ACG_NL37_Dec2011

8/19/2019 ACG_NL37_Dec2011

1/16Australian Centre for Geomechanics • December 2011 Newsletter 1

Ground support

considerations for deep

caving writes Iain ThinKSCA Geomechanics Pty Ltd, Australia

What’s in this volume?

Ground support considerations, Page 1Stress states in rock slopes, Page 6Paste research flows well, Page 9

Remediation of mine wastes, Page 10 Mine closure conferences, Page 13Industry events, Page 15 ACG event schedule, Page 16

Introduction

It was about 15 years ago that underground mine development was advancing in theorder of three to six cuts before ground support and reinforcement were installed,where personnel were freely allowed to work within an unsupported environment.During this era, ground support practices involved manual hand installation methods(such as cement grouted bolts and rolled mesh). These systems were a proven andreliable practice with decades of use. They were simple, robust and low cost systems.However, the practice wa iefciet – three pa ytem (drill the hole the remove

the rig, push the bolts fully encapsulating them with cement grout from a platform,

the leave to cure, ally itallig a plate). I additio to the iefciecy, ad moreimportatly, there were everal afety iue aociated with uch ytem – workig

under unsupported ground, working from height (off a platform), manual handling andarduous and repetitive tasks.

The i the late 1990, there wa a igicat hift i how ad whe groud cotrol

was installed. Primary ground support became part of a one pass mining system,

Continued page 2

www.deepmining2012.com

Deep Mining 2012Sixth International Seminar on Deep and High Stress Mining

28–30 March 2012, Novotel Perth Langley Hotel, Western Australia

As mines go deeper, it is inevitable that new challenges willpresent and industry will be required to develop newstrategies and taccs to cope with these mutable condions.

This Deep Mining Internaonal Seminarseries provides a forum for industry,academics and researchers to shareinformaon, experience and ideas on deepand high stress mining. Visit the eventwebsite to view the list of accepted seminarpapers.

Earlybird

registration ends

20 Feb 2012

Associated Workshop

Stress Measurement Workshop 31 Mar 2012

Keynote speakers

Professor Ted Brown AC“Progress and challenges for geomechanics in some areas ofdeep mining”

Professor John Hadjigeorgiou, Lassonde Instute for Mining,University of Toronto, Canada

“Where do the data come from?”

Peter Hills, BCD Resources (Operaons) NL“Managing seismicity at the Tasmania mine”

A U S T R A L I A N C E N T R E F O R G E O M E C H A N I C S V o l u m e N o . 3 7 D e c e m b e r 2 0 1 1

NEWSLETTER

8/19/2019 ACG_NL37_Dec2011

2/16Australian Centre for Geomechanics • December 2011 Newsletter2

© Copyright 2011. Australian Centre for Geomechanics (ACG), The University of Western Australia (UWA). All rights reserved. No part of this newsletter may bereproduced, stored or transmitted in any form without the prior written permission of the Australian Centre for Geomechanics, The University of Western Australia.

The information contained in this newsletter is for general educational and informative purposes only. Except to the extent required by law, UWA and the ACG makeno representations or warranties express or implied as to the accuracy, reliability or completeness of the information contained therein. To the extent permitted bylaw, UWA and the ACG exclude all liability for loss or damage of any kind at all (including indirect or consequential loss or damage) arising from the information inthis newsletter or use of such information. You acknowledge that the information provided in this newsletter is to assist you with undertaking your own enquiries andanalyses and that you should seek independent professional advice before acting in reliance on the information contained therein.

The views expressed in this newsletter are those of the authors and may not necessarily reflect those of the Australian Centre for Geomechanics.

applied to both active development headingsand areas requiring rehabilitation. The systemsadopted were fully mechanised, includingthe installation of sheet mesh as the surfacesupport (the use of sheet mesh tendedto be more popular, with greater use thanshotcrete). The systems provided immediatesupport to underground personnel, withreduced residual mining risks and hazards(particularly eliminating the need for exposureto uupported groud). A additioal beet

was a marked improvement to productivity.Over the years, the use of shotcrete hasevolved as a ground control system gainingincreasing acceptance within the miningindustry. The use of risk assessments appliedto the various components and activitiesassociated with the installation of ground

control has also gained acceptance, whereit now forms an integral part of the overallmining process.

Operational sites incorporated mandatoryground control task requirements or lifesavingrules (or other similarly termed expressions)within their respective Ground ControlMaagemet Pla (GCMP) that pecically

stipulated that ‘no person was to work underunsupported ground’. When the Departmentof Mines introduced the requirement thateach operational site had to develop andimplement their own GCMP, there was aninitial reluctance, possibly due to an initial lackof understanding of the importance of whatthe GCMP was aiming to achieve. However, astime has progressed, mine management, minetechnical services personnel and operationalsuperintendents and supervisors generallyappreciate its value.

Bearing in mind that the purpose of aGCMP is to provide a safe undergroundenvironment and prevent uncontrolledground failure and rockfalls (preventing injuryto personnel and protecting equipmentthrough the correct consideration, applicationand installation of ground support and

reinforcement), a GCMP can end up beinga ubtatially large documet – there i a

considerable amount of information thatneeds to be collated in order to comply withthe purpose of the GCMP. The danger of suchan end product is that important informationis ‘lost’ within the document. The challengeremains for geotechnical engineers/rockmechanics engineers to produce a concise andworthwhile GCMP.

Over the years the practice of installingprimary ground support and reinforcementhas improved, but there has always been thepreure to improve the efciecy of thi

process. Within the overall developmentcycle, ground support installation by far is thelargest component in terms of time and, bydefault, cot. Improved efciecie have come

about through direct and indirect effortsfrom site personnel, ground support suppliers,consultants and research organisations. Thesharing of individual experiences throughtechnical papers at a conference or througha joural, ite viit ad the reultat dig

from a pecic reearch project are ivaluable.

There is always the debate about researchprojects and whether non-sponsoringorganisations should be entitled to the

outcomes and learnings from the research.While it is appreciated that research projectsted to uually require igicat fudig,

those organisations that have contributedacially hould quite rightly be give the

beet of project dig rt. However,

the idutry overall would, I’m ure, beet

from the dig from all reearch project,

particularly those smaller organisations thatdo not have the luxury of research budgets.My feeling is that today we are all gaining thebeet of reearch – thi i certaily a good

thing.

With the beet of mechaically itallig

ground support and reinforcement, ourability to safely and successfully rehabilitateground damaged through mining inducedactivities has also improved, possibly to thepoint that previously a bypass would havebeen developed. Over the years, undergroundoperators have developed their skills, wherethey can install sheet mesh and bolts tightagainst the exposed rock face. Figures 1and 2 are two such examples showing thehigh standard of work being carried out atPoseidon Nickel Limited’s Windarra NickelProject during the decline refurbishment

work, where the installed sheet mesh tightlycontours the irregular shaped excavationprole.

