Mapping for safety and economic growth

Dr Taufeeq Dhansay, Manager of the Minerals and Energy Geoscience Mapping Programme, explains how important geoscientific mapping can be for every aspect of society and gives a progress report on the Council for Geoscience’s carbon capture research.

In recent mapping, what have you found in Mpumalanga?

Mpumalanga is very rich is terms of its geological variety. You find some of the earth’s oldest rocks that tell you about how the earth evolved and formed. Many international scientists visit the province to investigate these rocks, some that are more than four-billion years old. You also find some of the youngest rocks, so that variety from the oldest to youngest means that you have the entire history of the earth’s processes within the province. Some of these processes include how various minerals systems formed and evolved.

This implies that it is a very rich province in terms of its natural resources. This includes, coal, gold, platinum and other types of critical minerals that are needed to sustain future energy like renewable resources and batteries.

Now we are looking at integrated research. What happens as we shift away from coal in the province? Does it mean that the coal was the only drawcard of the province in terms of its economy? We are finding that the answer is no.

Is coal the province’s only resource?

Biography

After earning a bachelor’s degree in Geosciences from the University of Cape Town, Taufeeq spent time at the International Institute for Applied Systems Analysis in Austria on his way to a Master’s, where his focus was geothermal energy. Another overseas experience was at the Structural Geology and Tectonics Research Group at Jena University in Germany. Nelson Mandela University awarded Taufeeq a PhD in Geosciences in 2017.

There are other mineral resources that can also be looked at. That is a primary focus at the moment. More than two thirds of the province’s economy is now reliant on coal so this brings into context the idea of the just transition.

We are asking what geoscience can tell us about a transition in terms of sustainability.

Coexistence between mining and agriculture only happens if you understand the geology. We have to maintain the integrity of the groundwater in such a way that you can have mining and agriculture existing perfectly in harmony. We are finding that this is possible. Secondly, if you can identify an area where you might find a fossil fuel on the surface like coal, then you can dig a bit deeper and find gas. Deeper still and you might find gold. That means that in terms of the valuation and the investment potential, the land is looked at differently, both for the GDP and for the sustainability of life in the province.

If you draw a cross-section through Mpumalanga, within the top four kilometres we have found a number of mineral resources and natural resources such as groundwater. Secondly, this is a good natural laboratory where you can study and look into the issue of sustainability.

Mpumalanga is also the site of your Carbon Capture Utilisation Storage (CCUS) project. How is that progressing?

Mpumalanga has the highest CO2 emissions in the country, which is no surprise because this is where we have the bulk of the coal-fired energy plants.

We were challenged as scientists to look at the issue. We have to transition towards a low-carbon economy. This is known. If tomorrow you had to turn off coal what would happen to the 150 000 people directly employed by the coal industry? The challenge is how to manage this transition in a way that actually enables sustainability. This is where the just transition comes in.

The problem is CO2, carbon dioxide. Technologies exist where you can capture the carbon dioxide. You do not release the carbon dioxide into the atmosphere. Carbon dioxide has many uses. There are a number of things that you can do with the carbon dioxide. Many industrial processes require carbon dioxide: we drink sparkling water, we drink fizzy cooldrinks. Those products use carbon dioxide, for example.

We had assumed that South Africa’s larger storage potential for carbon dioxide was generally near-shore, so we were looking at coastal provinces and offshore. That’s because the relevant rocks are very spongy, or absorbent of CO2. Now we have gone back to Mpumalanga and we have looked underground to find if there are additional geological areas where you can viably and safely store the CO2. This is what we have found. We have recently published a paper that shows these rocks could very likely support the injection and sequestration of CO2.

Would the gas disappear or would it stay there forever?

The idea would be that we take the gas and convert it into a solid. When CO2 reacts with certain metals, it forms a new mineral that just has the carbon incorporated. By the way, this actually happens in nature. We stop the gas from going into the atmosphere, and put it in the ground. It reacts naturally with other types of minerals which are very reactive and then it forms a new mineral and it stays in the ground forever. That is the principle.

How far advanced are you along that road?

The first step is that we have identified the potential reservoirs. Everything comes down to making this financially viable so it is important to mention that these areas are below the current coal fields. You would not need to transport the CO2 very far to be stored.

The type of storage is quite critical. At a depth of about 1km you find saline aquifers. That holds the type of water that you can’t necessarily use for anything. If you pump the CO2 into that salty water, the CO2 slowly reacts with the salt in the water but it can take up to thousands of years before the CO2 becomes immobile. However, if you store the CO2 in the type of rocks that we are looking at, that reaction can theoretically happen much quicker. The sooner you convert the gaseous CO2 into a solid CO2, the sooner it is rendered immobile. Then it cannot move around and get back into the atmosphere.

