Coalification Jumps, Stages and Mechanism of High-Rank Coals in China

Abstract

Based upon the samples collected from more than twenty coal mining districts in China, the coalification jumps, stages and mechanism of high-rank coals were systematically studied in the light of coal petrology and coal chemistry. It was indicated that three stages, namely as meta-exinitic, meta-vitrinitic and meta-inertinitic stages, are undergone in succession during the development of the reflectance of high-rank macerals according to the measured data. A new coalification jump, occurred at about 8% maximum vitrinite reflectance, was found and was considered as one of major indicators in the classification of coalification stages. Six jumps of high-rank coalification were demonstrated in detail, and the Classification Scheme of Coalficaton Stages of High-rank Coals in China was established, in which three stages, i.e., hypo-, meso- and hyper-anthracites, were distinguished respectively at 2%, 4% and 8% maximum vitrinite reflectance. The Makingup, considered as a dynamochemical process and a special mechanism for high-rank coalification, was suggested, and its fundamental patterns and evolution were prelimitarily investigated.