Prominent South African mining CEO resigns amid JSE battle

Mantengu CEO Mike Miller has resigned as the CEO and executive director of the company, with effect from the end of this month.

In 2025, Miller and his company alleged that JSE directors and various other parties manipulated Mantengu’s share price.

On Friday, 20 February 2026, Mantengu announced that Miller would be resigning with effect from 28 February 2026.

“Mike played an integral role in the strategic leadership of the Company, and he diligently fulfilled his duties with the highest level of integrity, expertise and commitment,” the company said.

“Mike has taken the difficult decision to resign in order to allow him to spend more time with his young family.” 

“Mantengu’s operational ramp-up to steady state also demanded increased executive time on site, and it would have been difficult for Mike to commit this time.”

The company’s current CFO and deputy CEO, Magen Naidoo, will assume the role of CEO from 1 March 2026.

Mantengu said Naidoo is a qualified Chartered Accountant with more than 25 years of experience. 

He was previously an audit partner at Deloitte, where he spent over 17 years serving large listed clients, including mining giant Anglo American.

“Magen has been actively involved in operations as deputy CEO over the past few months, as well as the company’s various acquisitions and the group strategy over the past few years,” Mantengu said. 

“This will enable him to transition to the role of Chief Executive Officer seamlessly.”

As Naidoo takes the helm, Mantengu director Langton Mpofu will take over the role of CFO.

This leadership shake-up comes after Mantengu embarked on a warpath in 2025, filed a complaint with the Hawks against JSE executives for alleged share price manipulation.

The company explained that it had alerted the JSE in respect of its concerns about share price manipulation.

However, it claimed the JSE ignored the company’s concerns and instead investigated Mantengu for alleged breaches of certain Listings Requirements.

Following this complaint, the JSE told Daily Investor that it denies being a party to or “complicit” in any form of illegal or unlawful activity. It said Mantengu’s allegations in this respect are “false and rejected”.

Mantengu had previously made similar complaints about this alleged share price manipulation to the Financial Sector Conduct Authority, which found no evidence of wrongdoing.

In November 2025, the Johannesburg High Court ruled that Mantengu and Miller had to cease publishing their allegations against the JSE.