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


Dr Loren Lorig presenting his keynote (Photo curtesy of S Coetsee)


The Sixth Slope Stability Symposium was held in Cape Town from the 12th to the 14th of October 2015, hosted by SANIRE in conjunction with SAIMM. The symposium was originally held in Cape Town in 2006 and has subsequently been to Perth (2007), Santiago (2009), Vancouver (2011) and Brisbane (2013). Since it is the only dedicated slope stability conference internationally, it is consistently well attended. While attendance was less than in previous years, as is expected in current times, it still attracted just over 200 delegates, 130 of whom were international. Keynote speakers were Professor Doug Stead from Simon Frasier University, who presented his research on internal failure mechanism during failure, comparing it to current analysis technics; Dr Loren Lorig CEO of Itasca, presented on designing for extreme events; Geogg Beale (Director at Schlumberger Water Services) presented on the importance of surface water management and its impact on slope stability; and Louis Melis (Melis & Du Plessis Consulting Engineers (Pty) Ltd) presented the recent work he has been doing in designing rock fall protection. Fifty-four papers and ten posters were presented and published in a proceedings volume, a selection of which will be published in an upcoming issue of the SAIMM Journal. A slope stability monitoring workshop was presented on the 15th, organised and facilitated by Huw Thomas from the University of the Witwatersrand. Thanks goes out to the organising committee, SAIMM, presenters and the very generous sponsors!

Robert Armstrong,
Chair, Organising Committee.


A recent report on the 2015–2019 commissions was submitted by Prof Doug Stead. While the report was very positive, the lack of participation by the African region was highlighted. South Africa has made significant contributions to the ISRM commissions in the past and SANIRE would like to return to this tradition. Members of the commissions meet at the ISRM International Symposium each year and correspond by email in between. SANIRE will endeavour to raise funding to partially cover the costs of key individuals that would like to attend the 2016 commission meetings in Cappadocia, Turkey (2016-08-29 to 2016-08-31). The 2017 International Symposium (AfriRock 2017) will be hosted in Cape Town, South Africa and SANIRE would like to encourage members to participate then. Please contact William Joughin if you would like to participate in any of the commissions. The following commissions have been approved for 2015–2019:

  1. Application of geophysics to rock engineering
  2. Crustal Stress and Earthquakes
  3. Discontinuous Deformation Analysis (DDA)
  4. Design Methodology
  5. Education
  6. Evolution of Eurocode 7
  7. Grouting
  8. Tunnelling in Hard, Faulted, Water Bearing Rock, with Possible Squeezing or Rock Burst – Lessons Learnt and Recommended Best Practice (previously Hard Rock)
  9. Petroleum Geomechanics
  10. Preservation of Ancient Sites
  11. Radioactive Waste Disposal
  12. Rock Dynamics
  13. Soft Rocks
  14. Subsea Tunnels
  15. Testing Methods
  16. Underground Nuclear Power Plants
  17. Underground Research Laboratory (URL) Networking

Suggested methods

A new suggested method has been approved by the ISRM Board:

  • ISRM Suggested Method for In Situ Microseismic Monitoring of the Fracturing 2 Process in Rock Masses

South African research features in this suggested method.

Online lectures

A new online lecture has been recently presented and is available for viewing or downloading on the ISRM website.

  • 12th ISRM Online lecture: Prof Ove Stephansson. “Rock Stress and Stress Fields”

Rocha medal

Jaco Le Roux’s PhD was submitted for the Rocha medal 2017. Nominations are now closed. The Rocha medal is awarded to the best PhD in Rock Mechanics.

deonInterview questions

Full Name: Deon Louw

Position: Unit Manager – Rock Engineering Beatrix 3#

Company/Organisations: Sibanye Gold

Date and Place of Birth: Born in Bellville, Cape Town, on 4 March 1960

Education: Matriculated at Bothashof, Salisbury (now Harare)

First Job: Learner Official Mining, Buffelsfontein Gold Mine, Genmin

Personal Best Achievement/s: The design and actual early extraction of the Beatrix 3# Shaft pillar

Philosophy of Life: Too much of anything is not good. Live a balanced life.

