Ore sludge

Ore sludges are marine raw material deposits in the form of metals on the submarine plate edges .

Occurrence and origin

Ore sludge occurs at the edges of tectonic plates on the ocean floor. In these rift zones, magma rises from the earth's interior. If it comes into contact with the cold deep water, it is quickly cooled and solidified. Metals are leached out of the volcanic rock. Such metals are mainly iron , zinc and copper , but also silver and gold . The ore sludge is deposited on the mid-ocean ridges , which are formed by the constant formation of new rock over the rift zones.

Particularly important deposits are found in the Red Sea , the Horn of Africa, the Sunda Islands , the Galapagos Islands and all mid-ocean ridges.

Degradation and problems

The mining of ore sludge turns out to be problematic from two perspectives - both in terms of economic efficiency and in terms of environmental pollution .

The fact that the ore sludge occurs on the seabed increases the effort and thus the costs of mining (deep-sea trawls, drills) and transport. In addition, there are still sufficient reserves of metals on land so that submarine mining is not yet absolutely necessary.

Furthermore, some of the mining methods cause very massive environmental pollution. Fine particles can get into the gills of fish as a result of turbulence , which can lead to the death of the animals and thus to a disruption of the ecological balance . In addition, toxic heavy metals are released , which also have a negative effect on marine organisms .

These circumstances mean that ore sludge is currently only mined to a small extent. However, they remain a possible alternative to the shrinking reserves on land.