Research on Pore-forming in Soft Coal Seam Containing Iron Sulfide Nodule

For the problem of hole collapse, sticking of tool, the shallow pore-forming during the construction of bedding drilling in soft coal seam containing nodules of iron sulfide, the complex drilling technology of deep slot screw was proposed. The suitable drilling assemblies were developed, and the optimization and improvement of drilling tool were carried out by testing and accumulating in practice. The results show that the iron sulfide nodule is an important factor affecting drilling in containing iron sulfide nodule and soft coal seam is not the decisive element and the stability of a borehole is a decisive and primary one; the complex drilling technology of deep slot screw has its advantages and the high popularizing value on solving the drilling problem in soft coal seam containing iron sulfide nodules.