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The Zhungeer coal field is located in the eastern part of Zhungeer, Inner Mongolia. It is a Permo-Carboniferous coal field, about 1730 km2, and trends nearly south-north. The coal seams are thick, mineable, and of excellent quality. It will be one of the most important coal fields in China. As a result of lithofacies research and paleogeographical reconstruction of the Zhungeer coal field, some insights ar realized on the barier-island system of the epeiric sea in a coal-bearing sequence, the coal-forming environment of marine facies, the event deposits in coal-bearing sequences, and the method of preparing a lithofacies paleogeographical map in coal-bearing basins. The Shanxi Formation of Early Permian age in the Zhungeer coal field belong to the deltaic-fluvial system. In the author's research, however, the Benxi and Taiyuan Formations of Carboniferous age belong to the mutual system of barrier island-platform of the epeiric sea. Because of the transgression and regression of the epeiric sea, the alternative paleogeographical pattern of the barrier island and the lagoon-tidal flat are repeated many times in the same place. The platforms are located outside the barrier-island system. Along with the transgression and regressions, the terrigenous fragmental deposits of the are extensively mixed in space and time. There are two different types of coal-forming environments that also have two different features of coal quality and distribution in this coal field. The coal seams of the Shanxi formation are unevenly distributed. Coals with lower sulfur content are formed in the peat swamps of the deltaic-fluvial system. The author's research, however, shows that the coal seams of the Benxi and Taiyuan Formation are formed in coal-forming environments of the marine facies. The author calls this type of coal-forming environment “peat flats” (Liu Huanjie, 1982) defined as follows: Mangroves or tidal plants having a similar bioecology to mangroves could grow in the intertidal flats and some supertidal flats of the tropical and subtropical zones and could be formed into peats deposits over a large area; such direct coal-forming environments in the tidal flats are called “pet flats” including intertidal flats, supertidal flats, some subtidal flats, adn tidal channels. It can be divided into differnet types of peat flats such as: lagoon-peat flats, back barrier-peat flats, tidal delta-peat flats, carbonate platforms-peat flats, and estuary-peat flats distributed in the mutual system of the barrier island-platform. The coal seems formed in peat flats are distributed widely and stably and area easily contrasted; the thickness of oal seams changes greatly and their divergences are notable in some areas. Where organic sulfur is higher, it may be related to the presence of tidal plants. The event deposits, storm event and volcanic event deposits, are widely istributed in the coal-bearing sequence of the Benxi and Taiyuan Formations in this coal field. The main markings of storm deposits are as follows: the hummocks under the surface of the erosion, the storm detention bed, and hummock cross-bedding, the sequence association, and the trace-fossil association. The tempestites, according to the author's recent study, can be divided into carbonates and terrigenous clastics. The main types are as follows: the tempestite of the backflow type including the carbonate tempestite of distal, proximal, and proximal shallow water; the carbonate tempestite of stirring type; proximal storm sandstone type; and the gravel-fragment mudstone type. The volcanic event deposits occur in the middle and upper parts of the Taiyuan Formation. The main types are the clastic-fragment tuff, tuff lava, and tuff. The volcanic deposits can be divided into those that accumulated under water and those that accumulated above water. There are three to four seams of clastic fragment tuff formed in the lagoon between the No. 4 and No. 5 limestones. The thickness of each seam of clastic-fragment tuff is 5–10 cm and distributed very steadily. A large number of complete brachiopod fossils were often developed. This is a disaster induced from a volcanic event. In this research, the methodology utilized to reconstruct the lithofacies paleogeography of the Zhungeer coal field follows. The first is that the new theory of sedimentology is guided by the quantitative environmental analysis of the single section in the field; the second is from point to line, from line to face, and from face to three dimensions, field observation is combined with laboratory analysis; the third is based on the lithologic and lithofacies section from which single-factor basic maps are drawn; the fourth is using the sedimentary facies ratio to draw up the quantitative lithofacies-paleogeographical maps and from these to reconstruct the lithofacies-paleogeography of the coal basin and to determine the distribution law of coal seams. We are grateful to the Coal-Field Geological and Exploration Company of

SYNOPSIS In this paper, results of in-situ tests of rockburst in Ertan Hydropower Station area, 3-D photoelastic simulative experiments and finite element analysis are presented; causes of rockburst are analysed; a formula of rock core breaking onset point stress, a formula of critical stress and an expression relating the core discing thickness and surrounding-rock stress are derived, and a scheme for grading rockburst intensity is suggested.