Rock mechanics for underground mining, 3rd ed >i@gR
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by A 7DdU NR
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B. H. G. Brady YfF&: "-NU
Emeritus Professor, The University of Western Australia, and Consulting EX8]i,s|E
Engineer, Montville, Queensland, Australia
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E. T. Brown 5g/^wKhKG
Emeritus Professor, The University of Queensland, and Senior Consultant, 2MB\!fh
Golder Associates Pty Ltd, Brisbane, Australia K2:r7f
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KLUWER ACADEMIC PUBLISHERS "%A[%7LY
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2005 Springer Science + Business Media, Inc :qgdn,Me
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Preface to the third edition 6TPcG d Z
Sometimes it is suggested that mining engineering and its supporting engineering as~. XWa
sciences have reached a state of maturity. However, this proposition is inconsistent ,FS iE\
with major developments in the twenty years that have elapsed since the preparation of rw_&t>Ri;
the first edition of this book, and the ten years since it has been subject to any substantial fBw+Y4nCO7
revision. Over those periods, innovations and improvements in engineering practice UY%@i
in mining and mining rock mechanics, and advances in the engineering science of ^Fb"Is#S,
rock mechanics, have been extraordinary. For these reasons the third edition, which :Q$3P+6 a
results from comprehensive and thorough revision of the earlier editions, has involved cr,o<
the replacement or substantial modification of the equivalent of about half of the text f_.1)O'83
and figures of those versions of the book. 3S'V>:
One of the key drivers for many significant developments in fundamental rock mechanics N]+x@M @^3
over the period has been the mining industry’s recognition of the economic R%3H"FU9w
returns of better understanding and more rigorous application of the governing sciences #Yj0'bgK
embedded in its industrial operations and processes. The result has been some q2gc.]K\
notable advances in mining engineering practice, involving improvements in mining If!0w
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methods in particular. For example, caving methods are now more widely applied &~||<0m
as understanding of their scientific basis has improved and their economic and operational |[k6X=5
advantages have been realised. Whereas sublevel caving was once regarded >fs-_>1d
in some places as a method of marginal interest, the advent of very large scale sublevel X] Tb4
caving, made possible in part by improved drilling technology and in part by JJ qX2B
understanding of the governing rock mechanics, it is now an attractive proposition for _mXq]r0
many orebodies. Similarly, block caving is now conducted efficiently and reliably in V!"^6)
orebody settings that would have been inconceivable two decades ago. At the same \mWXr*;
time, methods such as overhand cut-and-fill stoping and shrink stoping have declined %,~; w0
in application, replaced in part by open stoping and bench-and-fill stoping, where large i&.F}bEi
scale mechanisation, improved backfill technology, reliable rock mass reinforcement ?xUz{O0/
of stope walls and the intrinsic advantages of non-entry methods of working have led 4B (*{
to superior economics and enhanced operational safety. .7E-
The scope of developments in mining rock mechanics science and practice has been HzH_5kVW
as impressive as that in mining engineering. Perhaps the most significant advance has b39;Sv|#
been the resolution of some longstanding issues of rock fracture, failure and strength fVR ~PG0
and their relation to the modes of deformation and degradation of rock around mining >k _Z]J6Pd
excavations. The fact that the key research on this topic was conducted at the Underground hTVN`9h7
Research Laboratory of Atomic Energy of Canada Limited demonstrates the )-9|3`
extent to which mining rock mechanics has benefited from fundamental research in T']*h8
other fields of rock engineering. The mechanics of blocky rock has also been a field of 0Xk;X1Xl
impressive development, particularly in regard to formulation of a broad spectrum of >+,1@R
methods of analysis of block jointed rock and their application in excavation engineering pok,`yW\
and support and reinforcement design. More generally, improved understanding \2eYw.I=
of the mechanics of discontinuous rock has had a profound effect on simulation of C. 8>
caving mechanics and therefore on the design and operation of block caving and }})4S;j
sublevel caving mines. Ds L]o
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Mining-induced seismicity and the related phenomenon of rockbursts have become |nU:
more prevalent in hard rock mining. Developments in mineworthy seismic equipment )m5<gp `
and associated data recording, processing and analysis hardware and software have 1T}|c;fc
contributed greatly to measurement, characterisation and management of the problem. 9n8;eE08
These developments have been complemented by measures in excavation design +".&A#wU
and extraction sequencing which have done much to mitigate the serious operating PMXnupt
problems which can occur in seismically active, rockburst prone mines. In large-scale 3%|<U51
open stope mining, Canadian developments based on pillarless stoping, formulation {} vl^b
of extraction sequences which promote the evolution and uniform displacement of a @$+l ^"#-]
regular mine stress abutment, and the extensive use of cement-stabilised backfill, have |W:kzTT-T
been successful in managing an acute mining challenge. Notably, these measures have d5^ipu
been based on sound conceptual and analytical models of the relation of damaging ua7I K~8l
seismicity to induced stress, geological structure, potential rock displacements and hw~cS7
strain energy release during mining. ;}|.crMF
Some remarkable developments in computational methods have supported these BIV]4vl-&
improvements in rock mechanics practice. Many mining rock mechanics problems aoF>{Z4&B
are effectively four-dimensional, in that it is the evolution of the state of stress over the EY2s${26%
time scale of the mining life of the orebody which needs to be interpreted in terms of L)B?p!cdLT
the probable modes of response of the host rock mass. The computational efficiency B#EF/\5
of tools for three-dimensional stress analysis now permits modelling of key stages of >]C;sP
an extraction sequence, for example, as a matter of routine rock mechanics practice. o#0NIn"GS/
Similarly, computer power and efficient algorithms provide a notable capacity to u!L8Sv
simulate the displacement and flow of rock in cave mining and to support design of 2(`2 f
optimum caving layouts. PO)5L
Notwithstanding these developments, it is encouraging to note continued attention @J"
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to formal mathematical analysis in solution of rock mechanics problems. The results `yuD/-j
of such analysis provide the canonical solutions for the discipline of rock mechanics Ux zwgVT
and ensure a sound base for both the science and engineering practice. e$F7wto
In preparing this extensive revision, the authors have been fortunate to have the B*DH^";t
support of many colleagues and several organisations. In particular, they would like 1{";u"q
to record the helpful advice and comment of colleagues on possible improvements {6/%w,{,
in earlier editions of the book and in identifying inevitable errors in the text. They qc*+;Wi+5
acknowledge the generous assistance of the Brisbane office of Golder Associates in WxO*{`T!
providing facilities and many helpful services, particularly in assistance with drafting .=^h@C*
of the figures for this edition. One of the authors was supported for part of the rw+0<r3|K
work of revision by The University of Western Australia, and the other by the Julius "lN<v=
Kruttschnitt Mineral Research Centre of The University of Queensland. This support, nR"k%$
including the associated library services, is acknowledged with gratitude. The authors 9h*$P:S;1v
thank the many individuals and organisations who generously gave permission to use TvI}yaCu/x
published material. Finally, they record the encouragement of publisher’s representative, NG5H?hVN=
Petra van Steenbergen, and her patient assistance and advice during this major )](8{}wo
undertaking. 5bZ`YO
B. H. G. B. ]p0m6}B
E. T. B. >(%im:_
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