De Thierry has 25 years' experience in mining and investment banking in Africa & Europe, and was a founder of Casa Mining, which has become Ortac’s key asset.
He has significant experience of raising capital for exploration and development of major mining projects in the Democratic Republic of Congo.
"I am delighted to welcome Jonathan to the board of Ortac,” said Ortac chairman Nick von Schirnding.
“Jonathan brings a wealth of experience having successfully developed a number of mining projects in the DRC. I look forward to starting 2018 with a highly experienced board and management team in place."