Rock mechanics for underground mining, 3rd ed qAp<OJ
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by 3]iw3M
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B. H. G. Brady Vh01y f
Emeritus Professor, The University of Western Australia, and Consulting
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Engineer, Montville, Queensland, Australia n=f?Q=h\3
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E. T. Brown G(A7=8vW
Emeritus Professor, The University of Queensland, and Senior Consultant, &'neOf/~
Golder Associates Pty Ltd, Brisbane, Australia Gqq<-drR
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KLUWER ACADEMIC PUBLISHERS zp4@T)
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2005 Springer Science + Business Media, Inc O*2{V]Y
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Preface to the third edition ZCK#=:ln
Sometimes it is suggested that mining engineering and its supporting engineering )(d~A?~
sciences have reached a state of maturity. However, this proposition is inconsistent 6wOj,}2Mn
with major developments in the twenty years that have elapsed since the preparation of )4ok@^.
the first edition of this book, and the ten years since it has been subject to any substantial f% 8n?f3;u
revision. Over those periods, innovations and improvements in engineering practice ("f~gz<<
in mining and mining rock mechanics, and advances in the engineering science of W-D4"
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rock mechanics, have been extraordinary. For these reasons the third edition, which dr8Q>(ZY
results from comprehensive and thorough revision of the earlier editions, has involved (w_b
the replacement or substantial modification of the equivalent of about half of the text *?Oh%.HgF
and figures of those versions of the book. U_9|ED:
One of the key drivers for many significant developments in fundamental rock mechanics XYV`[,^h&
over the period has been the mining industry’s recognition of the economic E-X02A
returns of better understanding and more rigorous application of the governing sciences .|:(VG$MfI
embedded in its industrial operations and processes. The result has been some $/u.F;
notable advances in mining engineering practice, involving improvements in mining '[[IalQ?
methods in particular. For example, caving methods are now more widely applied Us6~7L00
as understanding of their scientific basis has improved and their economic and operational _4{3^QZq5
advantages have been realised. Whereas sublevel caving was once regarded ?iaO+G&|
in some places as a method of marginal interest, the advent of very large scale sublevel i'ZnU55=
caving, made possible in part by improved drilling technology and in part by ee<'j~{A
understanding of the governing rock mechanics, it is now an attractive proposition for |+-b#Sa9
many orebodies. Similarly, block caving is now conducted efficiently and reliably in p-oEoA
orebody settings that would have been inconceivable two decades ago. At the same <e|B7<.
time, methods such as overhand cut-and-fill stoping and shrink stoping have declined uw>y*OLU+
in application, replaced in part by open stoping and bench-and-fill stoping, where large I_c?Ky8J_|
scale mechanisation, improved backfill technology, reliable rock mass reinforcement EAs^i+/
of stope walls and the intrinsic advantages of non-entry methods of working have led OK@yMGz1I
to superior economics and enhanced operational safety. IQ JFL
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The scope of developments in mining rock mechanics science and practice has been '\pSUp
as impressive as that in mining engineering. Perhaps the most significant advance has dphWxB
been the resolution of some longstanding issues of rock fracture, failure and strength [8b{Ybaz
and their relation to the modes of deformation and degradation of rock around mining P=ubCS'
excavations. The fact that the key research on this topic was conducted at the Underground %@I= $8j
Research Laboratory of Atomic Energy of Canada Limited demonstrates the Pr/q?qZY
extent to which mining rock mechanics has benefited from fundamental research in mphs^k< Z
other fields of rock engineering. The mechanics of blocky rock has also been a field of So NgDFD
impressive development, particularly in regard to formulation of a broad spectrum of mt *Dx
methods of analysis of block jointed rock and their application in excavation engineering >)`*:_{
and support and reinforcement design. More generally, improved understanding 6m9\0)R
of the mechanics of discontinuous rock has had a profound effect on simulation of 1LmbXH]%
caving mechanics and therefore on the design and operation of block caving and N]I::
sublevel caving mines. t,5AoK/NL9
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Mining-induced seismicity and the related phenomenon of rockbursts have become f1\mE~#}
more prevalent in hard rock mining. Developments in mineworthy seismic equipment Z1\=d =
and associated data recording, processing and analysis hardware and software have SR4 mbQ:
contributed greatly to measurement, characterisation and management of the problem. 4E$6&,\
These developments have been complemented by measures in excavation design
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and extraction sequencing which have done much to mitigate the serious operating pW<l9W
problems which can occur in seismically active, rockburst prone mines. In large-scale OQ3IkE`G
open stope mining, Canadian developments based on pillarless stoping, formulation [Z[ p@Ux
of extraction sequences which promote the evolution and uniform displacement of a bz\nCfU
regular mine stress abutment, and the extensive use of cement-stabilised backfill, have |kHzp^S
been successful in managing an acute mining challenge. Notably, these measures have m.yt?`
been based on sound conceptual and analytical models of the relation of damaging %pxHGO=)E
seismicity to induced stress, geological structure, potential rock displacements and nI`9|W
strain energy release during mining. VkC1\L6
Some remarkable developments in computational methods have supported these ur+ \!y7^R
improvements in rock mechanics practice. Many mining rock mechanics problems 7$kTeKiP
are effectively four-dimensional, in that it is the evolution of the state of stress over the S2V+%Z
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time scale of the mining life of the orebody which needs to be interpreted in terms of Gbb*p+(
the probable modes of response of the host rock mass. The computational efficiency !imjfkG
of tools for three-dimensional stress analysis now permits modelling of key stages of wA";N=i=
an extraction sequence, for example, as a matter of routine rock mechanics practice. #!jwn^yq
Similarly, computer power and efficient algorithms provide a notable capacity to `$] ZT>&
simulate the displacement and flow of rock in cave mining and to support design of g|{Ru
optimum caving layouts. W>$mU&ew[
Notwithstanding these developments, it is encouraging to note continued attention P.Qz>c^-C
to formal mathematical analysis in solution of rock mechanics problems. The results 9'O@8KB_
of such analysis provide the canonical solutions for the discipline of rock mechanics DPWnvd
and ensure a sound base for both the science and engineering practice. F,xFeq$/{
In preparing this extensive revision, the authors have been fortunate to have the AR)A <