Constantine is an experienced executive and professional engineer with more than 30 years of senior leadership roles in the rare earth elements, critical minerals, and advanced materials sectors. He has held senior executive and board roles across mining, processing and downstream materials businesses globally. He most recently served as President and Chief Executive Officer of Neo Performance Materials Inc. (NEO) until his retirement in July 2023, having held a range of senior leadership roles. As CEO, he oversaw  Neo’s global expansion and ultimately led the company through its US$1.3 billion acquisition by Molycorp Inc. in 2012. He holds Bachelor and Master of Applied Science Degrees in Chemical Engineering from the University of Toronto and is a registered Professional Engineer.