A seismic innovation
South Africa has some of the world’s deepest mines and richest mineral resources. However, mining at these depths presents risks and hazards that can affect the lives of mine workers and the stability of mines. There are also challenges with regard to mining-related earthquakes and methane gas, and the need to allocate resources to ensure that mines are built more efficiently.
Now, imagine if there was a way of detecting resources at ground level, of mapping the flow of methane gas and structuring a mine before it was even built?
“Mining in South Africa is incredibly interesting,” says Dr Musa Manzi, senior researcher and director of the Wits Seismic Research Centre at the University of the Witwatersrand in Johannesburg. “We have some of the deepest mines in the world that run to depths of 4km to 5km, and the mining itself takes place in a unique environment. As part of my PhD in geophysics, I enrolled in researching 3D reflection seismology to see if it would be possible to visualise a 3D environment of the mine before drilling takes place.”
Reflection seismology is a technology that injects energy into the ground, mapping how it propagates through the surface and when it returns. The way the energy moves provides insight into a variety of features, including where gold and platinum bodies are located at depths of 2km to 4km. It can also identify and locate oil and gas reserves, both onshore and offshore. The potential of this technology and its ability to redefine mining is what drives Manzi and his work.
“Because we mine so deeply, we are prone to hazards such as rock bursts. Nature wants to close the voids that mine workers make. This may trigger mining-related earthquakes that can take lives,” says Manzi. “Rock bursts and methane explosions are risks faced by mine workers on a daily basis. I wanted to save lives, and so, in my PhD I developed a technology that helps mines understand how methane gas migrates underground.
“If you know where the gas comes from and how it travels, then the mining companies can see which areas are prone to the influx and can plan their mining designs better.”
Previous studies that have used a variety of geophysical technologies haven’t been able to precisely locate the buried ore or minimise the risks associated with methane gas and earthquakes. Manzi’s work and research using new techniques, such as mathematical algorithms known as “seismic attributes”, has shown the value of integrating geophysics with mathematics to gain a deeper understanding of the earth’s subsurface.
“We are taking out rock samples, doing stress analyses and using reflection seismology to understand the complexities of the mining environment,” concludes Manzi. “It is all about using the fundamental principles of maths and physics, and applying these to studying the complexities of the earth. We want to stand on the surface and know exactly what is under our feet.”
Manzi’s research has generated more than 22 international peer-reviewed papers and more than 40 peer-reviewed abstract papers. Almost all of these papers have been published in high-profile international geophysics journals. He also collaborates with international researchers and was the first African researcher to win the Best Research Paper published in Geophysics of the Society for Exploration Geophysicists since its introduction in 1960.
His research is innovative and, literally, groundbreaking. It has the potential to save lives and drive the economy of the mining sector.