What effect would these processes have on the environment?

A lot of our work so far has been specifically on environmental monitoring. This is a critical point. Before we actually develop this technology, we are doing a significant amount of environmental research to make sure that we can understand the baseline environmental conditions on the ground.

We want to get a footprint of the area – the flora, the fauna, the chemistry of the groundwater, the amount of groundwater there is – all of that information.

Are CGS staff excited about the CCUS project?

Yes. It is a very big project. The principle is that it’s a challenge. There are a lot of different opinions around the transition. Some say we are not moving fast enough. Others say we are moving too fast. This is the nice thing about being pragmatic – a fundamental scientist if you like – being practical and finding solutions that will be sustainable.

Our technology for renewables is still developing; we are not there entirely yet. It’s a big challenge and we need to buy ourselves some time. For the first time in a long time, the issue is being looked at directly by scientists, not necessarily only by policymakers. We have to guide them, we need to show what is possible, scientifically and empirically. How do you present empirical data that has passed peer review? That is the principle that we are focusing on.

The carbon capture project is a large, integrated project. The project is funded both by the South African Government and the World Bank and the entire project budget is about $23-million.

We have to be very unbiased in terms of the type of research we do. We will be doing full Environmental and Social Impact Assessments (ESIAs) before we do any type of sub-surface investigation. Our data portal is available to the public online.

At the CGS you will find somebody who is working on hydrogeology, while another person is an environmental geologist, who might be interested in what this is going to do for the environment.

What is the nature of new mapping CGS is doing?

The first thing to touch on is that what we are doing is very much geoscientific mapping, not just geological. The second thing is that the scale is very important. We have generally mapped to a scale of 1:250 000, so that means if a hill is less than 250 metres, it will not appear on the geological map. We have shifted to the 1:50 000 scale. South Africa was only covered to 4% in terms of 1:50 000-scale maps. After about five years, we are now moving up to a figure of 12%.

People often think that mapping is for minerals only. What other functions does it have?

We have not exclusively focused on minerals. We’ve been able to identify certain zones and certain geological features where specific types of geohazards are concentrated. We are researching that further to mitigate possible natural disasters or loss of human life.

The recent landslides in KwaZulu-Natal are an example. Many of the landslides are due to specific geomorphology and geological controls. If we don’t have the map resolution required, we can’t necessarily create the necessary mitigation scenarios. The same is true in Gauteng. A large portion of Gauteng is built on dolomite, the type of rock that forms sinkholes. The state spends a lot of money on infrastructural development and the risks can be mitigated if we understand the geology.

There are many areas in the country where the dams are not efficient in supporting farming, so we look at groundwater resources. To understand those resources, you need to understand the geology of very specific structures, essentially pathways that allow the water to flow. The other aspect that is not necessarily being considered is the surface of the earth. This is where all of our food comes from. In areas where we want agricultural sustainability, you need to understand the geology of those areas. Similarly, you cannot build a large solar plant on soil that might sustain agriculture. We want to avoid sterilising the ground and ruling out the possibilities of groundwater or minerals.

Tell us more about groundwater.

We have been very successful in identifying significant groundwater resources, especially in the Karoo. We have been able to find, test and research many groundwater aquifers that can sustain groundwater resources in those areas.

And what are the new maps showing in terms of mineral resources?

We have focused on specific areas where we anticipate there to be some investment in exploration. Some of the mineral resources we are also looking at in terms of our developmental needs. We have to look for the type of minerals needed to sustain renewable energy, including batteries.

A number of mineral resources can support battery development. Specifically, mobile devices have lithium ion batteries and some of our mapping has discovered that South Africa has quite a significant quantity of lithium that can possibly be extracted and researched.

Where is lithium found?

It is mostly in the Northern Cape and it is also found in KwaZulu-Natal. We also found lots of vanadium, which is a critical metal needed for larger-format batteries. So mapping goes far beyond mining, it’s vital to every aspect of the economy.

Development hinges on earth science. We need to understand the earth. When we map, we try as hard as possible to look as deep as possible. Humans generally interact with the top five kilometres of the earth. We have gold mines that touch four kilometres. If you go to any province the geology you see just below your feet is not necessarily the geology that you will see at a kilometre below your feet. The Karoo might be dry but if you had to go down several hundred meters you would find significant natural resources to sustain socioeconomic development, such as water and minerals. ■