Non-executive chairman Sir Roderic Lyne said the appointment added to the appointments of James Cameron and Damien Hackett last month to give the company "four highly qualified independent non-executive directors".
He said Kenyon-Slaney would chair the board's safety, sustainability and workforce committee and be a member of the audit committee.
Kenyon-Slaney has over 33 years' experience in the mining industry, mainly with Rio Tinto where he was a member of the group executive committee until 2015 and held senior roles, such as CEO of energy, CEO of diamonds and minerals, leader of the titanium dioxide business and CEO of Rio subsidiary, Energy Resources of Australia.
The Russia-focused gold miner had to rebuild its board after booting out the previous group earlier this year.