The Bureau of Mines is investigating the use of complex gas mixtures, such as would be produced by coal gasification, for reducing iron oxide pellets. A semiempirical model was developed to predict a priori the reduction rate of an iron oxide pellet in a laboratory tube furnace with simulated coal gases at a total pressure of 1 atm. The model uses partial pressures of h2, CO, co2, ch4 (methane), water vapor, and a temperature-dependent term to predict the rate of reaction. The reduction rate (weight loss per unit of time) was determined with a thermogravimetric apparatus in the temperature range of 800 deg to 1,100 deg c. The ranking of the reductants, in order of decreasing reducing potential, is h2, CO, and ch4 at temperatures between 800 deg and 1,000 deg c; however, ch4 became a better reductant than CO at 1,100 deg c. Water vapor did not decrease the reduction rate as much as did co2. Carbon deposition was observed at temperatures below 1,000 deg c with gas mixtures with high CO and low h2 concentrations. With low-btu gas at 900 deg c, over 90 pct of the iron oxide was reduced to iron in less than 3 h. This compares with a reduction time of 1.5 H with medium-btu gas and 1 h with reformed natural gases.