Gordon Stein has been hired as chief financial officer, and Richard Laing, Al Njoo and Achmad Madjedi Hasan all join the board as non-executive directors.
Meanwhile, Ian Barby and Peter Kingston have stepped down from their positions as non-executive directors.
"We are delighted with the progress we have made in restructuring the team over the last few months and achieving the significant milestone of commissioning the Tsimiroro pilot,” said chairman Andrew Morris.
“We will continue to strengthen the team as the needs of the business evolve.
"I would like to thank the outgoing directors for their support and contributions, especially over the last few months and welcome the new directors and Mr. Stein who will bring a wealth of talent and experience to the team."