Rock mechanics for underground mining, 3rd ed {"Van,w
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by vCFMO3
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B. H. G. Brady ^UEI`_HO0
Emeritus Professor, The University of Western Australia, and Consulting U;`N:~|p#
Engineer, Montville, Queensland, Australia 7xMvf<1P
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E. T. Brown pzg|?U
Emeritus Professor, The University of Queensland, and Senior Consultant, VI74{='=
Golder Associates Pty Ltd, Brisbane, Australia sn@gchO9s
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KLUWER ACADEMIC PUBLISHERS r[q-O&2&
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2005 Springer Science + Business Media, Inc QPg
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Preface to the third edition O:{I9V-=>s
Sometimes it is suggested that mining engineering and its supporting engineering \WQ\q
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sciences have reached a state of maturity. However, this proposition is inconsistent q$(aMO&J
with major developments in the twenty years that have elapsed since the preparation of vfK^^S
the first edition of this book, and the ten years since it has been subject to any substantial =n
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revision. Over those periods, innovations and improvements in engineering practice c] $X+
in mining and mining rock mechanics, and advances in the engineering science of pTprU)sa7
rock mechanics, have been extraordinary. For these reasons the third edition, which #i%it
results from comprehensive and thorough revision of the earlier editions, has involved x5.HdKV
the replacement or substantial modification of the equivalent of about half of the text Kxn/@@z>u
and figures of those versions of the book. Rd&2mL
One of the key drivers for many significant developments in fundamental rock mechanics %qV=PC
over the period has been the mining industry’s recognition of the economic ZMt9'w;
returns of better understanding and more rigorous application of the governing sciences 4sP0oe[h
embedded in its industrial operations and processes. The result has been some -iR}kP|
notable advances in mining engineering practice, involving improvements in mining PL@hsZty~c
methods in particular. For example, caving methods are now more widely applied ]- " )r
as understanding of their scientific basis has improved and their economic and operational vCb3Ra~L`
advantages have been realised. Whereas sublevel caving was once regarded !)?n n3
in some places as a method of marginal interest, the advent of very large scale sublevel 0x4Xs
caving, made possible in part by improved drilling technology and in part by !0zbWB9
understanding of the governing rock mechanics, it is now an attractive proposition for K``MS
many orebodies. Similarly, block caving is now conducted efficiently and reliably in zFN:C()ig
orebody settings that would have been inconceivable two decades ago. At the same 4fT,/[k?
time, methods such as overhand cut-and-fill stoping and shrink stoping have declined /$|C s
in application, replaced in part by open stoping and bench-and-fill stoping, where large J LT10c3
scale mechanisation, improved backfill technology, reliable rock mass reinforcement 4;<?ec(dc
of stope walls and the intrinsic advantages of non-entry methods of working have led #@w8wCj
to superior economics and enhanced operational safety. Ew*_@hVC
The scope of developments in mining rock mechanics science and practice has been }cn46L%/
as impressive as that in mining engineering. Perhaps the most significant advance has Oq7M1|{
been the resolution of some longstanding issues of rock fracture, failure and strength `J'xVq#O
and their relation to the modes of deformation and degradation of rock around mining "|{NRIE
excavations. The fact that the key research on this topic was conducted at the Underground K9njD#/
Research Laboratory of Atomic Energy of Canada Limited demonstrates the ~-.}]N+([
extent to which mining rock mechanics has benefited from fundamental research in *Cz>r}W
other fields of rock engineering. The mechanics of blocky rock has also been a field of t:eZ`6o$T\
impressive development, particularly in regard to formulation of a broad spectrum of
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methods of analysis of block jointed rock and their application in excavation engineering l<ag\ d
and support and reinforcement design. More generally, improved understanding Mi%i_T^i
of the mechanics of discontinuous rock has had a profound effect on simulation of 2RFYnDN
caving mechanics and therefore on the design and operation of block caving and S*Qip,u
sublevel caving mines. ylUxK{
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Mining-induced seismicity and the related phenomenon of rockbursts have become WldlN?[j
more prevalent in hard rock mining. Developments in mineworthy seismic equipment aqQ
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and associated data recording, processing and analysis hardware and software have a:r8Jzr
contributed greatly to measurement, characterisation and management of the problem. 6y)TXp
These developments have been complemented by measures in excavation design f-F+Y`P
and extraction sequencing which have done much to mitigate the serious operating sX.L
problems which can occur in seismically active, rockburst prone mines. In large-scale 3=RV Jb
open stope mining, Canadian developments based on pillarless stoping, formulation EeIV6ug
of extraction sequences which promote the evolution and uniform displacement of a -y5^xR
regular mine stress abutment, and the extensive use of cement-stabilised backfill, have Q})x4
been successful in managing an acute mining challenge. Notably, these measures have ^ r-F@$:.
been based on sound conceptual and analytical models of the relation of damaging IlVz 5#R
seismicity to induced stress, geological structure, potential rock displacements and 6NPCp/
strain energy release during mining. e=<knKc
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Some remarkable developments in computational methods have supported these MCZTeYnx
improvements in rock mechanics practice. Many mining rock mechanics problems B5GT^DaT
are effectively four-dimensional, in that it is the evolution of the state of stress over the <4ccT l
time scale of the mining life of the orebody which needs to be interpreted in terms of *T-+Pm-Cq
the probable modes of response of the host rock mass. The computational efficiency aHNR0L3$}{
of tools for three-dimensional stress analysis now permits modelling of key stages of q6bi{L@/R
an extraction sequence, for example, as a matter of routine rock mechanics practice. /x c<&
Similarly, computer power and efficient algorithms provide a notable capacity to f=+|e"i#p
simulate the displacement and flow of rock in cave mining and to support design of oM G8?p
optimum caving layouts. UOJx-o!c?
Notwithstanding these developments, it is encouraging to note continued attention umaF}}-Q{
to formal mathematical analysis in solution of rock mechanics problems. The results B8F.}M-!
of such analysis provide the canonical solutions for the discipline of rock mechanics Dq/_^a/1
and ensure a sound base for both the science and engineering practice. t3|If@T
In preparing this extensive revision, the authors have been fortunate to have the )a
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support of many colleagues and several organisations. In particular, they would like k@L},Td
to record the helpful advice and comment of colleagues on possible improvements d&BocJ
in earlier editions of the book and in identifying inevitable errors in the text. They /BjM&v(5/
acknowledge the generous assistance of the Brisbane office of Golder Associates in qsOA(+ZP
providing facilities and many helpful services, particularly in assistance with drafting !_ZknZTT
of the figures for this edition. One of the authors was supported for part of the I<`K;El'
work of revision by The University of Western Australia, and the other by the Julius Se.\wkl#Y
Kruttschnitt Mineral Research Centre of The University of Queensland. This support, eee77.@y-p
including the associated library services, is acknowledged with gratitude. The authors z#ab
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thank the many individuals and organisations who generously gave permission to use DzydS=`w
published material. Finally, they record the encouragement of publisher’s representative, P"Lk(gY
Petra van Steenbergen, and her patient assistance and advice during this major V7[6jWgH
undertaking. wzVx16Rvc
B. H. G. B. E
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E. T. B. 9utiev~3
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