Operating difficulties are encountered when high coal injection rates are used into the blast furnace raceway. An insight into the problems has been gained using a wire mesh reactor, which has been modified to inject short (5-500 ms) pulses of air or O-2-enriched air through the sample holder, once the particles have reached peak experimental temperature. By manipulating the test procedure, it has been possible to measure the extents of successive pyrolysis, char combustion, and CO2-gasification that occur under simulated raceway conditions. In the wire-mesh reactor, the release of volatiles was completed within the heat-up period (similar to300 ms, at a heating rate of 5000 degreesC s(-1)). For 20 ms air pulse times, complete consumption of the inlet O-2 Occurred (with concentrations in the range 21-75%) and the extent of combustion was limited by the amount of O-2 supplied (i.e., it was diffusion-limited). Extents of CO2-gasification were measured in the temperature range 800-1500 degreesC, and the results suggest than many seconds are needed to achieve a reasonable extent of gasification. Overall, the results indicate that the extents of combustion and gasification of the char in the raceway (residence time < 50 ms) are likely to be low. However, a significant proportion of the char will subsequently react by gasification within the blast-furnace bed. Unreacted char and soot may either be trapped in the coke bed or entrained in the gas stream, giving rise to the problems observed at high coal injection rates.