A top official with South Africa’s ruling ANC said on Wednesday that the party was concerned about the souring of relations between the mining ministry and the main industry body, the Chamber of Mines.

Zweli Mkhize, who is seen as a potential candidate to replace President Jacob Zuma as head of the African National Congress at a party conference in December, made the remarks at a mining conference in Johannesburg.

The ministry and the chamber in the world’s top platinum producer are locked in a bitter legal battle over revisions to an industry charter which include raising the level of shares blacks should own in mining companies.