BHP Energy Coal South Africa president Wayne Isaacs told Reuters there was no particular reason for the delay and that a Black Economic Empowerment (BEE) company had been identified for the deal.

Earlier in the year, the mining giant said it wanted to sell the mine to a BEE group, to meet requirements set out by the SA Government's affirmative action policies to include more BEE companies in the economy.

"There are a lot of steps to making the sale happen - we are currently in the final stages of negotiating with the new owners, the BEE company, these things take time, there's all the legal documentation ... there's no inordinate delay," Isaacs said.

He declined to disclose how much the mine would be sold for or who the buyer was, but the newswire said sources close to the deal had previously indicated a price of around $300 million.

Despite off-loading its South African coal assets - the company has finalised the sale of its Koorfontein coal mine to a consortium of black investors for $61.20 million - Isaacs said BHP remains committed to the South Africa coal market.

"We have no intention to leave the South Africa coal market. Our strategy is to develop large, long life, Tier 1 assets," Isaacs said.

"To compete globally we need our South African operations to add to our Australian coal output."