Coal mining system and method of dual circulation drilling with mechanical reaming and abrasive jet

A mining method, applied to a mining system, wherein, the mining system comprises:

• a mechanical coal breaking module, an air lift reverse circulation module, a jet coal breaking module, and a coal-air-water separation module;
• wherein,
• the mechanical coal breaking module comprises:
• a drill pipe rotating device, a drill pipe, and a reamer bit;
• the drill pipe rotating device, the drill pipe and the reamer bit are connected sequentially to perform rotary cutting, drilling and slotting operations on a coal seam in a borehole;
• the air lift reverse circulation module comprises:
• an air compressor and a dual-wall drill pipe;
• the air compressor is configured to transport a coal-air-water mixture through an inner pipeline of the dual-wall drill pipe to the coal-air-water separation module;
• and
• the jet coal breaking module comprises:
• the drill pipe rotating device, a fracturing truck, the drill pipe, and a jet tool string;
• the fracturing truck, the drill pipe rotating device, the drill pipe, and the jet tool string are connected sequentially to mine the coal seam;
• wherein,
• the coal mining method comprises:
• performing the rotary cutting, drilling and slotting operations on the coal seam in the borehole through the mechanical coal breaking module;
• transporting the coal-air-water mixture formed after the rotary cutting, drilling and slotting operations to the coal-air-water separation module through the air lift reverse circulation module;
• performing coal breaking operations on the coal seam through the jet coal breaking module;
• transporting the coal-air-water mixture formed after the coal breaking operations to the coal-air-water separation module through the air lift reverse circulation module;
• and
• separating the coal-air-water mixture to obtain coal, coalbed methane and water through the coal-air-water separation module.