This paper presents a proof-of-concept discrete-event simulation model for examining the ability of the Canadian Forces (CF) to sustain operations, from a human resources perspective. Given a set of future operations for the CF, ranging from known ongoing domestic commitments to possible international missions, the goal is to identify potential shortages of deployable personnel by occupation, rank and unit, up to five years in advance of actual deployment. As a demonstration case, the proof-of-concept model was applied to a contingency analysis of the sustainability of Task Force Afghanistan over a three year planning horizon.