David Knox, CEO of the South Africa-focused coal exploration company since 2011, retired today effective immediately.

The news follows last month’s retirement of four directors from the Johannesburg and ASX-listed company.

Waterberg has its eyes set on Firestone’s 60% interest in the Waterberg coal project in South Africa’s Limpopo province. It already owns 43% of the company.

Waterberg is making a ferocious takeover bid for Firestone, a move likely driven by the expected mega profits from Waterberg which is a 60% joint venture with Sekoko Resources.

It has made numerous bids, increasing in value, to Firestone shareholders. Firestone has urged shareholders to reject each offer, but following recent board changes a takeover seems imminent.

Last month, Waterberg asked Firestone to convene a shareholders’ meeting to remove deputy chairman David Perkins as a director.

Perkins resigned along with non-executive directors Jack James and Oren Zohar, preventing the meeting.

A few days later, Waterberg asked for another meeting to remove Kobus Terblanche, also a non-executive director, but Terblanche also beat them to it, resigning three days later.

Waterberg executive director Stephen Miller and chairman Brian McMaster replaced James and Zohar.

Miller has now stepped up to become CEO, while Knox will remain on the board as a non-executive director.

Miller told Business Times that the changes were not aimed at preventing the board from obstructing Waterberg’s takeover bid, claiming Waterberg asked for these resignations so Firestone’s board would reflect his company’s shareholding.

Firestone chairman Tim Tebeila reportedly supports Waterberg’s takeover bid.

The company said in the announcement of Knox’s retirement that it expects the definitive feasibility study for the Waterberg project to be completed by the end of July.

The project already has 10Mtpa supply deal signed with major South African utility Eskom, expected to commence in Q1 2015.