Introduction to Marine Mineral Resources

Marine Mineral Resources are metal deposits in the oceans that may become of economic relevance in the near future. At present, almost all of the natural resources that are vital for human life, particularly minerals and metals, are mined on land. However, large high-grade deposits are becoming increasingly difficult to find, driving industry to lower-grade sites where mining has greater environmental impacts or to greater depth. At the same time, the global demand for metals is suspected to rise further due to steady population growth, expected to reach 9.7 billion by the year 2050 (United Nations, 2015), and economic growth of countries such as China, Brazil, and India. The population growth may cause increasing land use conflicts between the mining industry and the need to feed and house the growing population. In addition to the rising demand for metals, geopolitical issues can also limit the availability of metal resources. This was evident over the past years with China blocking export of “rare earth elements” from global markets awakening the media and policy. There is therefore a foreseeable risk of increasing resource supply shortages for metals that are important to the economy. Hence, a number of countries are looking for ways to ensure secure supplies of these critical metals beyond recycling and usage of less raw material. In this rapidly changing global economic landscape, mining in the submerged parts of the continental shelf or in the deep sea is one of the areas of interest not only for commercial entities but also for governments as they have to balance metal supply needs and environmental impacts (Hannington et al., 2017, 2023; Beaulieu et al., 2017; Petersen et al., 2016, 2018).  

The sea is already an important source of mineral raw materials for mankind. Sand and gravel as well as the energy raw materials oil and gas have been mined in the sea for many years. In addition, minerals that have been transported from the hinterland to the coast by erosion have long been extracted from the shallow coastal areas of the oceans. These include, for example, diamonds off the coast of South Africa and Namibia, as well as deposits of tin, titanium, and also gold along the coasts of Africa, Asia, and the Americas. Mining raw materials from the sea is therefore not new. In the future, however, a number of mineral raw materials are likely to be added. For example, there have recently been efforts to extend marine mining of mineral raw materials to the deep sea (deeper than 1000 meters). 

The raw materials to be extracted from the deep sea include manganese nodules, (mostly in water depths beyond 4000 meters), cobalt crusts along the flanks of submarine mountain ranges (mostly between 2500 and 800 meters), and the so-called "massive sulfides" and sulfide muds that form in areas of volcanic activity at plate boundaries in the oceans at water depths between 5000 and 500 meters. All three raw materials are often referred to as renewable resources, but this is misleading because the metals are enriched over a period of millions of years in manganese nodules and cobalt crusts, for example. Even the much faster growing massive sulfides need millennia to reach economically interesting tonnages.

More information on these deposits, and the associated MMR research, can be found in the links below.