as much as $500 million.

The world’s No. 1 miner has been trying to sell its 41.3% stake in Mount Nimba since July 2012, as part of a strategy to survive the mining downturn, which saw commodity prices falling, costs rising, project halted, workers fired and non-core assets sold.

The Mount Nimba project is 41.3% owned by BHP and 41.3% owned by Newmont Mining, France's Areva owns a 12.4% stake.

In February, Brazilian firm B&A Mineração lost interest after lengthy negotiations, because it found the project too costly, risky and difficult from an operational and political perspective.

Questions over Guinea's political stability and whether the government will allow firms to export through neighbouring Liberia, which is vital to making mines profitable at current prices, have complicated investment decisions on its big iron ore projects, including Mount Nimba and the giant Simandou deposit.

The sell is considered a boost to BHP’s plans to exit West Africa and focus its investments elsewhere in the world. The group’s CEO Andrew MacKenzie has made streamlining the company one of his main priorities, which includes cutting back spending on big, capital intensive projects.

Guinea has great mining assets, 50% of the world's reserves of bauxite and significant iron ore —the feedstock ore for aluminum— and significant gold and uranium, deposits.

Currently, the world’s top iron ore producers, Brazil’s Vale (NYSE:VALE) and Rio Tinto (LON, ASX:RIO) are in the midst of a series of billion-worth lawsuits, which came on the heels of Guinea’s President Alpha Conde revoking all mining rights for both companies over a corruption probe case.