"In order to ensure continuity and stability of leadership and management, the appointment of a new chairman is not considered appropriate at this time," it said.

The company said the board and nomination committee had considered the 22.12% vote recorded against Pouroulis' re-election as chairman in the context of Petra's ongoing three-year succession plan and also taken into account concerns raised by some shareholders.  

Despite the concerns, it said the board had reaffirmed its assessment that the chairman continued to "demonstrate the independence of thought and challenge required for his role, notwithstanding the number of years he has served as a director".

Pouroulis founded Petra in 1997 and has been chairman since it floated on AIM during the same year. he company moved to the LSE main market in 2011.

The other directors said they would continue to review the situation as the nomination committee was in the final year of its three-year succession plan, with further changes expected to be made to the composition of the board in 2019.

Petra recently appointed Richard Duffy as CEO to replace the outgoing Johan Dippenaar on April 1, and also added two new independent non-executive directors, Bernard Pryor and Varda Shine, to the board from January 1.

Pouroulis stepped down as non-executive chairman of private gold miner Toro Gold at the beginning of the year after a decade, but remains non-executive chairman at Benzu Resources, Alufer Mining, Rainbow Rare Earths, Chariot Oil & Gas and Desert Lion Energy.