Inclined layered solid-filling mining method in ultrathick coal layer

A method for solid-fill mining of an ultra-thick coal layer, comprising steps of:

• a. dividing an ultra-thick coal layer into a number of layers having a thickness of 2.5˜4.5 m according to a thickness of the ultra-thick coal layer under an overlying surface;
• b. arranging tunnels, installing equipment, and mining a first working face in a first coal layer by cutting the coal, advancing a scraper conveyer, and advancing a filling mining hydraulic support;
• c. constructing an artificial roof for a second layer on a bottom of a mine goaf by laying a metal mesh on the bottom of the mine goaf formed in the first layer, with an edge of the metal mesh arranged spaced from a base of the filling mining hydraulic support, laying bamboo fences on the metal mesh, with an edge of the bamboo fences arranged spaced from the edge of the metal mesh, and laying the metal mesh and bamboo fences along a direction parallel to the first working face, until the bottom of the entire mine goaf is laid with the metal mesh and bamboo fences, after laying the metal mesh and bamboo fences, filling a solid material into the mine goaf and compacting the solid material, so as to complete a first mining cycle;
• d. executing a second filling mining cycle, under the filling mining hydraulic support, laying a metal mesh and a bamboo fences on the bottom of the mine goaf and connecting the metal mesh and bamboo fences with the metal mesh and bamboo fences laid in the first filling mining cycle together respectively with iron wires, and filling the mine goaf, so as to complete the second mining cycle;
• e. repeating steps c and d until mining reaches a protective coal pillar, whereupon filling and mining of the first working face is completed;
• f. moving the first working face to a second working face, and repeating steps c-c, so as to carry out filling mining at working faces in the second layer under the first layer and;
• carrying out mining and filling of the second layer in a same manner as for the first layer at a corresponding position of the second layer, under cover of the artificial roof, after the first working face of the first layer is filled and mined, until mining and filling of working faces in the second layer is completed;
• and
• g. repeating steps c-f, to carry out mining and filling of a next layer under the artificial roof of the previous layer, until mining and filling of all layers in the ultra-thick coal layer is completed.