The skill or ‘art’ of mechanically installinggroud cotrol igicatly reduce the

exposure of underground personnel tothe various risks that are often associatedwith the rehabilitation of existing drivedevelopment. Figure 3 is an example of thesuccessful re-establishment of an accessdrive followig a igicat fall of groud. All

the ground control systems installed duringthe eventual rehabilitation process whereremotely and mechanically installed (as is usualwith underground rehabilitation, this particularprocess required a steady but slow approach).

Without a doubt, these collective changes(and more) have greatly improved the safetyof our industry for the better, particularlyas underground mining is advancing deeperand deeper below surface. The experienceand skills that our industry has developedover the years has allowed us to reach greatdepths as we endeavour to meet the everincreasing demand of our mineral resources.The continued quest to meet these demandsis forcing us to continue to advance deeperunderground, where mining depths well inexcess of 1 km below surface will become

more and more commonplace. With ageneral trend of mining at these increasingdepths, there is also an increasing interest inexploiting the vast mineral wealth throughcaving techniques (extracting large tonnagesat low cost). Appropriate ground controlsystems for such challenging conditions willbecome even more critical than they aretoday, establishing and maintaining a safe andcost-effective working environment.

Continue from page 1

Figure 1 An example of mechanically installed sheet

mesh and bolts tightly contoured to the

excavation prole at the Poseidon Nickel

Limited’s Windarra Nickel Project. In addition

to the sheet mesh and bolts, but not shown in

the photograph, are cable bolts that have also

been installed in this specic area

8/19/2019 ACG_NL37_Dec2011


Deep mining

Ground control and deep cavemining

Each operation requires its own groundsupport and reinforcement systems, whichare tailored to the individual groundconditions and operational requirements.The most effective use of ground supportand reinforcement is achieved by matchingthe ground control to the exposed groundconditions.

The aim of designing ground support for apotential cave mining operation is to providea safe work environment for personneland equipment whilst allowing the mosteconomical extraction of ore. An effectiveground support strategy must consider thegeotechnical environment and reaction ofthe rock mass to the mining method. Theinstalled support systems will likely need

to have a good resistance to static anddynamic loading, as well as a high resistanceto drive deformation. Such a combination willinevitably result in intensive ground control. Asshown in Figure 4, the three primary functionsof support elements are:

» Reiforcig – the upport elemet

reinforce the rock mass so as to preventfailure of the rock.

» Retaiig – if there i a failure i the rockmass, the support elements need to retainthe failed rock and absorb the energy withwhich the failed rock is being driven.

» Holdig – the upport elemet have tohold the failed rock mass and control theamount of displacement that occurs.

Approach

When considering the design of suitableground support and reinforcement for aproposed caving operation, there are fourmain areas to focus on:

» Identify the rock support demandand dominant mechanisms of failurefor the various excavations (based onthe understanding of the geotechnical

environment and the expected rock massbehaviour).

» Review historical and existing groundupport deig (if dealig with a broweld

project), best practice/benchmarkingfrom caving operations around the world(literature reviews and/or site visits) and

technology available from ground supportsuppliers.

» Dee poible olutio for eachexcavation and evaluate them throughnumerically modelled simulations (plasticstrain, displacements and dissipated

plastic energy for example), being awareof operational and constructabilityconsiderations.

» Dee al groud cotrol ytem for thepurposes of costing and scheduling.

Some ground control considerations

» A conservative support philosophy for acave i jutied by the evere coequece

of instability and loss of infrastructure,particularly on the extraction level of ablock cave. The cost of extensive groundcotrol meaure ca be jutied whe

compared to the consequence of losingcritical infrastructure.

» The applicability of utilising empiricalmethods can be questioned and/orchallenged for a cave planned at depthsin excess of 1 km. Calibrated numericalmodelling simulations that can account for

Figure 2 An example of mechanically installed sheet mesh and bolts tightly contouring the prole of a previously failed area that is undergoing rehabilitation at the Poseidon Nickel

Limited’s Windarra Nickel Project

8/19/2019 ACG_NL37_Dec2011


the designed excavation and its proposedground control elements, the rock massconditions and overall geotechnicalenvironment provide a more reliableoutcome than the historically acceptedempirical approaches.

» With cave mining, excavation backs areoften arched/curved but the walls aregenerally vertical. In civil engineering,concave surfaces are generally formedfor all excavation surfaces. Modifying theexcavation shape is a potential area where

ground support effectiveness and improvedexcavation stabilities may result (essentiallycreatig a horehoe prole).

» Flexible urface upport, uch a brecretecovered with mesh, strapping and cablelacing, has replaced the traditional andhistorically used rigid concrete lining andsteel sets installed on extraction levels.

» Cable bolts are generally used in widespan areas and sometimes systematically

throughout the extraction level, wherepreviously there had been little use of rockreinforcement or retaining elements.

» With drawpoint brows, steel sets aregenerally embedded in either a thickbrecrete layer or cocrete. For coditio

of deformation and high stress, there tendsto be the addition of cable bolts.

» The preferece for a pecic type of meh

tends to be dependent on the degree ofmechanisation at individual operations.Mechanically installed sheet mesh, which

has a lower energy absorption capacityis generally preferred in Australia, whilemanually installed chain link mesh ispredominantly used in South America andhas greater ductility.

» A igle brecrete layer with a trog

ductile mesh and/or strapping systemwill tend to offer load sharing andconnectivity between support elements.This combination will minimise the potential

for early and discrete or localised failure ofthe system.

» While deep de-bonded or yielding cablebolts offer ideal reinforcement for areaswith increasing damage levels that are oftenexperienced with cave mines, their use doesnot appear to be that common practice.

The geotechnical environment

A deep caving operation may likely requireground support that is able to manage largedeformations, absorb seismic energy and

be resistant to gravity induced rockfalls. Tounderstand these failure mechanisms thereneeds to be an appreciation of the depth offailure, displacements and seismic potential forthe different phases during the life of a cave.

Etimatig the depth of failure, or deig

the fractured zone around an excavation,can be established through site observationsand numerical modelling (which will dependo whether it i a broweld or greeeld

project). The selected support elementsshould be long enough to anchor in the stablerock mass beyond the fractured zone. Theelements should also be capable of bondingto the broken rock mass within the fracturedzone surrounding the individual headings.Another requirement is that the elementsshould be long enough to secure any wedgesthat may form through the intersection ofstructures. In areas of exceptionally poorground conditions, where the anticipateddepth of failure may exceed the length of theground support elements, it may be necessaryto create a reinforced rock mass arch in theimmediate boundary of the excavation.

