Practices on Secondary Mining Technology of Goaf Coal Pillars in Previous Gateway of Fully Mechanized Coal Mining Face

In order to enhance the recovery rate of coal resources, and alleviate the alternation of mining and driving, and to achieve safe and high – efficient re – mining of fully mechanized mining face. The paper detailed the technology measures of old roadway secure driving in fully mechanized mining face and the safety mining technology of fully mechanized mining face crossing old roadway. The engineering practice of re – mining technology in old – entry goaf of fully mechanized mining face shows that, the recovery rate of working face is 55.50% without the re – mining of old – entry goal, and with re – mining of the goaf, the working face recovery rate reaches 96. 67%.