ABSTRACT

International Mining Forum 2004, Kicki & Sobczyk (eds) © 2004 Taylor & Francis Group, London, ISBN 90 5809 607 6

1. INTRODUCTION

In the Polish underground (deep) mining bump hazard occurs in about 70 per cent of collieries and in all copper mines. The term of bump hazard means a possibility of a bump occurrence as a result of unfavourable geologic and mining-technological conditions in an underground working or its vicinity. A bump itself is a dynamic phenomenon causes by a rock-mass tremor resulting in a violent damage or destruction of a working or a part of it, which caused a complete or partial loss of its functionality or safety of using it (Kidybiński 2003). Thus a bump is a particular kind of rock-mass tremor. In hard coal mining and copper ore mining there are rock-mass tremors of seismic energy of up to 1010 J (up to 4, 5 magnitude of Richter scale). The lowest energy values at which bumps were observed in collieries amounted to 5·103 J, in case of copper ore mines they were one order of energy values higher and amounted to 5·104 J. The higher the seismic energy of a rock-mass tremor the higher is the probability of bump occurrence. While at a rock-mass tremor with the seismic energy of the order of 104 J that probability amounts to circa 10−4, at the tremor energy of the order of 1010 J it approaches the value of 1,0.