Page 12 - Rock Mechanics For Underground Mining

PREFACE TO THE THIRD EDITION

Mining-induced seismicity and the related phenomenon of rockbursts have become
more prevalent in hard rock mining. Developments in mineworthy seismic equipment
and associated data recording, processing and analysis hardware and software have
contributed greatly to measurement, characterisation and management of the problem.
These developments have been complemented by measures in excavation design
and extraction sequencing which have done much to mitigate the serious operating
problems which can occur in seismically active, rockburst prone mines. In large-scale
open stope mining, Canadian developments based on pillarless stoping, formulation
of extraction sequences which promote the evolution and uniform displacement of a
regular mine stress abutment, and the extensive use of cement-stabilised backfill, have
been successful in managing an acute mining challenge. Notably, these measures have
been based on sound conceptual and analytical models of the relation of damaging
seismicity to induced stress, geological structure, potential rock displacements and
strain energy release during mining.
Some remarkable developments in computational methods have supported these
improvements in rock mechanics practice. Many mining rock mechanics problems
are effectively four-dimensional, in that it is the evolution of the state of stress over the
time scale of the mining life of the orebody which needs to be interpreted in terms of
the probable modes of response of the host rock mass. The computational efficiency
of tools for three-dimensional stress analysis now permits modelling of key stages of
an extraction sequence, for example, as a matter of routine rock mechanics practice.
Similarly, computer power and efficient algorithms provide a notable capacity to
simulate the displacement and flow of rock in cave mining and to support design of
optimum caving layouts.
Notwithstanding these developments, it is encouraging to note continued attention
to formal mathematical analysis in solution of rock mechanics problems. The results
of such analysis provide the canonical solutions for the discipline of rock mechanics
and ensure a sound base for both the science and engineering practice.
In preparing this extensive revision, the authors have been fortunate to have the
support of many colleagues and several organisations. In particular, they would like
to record the helpful advice and comment of colleagues on possible improvements
in earlier editions of the book and in identifying inevitable errors in the text. They
acknowledge the generous assistance of the Brisbane office of Golder Associates in
providing facilities and many helpful services, particularly in assistance with draft-
ing of the figures for this edition. One of the authors was supported for part of the
work of revision by The University of Western Australia, and the other by the Julius
Kruttschnitt Mineral Research Centre of The University of Queensland. This support,
including the associated library services, is acknowledged with gratitude. The authors
thank the many individuals and organisations who generously gave permission to use
published material. Finally, they record the encouragement of publisher’s represen-
tative, Petra van Steenbergen, and her patient assistance and advice during this major
undertaking.

B. H. G. B.
E. T. B.

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