The Ingula powerhouse caverns and tunnels are being excavated in mudrocks of the Lower Beaufort and Upper Ecca Groups of the Karoo Supergroup. Geotechnical investigations were carried out during the tender and detailed design phases and Gerhard presented the parameters used for the design of the tunnels and caverns.
He described the design methods used and support selection criteria developed for construction of the tunnels, with special attention to:
Gerhard also compared cavern design support pressures and rock support lengths used in the Ingula caverns with those used in other large caverns. He concluded the presentation with a discussion on cavern convergence trigger levels adopted at Ingula and the quality control testing employed during the installation of rockbolts, cable bolts and cable anchors in the powerhouse caverns.
For more information, contact Gerhard on email@example.com
The surface mining industry in South Africa is extremely diverse, with slopes being designed in hard and soft rock environments, soils and even beach sands.
Palaborwa was the steepest and deepest pit in the world at one stage (it has now been surpassed by the copper mines in Chile), Mokgalakwena is currently the largest open pit platinum mine and Sishen mine in the Northern Cape is one of the four largest open pits in the world.
Despite this rich history, there has never been a dedicated surface mining group. Practitioners have tended to meet only informally to discuss issues and share information.
“A group of practitioners representing several mining houses and mining and civil engineering consultancies identified the need for a surface mining branch,” relates branch chairman Glen McGavigan.
“Our main concern was the competency of current practicing surface mining and civil practitioners. The open pit Rock Engineering Certificate has only been in existence since 2008. However, open pit practitioners have been recognised in their own right internationally for many years.”
Many of the concerned practitioners were not members of the South African National Institute of Rock Engineering (Sanire) as there was not a specific focus on surface mining within the institute.
“Sanire is the unifying body for rock engineering practitioners in South Africa and therefore we approached the institute to form a surface mining branch,” Glen explains.
What’s the aim?
The aim of the branch is similar to that of Sanire: to be the voice of surface mining rock engineering/geotechnical practitioners in South Africa.
“We aim to establish a platform where information and knowledge can be shared and where a network of not only surface mining, but all rock engineering, practitioners can be built up,” says Glen.
“Our first priority is to address the competency of current surface mining practitioners. We have proposed a grandfathering and recognition of prior learning process for current practitioners to the Department of Mineral Resources (DMR). This will address the current shortcomings in the Mines Health and Safety Act, which excludes a competency definition for surface mining.”
Other aspects that the branch would like to address are:
An exciting future
There are at least 18 surface mining practitioners in positions of responsibility in South Africa. This excludes neighbouring countries such as Botswana and Namibia and excludes quarrying and civil engineering practitioners.
“We hope to include all practitioners in Southern Africa,” says Glen.
“Members can look forward to technical evenings dedicated, but not limited, to surface mining geotechnical/rock engineering practice. They will enjoy opportunities to engage with open pit geotechnical equipment suppliers and service providers.
“We aim to provide access to a network of specialised surface mining practitioners who can share information and knowledge. On the committee alone, we have more than 90 years’ combined specialist geotechnical experience.”
Through the Sanire website forum, members will have the opportunity to network with surface mining practitioners. They can, for example, liaise with suppliers of slope monitoring equipment and gain guidance as to future technology development.
Where to find the branch
The branch is based in Gauteng and committee members work in Pretoria and Johannesburg.
When the new Sanire council took charge in July this year, they combined the responsibility for the website and the newsletter into one portfolio, Communication.
Geoff Potgieter got out of the starting blocks at full speed and this newsletter is the result. Many readers may have the seen the redesigned website too.
“Thanks to Friedemann Essrich’s initial efforts and the talent and hard work of Bounce Communication and Quba Design and Motion, Sanire boasts a professional website and a brand new electronic newsletter,” says Geoff.
The Council for Scientific and Industrial Research (CSIR) hosted Sanire’s first website. The technology was very new and many of the services available today were yet to be developed.
In 2006, the new webmaster, Stewart Wood, moved the website to ITLogic. Unfortunately the billing and other member administration functions still relied on the CSIR's MSSQL data base. During 2006, many changes were made to the content, with only minor changes to the structure and look.
“When Friedemann took over in 2007, he implemented the first real overhaul of the site. It got a more professional look and contained the first real catalogue of past papers and memorandums,” explains Geoff.
“The site had three versions, or sizes, and although this was standard practice at the time, it limited flexibility. It caused much frustration – most of the members remember the now infamous floating menu. Despite all the problems, traffic to the site kept increasing and the aging technology resulted in problems with migration, access and updating.”
Creating a community
“We hope the new website will create an active online community and a useful online shop. It should also be a valuable resource to learners.
“The newsletter, ROCKtalk, is integral in creating this community. It will feature regular competitions, contributions from the pioneers of some of the things we take for granted, and topical stories. It is also the perfect medium to keep members up to date with reports from council portfolios. The aim is to deliver real benefits for all Sanire members,” concludes Geoff.
Sanire would like to congradulate Oskar Steffen, Luis-Fernando Contreras, Peter Terbrugge and Julian Venter of SRK Consulting on recieving the2009 rock mechanics award in the catagory 'Applied Rock Mechanics Reserch' from The American Rock Mechanics Assosiation (ARMA) for their paper entitled A Risk Evaluation Approach for Pit Slope Design.
Gauteng Branch Technical Evening – 15th October 2009
Sanire Gauteng Branch held its 19th Technical Evening at CSIR Centre for Mining Innovation in Auckland Park. The theme was “The future of Rock Engineering Research in South Africa. Where is it going and what resources do we have?”. Invited speakers were Navin Singh on the Mine Health and Safety Council, Greg More O’Ferrall (now of SRK) on the PlatMine Collaborative Research Program, Prof. Dick Stacey on research from an academic perspective and Dr. Declan Vogt of the CSIR Centre for Mining Innovation.
SANIRE has written a letter to the Chief Inspector of the DMR (Mr. Thabo Gazi) requested to highlight concerns that have been raised regarding the definition of a competent person (rock engineering) in terms of the Mine Health and Safety Act, Act 29 of 1996 (MHSA).
SANIRE has been informed that the Exams have been postponed by one week and now will run from the 26th rather than the 20th.
The SANIRE 2009 symposium “Informative Rock Engineering Practice” was held at the Maccauvlei Conference Centre in Vereeniging on the 18th September 2009. The symposium comprised 15 high quality presentations in from a variety of fields:
The 2009 SANIRE symposium is taking place this week on the 17th and 18th of September. The 17th is a golf day where you can catch up with old friends and relax before the symposium which will be held on Friday the 18th.
The Key note address is by Gerhard Keyter, “The planning and construction of civil engineering tunnels and large caverns with a special focus on geotechnical investigation, design, construction, support installation and quality control.”
For those of you still not registered for the symposium please head over to our downloads section to get a copy of the registration form. If you want to do your bit for the environment please head over to the forums to organize a lift club to and from the event.