Rock mechanics for underground mining, 3rd ed qnp}#BZ
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by |,$&jSe
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B. H. G. Brady #Nh'1@@
Emeritus Professor, The University of Western Australia, and Consulting {'M<dI$
Engineer, Montville, Queensland, Australia -Rpra0o.
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E. T. Brown _Ay^v#a
Emeritus Professor, The University of Queensland, and Senior Consultant, x@OBGKV
Golder Associates Pty Ltd, Brisbane, Australia %D4)Bqr
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KLUWER ACADEMIC PUBLISHERS blQ&QQL
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2005 Springer Science + Business Media, Inc @:?[R&`
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Preface to the third edition 8{ZTHY-
Sometimes it is suggested that mining engineering and its supporting engineering !'N@ZZ
sciences have reached a state of maturity. However, this proposition is inconsistent B@(d5i{h
with major developments in the twenty years that have elapsed since the preparation of _Q1p_sdg
the first edition of this book, and the ten years since it has been subject to any substantial $E@n;0P
revision. Over those periods, innovations and improvements in engineering practice E<jajYj
in mining and mining rock mechanics, and advances in the engineering science of Lng. X8D
rock mechanics, have been extraordinary. For these reasons the third edition, which 8m{e,o2.
results from comprehensive and thorough revision of the earlier editions, has involved wY<s
the replacement or substantial modification of the equivalent of about half of the text 8JY0]G6
and figures of those versions of the book. _bCAZa&&
One of the key drivers for many significant developments in fundamental rock mechanics j,.M!q]
over the period has been the mining industry’s recognition of the economic M=raKb?F
returns of better understanding and more rigorous application of the governing sciences p3Ux%/ZqPV
embedded in its industrial operations and processes. The result has been some O.+J%],
notable advances in mining engineering practice, involving improvements in mining S($/Ov
methods in particular. For example, caving methods are now more widely applied o ks;G([
as understanding of their scientific basis has improved and their economic and operational W_}j~[&
advantages have been realised. Whereas sublevel caving was once regarded -yf8
in some places as a method of marginal interest, the advent of very large scale sublevel "B{3q`(
caving, made possible in part by improved drilling technology and in part by ;<M}ZL@m
understanding of the governing rock mechanics, it is now an attractive proposition for Tow=B
many orebodies. Similarly, block caving is now conducted efficiently and reliably in Rt?CE jy
orebody settings that would have been inconceivable two decades ago. At the same Ca0sm
time, methods such as overhand cut-and-fill stoping and shrink stoping have declined s6~;)(r
in application, replaced in part by open stoping and bench-and-fill stoping, where large }? _KZ)
scale mechanisation, improved backfill technology, reliable rock mass reinforcement 4v`/~a
of stope walls and the intrinsic advantages of non-entry methods of working have led 1O`V_d)
to superior economics and enhanced operational safety. _[R(9KyF0f
The scope of developments in mining rock mechanics science and practice has been jkL=JAcf~
as impressive as that in mining engineering. Perhaps the most significant advance has 4NID:<
been the resolution of some longstanding issues of rock fracture, failure and strength )7 & -DI1
and their relation to the modes of deformation and degradation of rock around mining 486\a
excavations. The fact that the key research on this topic was conducted at the Underground b1?^9c#0d
Research Laboratory of Atomic Energy of Canada Limited demonstrates the Ss%Cf6qdWL
extent to which mining rock mechanics has benefited from fundamental research in _-C/sp^
other fields of rock engineering. The mechanics of blocky rock has also been a field of q=W.82.U
impressive development, particularly in regard to formulation of a broad spectrum of _p6r5Y
methods of analysis of block jointed rock and their application in excavation engineering K? o p3}f?
and support and reinforcement design. More generally, improved understanding L?/AKg
of the mechanics of discontinuous rock has had a profound effect on simulation of e8<}{N0,n
caving mechanics and therefore on the design and operation of block caving and HF*0
sublevel caving mines. C7dq=(p&
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Mining-induced seismicity and the related phenomenon of rockbursts have become
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more prevalent in hard rock mining. Developments in mineworthy seismic equipment 0;l~B
and associated data recording, processing and analysis hardware and software have D\_nqx9O
contributed greatly to measurement, characterisation and management of the problem. v;\cM/&5
These developments have been complemented by measures in excavation design R0qZxoo
and extraction sequencing which have done much to mitigate the serious operating 8r(awp
problems which can occur in seismically active, rockburst prone mines. In large-scale "Ol:ni1
open stope mining, Canadian developments based on pillarless stoping, formulation B{)#A?Rh.
of extraction sequences which promote the evolution and uniform displacement of a 7"'RE95
regular mine stress abutment, and the extensive use of cement-stabilised backfill, have >UCg3uFj
been successful in managing an acute mining challenge. Notably, these measures have iHhdoY[]
been based on sound conceptual and analytical models of the relation of damaging nriSVGi
seismicity to induced stress, geological structure, potential rock displacements and 7K.75%}
strain energy release during mining. w( V%EEk
Some remarkable developments in computational methods have supported these $_F_%m"\
improvements in rock mechanics practice. Many mining rock mechanics problems )vO"S
are effectively four-dimensional, in that it is the evolution of the state of stress over the cjN)3L{
time scale of the mining life of the orebody which needs to be interpreted in terms of \(pwHNSafk
the probable modes of response of the host rock mass. The computational efficiency _O}m0c
of tools for three-dimensional stress analysis now permits modelling of key stages of p/(Z2N"
an extraction sequence, for example, as a matter of routine rock mechanics practice. Sesdhuy.@
Similarly, computer power and efficient algorithms provide a notable capacity to C_N|o|dX
simulate the displacement and flow of rock in cave mining and to support design of }W'j Dz7O
optimum caving layouts. _G'ki.[S7
Notwithstanding these developments, it is encouraging to note continued attention e#/&A5#Ya
to formal mathematical analysis in solution of rock mechanics problems. The results <<01@Q <