Observational Study to Mitigate Seismic Risks in Mines:a New Japanese - South African Collaborative Project

Durrheim, RJ; Ogasawara, Hiroshi; Nakatani, Masao; Yabe, Yasuo; Milev, A.; Cichowicz, Artur; Kawakata, Hironori; Moriya, Hideshige

doi:10.3997/2214-4609-pdb.241.durrheim_paper1

Cited by 4 publications

(7 citation statements)

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“…Firstly, we believe that there is scope to improve our knowledge of the dynamic response of the hangingwall and the stope. A project initiated in 2010, 'Observational studies to mitigate seismic risk in mines' (Durrheim et al, 2010;2012), seeks to do just this. While it is likely that dynamic phenomena are highly variable, it may be possible to constrain certain parameters.…”

Section: Resultsmentioning

confidence: 99%

Functional specifications for in-stope support based on seismic and rockburst observations in South African mines

Durrheim¹

2012

Proceedings of the Sixth International Seminar on Deep and High Stress Mining

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Rockbursts pose a significant risk to workers in deep gold and platinum mines in South Africa. In-stope support systems are one of the measures used to mitigate the risk. Over the last two decades several new technologies have been introduced, such as prestressed elongates, roofbolts and nets. However, seismic theory and observations present several characteristics of seismically-induced ground motion that are not taken explicitly into account in the functional specifications for support design, i.e. multi-cyclic shaking, shear motion between hanging-and footwall, transient tensile forces, and structural resonances. Investigations of rockburst damage were reviewed to evaluate the significance of these phenomena. Similar phenomena affect surface structures exposed to earthquake-induced shaking, and earthquake engineers have developed a range of solutions to mitigate damage. These solutions are reviewed to evaluate whether the principles of earthquake-resistant design can be adapted to the underground environment. Finally, functional specifications for rockburst-resistant in-stope support are proposed. Over the last two decades, new types of prestressed yielding props and packs, in-stope roofbolts and nets have been introduced. However, the risk posed by rockbursts has not been eliminated, and efforts to improve the effectiveness of support systems continue. A first attempt to apply the techniques used by earthquake engineers to the design of rockburst-resistant excavations was made by Durrheim et al. (1998a). The work was extended by Hagan et al. (1999), Milev et al. (2002) and Cichowicz et al.

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Section: Resultsmentioning

confidence: 99%

Functional specifications for in-stope support based on seismic and rockburst observations in South African mines

Durrheim¹

2012

Proceedings of the Sixth International Seminar on Deep and High Stress Mining

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“…A five year Japan-South Africa collaborative project (~USD 3 m) entitled 'Observational studies in South African mines to mitigate seismic risks' was launched in August 2010 under the auspices of the JST-JICA Science and Technology Research Partnership for Sustainable Development (SATREPS) (Ogasawara et al 2009;Durrheim et al 2010). The project draws on over a century of studies of mining-related and tectonic earthquakes by South African and Japanese researchers, respectively (Durrheim 2010;Utsu 2003).…”

Section: Observational Studies In South African Mines To Mitigate Seimentioning

confidence: 99%

Has research and development contributed to improvements in safety and profitability of deep South African mines?