The post-peak rock mass behaviour canbe deed ad imulated through umerical

modelling so that ground deformations/displacements can be understood. The depthand volume of failed rock can be estimatedfrom the predicted plastic strain. The loadingand deformations of ground support can beaccurately simulated within a numerical model,including the direction of the deformations,

Figure 5 Numerically modelled cave mining induced damage within yielding arches installed in a horseshoe drive

prole (after Beck Engineering, 2011)

Figure 3 An example of a rehabilitated access drive following a signicant fall of

ground (after Thin et al., 2004). Note the vent bag in the top left hand

corner of the original 5 x 5 m drive prole in the background

Figure 4 The primary functions of ground support elements – reinforce, retain and hold

(after CRRP, 1990–1995)

8/19/2019 ACG_NL37_Dec2011


Deep mining

Iain ThinKSCA Geomechanics Pty Ltd Australia

which is fundamental in matchingreinforcement systems to the expected rockmass deformation.

The numerically derived magnitudes of

displacement can be used as a guide for thedisplacement capacities required for theground support systems, appreciating that aproportion of the rock mass displacementmay well occur before the ground supporthas been installed. The numerical simulationsmay alo highlight pecic area where

the rock mass demand would exceed thenormal ground support capacity, leading tolarger displacements. This may result in somespecialised ground support solutions beingdeveloped, an example of which is shownin Figure 5, in the form of yielding archescombied with a horehoe drive prole.

Mining induced seismic activity is aninevitable consequence of caving, particularlyat great depth. The intensity and duration ofthe seismic activity will, in part, be dependenton the caving method. For example, takethe undercut level of a block cave. The mostseismically active period in the undercutwill be when the critical hydraulic radius isreached and cave propagation is initiated. Ascaving propagates upwards, the seismic activitydiminishes, with respect to the extraction leveland the subsequent reduction of the seismicrisk to personnel.

Understanding the potential cave induceddynamic demand needs to be establishedin order to design the energy absorptioncapacity requirements from the groundcontrol. Rockburst scenarios can be simulatedfor different sizes of rock ejection. Themaximum credible seismic event can beinvestigated through numerical modelling(with dissipated plastic energy). The resultsof such an approach, with the inclusion ofengineering judgement and experience, will aidin determining the most appropriate groundcontrol systems to use.

Conclusion

When undertaking a deep cave miningproject through the different study phases,there will be many dependencies, relationshipsand integrations between the necessarygeological and geotechnical studies. Theresultant geological model will inform thegeotechnical model, with these models thenforming the basis of the extensive overall minedeig proce – etablihig the eceary

ground control is one of several componentsthat must be adequately completed.

Numerical modelling is becoming more of akey element in cave mining projects becauseof its ability to consider and integrate themany different components associated withdeep miig – experiece ad egieerig

judgement also play an important role andshould not be underestimated in the value

they offer.

When designing ground support andreinforcement for a deep cave, considerationshould be given to minimising the need for

rehabilitation during the life of the cave. Thedesign process should consider the following:

» Demand and failure mechanisms.

» Reviewing current and best practices fromcaving operations around the world.

» Evaluating designs through detailednumerical modelling.

Several key concepts are seen to potentiallymaximise the effectiveness of different groundsupport and reinforcement elements:

» Ue of curved excavatio prole.

» Routine use of bolting systems with largeforce, displacement and energy absorption

capacity. » Reduced bolt spacings.

» Civil engineering design approaches.

» Fibrecrete coverage with the ability todeform.

Inevitably, underground mining is movingdeeper and deeper below surface as theshallow ‘cream’ has all but gone. Cost-effectiveground control is becoming more andmore critical to the success of deep miningprojects. Indeed, mining depths in excess of2 km below surface will be considered the‘norm’ in the not too distant future. Who

knows what we will be installing as cost-effective ground control then? Much will belearnt from now until this time through casestudies, rock mass characterisation, numericalmodelling techniques, in situ and laboratorytesting, rockfalls and failure mechanisms, civilengineering and tunnelling, design, corrosionand surface support. The combined outcomesof these various areas will aid in our successfulability to oce agai deig for the igicatly

demanding operational conditions at theseigicat depth.

References

Beck Engineering (2011) Ground Support:

Squeezing Ground and High Deformation, viewedOctober 2011, www.beckengineering.com.au.

CRRP (1990 –1995) CAMIRO Mining Division,Canadian Rockburst Research Program. 1990–

1995: A Comprehensive Summary of Five Years

of Collaborative Research on Rockbursting inHardrock Mines, Volume 1.

Thin, I., Andrew, B., Beswick, M. and de Vries, T. A.

(2004) Fall of Ground Case Study – An Improved

Understanding of the Behaviour of a Major

Fault and its Interaction with Ground Support,

in Proceedings Fifth International Symposiumon Ground Support in Mining and UndergroundConstruction, 28–30 September 2004, Perth,

Australia, Balkema, pp. 65–76.

8/19/2019 ACG_NL37_Dec2011


The i itu tre eld ear large ope pit

mines is seldom measured, in spite of the factthat it is entirely feasible. This is because thei itu tre eld i geerally coidered to

be of mior igicace. Thi aumptio may

be adequate for the majority of small open

pit mines, although there is evidence thatthe horizontal to vertical stress ratio can begreater than 50:1 at depths of 10 m belowsurface (Franklin and Hungr, 1978). It certainlyneeds to be questioned for the design of verylarge/deep slopes (Hoek et al., 2010). Thispopular notion, however, does not sit wellwith the proliferation of numerical studieswhich assume a stress distribution, based onregional tectonics such as presented by Lee etal. (2010), and perhaps using (at least initially) amodulu derived from rock ma claicatio

(Hoek ad Diederich, 2005 – RocLab®).

Later, one hopes that this will be calibrated

to actual slope movement (if a case exists).Of course calibration is one of the best waysto assess slope development where there isalready a history that can be used (Beck et al.,2009).

Bullnoses or slopes that are convex in

plan are less stable than concave slopes.This is generally considered to be due tostructural relief, but it is also a function ofthe lack of lateral coemet i covex

lope which i a beet i cocave lope.

These observations provide practical evidence

that tangential stresses have an importantiuece o lope tability. May lope i

steep topographic relief experience landslidesi uch geometric coguratio, e.g. the

Randa slide, Switzerland, 1991 (Eberhardtet al., 2004). In the current state of practicein rock slope design in mines, these lateralstresses are usually ignored or are dealt within a very simplistic manner. In fact, all limitequilibrium models are based upon gravityloading only and these stresses are excludedfrom the slope stability analysis. Numericalmodels can incorporate lateral stresses,but most analyses using these models are

based upon a very simple approximation inwhich the horizontal stress applied to themodel is some proportion of the verticalstress. As noted previously, this assumptionmay be adequate for small slopes, but itneeds to be questioned for the design ofvery high slopes. Lorig (1999), based on the

results of numerical analysis, suggests thati itu tree have o igicat effect o

the factor of safety. However, they do haveiuece o deformatio, ad if the lope i

composed of materials that weaken as a resultof deformation, then the in situ stress can

have a very important effect as the strength tostress ratio decreases, thereby affecting slopestability. In addition, rock fabric and anisotropyalso play a major role in the stress distributionand slope behaviour.

