Sulfide oxidation using thermophile can be employed to decrease the sulfur content in ore surface to reduce the risk of spontaneous combustion. In this study, the experimental results show that, under the influence of thermophile, the maximum degree of oxidation of 32.9% can be achieved in 28 days and the degree of oxidation is inversely proportional to the ore particle size. Further analyses indicate that, the oxidation weight gain rate of the sulfide ore in the first 5 days decreases from 2.55% to 0.64% while the spontaneous combustion point of the ore increases from 140.7 degrees C to 368.7 degrees C. As a result, the spontaneous combustion tendency level of the sulfide ore has been downgraded from level I to level III. This work demonstrates and quantifies the effectiveness of using thermophile oxidation to reduce the risk of spontaneous combustion in mining high-sulfur content ores. (C) 2013 Elsevier Ltd. All rights reserved.