Durrheim¹

2014

Proceedings of the International Conference on Deep and High Stress Mining

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The remarkably rich and persistent gold and platinum deposits in South Africa stimulated the development of a deep mining industry. The challenges of mining laterally-extensive orebodies at depths as great as 4 km include high rock stress and temperature, and large vertical and horizontal distances over which personnel, materials and rock must be transported. Innovation was driven by entrepreneurial zeal, private-public partnerships, government regulation, and labour activism. Despite the development and widespread implementation of many technologies critical to successful deep mining, there has been a major decline in domestic research and development (R&D) activity and capacity during the past two decades. Nevertheless, there are some areas of research where South African researchers continue to break new ground, notably the application of reflection seismology in the hard rock environment, studies of rockburst mechanisms, and the development of systems to monitor the underground environment. Changes in the social, economic and political landscape since the advent of democracy in South Africa in 1994 have also had a major impact on the deep mining industry, and will most likely accelerate efforts to increase the level of mechanisation and automation. This paper briefly reviews the history of innovation in the South African deep mining industry, discusses current initiatives, and seeks to assess the contribution made by R&D and to forecast future trends. 2 Deep mining in South Africa Gold was discovered in quartz pebble conglomerates that crop out in present-day Johannesburg in 1886 (Viljoen & Reimold 1999). Since then, the Witwatersrand Basin has produced almost one third of the gold ever mined (Handley 2004), and arguably still contains over half of the world's identified remaining gold resources. The conglomerates were deposited in an Archaean sedimentary basin, and were subsequently covered by younger strata. Magnetic and gravity surveys were used to trace the orebodies (locally known as reefs) beneath the cover rocks, and new gold fields were discovered in the East Rand in 1914, the Far https://papers.acg.uwa.edu.au/p/1410_0.2_Durrheim/ Has research and development contributed to improvements in safety and profitability of RJ Durrheim deep South African mines? 24 Deep Mining 2014, Sudbury, Canada West Rand and Klerksdorp districts in 1937, the Free State province in 1946, and the Kinross district in 1955. The reefs persist to great depths, bringing about many challenges; notably increases in rock stress and temperature, and the distances over which personnel, materials and rock must be transported. Deep gold mining poses many safety and health risks to mine workers, including falls of ground and heat stroke. Mining-induced seismicity and its hazardous manifestation, rockbursts, were first encountered in the early 1900s when extensive stopes, supported solely by small reef pillars, reached depths of several hundred metres. These problems required innovative solutions, the success of which has enabled mining ...

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“…Data from these projects will be augmented with data from the mine-wide seismic network data and stress modelling in collaboration with the mine rock engineers. It is also planned to monitor ground motion in stopes and on the surface (Durrheim et al, 2010). This equipment will be installed in 2012.…”

Section: Scope Of Researchmentioning

confidence: 99%

“…in Japan) and elsewhere. A five year Japan-South Africa collaborative project (~US$3 million) entitled 'Observational studies to mitigate seismic risks in mines' (Ogasawara et al, 2009a) was launched in August 2010 (Durrheim et al, 2010). The project has three main aims, summarised in Figure 1: 1.…”

Section: Introductionmentioning

confidence: 99%

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Establishment of SATREPS experimental sites in South African gold mines to monitor phenomena associated with earthquake nucleation and rupture

Durrheim¹,

Ogasawara²,

Nakatani³

et al. 2012

Proceedings of the Sixth International Seminar on Deep and High Stress Mining

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Mining-induced earthquakes pose a risk to workers in deep mines, while natural earthquakes pose a risk to everywhere, but especially near plate boundaries. A five year Japanese-South African collaborative project entitled 'Observational studies to mitigate seismic risks in mines' commenced in August 2010. Here we report on the achievements of the first 18 months of the project. Faults at Ezulwini, Moab-Khotsong and Driefontein gold mines considered likely to become seismically active during mining activity were modelled using pre-existing geological information supplemented by cores and camera images from new boreholes. As of 30 January 2012, about 90% of about 70 planned boreholes totalling more than 2 km in length had been drilled at project sites to locate fault zones accurately and to deploy sensors. Acoustic emission sensors, accelerometers, strainmeters, and controlled seismic sources were installed to monitor the deformation of the rock mass, the accumulation of damage during the earthquake preparation phase, and changes in stress produced by the propagation of the rupture front. The suite of sensors has greater sensitivity and dynamic range than those typically used in civil or mining engineering applications, making it possible to record very small changes in stress and strain as well as violent rock mass deformation associated with large seismic events. These data sets will be integrated with measurements of stope closure, strong ground motion in stopes, and seismic data recorded by the mine-wide network.

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Observational Study to Mitigate Seismic Risks in Mines:a New Japanese - South African Collaborative Project

Cited by 4 publications

References 6 publications

Functional specifications for in-stope support based on seismic and rockburst observations in South African mines

Functional specifications for in-stope support based on seismic and rockburst observations in South African mines

Has research and development contributed to improvements in safety and profitability of deep South African mines?

Establishment of SATREPS experimental sites in South African gold mines to monitor phenomena associated with earthquake nucleation and rupture

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