Integrated Water Control Technology for Limestone Water-inrush from Coal Floor Fissures

摘要

Appropriate water control measures were studied to prevent Limestone Water-inrush from Coal Floor Fissures. Based on the hydrogeological conditions and coal floor limestone fissures of Yongcheng coal mine area, the characteristics of water-inrush were analyzed and summarized. Water-rich area was detected by seismic impedance inversion and underground transient electromagnetic method (TEM), and then we carried out the grouting reconstruction project on the local coal floor delineated by these methods. This water control measures showed good effects. The result shows that L8 limestone of the Taiyuan Formation is the main origin-water, which is about 80m away from the 2-2 main coal seam floor. The water-inrush from coal floor is closely related with fissure. According to the situation of fissure, water-inrush in Yongcheng coal mine area can be classified into three categories: water-inrush through open fissure, water-inrush through closed and re-open fissure, and water-inrush through growing fissures. Water-rich areas identification and fissure-channel plugging are the key point of water control. The relationship between porosity and acoustic impedance constructed by Willie average equation shows the porosity value decreases monotonously with increasing acoustic impedance, and the limestone water-bearing capability can be analyzed macroscopically by impedance inversion. The limestone water-rich area can be analyzed effectively and locally by TEM according to the low resistance of water-rich region. In the water-rich region, grouting boreholes are laid uniformly in a certain way, but also selectively on some of the floor reinforcement position. Integrated control techniques in this paper put an end to water-inrush from the coal floor limestone fissures in Yongcheng, and enrich the mine water control techniques.