黔中某矿区灯影组断控白云岩富水性差异研究及防治水意义

黔中地区矿床水文地质条件复杂，磷矿的主要充水层灯影组富水性中等至强，矿坑突水严重影响区域磷矿资源的安全开采。因此，掌握该区域灯影组的富水性特征极为重要。文章依托贵州省2020年矿产资源大精查项目资料，采用研究与生产相结合、典型矿区解剖的方法开展该矿床灯影组富水性研究。结果表明：黔中地区大湾磷矿为顶板直接充水的岩溶矿床，充水层灯影组的岩性、结构以及断裂构造是控制矿床充水条件的主要因素，灯影组含水性和透水性具有明显的“平面分块”和“垂向分层”的分布规律。充分利用该特征对于矿井防水设计并指导矿山开采，对保障黔中磷矿安全生产、降低开采成本具有重要意义。

Study on the difference of water-bearing capacity of fault-controlled dolomites in Dengying Formation of a mining area in central Guizhou and its significance of water control

The central region of Guizhou Province enjoys global fame of its areas with large-scale production rich in phosphorus. For a long time, the phosphate rock resources in this area have provided a reliable guarantee for the domestic economic development. At present, this region has also become an important raw material base of phosphate rocks and a production base of fine phosphate chemicals in China. After decades of mining, phosphorus mines in this area have gradually changed from open pits to underground ones and from shallow to deep, and thus the hydrogeological conditions of deposits become increasingly complex. Dengying Formation, the main aquifers of phosphate rocks, is composed of dolomite with the water-bearing medium of solution pores and cracks. It is a water-bearing formation comprised of pure carbonate rocks with medium to high water abundance. Consequently, the high cost of mine drainage has imposed a heavy burden on mining enterprises. In addition, mine water inrush has severely threatened the exploitation safety of phosphate rock resources in this region. Therefore, it is very important to research the characteristics of water abundance of the Dengying Formation. The phosphate mine of Dawan, a water-filling deposit with deeply covered karst, is located on the western flank of the Baiyan anticline. The high bearing capacity of groundwater and complicated hydrogeological conditions of Dengying Formation are representative and typical in the Baiyan anticline area. Due to the super large scale and high grade of phosphate ore resources, the phosphate mine of Dawan was listed as a key project of mineral resource exploration in Guizhou Province in 2020. During the exploration work, a large amount of geological data was obtained through surface surveys, geophysical and hydrological logging, drilling, and hydrogeological experiments. In this paper, a study on the water abundance of the Dengying Formation of the deposit has been conducted based on the data from the exploration of the phosphate mine as well as the anatomy of typical mining areas. The research results show that the phosphate mine in Dawan is a karst deposit with water-filled roof, and the lithology, structure and fracture structure of the Dengying Formation in the water-filled layer are the main factors controlling the water-filling condition of the deposit. With an obvious distribution law, the water content and permeability of Dengying Formation present obvious characteristics of "plane partition" and "vertical stratification". In the plane of exploration area, there is a significant difference in water abundance of the Dengying Formation near and far from the structural area. The differences in fault properties also result in different water abundance of the Dengying Formation. In the vertical direction, there is a weak permeable layer with poor water content and relative water resistance in the middle and lower parts of the Dengying Formation. The waterproof design of mine based on the characteristics of water abundance in Dengying Formation is of great significance to ensure the safe production of the phosphate mine in central Guizhou, and to reduce the cost of mining drainage.