School of Resources and Geosciences;
China University of Mining and Technology;
Xuzhou 221116;
China;
Baodian Coal Mine;
Yanzhou Mining Group Co.;
Ltd.;
Zoucheng 273500;
China;
Baodian Coal Mine;
Yanzhou Mining Group Co.;
Ltd.;
Zoucheng 273500;
China;
Baodian Coal Mine;
Yanzhou Mining Group Co.;
Ltd.;
Zoucheng 273500;
China;