Funding for this research was provided by:
the Jiangsu Province Science Foundation for Youths (BK20180658)
State Key Laboratory of Coal Resources and Safe Mining (SKLCRSM18X009)
China Postdoctoral Science Foundation (2018M632422)
Article History
Received: 25 November 2018
Accepted: 2 April 2019
First Online: 9 April 2019