Consider some basic assumptions when it isasserted that stress is of little consequence inopen pit mining:

» Geometry of tructure ad their iueceo tability i a rt order effect.

» Open pit mining involves unloading a slope,so that the only stress concentration is atthe toe.

» The intact rock is hard/strong and unlikelyto crush or shear.

The rt aumptio i upported by

plety of eld evidece ad i iheret whe

coiderig rock ma claicatio a the

most import consideration when examiningslope stability.

Stress states in rock slopes –“the known unknowns”by Phil Dight, Australian Centre for Geomechanics, Australia

Appropriate slope design criteria will continually evolve due to changing geotechnical conditions, historical performance of slopes and the level of onsite geomechanics exper tise

8/19/2019 ACG_NL37_Dec2011


Open pit

Phil Dight Australian Centre forGeomechanics

Australia

The second assumption is also true, althoughthe growing evidence of microseismicity inopen pits (Lynch, 2007; Wesseloo et al., 2009;Sweby et al., 2007) suggests that there is farmore going on behind and below the pit thanhas previously been considered, althoughsuggested by people like Stacey (1981, 2007);Dight (2007); Simmons et al. (2007); andSimmons (2011).

The third assumption is the mostcontentious, as pit slopes are created inmaterials ranging from sand and clays inpalaeochannels through to soft, weak,weathered rocks in depths below thesurface of up to 170 m, to open pits nowextending beyond 1,000 m below surfacewith many more in the planning, feasibility or just commencing. At the 2009 International

Symposium on Rock Slope Stability in OpenPit Mining and Civil Engineering held inSantiago, in response to a question from theoor, oe of the umerical modeller ued a

stress measurement that had been conductedfor the project they were working on. Thiswas repeated in the Slope Stability Symposiumheld in Vancouver in 2011.

It is a popular notion that the stressesaround mineralised systems relate to theregional tectonic regime as inferred byreference to the World Stress Map (Heidbachet al., 2009). While this is an excellent source

of data, it is predominantly based on faultmovement and earthquake analysis. It is

probable that the regional tectonics helpedprecondition the ground for the emplacementof the mineralisation (and here this isreferring to intruded systems) while thereis very strong evidence that local tectonicsplayed a much more igicat role i the

emplacement of the ore. Obviously this makesa complex interaction as evidenced at ElTeiete where the tre eld i the orebody

i predomiatly orth–outh (McKio et

al., 2003), while apparently in the surroundingrocks it is inferred by palaeo-strain analysis tobe eat–wet (Widor et al., 2009).

So far this discussion has ignored theiuece of topography which i igicat i

so many parts of the world including PapuaNew Guinea, South America, North Americaand Asia. This is where it is important that the

geological history for both open pits and civilslopes is taken into account when looking atthe current in situ stress state.

There are several techniques for measuringstress such as hydraulic fracture, overcore(e.g. Sigra) and rock memory techniques suchas DRA and AE (Dight, 2009; Villaescusa et al.,2003). The rt two techique aume that

one of the stresses is parallel to the axis ofthe core, and the former is constrained totre eld where the miimum pricipal

stress is sub-horizontal. The rock memorytechniques are independent of elastic theory,

unaffected by rock anisotropy (particularlyimportant around mineralised systems)

and can be undertaken in the laboratoryon oriented diamond core recovered fromdrilling investigation programs.

Why should the current in situ stress be a

known ‘unknown’ when so much is at stakeand it can be measured easily (Dight, 2011)?

Article references available on request.

International Symposium on

Slope Stabili tyin Open Pit Mining and Civil Engineering 2013

Austral ia | 2013

Excellent delegate attendance at the 2011 International Symposium on Rock Slope Stability in Open Pit and Civil Engineering held in

Canada in September 2011 reflects industry’s keen interest in the novel and rapidly evolving slope monitoring and design technologies.

Slope Stability 2013 Symposium chair, Dr Phil Dight, looks forward to hosting this innovative event that will explore the most

recent developments in the design, analysis, excavation and management of rock slopes. From mining in palaeochannels,

lake basin sediments to fresh rock, best practice will be discussed during the 2013 symposium with respect to pit slope

investigations, design, implementation and performance monitoring. The ACG hosted the 2007 International Symposium onRock Slope Stability in Open Pit and Civil Engineering in Perth in September 2007 and we are very excited to be hosting Slope

Stability 2013.

The symposium will be accompanied by an ACG Mining in Saprolites Seminar. Given the increasing development of deep open pits inareas of the world where significant depths of saprolitic and residual soils exist, there will doubtless be more and more attention paid tothe unique engineering properties of these materials in the future. The main objective of the seminar will be to identify what is known

and what is not known in the investigation, analysis and design of pit slopes in saprolites, transported materials and laterites.

www.s lope2013 .acg .uwa .edu .au

8/19/2019 ACG_NL37_Dec2011


MINEFILL

Australia, 2014

ACG 11th International Symposium

on Mining with BackfllMine ll is recognised as an integral component

of most underground mining operaons. The

stability of and safety within underground mines

are enhanced by the closely controlled placement

of mine ll into stope voids. The 11th Internaonal

Symposium on Mining with Backll will explore

both the theorecal and praccal aspects of the

applicaon of mine ll, with many case studies

expected from both underground and open pit mines.

Minell 2014 will be of interest to mining praconers, engineering students, operangand regulatory professionals, consultants, researchers and interested individuals and

groups from within the wider community.

It is expected that the technical programme will include comprehensive and highly

relevant technical papers emphasising innovaon and applicaon of the state-of-the-

art mine ll technologies by mine operators in their quest to improve mine safety and

producvity. There will be a trade show and social programme.

Symposium Chair

Professor Yves PotvinDirector

Australian Centre for Geomechanics

www.minefll2014.com

This ACG publicaon features 30 papers

(377 pages) that were presented at theACG’s Fourth Internaonal Seminar on

Strategic versus Taccal Approaches

in Mining held in Perth, Western

Australia, 8–10 November 2011.

The hardbound, black and white

proceedings will be of benet and

value to mining execuves and

analysts, nanciers and bankers, OH&S

personnel, mining, metallurgical and

mine engineering personnel, mine

planners, project leaders, consultants,

contractors, researchers, suppliers and

recruiters.

Strategic versus Tactical

Approaches in Mining 2011

Proceedings

Visit www.acg.uwa.edu.au/shop

The aim of this new 40 minute DVD is to provide all

underground mine workers with the crical knowledge on

drilling and blasng processes and their related hazards.Content: rock breaking process; handling, storing and

transportaon of explosive products; development drilling

and blasng pracces; producon drilling and blasng.

