Meikuang Anquan (May 2024)
Characteristics of water-rich coal seam in Balasu Mine Field of northern Yuheng Mining Area
Abstract
This paper takes No.2 water-rich coal seam of Balasu Coal Mine in northern Yuheng Mining Area of Jurassic Coal Field in northern Shaanxi as the main research object, and studies the basic characteristics and fracture characteristics of the coal seam. Combined with field measurement, laboratory experiment, theoretical calculation and other methods, the inorganic mineral composition, physical and mechanical properties of coal seam, coal structure discrimination, coal crack main parameters and other analyses were carried out, and the major characteristics of No.2 water-rich coal seam were found. The results show that, compared with other non-water-rich coal seams, the contents of carbonate minerals and clay minerals in No.2 water-rich coal seam in Balasu Mine Field are lower, and the coal cracks are not easy to be filled and blocked. The pyrite in the coal seam is distributed in veins and strips. The occurrence state is the product of fluid precipitation, which reflects the active fluid runoff in No.2 coal seam. In addition, the No.2 water-rich coal seam has relatively small compressive strength and elastic modulus, and is more likely to produce plastic failure under the action of original in-situ stress, resulting in the formation of cracks. And the coal body structure of the coal seam is fractured coal in some areas. At the same time, the No.2 water-rich coal seam is affected by small structure in the area to a certain extent, and the main parameter value of coal seam fracture is much higher than that of other coal seams. That is, the average density of coal seam cracks is 11.48 per m, the number of coal volume cracks is 4.01 per m3, and the coal integrity coefficient is 0.72, the average fracture rate of coal seam section is about 3.12%. It is concluded that the No.2 coal seam in Balasu Mine Field has the advantageous medium conditions for storing and migrating groundwater.
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