Characteristics and prevention and control techniques of typical water hazards in coal mines in Shaanxi Province

Shaanxi province is rich in coal resources and is one of the main coal-producing provinces in China, with a coal production of 746 million tons in 2022. Due to the obvious differences in geological and hydrogeological conditions in the coal mining areas of the province, there are various types of water disasters in its coal mines. With the increase of coal mining intensity in recent years, the frequency of water disasters increases significantly, and the situation of water prevention and control is challenging. On the basis of the overall analysis of the hydrogeological conditions in the coal mining areas of Shaanxi province, combined with the types of water disasters revealed in the mining process of various mining areas in the province, the regional distribution of all kinds of water disas-ters is systematically summarized, and the formation mechanism and characteristics of typical water disasters are discussed. Also, the corresponding prevention and control technology and progress are put forward. The results show that ① the main coal producing areas in Shaanxi province are divided into northern Shaanxi, Huanglong and Weibei. The Jurassic coalfield in northern Shaanxi is mainly affected by the water disaster of roof's loose sand layer, the water disaster of thick sandstone, water and sand burst disaster, and the burnt rock flood exists in some coal mines. The Huanglong coalfield is mainly threatened by roof super-thick sandstone water, separated layer water, mud and sand burst disaster or hidden danger. The Carboniferous-Permian coalfields in northern Shaanxi and Weibei are mainly threatened by the water damage of Ordovician limestone on the coal seam floor. ② The hidden danger of roof flood in the Jurassic coalfield in northern Shaanxi is mainly formed by the disturbance of roof aquifer by mining water diversion fracture zone, which can form a continuous large flow water gushing through sandstone aquifer or loose sand layer, and the water filling intensity is large in some areas. Roof flood occurs when the amount of water exceeds the capacity of the drainage system in a short time, and it can be transformed into water and sand burst disaster when the collapse zone in the thin bedrock area directly leads to the loose sand layer. When the water-conducting fracture zone affects the water-rich area of burnt rock, it can form a flood of burnt rock with large instantaneous water volume and continuous flood. The super-thick sandstone aquifer on the roof of the Huanglong coalfield is swept by the mining water-conducting fracture zone to form a high-intensity continuous water gushing and may form roof flood. When the thickness of the lower aquifer is large, the separated layer water burst disaster may be formed. When the roof strata near the coal seam is soft and easy to collapse, it can be transformed into mud and sand burst disaster. In the Carboniferous-Permian coalfield and the Weibei coalfield in northern Shaanxi, when structures such as coal seam mining floor disturbance failure zones or faults lead to the Ordovician limestone aquifers, they will cause extremely serious floor water inrush disasters, which are characterized by strong sudden occurrence and large instantaneous water volume. ③ The roof water disaster treatment technology in each region mainly includes drilling hole drainage, grouting treatment, mining parameter control and so on, and the floor water damage is mainly treated by regional grouting reinforcement and plugging. Burnt rock water disaster is mainly treated by the combination of curtain grouting and drilling exploration.