Development and Properties of a Similar Material to Coal

Abstract

In the mining process, protective-seam mining is one of the most effective measures to prevent and control coal and gas outburst accidents across the world. To accurately obtain the fracture development characteristics for protected coal in a similar physical simulation (to two-dimensional (2D) protective-seam mining), a novel and similar material to coal was developed. The similar material was prepared by mixing pulverized coal with a certain particle-size distribution and a water solution of sodium humate, which were separately taken as the aggregate and binder, followed by pressing and drying. Numerous orthogonal proportioning tests revealed that, under the molding pressure of 15 MPa, the unit weight and porosity of the similar material tended to be stable and approach that of raw coal. The similar material has a high compressive strength that is regulatable over a range as wide as 0.5~2.8 MPa and has an approximately linear direct proportional relation with the binder concentration. The adsorption and desorption tests revealed that the similar material features favorable adsorption properties, and its adsorption isotherm agrees with that of raw coal. The similar material is also characterized by a low price for its raw materials, no toxic or side effects, simple proportioning, stable properties, and the convenient regulation of various physical and mechanical parameters. Therefore, it can be used to simulate raw coal with different strengths.