Favourite Food/Drink: A good Irish whiskey (Here, I ignore my philosophy). I love chicken – braaied or grilled – with Portuguese spice.

Favourite Sport: I work only because my golf is not good enough.

1. How did your career in the mining industry begin and where are you now?

Following the completion of my military service in 1980, I started off at Buffelsfontein Mine as a Learner Official and later became production Shiftboss, mostly at Orangia Shaft. In 1987, a neck injury in rugby forced me to assist the Rock Engineering Dept for 6 months, while I could not go underground. This was the first time that I was really exposed to Rock Engineering and I immediately became very interested in the subject. Shortly after my return to underground, I applied for the position of Strata Control Officer and Joined the RE Dept. I obtained my COM Cert in 1990 and moved to Beatrix mine in the Welkom area in the same year. During the next 10 years, I toured the Welkom Goldfields, working at Oryx Mine, St Helena and back to Beatrix again, working for the same company. (Genmin, Gengold, Gold Fields). In 2002, I joined Brentley, Lucas and Associates, and was based at Bambanani Mine until 2011. It was an interesting 9 years, with Bambanani experiencing serious problems in their orepass systems, and eventually scaling down to a shaft pillar extraction. During this time, I also did a lot of consulting work on smaller diamond mines, as well as at the Afrikander Lease operation in North West. In 2011, I was offered the position of Chief Rock Engineer at Beatrix mine and moved back there, saw the unbundling of Goldfields and the creation of Sibanye Gold, and am still quite happy in my role as Rock Engineer at Beatrix 3#.


“Confidence. You need to show confidence”                            “Confidence sells!”


2. Why did you choose Rock Engineering?

I was very fortunate to be exposed to RE early in my career and to then be able to make the career change to Rock Engineering. It is probably the most interesting, challenging and exciting discipline in the mining industry. No two days are the same, no two problems are the same, and no two people are the same. Every day, there is something new and you keep on learning and gaining experience every day.

3. Please tell us a bit more about your career journey?

Covered in 1.

4. In your opinion, what are some of the challenges that the fraternity is currently facing?

I think our biggest challenge currently is that our design function is under threat. There is a tendency that we shouldn’t design support to suite, but rather to design for the worst case; if one operation utilises a system, it must be implemented throughout, whether it is relevant or not. It is no longer a case of designing out or reducing the risk in the mining of a block ground, but rather that if there is risk, abandon it. We can only overcome this by educating the prescribers and enlightening them in the principles of Rock Engineering.

5. What are some areas that you believe will become of increasing importance in the near future of the rock engineering discipline?

I believe we will be required and that we need to play a much larger role in the ongoing planning of workings. The expertise is no longer there, as it used to be, and once again, we need to coach and educate.

6. What advice would you offer people aspiring to be in your position?

Confidence. You need to show confidence: when you present a plan, or when you motivate a new support system, mining sequence, whatever. Confidence sells! Even if you yourself are not too confident in what you propose, propose it with confidence.

7. Who is your role model/mentor?

I cannot single out one person. There are too many people that I came into contact with in my career who all contributed in my life, whether big or small. Each person has something to offer which will benefit you in some way.

8. What is the best advice you have ever been given?

It’s a golfing tip – Aim high, don’t set a low target because then you will hit the ball low. And it is the same in life, set your goals high.


darrylInterview questions

Full Name: Darryl James Slawson

Position: Senior Rock Engineer

Company/Organisations: Northam Platinum: Booysendal Division

Date and Place of Birth: 13 October 1987, Morningside, Johannesburg

Education: BSc Geology; BSc Hons Environmental Management

First Job: Pharmacy Assistant

Personal Best Achievement/s: Obtaining my Rock Mechanics Ticket

Philosophy of Life: Everything happens for a reason

Favourite Food/Drink: Pasta/Hansa

Favourite Sport: Rugby

1. How did your career in the mining industry begin and where are you now?

I started my mining career at AngloGold Ashanti (Tau Tona Mine) in 2011 as a Rock Engineering MT.

