Mining;
and;
Designing;
Branch,;
Central;
Coal;
Research;
Institute,;
Beijing;
100013,;
China;
Department;
of;
Earth;
Sciences,;
Simon;
Fraser;
University,;
Burnaby;
VSC2Z9,;
Canada;
School;
of;
Mines,;
China;
University;
of;
Mining;
&;
Technology,;
Xuzhou,;
Jiangsu;
221008,;
China;