The research on mining along next goaf technology of double gateways excavation in super-long forward distance working face

With theoretical analysis and field measurement, the research is conducted on mining along next goaf technology of double gateways excavation in super-long forward distance working face. Mining along next goaf technology of double gateways excavation is proposed to solve larger leaved protective coal pillar caused by ventilation and auxiliary haulage in double gateways excavation in super-long forward distance. On this basis, a method is given to determined larger pillar in double gateways excavation, small coal pillar in gob-side entry driving and dip separation of driving direction in driving face along next goaf to the first mining face and continuous face. Finally, we propose the technology in 5 000 m super-long forward distance where skip-mining is impossible to apply and give critical technical parameter. The technology application not only improves present situation of roadway maintenance difficultly, but also helps to mine more than 1.01 million t coal between two faces, generating significant economic and social benefits.