Mr. Walther, one of the most important topics right now at the World Climate Conference in Glasgow is the reduction of CO2. What can Xella do to improve the extraction of sand, an important raw material for autoclaved aerated concrete and calcium silicate units?

Because we cannot do without this raw material, we naturally work as CO2-efficiently as possible. This starts with the transport routes, which we keep short. But we don't accept the idea of buying the material at a lower price somewhere else, even though the CO2 footprint would be much higher. Instead, we extract raw materials responsibly on site and recultivate our pits. We also want future generations to find a usable, diverse natural environment.

However, digging a pit into the landscape remains a major intervention in nature. How does Xella ensure that plants and animals are not damaged in the long term?

By thinking about the recultivation of a new pit from the very first consideration and throughout all project phases.

What does that mean for flora and wildlife?

You can see this, for example, in the case of the sand martins. They nest in the excavation walls of the pits, which is why mining is stopped in these areas during the breeding season. They are also closed to the passage of vehicles.  With these swallows, species protection is clearly visible to people. But it's just as important in the places that don't immediately come to mind, such as puddles. In the wet areas of pits and on muddy passageways, amphibians spawn. To protect them, we temporarily close such passages.

Or let's take reeds: We allow them to spread in the pits. Animals then settle there very quickly. They find shelter in the reeds and in the bushes, even in "carelessly thrown up piles of stones" or "rootstocks lying around the edges". In addition, pits are closed to visitors and there are neither walkers nor dogs. Animals appreciate this peace and quiet. Endangered plant species often settle on free nutrient-poor sandy areas. People often think: what a barren landscape. But some species need exactly that.

Another example are pine forests. When we have removed the sand deposited underneath, we do not simply plant another monoculture. By also planting new tree species in consultation with the landowners, we make  this forest more stable for climate change at the same time.

And what does a recultivated pit look like after many years?

It is almost always richer in species than before. Twenty years ago, we already planted hundreds of metres of multi-rowed and, above all, varied hedges with individual trees in and around the sand pit of our Loosdorf Ytong plant in Austria. Today, they are breeding grounds and retreats for many animals and also for plants. From the outside, these hedges are also a visual screen into the pit. From the inside out, they serve as noise, sand and dust traps. We do this out of conviction and because we think it is important that the mine operation disturbs local residents as little as possible. The successful recultivation of an existing pit is also a good reference for Xella.

What is important to you beyond this practical nature conservation?

We must help to use deposits as fully as possible in principle. For example, the sand we need is often deposited together with gravel over a coal seam. The industry must also use this sand, just like the gravel, wherever possible. Coal is still being mined in some areas and the sites will be excavated in a few years. That's why it must be the endeavor of everyone involved in a mine not to dispose of such valuable raw materials in a dump, but to produce new usable products from all the material mined. For Xella, this means that we also purchase sand from suppliers who extract and process it in the run-up to opencast lignite mines – that is, the area that is subsequently dredged over. These pits "migrate" with the opencast mines.

Sand mining is subject to strict regulations and standardized processes, not just in Germany. How much flexibility does that give Xella?

Plenty! Because we not only do the minimum required by law to protect nature, but we also look for all options that are realistically feasible beyond that. However, we can only do this just as realistically where we are directly responsible for the pits. Many of our plants buy the sand they need from external suppliers.  We then work towards ensuring that the same or similar standards apply there.

You are very committed to protecting nature. What motivates you to work for sustainable and CO2-friendly sand mining at Xella?

As a mineralogist and geologist, I want to make the mining of raw materials as environmentally friendly as possible. But I also know that we humans depend on the extraction of raw materials and that we thus temporarily restrict nature. At Xella, we are constantly looking for new options minimizing these restrictions and optimally recultivating the landscape we can have an impact on. It's great to know that we can use raw materials and protect nature at the same time.