2. Why did you choose Rock Engineering?

Well, I think Rock Engineering chose me …. When I went for an interview at AngloGold Ashanti in 2011, I really had no idea what Rock Engineering was all about. After making it through the second round of interviews and a rather intense psychometric test, I was offered employment at Tau Tona mine. After having done some research about the mine, I automatically felt proud of being an employee of one of the world’s deepest mines. When I started working it was all rather overwhelming, which literally forced me to learn quickly. Within a few weeks of working at Tau Tona, I quickly gained a keen interest in mining and, of course, Rock Engineering. Since then, I’ve always tried to learn and gain as much knowledge as possible. I still have a huge amount to learn and am looking forward to the challenges ahead.

Study … study … study. Take the time to learn from experienced professionals. Never be too scared to ask questions.

3. Please tell us a bit more about your career journey?

My career in Rock Engineering started on the 5th of April 2011 at Tau Tona Mine. Eight months later, I obtained my Strata Control Ticket. In 2013, I then joined Moab Khotsong Mine where I really learnt a huge amount about Rock Engineering from my peers and supervisors, which stood me in good stead for obtaining my Rock Engineering Ticket in 2014. I have currently worked at Northam Platinum: Booysendal Division for the past year as a Senior Rock Engineer.

4. What are some areas that you believe will become of increasing importance in the near future of the rock engineering discipline?

With the current economic climate, and specifically commodity prices, our (Rock Engineering) role in ensuring safe production at the lowest possible cost will become of increasing importance.

5. What advice would you offer people aspiring to be in your position?

Study … study … study. Take the time to learn from experienced professionals. Never be too scared to ask questions.

6. Who is your role model/mentor?

Gary Dukes and Johan Oelofse have had the biggest influence on my career and gave me a huge amount of support and guidance with regard to working towards the Rock Mechanics Ticket.

7. What is the best advice you have ever been given?

Never underestimate yourself ….

histSouth Africa is without doubt one of the best places in the world to study the entire history of the planet. Because of its particular, and perhaps unique, geological environment, situated as it is on one of the oldest and most stable cratons in the whole world, it has exposures of the earliest rocks on the planet, dating back almost to the very first quarter of the Earth’s existence, once the fireball had cooled down. They tell of the break-up of super-continents long before Gondwanaland ever existed – lavas spewed out in the depths of deep, ancient oceans, similar to those currently being extruded along the mid-Atlantic ridge and elsewhere.

South Africa’s not very much younger sediments, their deposition dating back to as much as three billion years ago, not only contain some of the world’s largest repositories of base and precious metals and minerals, but also trace the conversion of the hostile, oxygen-deficient environment of our planet to the more benign environment that we enjoy and that we are busy destroying today, together with evidence of the very first life-forms to appear; life forms that were in fact instrumental in the process of converting the atmospheric and terrestrial environment, paving the way for our own evolution. The exposure of this evidence close to surface was facilitated in part by one of the largest, and certainly the oldest, known meteorite impacts the world has evidence of. All of this evidence of the pre-history of our planet can readily be seen in numerous exposures situated within short walking distances of the centre of Johannesburg.

