INAUGURAL ADDRESS: PROF DF MALAN RESEARCH IN ROCK ENGINEERING PAVES THE WAY FOR SUSTAINABILITY IN THE MINING SECTOR To mark his promotion to full professor, Prof Francois Malan discussed rock engineering research as a prerequisite for sustainability and growth in the mining sector during his inaugural address. South Africa has a proud history of mining. In 2020, it contributed R361.6 billion to the country’s GDP and employed 451 427 people. The country’s huge mineral endowment is ranked very highly globally in terms of Platinum Group Metals (PGM), chrome and manganese reserves. This, however, represents a decline in terms of contribution to GDP, gold production and employment relative to the situation a decade ago. Prof Malan believes that rock engineering research can help turn this situation around, paving the way for sustainability and growth in the mining sector. As a discipline in which Prof Malan is a renowned specialist, rock engineering examines the mechanical behaviour of rock in relation to the physical environment. It also focuses on methods to determine the strength of underground pillars, and hence ensure the safety of mineworkers. According to Prof Malan, South Africa’s economically viable underground ore bodies have a unique tabular structure. It has long been acknowledged that no other mining region of economic significance has ore bodies of a similar geometry, and no country outside South Africa can find a solution to this problem. Home-grown research is therefore essential to understand and improve the exploitation of the country’s mineral reserves. Prof Malan’s areas of research expertise include numerical modelling, pillar behaviour and mine design criteria. His current research interests include the inelastic numerical modelling of tabular excavations, and simulating pillar behaviour and pillar strength. He is currently exploring the use of a limit equilibrium model to approximate the timedependent relationship between reefs’ normal stress and parallel stress components. This research emanated from the realisation that time-dependency could not be simulated using elastic theory, and even earlier attempts to simulate the fracture zone with viscoelastic theory only proved to be partially successful. Using the limit equilibrium model, Prof Malan was able to simulate closure data, which provided a much better approximation of actual underground closure. This method allows for the simulation of mining increment size and mining rate. However, it is difficult to calibrate the large number of parameters using this model. This highlights the need for ongoing closure monitoring in underground slopes. An important element of Prof Malan’s work is the development of a pillar strength formula that will be effective in South Africa’s bord and pillar mines as the depth increases. Several other studies are being undertaken by the Department’s Rock Engineering Research Group in close collaboration with industry stakeholders.
DEPARTMENT OF MINING ENGINEERING
“Everything we depend on in our daily lives is either made from minerals or relies on minerals for its production. Future innovations would not be possible without the support of the mining industry. From renewable energy to electric vehicles and commercial space travel, none of these initiatives would be viable without an increased source of materials, which need to be mined.”
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ANNUAL REVIEW 2020/21
