The reduction roasting of chromite overburden with CO/CO2/N-2 gas mixture in the temperature range 700-750 degrees C has been shown to result in the formation of metallic nickel and different lower valence states of iron, viz : magnetite, wustite and metallic iron. The reduced calcine was cooled to room temperature under an inert atmosphere and leached with ammonia-ammonium carbonate solution to bring the metallic nickel into soluble form. This paper reports the results from estimation, by thermogravimetric (TG) and chemical methods, of the percentage iron reduced to lower oxide stages such as magnetite and wustite in the calcine under different experimental conditions. Further, the percentage extraction of nickel is correlated with iron reduction.y