ABSTRACT
In the process of coal mining, collapse column has a great threat to mine safety production. A collapse column was exposed during the construction of the third west roadway at -500m level in Zhangshuanglou Coal Mine. The water head values of Taiyuan Formation No.4 limestone aquifer and Ordovician limestone aquifer are 4.35MPa and 4.79MPa respectively. Through the implementation of underground drilling and ground high-resolution three-dimensional seismic exploration, the collapse column is identified as a large-scale hidden collapse column with a long axis length of 220m, short axis length of 180m, and caving height of more than 346m; the rock mass in the collapse column is cemented again in the later stage, and the column has a certain strength. According to the analysis and research, the large-scale hidden collapse column is a dead collapse column that is not rich in (conducting) water, and is in the late development stage; the distances between the third West roadways and the fourth limestone and Ordovician limestone aquifers are 61m and 219m respectively, which are greater than the safe water-resisting layer thickness of 1.45m and 1.52m. The mine demonstrated and optimized the construction scheme that the roadway directly passes through the collapse column according to the current construction orientation, adjusted the roadway support mode, formulated safety technical measures to prevent water inrush, and ensured the safe excavation of the main roadway through the collapse column. The research results provide technical support and practical bases for safe and efficient passing through large-scale hidden collapse columns.
