Shift Of Mine Water Inflow From Fissured Coal Layer Aquifer To Thick Overlying Aquifers: A Western Jurassic Coal Mine, China
Liu, Shucai; Wang, Changshen
China University of Mining and Technology, China, People's Republic of
The Ordos Jurassic coalfields basin in the western arid China now is becoming the key base of China coal industry. However, the more serious challenge are that the mining hydrogeological conditions disclosed by the active coal mines are actually varied and more complicated. The Xialjiao coal mine located in the east of the Ordos basin is a fully mechanical modern coal mine, has the production capacity of 10 million tonnes and commenced coal mining in 2014.
At the initial period of disclosing the upper coal layers of the Middel Jurassic Yan’an Formations through constructing its ventilation shaft, main roadways and the first long wall face, rare water inrush from fissured-coal-layer aquifers frequently and hazardously occurred, which was completely far beyond the exploration results and had never happened in China before. Then, the Xiaojihan coal mines was categorized as the hydrogeologically middle-complicated coal mines with a maximum special fissured-coal-layer aquifers inflow up to 800 m3/h.
But 3 years later, after more long wall faces have been excavated and the mining continuously goes western and deep step by step, the fissured coal seams are contributing less and less mine water inflow. The overlying roof Zhiluo and Anding formations of the Middel Jurassic, which had previously showed bearing no ground water, began to account for the most of the total mine water inflow about 1200 m3/h. The mining hydrogeologic features of Xiaojihan has definitely varied.
The article presents a series of evidences to prove the change, explores the reasons for thiis phenomena and suggests what measures should be taken to guard against future inrush hazards. We should take a new view to deal with mine water issues.