The Zimbabwe unit of Impala Platinum, the world's second largest producer of the precious metal, said on Thursday that the Zimbabwe government had taken steps to revoke its operating license but it remained in talks with authorities.

It is the latest piece of brinkmanship in a drama over a government bid to get mining companies to transfer 51 percent stakes in their local operations there to black Zimbabweans.

Implats' shares earlier closed over three percent lower after the official Herald newspaper said the Zimbabwe government had begun the process to suspend the licence of its Zimplats unit, which accounts for about 10 percent of group output.

Zimplats said in a statement that the country's empowerment minister, who has rejected its share transfer plan, had asked the mining ministry to cancel its operating licence.

It said the company's operating licence has not been cancelled and discussions between management and the relevant authorities.

It also said that the only major area of disagreement was a mining area that Zimplats gave up in 2006 -- known as a release of ground -- that it wants counted as credits in its plan to comply with the law.

The government acknowledges the existence and validity of the agreement, but wants to renegotiate certain terms, it said.