Research mines SA's geological treasures

Professor Gary Stevens looking at the products of melting of the crust that occurred in Limpopo 2.7-billion years ago, when the rocks that are now at the surface were buried below a mountain range as high as the Himalayas. (Jeanne Taylor)

Professor Gary Stevens looking at the products of melting of the crust that occurred in Limpopo 2.7-billion years ago, when the rocks that are now at the surface were buried below a mountain range as high as the Himalayas. (Jeanne Taylor)

Gaining a deeper understanding of geological forces and formation is the basis of two Research Chairs that hold tremendous value for South Africa’s extractive industries.

Professor Gary Stevens at Stellenbosch University is involved in the study of geological formation under the Chair in Experimental Petrology. The work of the Chair relates primarily to understanding the processes that occur underground at extreme pressures and temperatures to produce mineral-bearing rock.

Given the importance of mining to South Africa, this work is particularly important to help in building a better understanding of how high temperature deposits of platinum, gold, base metals and diamonds form.

The underground conditions are replicated by experimental means in a laboratory where the high pressures and temperatures that occur below the Earth’s surface can be replicated, to gain understanding of what occurs and how this knowledge can be used by geologists.

“Ours is the only laboratory of its kind on the continent, providing a unique opportunity for Master’s and Doctoral students to participate in this highly specialised field of research,” says Stevens.

Developing these high-level skills is crucial to the mining industry, with the SARChI Chair also playing a significant role in exposing students to the international research community.

While most of the graduates enter the industry, a number have gone on to make even greater contributions in the field, by securing prestigious post-doctoral fellowships at universities abroad.

The impact on the mining industry is considerable, as the Chair’s work presents more accurate models of how underground processes occur, enabling exploration and mining geologists to more accurately understand how the deposits they seek and mine are formed.

Another area of his research is exploring the unique and ancient rock formations in Mpumalanga and Limpopo, as well as Swaziland, dating back as far as 3.5-billion years ago. These areas contain possibly the best preserved rock record on Earth, documenting the formation and evolution of the first continental crust. The research work around these formations is significant because the formations are part of the country’s unique natural heritage and the research focuses on an area of science that has huge international interest. Successful research in this area greatly enhances South Africa’s international scientific status.

A related area of study is that of Professor Ray Durrheim, who heads the Research Chair in Exploration, Earthquake and Mining Seismology at the University of the Witwatersrand (Wits).

He is less interested in the stresses and pressures that form rocks than in geologic phenomena such as earthquakes and fault formation. This is of particular significance to the mining industry given the potential for seismic events due to deep-level mining, which pose a significant risk to workers in deep gold and platinum mines.

He combines his research work through Wits with his role as principal geophysicist at the Natural Resources and Environment Unit of the Council for Scientific and Industrial Research.

The research is concerned with not only the causes of events such as earthquakes, but also the hazards they pose. This knowledge is naturally of great interest to the mining sector, considering the threat to underground workers, but can also be used to plan the positioning of facilities such as nuclear plants and waste disposal sites. The knowledge will also be useful in understanding the risks of locating settlements near or around mines that are no longer operational. His research also involves the use of seismic waves to explore for mineral, oil and gas deposits.

Durrheim has established a number of international collaborations, with close relations built with Japanese scientists who are trying to build more robust early-warning systems.

Another outcome from this work is the establishment of the AfricaArray research and capacity-building programme, which includes a network of 51 geophysical observation stations that span sub-Saharan Africa and collect data that is used to investigate phenomena such as the splitting of the continent along the East Africa Rift System and assess the hazards of and mitigate risks from earthquake activity.