Rock mechanics for underground mining, 3rd ed $i&u\iL
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by e1ru#'z
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B. H. G. Brady U5 ~L^
Emeritus Professor, The University of Western Australia, and Consulting $OK}jSH*v)
Engineer, Montville, Queensland, Australia 2Uf]qQ1
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E. T. Brown C<Q;3w`#1j
Emeritus Professor, The University of Queensland, and Senior Consultant, u!TVvc
Golder Associates Pty Ltd, Brisbane, Australia .c~`{j}
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KLUWER ACADEMIC PUBLISHERS Jsf-t
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2005 Springer Science + Business Media, Inc HY[eo/nM1d
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Preface to the third edition A<esMDX
Sometimes it is suggested that mining engineering and its supporting engineering Jybx'vZj
sciences have reached a state of maturity. However, this proposition is inconsistent 8Qtd,
with major developments in the twenty years that have elapsed since the preparation of >q0c!,Ay
the first edition of this book, and the ten years since it has been subject to any substantial CCp&P5[67
revision. Over those periods, innovations and improvements in engineering practice "I.PV$Rxl
in mining and mining rock mechanics, and advances in the engineering science of T\\Q!pY
rock mechanics, have been extraordinary. For these reasons the third edition, which wmh[yYWc
results from comprehensive and thorough revision of the earlier editions, has involved !e*BQ3
the replacement or substantial modification of the equivalent of about half of the text vCE1R]^A.]
and figures of those versions of the book. };%l <Ui;
One of the key drivers for many significant developments in fundamental rock mechanics Q$_S/d%*
over the period has been the mining industry’s recognition of the economic c%,~1l
returns of better understanding and more rigorous application of the governing sciences QF 2Eg
embedded in its industrial operations and processes. The result has been some zRDBl02v$T
notable advances in mining engineering practice, involving improvements in mining -z%|
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methods in particular. For example, caving methods are now more widely applied /(-X[[V
as understanding of their scientific basis has improved and their economic and operational /L,VZ?CmtK
advantages have been realised. Whereas sublevel caving was once regarded ]DcQ8D
in some places as a method of marginal interest, the advent of very large scale sublevel 6X{RcX]/
caving, made possible in part by improved drilling technology and in part by -xi]~svg
understanding of the governing rock mechanics, it is now an attractive proposition for TqURYnNd
many orebodies. Similarly, block caving is now conducted efficiently and reliably in @m14x}H
orebody settings that would have been inconceivable two decades ago. At the same G&FA~c
time, methods such as overhand cut-and-fill stoping and shrink stoping have declined ^3*k6h[(
in application, replaced in part by open stoping and bench-and-fill stoping, where large HS!O;7s'
scale mechanisation, improved backfill technology, reliable rock mass reinforcement G
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of stope walls and the intrinsic advantages of non-entry methods of working have led >W%tEc
to superior economics and enhanced operational safety. GY9CU=-
The scope of developments in mining rock mechanics science and practice has been mup<%@7m
as impressive as that in mining engineering. Perhaps the most significant advance has (vHB`@x
been the resolution of some longstanding issues of rock fracture, failure and strength {1
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and their relation to the modes of deformation and degradation of rock around mining Zr`pOUk!4
excavations. The fact that the key research on this topic was conducted at the Underground @?,iy?BSG
Research Laboratory of Atomic Energy of Canada Limited demonstrates the qF!oP
extent to which mining rock mechanics has benefited from fundamental research in kqJ\kd
other fields of rock engineering. The mechanics of blocky rock has also been a field of 7I>@PVN
impressive development, particularly in regard to formulation of a broad spectrum of C^vB&3ghi
methods of analysis of block jointed rock and their application in excavation engineering
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and support and reinforcement design. More generally, improved understanding }r`m(z$z
of the mechanics of discontinuous rock has had a profound effect on simulation of Cf#[E~2 4
caving mechanics and therefore on the design and operation of block caving and bL>J0LWQ
sublevel caving mines. '5j$wr zt
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Mining-induced seismicity and the related phenomenon of rockbursts have become f"emH
more prevalent in hard rock mining. Developments in mineworthy seismic equipment #P8R
and associated data recording, processing and analysis hardware and software have mouLjT&p
contributed greatly to measurement, characterisation and management of the problem. % j4
These developments have been complemented by measures in excavation design 9Yg=4>#$
and extraction sequencing which have done much to mitigate the serious operating $@y<.?k>UP
problems which can occur in seismically active, rockburst prone mines. In large-scale EN^C'n
open stope mining, Canadian developments based on pillarless stoping, formulation JY4sB8
of extraction sequences which promote the evolution and uniform displacement of a XD>(M{~
regular mine stress abutment, and the extensive use of cement-stabilised backfill, have IyvJwrO
been successful in managing an acute mining challenge. Notably, these measures have 1^<R2x
been based on sound conceptual and analytical models of the relation of damaging =m{]Xep
seismicity to induced stress, geological structure, potential rock displacements and :sD/IM",},
strain energy release during mining. FOz7W
Some remarkable developments in computational methods have supported these 9/N=7<$
improvements in rock mechanics practice. Many mining rock mechanics problems "/v{B?~%!
are effectively four-dimensional, in that it is the evolution of the state of stress over the ^(5Up=.EA
time scale of the mining life of the orebody which needs to be interpreted in terms of dq$H^BB+>
the probable modes of response of the host rock mass. The computational efficiency $6~ J#;
of tools for three-dimensional stress analysis now permits modelling of key stages of KtWn08D!
an extraction sequence, for example, as a matter of routine rock mechanics practice. uh`W} n
Similarly, computer power and efficient algorithms provide a notable capacity to E3X6-J|
simulate the displacement and flow of rock in cave mining and to support design of wm>I;|gA)
optimum caving layouts. W10=SM}
Notwithstanding these developments, it is encouraging to note continued attention Lyjt$i W%
to formal mathematical analysis in solution of rock mechanics problems. The results Qs(WyP#
of such analysis provide the canonical solutions for the discipline of rock mechanics x^_(gve:
and ensure a sound base for both the science and engineering practice. s&-m!|P
In preparing this extensive revision, the authors have been fortunate to have the i@7b
support of many colleagues and several organisations. In particular, they would like
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to record the helpful advice and comment of colleagues on possible improvements Sl@$
in earlier editions of the book and in identifying inevitable errors in the text. They ~/0t<^
acknowledge the generous assistance of the Brisbane office of Golder Associates in ;{xk[fm=
providing facilities and many helpful services, particularly in assistance with drafting ?2D1gjr
of the figures for this edition. One of the authors was supported for part of the 1_}*aQ
work of revision by The University of Western Australia, and the other by the Julius ZMs$C3
Kruttschnitt Mineral Research Centre of The University of Queensland. This support, ROZOX$XM
including the associated library services, is acknowledged with gratitude. The authors h *J=F0KM
thank the many individuals and organisations who generously gave permission to use hq}kAv4B=
published material. Finally, they record the encouragement of publisher’s representative, >0yx!Iao
Petra van Steenbergen, and her patient assistance and advice during this major V-Ebi^gz5W
undertaking. L`>uO1O
B. H. G. B. QH:PClW![
E. T. B. I7!+~uX
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