Admittedly, there then follows a short billion year gap in the South African record, during which time the trilobites ruled the planet and nothing much else happened, until one is once again able to trace the course of history in the sediments of the Karoo sequence, and follow the evolution of fish, plants, insects and reptiles, starting in a frozen wasteland and progressing through the most luxuriant rain-forests the world has ever seen, to arid desert conditions just before the onset of the eventual break-up of the Gondwanaland super-continent into the land masses that we are so familiar with in the southern hemisphere today. Even the conversion of some reptiles into our mammalian ancestors can be witnessed during the latter stages of the life of this super-continent. This entire record, including evidence of the break-up, can be readily traced during a short three-hour drive from the seaside of the Natal coast to the mountains of the Drakensberg range. Nearly 200 million years of pivotal history in space of only a few hours, right here, under our noses!

hist1If this were not enough, our own evolution from apes to something perhaps only slightly more intelligent and upright is traced in the detritus of world-renowned archaeological cave sites dotted around the country. Admittedly, one would perhaps need some form of vehicular transport, like a bicycle, to get to some of these exposures in less than a day from central Johannesburg. Even evidence of our progress in learning to at last be able to harvest the bounty of the seas, which began about 150 000 years ago, and which is not recorded anywhere else in the world, and the world’s oldest decorated tools for creating works of art more than 75 000 years ago, are to be found locally (albeit you might have to catch the train from Johannesburg – assuming that they still run in the new South Africa) in the caves of our Cape coast. We may even have the direct descendants of these ancient people living amongst us today – although, of course, their hunter/gatherer lifestyle is under enormous threat and is likely to disappear, together with the rhino, elephant and other endangered species, in the not too distant future.

Moving on to relatively more recent times, the remains of settlements and of pre-historic and historic tunnelling and mining operations by our ancestors are to be found all over southern Africa, including Johannesburg itself where, for example, stone-age hearths and foundries for the production of ironware are battling to be preserved in some of the koppies surrounding the city.

The history of modern mining in South Africa is inextricably tied up with the more recent history of South Africa itself, or, perhaps more correctly put, the history of the country as a whole since the middle of the nineteenth century, which has been dominated and determined by the history of its mining activities. Although early mining ventures in the colonies, such as the exploitation of copper deposits around Springbok, and even the much later gold rushes of the Barberton and Pilgrims Rest areas, did not have a profound effect on the development of the country, it was the discovery in 1869 of the volcanic source of vast diamond reserves, centred initially around what became the Northern Cape town of Kimberley, which paved the way for the conversion of the country from a rural and pastoral backwater into the industrialised powerhouse of sub-Saharan Africa, and which set the stage for the economic, social and political transformation and expansion of the country. The discovery seventeen years later in 1886 of the world’s largest repository of gold in the conglomerate rocks of the Witwatersrand ridge adjacent to what was to become Johannesburg, one of the largest, richest, and most influential cities on the African continent, sealed its fate and changed the course of the country’s fortunes forever. The exploitation of these deposits, together with the concurrent working of abundant coal seams and the later discovery of other important metal and mineral reserves, has had, and continues to have, an overwhelming effect and fundamental impact on the broad economic environment of the whole of the southern African region, and has profoundly influenced the historical course of events in the sub-continent.

It seems fitting, therefore, that the introduction and development of our rock mechanics discipline in South Africa during the course of the last century should also have played out against this vast and vibrant historical, economic, social, political and mining backdrop.

dave This story was written by Dave Arnold.
Please feel free to contact Dave with any historical stories for the next edition.    


As most anyone in the Bushveld sphere of rock engineering (RE) will know (unless being exposed to the epiphanies of daylight is elusive), a broad-reaching project to equip RE practitioners in risk based support design was initiated through the Mine Health and Safety Council (MHSC), facilitated by SRK Consulting and Open House Management Solutions (OHMS) in 2015. Two phases of the project have been carried out, viz SIM120201 in 2012 and 2013 and SIM140201 in 2014 and 2015. On completion of the programmes, some 100 practitioners in the industry have received training in the technology. These include rock engineers, strata control officers, strata control observers and a limited number of geologists.

The purpose of the project is two-fold:

(i.)            To promote and revive technical research and scientific solutions to rock engineering challenges within the industry; and

(ii.)           Encourage practitioners to apply a risk based approach to support design.

