State Key Lab. of Coal Resources, China University of Mining and Technology, D11, Xueyuan Road, Haidian District, 100083 Beijing, China, Fax: +86 10 6234 1868, Tel: +86 10 6234 1868, Email: daishifeng@gmail.com
C.Ö. Karacan
Pittsburgh Research Laboratory, DPRB-Ventilation and Explosion Prevention Section, National Institute for Occupational Safety and Health
(NIOSH), 626 Cochrans Mill Road; Bldg. 143, Pittsburgh, PA 15236-0070, USA, Fax: +1 412 386 6595, Tel: +1 412 386 4008, Email: cok6@cdc.gov
R. Littke
Inst. of Geology and Geoch. of Petroleum and Coal, Rheinisch-Westfälische Technische Hochschule Aachen (RWTH), Lochnerstr. 4-20, 52064 Aachen, Germany, Fax: +49 241 8092152, Tel: +49 241 8095748, Email: littke@lek.rwth-aachen.de