A safety training DVD for underground metalliferous mine workers

ACG Underground Drillingand Blasting DVD

Visit www.acg.uwa.edu.au/shopwww.ancold.org.au

Conference themes:

» Water supply dams

» Tailings dams

» Flood mitigation (protecting communities)

ACG–ANCOLD Design of Tailings Storage Facilities for

Seismic Loading Conditions: Operational and Long Term

Considerations Workshop

Wednesday 24th October 2012Burswood Entertainment Complex, Perth, Western Australia

Workshop facilitator:

Winthrop Professor Andy Fourie, The University of Western Australia

8/19/2019 ACG_NL37_Dec2011


Paste

The Southern African Institute of Mining and MetallurgyFounded in1894

15th International Seminar on Paste and Thickened Tailings

The Australian Centre for Geomechanics is the founding body for this seminar series and

The Southern African Institute of Mining and Metallurgy is the hosting and organising body

OBJECTIVES

The objective of the seminar series is to disseminate the latest advancements in

the field of paste and thickened tailings technology by providing a forum to present

the work that is being done in the field, and obtain feedback based on case studies

and operating installations from practitioners.

WHO SHOULD ATTEND

The seminar is aimed at all those involved in the design and management of

mine waste disposal facilities, and includes

• engineers • operators • mine owners • legislators and • research academics.

For further information contact:

Head of Conferencing, Jacqui EʼSilvaSAIMM, P O Box 61127, Marshalltown 2107

Tel: +27 11 834-1273/7Fax: +27 011 833-8156 or +27 11 838-5923

E-mail: [email protected]: http://www.saimm.co.za

SPONSORS

PRIMARY PRINCIPAL SPONSOR

FLSmidth

PRINCIPAL SPONSORSStefanutti StocksBASF

MAJOR SPONSORS

AranWestechAker Wirth

TRADE EXHIBITORS

Feluwa Pumpen GmbH

Immatech

Weir Minerals Netherlands

Flowrox Oy

DINNER SPONSOR

FLSmidth

MEDIA SPONSOR

International Mining

Venue: Sun City, PilansbergSouth Africa

16–19 April2012

The ue of occulat “i-lie” durig

tailings deposition is an emerging technologythat has been implemented at a handfulof locations, and is planned for a numberof other. I-lie occulatio i aimed at

enhancing the release of supernatant waterat discharge and expediting consolidation andmay well produce steeper beaching angles. Thisis achieved by increasing the effective particleize, ad hece ettlig time, of e graied

particle whe occulat i mixed with lurry.

While this technology is promising, littlei kow regardig the effect of occulat

addition on many geotechnical properties.Quaticatio of thee effect i eetial

given the likely acceleration of the use of thistechnology in the near future. Liquefactionrelated parameters are of particular interestas the steeper beaches produced by in-lineocculatio offer the potetial to develop

a tailings stack higher than the perimeter

embankment. This can provide excellentecoomic beet, provided the icreaed

liquefaction risks are properly understood andaccommodated for by the design.

ACG sponsored research project

David’s research will initially consist of aseries of laboratory tests on tailings with,ad without occulat. Careful ample

preparation methods are to be employedto allow occulated ample to be ierted

into geotechnical testing equipment withoutditurbace of the occulated tructure

created during deposition. Testing will include:

» Particle size determination.

» Rowe cell consolidation testing.

» Determination of critical state parametersthrough triaxial testing.

» Cyclic testing.

» Scanning electron microscope imaging.

The initial laboratory programme will beexpanded depending on the results. This mayinclude quantifying ageing effects and shearbreakdow of occulated particle. Cetrifuge

and numerical modelling will eventually beemployed to further investigate the effects of

occulat.David would be interested in discussing the

potential of including in situ testing at sitesthat are using or are planning to implement

i-lie occulat at dicharge. He ca be

contacted at [email protected].

The ACG is funding the costs of laboratorytesting at UWA.

A new ACG sponsored PhD student recently commenced study at The University of Western Australia (UWA). David Reidcommenced research in April 2011 in the School of Civil and Resource Engineering of UWA. David’s research is primarily

directed towards assessing the impacts of occulant addition to tailings on a number of important geotechnical parameters,

particularly those related to liquefaction. David writes of his progress.

The ACG is delighted

to advise that income

from sales of our

highly acclaimed

“Paste and Thickened

Tailings – A Guide (Second Edition)”

helps fund David’s timely industry

research. We are very pleased to

make this contribution and thank the

publication’s editors Richard Jewell and

Andy Fourie, authors and sponsors.

8/19/2019 ACG_NL37_Dec2011


Turning over a new leaf oncontaminated land rehabilitation

Metal-contaminated mine wastes areacial, health ad evirometal rik that

can burden operations, prevent scheduledmine closure and expose operators tosevere penalties. The irreversible binding oftoxic soluble metals from surface layers ofmetalliferous waste deposits can minimisethese risks through reduced leaching,enhanced vegetation establishment, reducederosion and contaminant dispersion intosurrounding environment, and sustainable,safe habitat development for browsingfauna. To this end, Rossato et al. (2009) havedeveloped a metal-binding degradable polymer('X3') that facilitates plant growth on highlycontaminated mine soils. The X3 technology

has the potential to be a low cost tool forthe in situ remediation of metal-contaminatedmine and industrial sites. This technology wasrecently acknowledged by the mining industryand received the Excellence in EnvironmentalManagement Award at the 2011 AustraliaMining Prospect Awards presentation. The X3particle technology has been demonstrated oncontaminated mine soil in a glasshouse withacial upport from Xtrata Techology ad

assistance from the Queensland Departmentof Employment, Economic Development andInnovation (DEEDI). UniQuest, The Universityof Queensland’s (UQ) main commercialisation

company, has established MetalloTek Pty Ltdto manage further development andcommercialisation of the technology inpartnership with industry stakeholders.

Mine wastes

The mining and minerals processingindustries are critical to the economic wellbeing of Australia, however, they produce largequantities of metal-contaminated waste rockand mineral processing tailings. The quantityof tailings wastes in 1995 was estimated to be700,000 tonnes and their placement in surface

storage areas is not without environmentalconsequences. In addition, waste rock andother parts of mining or processing sites maycontain toxic concentrations of metals thatare available for uptake by organisms andtherefore pose environmental risks.

Current legislation and administrative

Novel approach for in situ remediation of

metal-contaminated mine wastesby Drs Laurence Rossato, Alex Pudmenzky and David Doley,

MetalloTek Pty Ltd, The University of Queensland, Australia

regulations require the owners and operatorsof mines and minerals processing sites tominimise the risk of contaminant movementfrom their sites through the transfer ofcontaminated soil or water. Furthermore, the

holders of mining leases must demonstratethat the lease area has been brought to asatisfactory condition where it is safe to usefor other purposes and where contaminantsare not released to neighbouring properties.In many situations it is necessary to restorenative vegetation that may have occurredpreviously on the site or to establishconditions that will support commercialagricultural or grazing activities. Failure tocomply with these mine closure requirementsmay incur heavy penalties as well as damagingthe company’s reputation.

