The Jones-Wilkins-Lee (JWL) EOS is widely used to capture detonation energy release but not the energy release from secondary combustion, or afterburn. To account for the burn mechanism of detonation products with that of combustion, the JWL EOS had been extended such as in the work of Miller[1], whose reactive flow model for highly non-ideal metallised explosives displays characteristics of both fast detonation and slow metal combustion chemistry. In this work, the focus is on non-detonating aluminum-containing nanothermite composites, in contact with and ignited by a detonating explosive. A small scale test is set up to study the enhancement in burn front propagation in the presence of nanothermites. Miller's original Moby Dick test had been modified wherein the slow burning component is in contact with the explosive. Thermochemical calculations of the afterburn phase were made with a modified version of the thermochemical code EXPLO5 to determine the afterburn release energy. Analysis of the experimental findings and subsequent calibration work will allow determination of the system-specific EOS. This reported methodology can be applied to study and calibrate the afterburning of other energetic materials.