1. Associate Professor, Mining College of Guizhou Univ., Guiyang, Guizhou 550025, PR China; Guizhou Coal Mine Design and Research Institute, Guiyang, Guizhou 550025, PR China; China Univ. of Mining and Technology (Beijing), Beijing 100083, PR China.
2. Mining College of Guizhou Univ., Guiyang, Guizhou 550025, PR China (corresponding author).
3. Associate Professor, School of Safety Engineering, North China Institute of Science and Technology, Beijing 100083, PR China.
4. Associate Professor, Mining College of Guizhou Univ., Guiyang, Guizhou 550025, PR China.
5. Professor, Mining College of Guizhou Univ., Guiyang, Guizhou 550025, PR China.