Bingham open pit copper mine in aerial view @ Allen-stock.adobe.com
Copper is mainly mined in open pits, with smaller shares being extracted underground. The main producing countries are Chile, Peru and China. The copper content in the mined ores is generally very low, so the effort required for enrichment is high and resource-intensive.
As copper is used both in electrical cables and as a cathode material in batteries (e.g. vehicle batteries), demand is expected to rise steadily due to the expansion of renewable energies (e.g. off-shore wind farms) and electromobility.
Resource consumption during reprocessing
Since the ores only have a very low copper content of between 0.6 - 0.7%, the resource consumption until copper is available in pure form is enormous. Since the majority of copper ores are mined in open pits, land consumption is high. In addition, a lot of overburden is produced, which is also stored in stockpiles and consumes land. To extract the copper from the ore, a lot of water is needed, which is also mixed with chemicals. Some of the water can be recovered and reused; the remaining water is stored in settling ponds. Smelting the copper ores at high temperatures also consumes high amount of energy.
Copper is an essential element for some living organisms. Nevertheless, too high concentrations can have a harmful effect. For example, inhalation of dust containing copper can cause lung irritation in humans. As with other dusts, the small, respirable particles are particularly critical here. This is particularly relevant for open-pit mining, which often takes place in very dry areas, favoring high dust levels. In addition to copper, the dusts often contain other heavy metals that are toxic to humans and the environment. Copper is very toxic to aquatic organisms from both short-term and long-term exposure.
Wastewater from copper mining also usually contains other toxic heavy metals (e.g., lead) and semimetals (e.g., arsenic) that pollute the environment.
High amounts of CO2 are released during the mining and further processing of copper. The CO2 emissions occur during mining (fuel for machinery), during further processing of the ore and smelting, and for transport. Smelting also produces sulfur dioxide, the emissions of which are largely captured by filters and processed into sulfuric acid.
Mining produces overburden, which is mostly deposited in tailings piles in the vicinity of the extraction sites. It is estimated that approximately 570 t of various residues are produced per ton of copper. Washing the ore also produces water contaminated with process chemicals and heavy metals. In some mining regions, the water is discharged into rivers and causes fish kills.
Copper mining often offers good income opportunities even in remote areas, and leads to the creation of further jobs in other industries. Conflicts occur mainly in countries with weak governance and concern fair pay, working conditions, and occupational health and safety. In some regions, conflicts arise with the local population regarding land and water use or even resettlement.
Entrepreneurial concentration in copper mining is considered to be low. This is advantageous because it means that not only a few companies profit. The value added in mining and processing the ore is good, so that the respective countries benefit, even if no further processing of the copper takes place in the country.
The weighted country risk (reference in German) for the mining countries, into which the indicators of the World Bank are incorporated (Worldwide Governance Indicators), shows a medium risk. This means that there is room for improvement in some producing countries in areas such as political stability, voice and anti-corruption.
For responsible metal production, due diligence in supply chains is becoming increasingly important in the EU. The law requires the documentation or certification of social standards and occupational health and safety, but initially only for companies with more than 3,000 employees. There are numerous initiatives (e.g. for certifications) to improve social and environmental conditions and thus sustainability in copper mining.
Disposal and recycling
Copper can be recycled almost infinitely without any loss of quality. A distinction is made between unmixed scrap, which can simply be melted down and reprocessed, and old scrap, which also contains other materials and from which copper has to be extracted again in complex processes. The share of secondary copper from recycling processes is about 17% worldwide and 41% in Germany. In general, however, it is estimated that 30-80% less energy is required for recycled copper than for virgin copper, depending on the type of processing.
For batteries, there are legal requirements for recycling rates. The European Battery Regulation specifies a recycling rate of 90% for copper in 2027.
How to make the material more sustainable?
In the main applications (e.g. power cables, printed circuit boards) substitution is difficult; in some cases copper can be replaced by aluminum in electrical applications. The recycling rate or recycling processes can be improved, especially for old scrap. However, copper is readily available and many new mining sites can still be developed, which reduces the motivation for recycling.