Potash deposits worldwide
These potash deposits were created several hundred million years ago, but were only discovered in 1856, when potash salts were found to be embedded in a German rock salt deposit. Extraction of these previously unknown salts began as early as 1861, as these salts’ special qualities as fertilisers became apparent. Until the end of the 20th century potash mining was limited to Germany; but beginning in the 1930s, numerous potash deposits were discovered and mined in Europe and overseas.
Major deposits may mostly be found north of the equator
Experts have assessed worldwide, known potash deposits to have a volume of 210 billion tons K2O (potassium oxide as a measure for potash content) and consider up to 16 billion tons to be recoverable with today’s mining technology. Approximately 60% of the world potash deposits are located in the Canadian province of Saskatchewan; recoverable deposits there amount to nearly 10 billion tons. The second-largest potash deposit is located in Russia (up to 2.2 billion t K2O), followed by up to 1.0 billion t K2O in Belarus. Germany’s deposits with exploitable reserves of up to 0.8 billion t K2O are considered to be the fourth-largest worldwide.
Additional, smaller potash deposits have been developed in the United States, Great Britain, Spain, Brazil, Italy and the Congo, and efforts are under way to begin mining in Argentina, Thailand and Ethiopia. In addition to solid underground deposits, potash may also be present as brine. These brines may be found in subterranean or in aboveground salt lakes. The largest such deposit is the Dead Sea.
Depending on local conditions, development and mining of potash deposits may require significant technical efforts and investments. Due to their characteristically sloped or steep horizons German deposits are particularly demanding.
Particularities of the German deposits
All major solid potash deposits are of marine origin and were formed by the evaporation of seawater. In contrast to the globally prevalent chloride-type potash deposits, German deposits are mainly sulphatic, characterised by additional magnesium sulphate minerals in the crude salt. The oldest currently mined potash deposits formed approximately 350 – 400 million years ago, during the Devon period. These deposits are located in Canada and in Belarus. Deposits in Germany, Great Britain and Russia were formed approximately 250 to 280 million years ago, during the Permian era. The deposits on the Brazilian north coast and on the Congolese west coast of Africa were formed during the Cretaceous era, approximately 120 million years ago. Aged 20 to 40 million years, the deposits in Alsace, in northern Spain and on Sicily are comparatively young.