Application of pressure relief and permeability increased by slotting a coal seam with a rotary type cutter working across rock layers

作者：Shen Chunming^*; Lin Baiquan; Meng Fanwei; Zhang Qizhi; Zhai Cheng

来源：International Journal of Mining Science and Technology, 2012, 22(4): 533-538.

DOI：10.1016/j.ijmst.2012.01.016

• Broad application
• Coal and gas outburst
• Coal seams
• Development rate
• Gas drainage
• Gas extractions
• Longwalls
• Low permeability coal seam
• Penetrate layer
• Permeability increase
• Pressure relief
• Rock layers
• Slotted
• Special drill

Pressure relief to increase permeability significantly improves gas extraction efficiency from coal seams. In this paper we report results from simulations using FLAC3D code to analyze changes in coal displacement and stress after special drill slots were formed. We investigated the mechanism of pressure relief and permeability increase in a high-gas and low-permeability coal seam through the modeling of gas flow. This allows the development of the technology. Slotting across rock layers in the coal seam with a rotary type cutter was then applied in the field. The results show that pressure relief and permeability increases from slotting the coal seam can increase the transport and the fracture of the coal. This expands the range of pressure relief from the drilling and increases the exposed area of the seam. The total quantity of gas extracted from slotted bore holes was three times that seen with ordinary drilling. The concentration of gas extracted from the slotted drills was from two to three times that seen using ordinary drills. The gas flow was stable at 80%. Improved permeability and more efficient gas extraction are the result of the slotting. The roadway development rate is increased by 30-50% after gas drainage. This technology diminishes the lag between longwall production and roadway development and effectively prevents coal and gas outburst, which offers the prospect of broad application.

• 出版日期2012
• 单位中国矿业大学（北京）