Ventilation method for high gas working face based on alternating intake and air return in mine gallery

A ventilation method for a gas-containing working face based on alternating intake and air return in a mine gallery, comprising:

• (a) tunnelling a first mine gallery at a dip-direction lower side of an isolated island working face along a strike direction;
• leaving a first coal pillar between the isolated island working face and a first goaf;
• and reinforcing the first coal pillar by grouting and concrete pouring;
• and
• tunnelling a second mine gallery at a dip-direction upper side of the isolated island working face along the strike direction;
• leaving a second coal pillar between the isolated island working face and a second goaf;
• and reinforcing the second coal pillar by grouting and concrete pouring;
• (b) making an open-off cut to communicate the first mine gallery with the second mine gallery;
• and deploying a coal mining device in the open-off cut;
• (c) dividing the isolated island working face into N sections from the open-off cut along the strike direction, wherein the N sections are sequentially numbered as 1, 2, . . . , and N;
• dividing the first coal pillar into a plurality of first conventional sections and a plurality of first gas-drainage sections;
• and dividing the second coal pillar into a plurality of second gas-drainage sections and a plurality of second conventional sections;
• wherein the plurality of first conventional sections and the plurality of first gas-drainage sections are alternately arranged;
• the plurality of second conventional sections and the plurality of second gas-drainage sections are alternately arranged;
• the plurality of first conventional sections are respectively opposite to the plurality of second gas-drainage sections;
• and the plurality of first gas-drainage sections are respectively opposite to the plurality of second conventional sections;
• (d) within a section 1 among the N sections, drilling a first gas-drainage hole in a gas-drainage section of the second mine gallery, wherein the first gas-drainage hole is communicated with the second goaf;
• and
• performing stoping at the section 1;
• and feeding a first fresh air into a coal mining area through the first mine gallery to form a first ventilation air methane (VAM) which is discharged through the second mine gallery;
• (e) within a section 2 among the N sections, drilling a second gas-drainage hole in a gas-drainage section of the first mine gallery, wherein the second gas-drainage hole is communicated with the first goaf;
• and
• performing stoping at the section 2;
• and feeding a second fresh air into the coal mining area through the second mine gallery to form a second VAM which is discharged through the first mine gallery;
• and
• (f) sequentially carrying out stoping and alternating intake and air return on sections 3-N among the N sections, wherein the stoping and the alternating intake and air return for odd-numbered sections are performed according to step (d);
• and the stoping and the alternating intake and air return for even-numbered sections are performed according to step (e).