Current soil remediationtechniques

Radical treatments for urban areascontaminated with metals are expensiveand often highly disruptive. For example, theexcavation and removal of contaminatedmaterial to a ladll ite imply relocate

the problem. Chemical stabilisation of toxicmaterial i ofte techically difcult ad

expensive, while capping or covering of thecontaminant with a permanent impermeablebarrier is also expensive and not alwaysguaranteed to succeed. These remedies are

jutied if the ubequet lad ue ha ahigh value, but in rural and remote mininglocations, the ongoing value of the land cannot justify such costly remediation.

Old mining and mineral processingenvironments often contain total metalconcentrations that warrant theirreprocessing. However, for health andenvironmental purposes, the criticalconcentration of a metal in waste, or even ina naturally outcropping mineral deposit, is itsbioavailable cocetratio. Thi i deed a

the quantity of contaminant that can be takenup and accumulated by plants and animals.The sensitivities of organisms to a particularbioavailable metal concentration vary widelyand plant species that are especially tolerantto high metal concentrations are knownas metallophytes. These plants may survivein metal-rich environments by different

means, including the restriction of metalaccumulation to the root system (excluders)or the accumulation of metals in the shoots(accumulators). Species with very high rates ofaccumulation (hyperaccumulators) have been

used in bioprospecting for many years.

Metallophytes are obvious candidates forinclusion in phytoremediation programmes(site remediation using vegetation) on metal-contaminated sites. However, even modernmine wastes sometimes contain plant availablemetal concentrations that are far in excessof the toxic thresholds for metallophytes,as shown in the upper part of Figure 1.Together with adverse levels of acidity, thesebioavailable metal concentrations may preventplant growth on many mine waste areas fordecades, such as those at Broken Hill, New

South Wales or Mt Morgan, Queensland.To allow any plant to establish and survive

in highly toxic metal conditions (above theirphytotoxicity threshold), the soil quality ofthe root zoe mut be improved ufcietly

at the time of planting. Conventional in situremediation of metal-contaminated soils usesadded topsoil (which has to be removed fromelsewhere and is often scarce), or additivessuch as siliceous slag, zeolite, organic matter(straw, woodchips) and lime or gypsum torectify acidic or alkaline conditions. Theseamending materials have relatively lowmetal-binding capacities per unit weight, andtherefore require large quantities of materialto be applied per hectare, with consequentexpee, eve if oly a upercial treatmet

is used. Where amending materials areremoved from other locations, they createa chain of impacts whereby the excavationsites may be degraded and in need ofadditional rehabilitation. As a result, there isa widespread need for a simple, robust andcost-effective means of treating mined orindustrial lands that stabilises the surface sothat wind and water-erosion are reducedand the subsequent metal-contamination

of ground water, food chain and the air areprevented.

Novel X3 particle technology

Technology developed at UQ combines apatented site amendment process, known asX3 particle technology, with the establishment

8/19/2019 ACG_NL37_Dec2011


Mine closureof carefully selected native metallophytes toinitiate phytostabilisation with lower inputsand greater certainty than can be achievedby conventional means. The X3 technologyis based on an approved and widely usednon-toxic and economical personal hygieneand soil amendment polymer. It allows highlyefciet metal bidig particle to be added to

contaminated soil, mine waste rock or tailingsso that the availability of toxic metals in theroot zone is reduced and soil quality improvedto the point where metallophytes can becomeestablished as shown in the lower scheme ofFigure 1.

Native metallophytes that are best suitedto a particular climatic region, the prevalentmetals and other soil conditions (such assalinity) can be selected from a database

developed for this purpose by Pudmenzky etal. (2009). The combination of metal bindingby X3 particles and accumulation by themetallophytes is designed to reduce plantavailable metal concentrations in the soil tothe point where other less tolerant plantspecies can become established. No othersoil amendments, for example, lime, organicmatter, are required for X3 to be effective andit degrades over a period of about 10 yearsto release simple plant nutrients, in particular,nitrogen. Preliminary results suggest that theeffect of the particles may extend below thedepth of application, over the course of agrowing season. The water holding capacityof the soil is also increased and plant wateravailability enhanced via a substantial reductionin salinity.

Benets of the X3 particletechnology

Compared with existing soil remediationtechniques (Table 1), the X3 particletechnology offers the potential of a simpleand relatively cheap means of improving thecapacity of a metal-contaminated site tosupport permanent vegetation cover whereit was not possible previously. By helping toestablish vegetation and stabilise contaminatedland, the risk of contaminating the surroundingenvironment via wind and water-erosionis also reduced. This potentially enablesmine owners to relinquish leases early andavoid crippling rehabilitation costs and legalpenalties.

Particles could be applied sparingly andeconomically as a surface application along

Technology X3 Particles Capping Excavation Chemical

Stabilisation

Cost Low Medium High Medium

Ease of application

Environmental impact Low Medium High Medium

Soil remains in place

Reduces water and air pollution

Reduces acidity

Reduces salinity

Increases water availability

Figure 1 Relationships between plant available metals in the soil (small circles) and metallophyte development in

conventional remediation (upper scheme), and in soil treated with X3 particles (large circles, lower scheme).

Metallophytes suited for the specic site contamination problems are selected from the spatial metallophyte

database developed by Pudmenzky et al. (2009)

Table 1 Comparison of X3 particle technology with existing soil remediation technologies

This 2 volume proceedings containsover 120 technically reviewed papersand a range of mine closure topics.

To purchase these and other publicationsplease visit the ACG shop at

www.acg.uwa.edu.au/shop

MINE CLOSURE 2011PROCEEDINGS

MInE PIT LAKEs:CLOSURE AND MANAGEMENT

This 183 page book is a concisesummary of the considerable body

of mine pit lake knowledge and

experience.

8/19/2019 ACG_NL37_Dec2011


Laurence Rossato MetalloTek Pty Ltd The University of Queensland

Australia

Alex Pudmenzky MetalloTek Pty Ltd The University of Queensland

Australia

David Doley MetalloTek Pty Ltd The University of Queensland

Australia

Figure 2 This photograph dramatically illustrates the potential of the technology.

The pot on the left has highly acidic, saline and metal-contaminated

mine waste on which no vegetation has grown for 30 years. The pots to

the right have the same waste to which the X3 particle technology has

been applied to the top 50 mm only allowing grass to grow

Figure 3 Healthy plant growth after nine months of X3 particle treatment. Average grass

height reached one metre with no visible signs of toxicity

rip lines or in discrete spots that are thenused to establish vegetation. This wouldminimise disturbance and reduce the numberof operations required for site preparationand planting. Application to the site shouldtherefore be relatively inexpensive (applicationrate per ha depending on contaminationlevel) and should not require large or heavymachines that cause site compaction. Thisrepreet a igicat cot avig over

existing solutions.