The project is was completed in November 2015.


The first objective is in line with requirements of the Mining Charter which was brought into being in 1996 as a collective assignment between mining stakeholders to promote transformation in the industry. Following on from the 1996 agreement, an addendum in 2002 further required that research outcomes be adopted within the industry to promote skills development and improve performance within the mining industry. In view of flagging attention and committed resources to this kind of output, it is especially encouraging to have had the funding for this initiative.

The second objective is where the programme becomes more meaningful for us as rock engineers. That is: how do we achieve risk based support design in the tabular underground mining environment and what does it actually mean?

Risk based support design

First, we need to understand what the risk based approach actually means and why we should apply it. The risk based approach is essentially a quantified risk assessment of the consequences associated with falls of ground (FoG).

PN1We could ask ourselves, “why not base the support design on the 95% fallout thickness?” Or better yet, using a FoG hazard distribution such as JBlock? These are indeed valid approaches; however, there are distinct limitations. The most obvious limitation is the question, “so what?”, i.e. if a keyblock falls and there is no loss of production and no injury to a person, then does it matter? Or alternatively, what is the potential for a keyblock to result in a significant consequence to the operation? And lastly, what is a significant consequence?

This is where RiskEval is applied, to quantify the consequence of keyblock failure in terms that are meaningful and relevant to the operational decision-making, i.e. personal liability (safety) and cost (finance).

A detailed explanation of the risk evaluation process is not given in this summary; however, for reference, the publications of Joughin et al (SAIMM vol 112, February 2012) can be sourced online from the SAIMM.


Following the first phase of training in 2012 (SIM120201), the format of the second phase (SIM140201) was revised to accommodate an increased number of RE practitioners and promote the completion of each phase before continuing to the next.

Without labouring the training programme, it is worthwhile to mention that practitioners were exposed from all of the major mining houses, including Anglo, Lonmin, Impala, Northam, XStrata, Hernic and Aquarius in both the western and eastern platinum limbs (inset: training venue, Northam Platinum – Booysendal).

RE practitioners engaged in the principal components of the process as follows:

  • Characterisation of the geotechnical setting (joint sets) by structural mapping and processing the results in DIPs and MSExcel
  • Applying the joint set data in JBlock to evaluate a FoG hazard distribution
  • Translating the FoG hazard distribution (JBlock outputs) into a quantified safety and economic risk by applying consequence data to the hazard estimates using RiskEval.


All of the RE practitioners participated in carrying out the risk evaluation process, and several completed reports have been received in which the process has been applied successfully. However, a number of challenges were encountered, both on a technical level and in terms of resource availability and resource capability (software limitations).

pn3Technical challenges

It’s no mystery that the principal focus of operational RE practitioners continues to be diverted to day-to-day troubleshooting of production-related challenges with the result that development of basic skills such as interpretation of joint orientations and manipulation of spreadsheet calculations is frequently compromised.

This became particularly evident during mapping and processing of results obtained using different tools such as clinorules, compasses and electronic measuring devices (EMD, i.e. iPhone or Android or similar). Interpretation of joint orientations may be rotated up to 90° if the practitioner did not have a clear sense of the true underground orientation.

Risk based support design is best carried out by an experienced rock engineering practitioner with a CoMCRM. Constituent elements such as joint mapping and geotechnical data processing using DIPs and JBlock are well-suited to the capabilities of strata control officers (holders of a CoMCSC). However, strata control observers should be coached and trained to correctly collect the required geotechnical (joint set) information. Geologists with an engineering geology background were able to collect and interpret joint set data suitably well, while the construction and interpretation of FoG hazard and risk evaluation was left to the RE practitioners.

