Grocott was most recently chief advisor, processing at Rio Tinto.
Current chief technical officer Peter Voigt will refocus his attention on Clean TeQ’s water treatment business.
Founding Platina Resources managing director Robert Mosig has resigned.
Chris Hartley will act as an interim executive director while the company looks to appoint a new CEO, while company secretary Paul Jurman will also temporarily join the board.
Robert Gregory has been appointed as CEO of Sumatra Copper & Gold, replacing David Fowler who will remain a non-executive director.
Gregory has been chief operating officer of the company since mid-2016.