X3 in action

The research group behind the X3technology is based at UQ and includesparticipants from the University of NewSouth Wales. The present prototype particlehas the capacity to drastically reduceplant available concentration of aluminium,cadmium, copper, lead, manganese, zinc andnickel from contaminated soil and increase

the water availability to plant roots, allowingplants to grow under extreme environmentalconditions (such as metal-contamination,salinity and/or drought). Laboratory tests haveshown that the addition of X3 to soils enablesthe germination of grass seeds on mine wastesand tailings that are otherwise completelytoxic to these species. The addition of X3 tothe surface 50 mm of highly contaminatedmine waste, on which no vegetation had beengrown for 30 years, enabled a metallophytegrass to germinate and grow vigorously,reaching a height of 20 cm in three months(Figure 2) ad up to 1 m with owerig ad

seed set in nine months (Figure 3).

Commercial applications

Xstrata Technology chief executive, JoePease, says the research showed the potentialto deliver smart and sustainable ways of

dealing with metal-contamination in soils, acritical concern for mining companiescommitted to sustainable rehabilitation.

Ongoing work is planned to develop the X3particle technology further and validate it ina pilot eld trial at a mie ite uder extreme

environmental conditions. MetalloTek Pty Ltd

will help accelerate commercialisation of theresearch outcomes so that the technologyis made available to the mining industry as asafer, sustainable, more economical, practicaland less environmentally disruptive solution tothe worldwide metal-contamination problemthat can be used effectively by many pollutedsites globally. The X3 particle technology is

expected to assist companies reduce theirenvironmental impacts and potential damageto their corporate reputations, relinquishtheir lease obligations earlier and minimiserehabilitation costs and possible penalties.

References

Pudmenzky, A., Rossato, L., Doley, D., Ramirez,C. and Baker, A.J.M. (2009) Development of ametallophyte spatial database covering Australia,in Proceedings Fourth International Conferenceon Mine Closure (Mine Closure 2009), A.B.

Fourie and M. Tibbett (eds), 9–11 September

2009, Perth, Australia, Australian Centre forGeomechanics, Perth, pp. 311–316.

Rossato, L., Pudmenzky, A., Doley, D., Monteiro, M., Whittaker, M., Schmidt, S., Macfarlane, J. and

Baker, A.J.M. (2009) Metal-binding particles

enhance germination and radicle tolerance indexof the metallophyte grass Astrebla lappaceaLindl. under phytotoxic lead and zinc conditions,in Proceedings Fourth International Conferenceon Mine Closure (Mine Closure 2009), A.B.

Fourie and M. Tibbett (eds), 9–11 September

2009, Perth, Australia, Australian Centre forGeomechanics, Perth, pp. 301–310.

8/19/2019 ACG_NL37_Dec2011


Mine closure

MineClosure

2012

The wide range of perspectives, as well ascountries of origin, brought a high level ofvalue to the Mine Closure 2011 Conference,held 18–20 september i Alberta, Caada.

One of the most interesting sessions was apanel discussion on oil sands closure, offeringviews from industry, NGOs, regulators,government and First Nations. Facilitated byGord McKea of BGC, pael participat

included Terry Bachynski of JDEL AssociatesLtd., Shannon Flint of Alberta Environment, Jennifer Grant of the Pembina Institute,Richard Houlihan of the Alberta Energy andResources Conservation Board, and MelodyLepine of the Mikisew Cree First Nation.Each stakeholder representative presentedtheir viewpoint, combined with audienceparticipation.

About 30 per cent of delegates werefrom outside of Canada, representing over30 countries. Delegates included students,academics, mine planners and operators,

reclamation scientists and practitioners,engineers and regulators.

The purpose of the conference was to sharesome of the current state-of-the-art ideason mine closure, and to provide delegates achance to learn from each others’ views onthe subject.

The four day event, hosted by theUniversity of Alberta and organised byGolder Associates, exceeded organisers’

Different viewpoints add

value at Mine Closure 2011

expectations regarding attendance, sellingout at 600 registrations. There were eightpre-conference short courses, 15 plenaryspeeches, and 124 technical presentationsdurig ve parallel breakout eio. Optioal

aspects included a tour of Suncor’s reclaimedtailings impoundment in Fort McMurray, andtwo post-conference tours to Hinton, AB andKimberley, BC.

Plenary speakers included a keynote byLes Sawatsky of Golder Associates, closingthoughts by Gord Ball of Syncrude CanadaLtd., Annika Bjelkevik of the ICOLD TechnicalCommittee on Tailings Dam Decommissioning,Ben Chalmers of the Mining Association of BC,Hugh Jones of Golder Associates, Australia, Jean-Michel Gires of Total E&P Canada, AndyRobertson of Robertson Geotechnical andother noteworthy speakers.

Conference chair was Les Sawatsky andconference manager was Catherine Puchalski,Golder Associates.

A orgaier of thi ot-for-protconference, Golder Associates will donateall conference proceeds after expenses toclosure/reclamation research at the Universityof Alberta and the University of BritishColumbia.

More at www.mineclosure2011.com

writes Catherine Puchalski, Golder Associates, Canada

Conference chair Les Sawatsky

Six hundred mine closure practitioners attended MineClosure 2011

This ACG iniated conference series is a well recognised internaonal forum that puts

technical excellence rst. Mine Closure 2012 will provide industry professionals commied

to responsible and sustainable mining with a unique opportunity to interact with their

counterparts from dierent countries, and share ideas and experiences on innovaons relatedto mine closure design, planning and operaon. We are delighted to host this conference in

Brisbane for the rst me.

Collaborang Organisaon

Abstracts due 26 March 2012

Seventh InternationalConference on Mine Closure25–27 September 2012 | Sofitel Hotel | Brisbane | Australia

www.mineclosure2012.com

8/19/2019 ACG_NL37_Dec2011


Narrow Vein MiningConference 2012

Working Smarter Through Technical Collaboration

26 – 27 March 2012, Perth, Western Australia

THE CONFERENCE

Narrow vein mining operations form a relatively small but important part ofthe global mining industry, principally focused on commodities such as gold,silver and tin. Many historical narrow vein mineral fields are now beingreworked or redeveloped in Australia and beyond.

The skills and expertise required to manage these resources are arguablyhighly specialised and relatively rare at this time. The challenges of narrowvein deposits include: dealing with issues of complex geology; high toextreme nugget effects; ore/waste misclassification; high planned andadditional dilution; the need for strong selectivity; high-stress conditions; lowtonnes per vertical metre; and coarse gold and/or complex metallurgy. Today,there is an overarching need for lower costs, mechanisation and a zero harmenvironment.

The purpose of this Conference is to gather all involved in narrow veinmining, including geologists, mining/geotechnical engineers, andmetallurgists. The future of narrow vein mining depends upon skilled

professionals and on developing practical and innovative methods fororebody definition, mining and processing.

Dr Simon Dominy FAusIMM(CP), Conference ChairSnowden Group, WA School of Mines

THE THEME

The theme for this conference is “working smarter through technicalcollaboration” and will incorporate papers on the following topics:

• Geological controls on narrow orebodies

• Resource/reserve estimation and reporting

• Monitoring and controlling dilution

• Best practices in mining

• Bulk or selective mining methods?