pn4Resource availability

Sharing of resources presented somewhat of a challenge during the courses in that several practitioners did not have access to hardware (notebook computers) and software (application licenses). Several operations are in possession of limited software licenses due to the sporadic use of these applications which does not justify the purchase of a license per user. Strategic planning of resources helped in some cases to overcome the resource shortage; however, several operations were unable to secure the necessary software with the outcome that they could not satisfactorily complete the project.

pn5Software limitations

Several limitations within both JBlock and RiskEval were encountered that warrant further development. However, in spite of these limitations, FoG hazard estimations and risk evaluations were successfully carried out using the applications by tailoring the format of input data to suit the structure of the applications. A particular example, is the input of steep-dipping joint sets that “wrap-around” the stereonet plot (inset) with the effect that two distinct joint sets had to be defined in order for JBlock to correctly interpret the variability in dip direction within the joint set.

Going forward

Final results for the project were submitted in November 2015 to the MHSC in a report which is available through the MHSC.

A large body of RE practitioners representing a broad selection of the platinum industry now have the technical tools to provide engineered risk-based solutions for rock engineering challenges on the operations.

pn6Thanks and acknowledgements

In spite of all of the challenges that were encountered, it was truly inspirational to be part of the enthusiasm and willingness with which the RE practitioners engaged in the technology transfer process. Thanks to the facilitators from Impala, Lonmin and Northam for making underground and training sites available, without whom the programme would never have been able to happen. Acknowledgements go the MHSC for funding and the SRK and OHMS teams for presenting and managing the project. Looking forward to continued feedback and suggestions for improvement and applicability of the technology.


Article by Jeanne Walls, SRK Consulting

jacoFull Name:                  Petrus Jacobus (Jaco) Le Roux

Company:                   Brentley, Lucas & Associates

Designation:               Principal Rock Engineer

Qualifications:             N.Dip. Metalliferous Mining, Advanced Certificate in Rock Engineering, Graduates Diploma Engineering (GDE), MSc. Mining Engineering

Contact Details

Telephone:                  0574524405

Facsimile:                   0866105279

Cellular:                      0829299400

E-mail:                         jaco.leroux@harmony.co.za

The South African Council for Natural Scientific Professions (SACNASP) now requires its members to renew their membership every 5 years. Renewal acceptance is based on your continued professional development, measured by the CPD points system. Points are allocated to various professional activities, and the accumulation of the required points will ensure the renewal of your registration. The creation of the CPD culture is to ensure that all registered persons maintain their competence throughout their period of registration.

How it will work?

The allocation of CPD points is based on the system currently in use by ECSA. Once the build-up phase (discussed below) is complete, each member will reapply for registration every five years, when his or her application must be submitted three months prior to membership expiration. During the five-year period, each member must accrue a total of 25 CPD points with no less than three points per year; additional points can be carried over to subsequent years and all accrued points must be submitted on a yearly basis. As per the build-up phase, renewal cycles will depend on your first year of registration.

In November 2015, the COM metalliferous practical for the platinum industry was hosted by the SANIRE Eastern Bushveld Branch at Ivanplats Mine, Mokopane Office. A total of 22 candidates attempted the practical of which 18 attempted the portfolio section, 17 the conventional section, and 11 the bord and pillar section. Overall, it was a successful day and I (Adam Cooper) would like to thank the Ivanplats staff for assisting with the venue arrangements; the Eastern Bushveld Committee for assistance in setting the exams, and especially Andre Esterhuizen for his contribution with respect to candidate applications, and the examiners for their commitment, time and effort.

I would like to congratulate Tati Bantu on obtaining the COM Rock Mechanics Certificate, as well the following people for outstanding achievement in specific sections of the practical examination:

  • Craig Slement – Portfolio
  • Tati Bantu – Portfolio
  • Obed Masinge – Conventional
  • Gordon Rabey – Conventional + Bord and Pillar
  • Omberai Mandingaisa – Bord and Pillar


Adam Cooper

Closing date for Rock Mechanics practical examinations will be 15 January 2016 and NO late entries will be accepted.