"About the Authors Raghu N. Singh was Professor of Mining Engineering at University of Wollongong, Australia from 1989 to 2004. He has a Ph.D and D.Sc in Mining Engineering, a Master of Engineering, and also a First Class Manager’s Certificate of Competency to manage coal mines in India and the U.K. He has some 44 years of experience with expertise in the area of rock mechanics, mine water, spontaneous combustion and environmental impact of mineral operations. He is author of some 250 technical and research papers, a book on fracture mechanics and another on mine water. Ajoy K. Ghose, former Director of Indian School of Mines, Dhanbad, is currently a Visiting Professorial Fellow at the University of Wollongong and also an Adjunct Professor at Bengal University of Engineering and Science. He was Professor of Mining Engineering between 1966 to 1991 at the Indian School of Mines and was instrumental in developing a strong school of rock mechanics and excavation engineering. He is a Fellow of Indian National Academy of Engineering, a Foreign Member of the Academy of Mining Sciences of Russia, a Vice Chairman of World Mining Congress and a Past President of the Institution of Engineers (India). He is the author of over 350 technical and research publications and co-author of a monograph on ""Environment-friendly Techniques of Rock Breaking""."