Geological subsurface resources like peat, gravel, sand, lignite and other materials are needed for economic development. The shallow extraction of resources (peat and brown coal more in the past, currently still sand, clay and gravel) influence landscapes strongly. Extractions (shallow and deep extraction such as salt) also leave space that can be reused or re-developed. Resource extractions highly influence the soil-sediment-water system and its ability to deliver ecosystem services.
Depletion of many non-renewable natural resources, such as minerals and nutrients, is an increasing problem. Sand and gravel has been used for decades in the construction of buildings and infrastructure. Some resources, such as gravel and good quality building material, have become scarce close to their consumption in cities and have to be transported considerable distances. Promoting the recycling of materials and alternative materials (biomass) can help to guarantee their availability and decrease environmental impacts, but methodology and procedures need to be further developed. As extraction activities are often only temporary, the re-use of land areas is an important issue and can provide new opportunities. Special attention should be given to re-use, re-built, and recycling to come not only to a circular economy but find examples for up-scaling of wasted materials.
Peat is known as a big source of energy and is also used in agriculture and horticulture. But peat is also a sink for CO2 and thus a form of climate mitigation. When used it is a source of CO2 and contributing to climate change. That is why alternative for peat have to be found and establish.
Lignite resources are great especially in the North of Europe but for instance Germany will bail out from the lignite mining. Because of remediation needs in shorter timer and on greater scale (mostly used as open pit mines) there will be a higher need development of effective remediation techniques than before.
Stones, gravel and sand are the most needed materials in the building industry. As far as we have activities in infrastructure development the materials are urgent needed. In some countries new sites to mine gravel and sand have to be developed because the known deposits are either depleted or blocked by conflicting uses.
On the other hand the underground itself is an important resource e.g. for Aquifer thermal energy storage (ATES) and geothermal energy. The relative amount of geothermal energy will develop from 2.2 to 13 per cent from 2010 to 2050 in Europe and the potential is referred to 300 TWh/y for Germany only. In the geological underground, instruments to weigh up underground land-use claims are missing with special attention to geothermal energy, fracking and building activities. Traditional uses of the underground like mining of fossil fuels and minerals and ore mining have to take into account their impacts to the SSW-Complex as well.
Therefore a competition in land use is remarkable between the different use of land and soil. Key questions include:
• Is there a need for more effective restoration measures of landscapes used for excavation of fossil fuels, minerals and ores? How could the energy demand be satisfied with traditional or new techniques by minimizing the impacts?
• How to manage the supply and demand of soil and aggregates in local and regional level through effective and appropriate (re-)use of various types of excavated soil, and organization of temporary storage for classified materials?
• How to advance the recycling of limited mineral and nutrient resources (e.g. through capturing phosphorous from wastewater or landfill mining)?
• What are the opportunities to recycle (C2C) excavated sand, clay, gravel? To what extend will this result in less excavating areas and contributes to circular economy (e.g. use as building material)?
• How to use the high amount of recycling material in a propper (safe and environmentaly good) way?
• How to re-use sediments as secondary resource instead of primary resources?