I will definitely be looking for those missing millions in the annual report. By my count, there's USD$17.5m unaccounted for. As follows:
GXY had USD$169m COH at the end of Q3. They also had an outstanding payment of USD$10-11m from a Q3 shipment that was to be received in Q4. Add on Q4 sales of ~USD$11m (24,528 t x $450/t) and you get a starting point of USD$191m.
$191M - $143M = USD$48m expended in Q4.
Production was 43,222 tonnes at $406/t, which equals USD$17.5m production costs.
$48m - $17.5m = $30.5m
There was $10m on CAPEX across all three projects and $3m for corporate costs.