Study On Coal Accumulating Characteristics Of Yan’an Formation Coal Of Xinbai Mine Field

Xinbai Mine Field is located in the east of Ankou-Xinyao coal field, which is lied between eastern Liupanshan and Loess plateau of Longdong. The coal-bearing stratum is Yan’an Formation of Jurassic system. The coal seams are stable and thick. The Yan’an Formation Coal has larger reserves, and the coal’s quality is good, which is called Non-caking coal. This kind of coal is low ash, low sulfur, high volatile, high calorific, and it can be served as coal for gasification and chemical coal. Xinbai Mine Field didn’ t have deep geological exploration level, which made the good coal resource advantage not be able to get reasonable development and utilization. So, the study of coal accumulating characteristics of Xinbai Mine Field is very necessary. It will cause important theoretical and realistic significance on the reasonable and comprehensive utilization of coal and the the development and construction of coal field.In this article, the author stydied the coal petrology characteristics, coal seam and its occurrence characteristics, coal accumulating environment of coal-bearing stratum in Xinbai Mine Field by using coal basin analysis theory, combining Sedimentology, Petrology, Coal Geology, Sequence Stratigraphy and Structural Geology, and finally summed up the coal accumulating characteristics.The coalification of coal-bearing stratum occurred mainly in River Sedimentary System and Lake Delta Sedimentary System. The former stands at the bottom and the top of Yan’an Formation and formed No.6, No.5, No.1 coal. It distributes large area of alluvial plain, and multiphase and stable peat bogs developed in it. The latter stands at the middle of Yan’an Formation and formed No.4, No.3, No.2 coal. Large-scale of deltaic plain developed polyphase peat accumulation. Because of the combined action of the paleoclimate, the ancient plant, the paleogeography and the paleostructure, the coal accumulating period of Xinbai Mine Field had gone through a process from development stage to peak period, and then stable period, finally end in recession and extinction.