• Geotechnical challenges

• Managing narrow vein operations

• Removing technical silos to achieve professional unity

• Health & Safety issues

• Mineral processing – from core to brick

SPONSORSHIP & EXHIBITION OPPORTUNITIES

Showcase your business at the Conference and register your interest in

sponsorship today! A Trade Exhibition will be held in association with the

event and will provide an excellent opportunity for companies to display their

products and services to the participants. Should you wish to discuss

opportunities, develop a package to suit your budget, or if you have any

enquiries, please do not hesitate to contact Event Management.

EVENT MANAGEMENT: The AusIMM

For further information on the above including registration, sponsorship and

exhibition opportunities please contact:

Belinda Martin, Senior Coordinator, Conferences & Events

Telephone: +61 3 9658 6125 | Email: [email protected]

Platinum Sponsor

www.ausimm.com.au/narrowveinmining2012

Australian Centre for Geomechanics Presents:

Deep Mining 2012Sixth International Seminar on Deep and High Stress Mining

28-30 March 2012, Novotel Perth Langley Hotel, WA

For more information visit www.deepmining2012.com

RegisterNow!

8/19/2019 ACG_NL37_Dec2011


ACG newsACG team news

Marina enrolled in the Master of EngineeringScience by research at the School of Civiland Resource Engineering, The Universityof Western Australia in 2009 to join theACG’s Mine Seismicity and Rockburst RiskManagement project team led by Dr Johan

Wesseloo.

Marina’s research objective is to assess therelevance of using seismic data to quantifyrock mass damage in mining. Marina hasapplied the calculation of known seismicdamage parameters on real monitoring dataavailable from a few mine sites utilising theACG’s MS-RAP version 4 software.

Marina is currently writing her thesis withguidance and assistance from supervisors,Winthrop Professor Yves Potvin and Dr JohanWesseloo. The project not only challengesMarina to learn about mine seismicity but also

to learn the mechanism of fracturing in rockmass in an attempt to understand the relationof seismic data to rock mass damage whichis essentially stress-induced fractures due tomining excavations.

Potvin, ACG director, and Dr Johan Wesseloo,project leader for the ACG “Mie seimicity

ad Rockburt Rik Maagemet” reearch

project.

In the last two decades, rockbursting has

been a serious issue for underground mining,and as mining continues to go deeper, theunderstanding of this phenomena is a decisivefactor when considering mining at deeperlevel. Rockburtig i iueced by groud

support, particular ground conditions andto the seismicity generated by the miningdisturbance of the rockmass. There does notappear to be a globally accepted method toevaluate future seismic hazard on differentmine sectors over time. Thus, a methodologyto analyse the seismic response of therockmass is needed. This research project willfocus on the sources of the largest events,

deig a methodology to repreet theseismic response of the shear zones whentriggered by mining.

Although based in Chile, Juan will visit theACG in Perth over the coming years to meetwith his supervisors and progress his thesis.

Marina Masters studentThe University of Western Australia

Matylda Thomas ACG events and proceedings

Juan Andres Jarufe Troncoso (centre), with the ACG’s

Johan Wesseloo (left), and Paul Harris (right)

The ACG was delighted to welcomeMatylda to the team earlier this year. Prior to joining the ACG, Matylda was responsible forcoordinating events and administration at thenow closed Centre for Land Rehabilitation,The University of Western Australia.

Matylda maintains and develops the ACGwebsites and event promotional literature.Matylda also works on the ACG’s varioussymposium proceedings and course notes.

An ACG PhD thesis to quantify

shearing zones’ response to mining

The ACG warmly welcomed Juan Jarufe,Codelco VP, Chile to our team in September2011. Juan is undertaking his PhD thesisetitled “Quatifyig seimic Repoe of

Major Discontinuities in Response to MiningUig numerical Modellig” via the ACG,

The University of Western Australia, Schoolof Civil and Resource Engineering. Juan’ssupervisors are Winthrop Professor Yves

Monitoring and Modelling the Seismic Rock Mass Response to Mining

27 March 2012 | Pa Pacic Hotel | Perth | Autralia www.imeimology.org

15th International Seminar on Paste and Thickened Tailings

16–19 April 2012 | su City | south Africa www.aimm.co.za

Second Southern Hemisphere International Rock Mechanics Symposium

14–17 May 2012 | su City | south Africa www.aimm.co.za

ANCOLD 2012: The Importance of Dams in Our Developing Economy

25–26 October 2012 | Perth | Autralia www.acold.org.au

Non ACG events and courses

8/19/2019 ACG_NL37_Dec2011

16/16

The ACG team wishes you and your family a very

merry Christmas and a happy New Year. We thank

you for your support and encouragement during 2011

and look forward to an exciting 2012.

Our office will be closed from Monday, 26th December,

reopening on Monday, 9th January 2012.

ACG event schedule*Environmental Geochemistry of Mine Site Pollution – An Introduction, Short Course Perth, 21–22 March 2012

Sixth International Seminar on Deep and High Stress Mining Perth, 28–30 March 2012

Stress Measurement Workshop Perth, 31 March 2012

Advanced Application of Seismology in Mines Seminar Perth, 15–18 May 2012

Hydro-geology and Water Management in Open Pit Mining Seminar Perth, 19 June 2012

Slope Stability in Weak and Soft Rock and Saprolites Seminar Perth, 20–21 Jue 2012

Practical Rock Mechanics (Introduction) Short Course Perth, 20–21 Augut 2012

Ground Support in Mining (Basic Level) Short Course Perth, 22–24 Augut 2012

Interpretation of Geochemical Data for Environmental Applications Workshop Brisbane, 23 September 2012

Designing for Closure: Appropriate Design Criteria and Methods of Analysis Workshop Brisbane, 24 September 2012

Delivering Effective Rehabilitation: Monitoring and Manipulating the Soil Biota for Success Workshop Brisbane, 24 September 2012

Seventh International Conference on Mine Closure Bribae, 25–27 september 2012

ACG–ANCOLD Design of Tailings Storage Facilities for Seismic Loading Conditions: Operational and

Long Term (Post Closure) Considerations WorkshopPerth, 24 October 2012

Blasting for Stable Slopes Seminar Perth, 14–16 november 2012 (TBC)

Seventh International Symposium on Ground Support in Mining and Underground Construction Perth, 14–16 May 2013

International Symposium on Slope Stability in Open Pit Mining and Civil Engineering Australia, 2013

11th International Symposium on Mining with Backfll Australia, 2014

Ninth International Symposium on Field Measurements in Geomechanics Australia, 2015

*The ACG event schedule is subject to change. For event updates , please visit www. acg.uwa.edu.au/current_events_and_courses

Autralia Cetre for Geomechaic | PO Box 3296 – Broadway, nedlad, Weter Autralia, Autralia 6009

Documents

ACG_NL37_Dec2011