Adelaide, SA 5005, Australia; 4 Beijing Haohua Energy Resourse Co., Ltd., Beijing 102304, China; jingyuanbjhh * Correspondence: zybsdust (); qyue2016 () Received: 17 January 2019; Accepted: 11 February 2019; Published: 13 February 2019 Abstract: Using gangue backfilling in underground coal mining not only controls the .