He will take over from Joe McCoy, who will remain Orezone's vice president of administration and corporate secretary.
Tam was most recently VP of finance at Nevsun Resources (CN:NSU) and, prior to that, was CFO at Elgin Mining from 2012 until it was acquired by Mandalay Resources (CN:MND) in September 2014.
He has also served as VP of finance for Aura Minerals (CN:ORA) and treasurer for Thompson Creek Metals (CN:TCM).