Potash is a term used to denote a variety of mined and manufactured water-soluble salts of potassium and particularly potassium chloride, KCl (sometimes called Sylvite) and potassium sulphate, K2SO4. The extraction of potash has been a major industry of that part of Germany west of Magdeburg and east of the Harz Mountains since the mid-19th century.
Some of the best monuments of the industry are at Bleicherode, a town of less than 7,000 people with a rich heritage of timber framed-buildings, in the southern Harz on the River Wipper, 17 km south-west of Nordhausen. Deposits of potash were recognised in the vicinity in 1888, mining began in 1899, a Gluckauf miners’ association was formed in 1901, and a processing plant and a generating station to supply it with power were operational from 1903. The Bleicherode mines pioneered methods of backfilling excavated area with slurry from 1908, but mining nevertheless created huge cavities that were of great importance during the Second World War.
Treasures from the great museums in Berlin were stored there, and in the latter part of the war a huge armaments manufacturing capacity, largely manned by prisoners of war and forced labourers from Eastern Europe was set up. Some of the workings were 600 m below ground level, and thus safe from bombing attack, but the corrosive effects of salt in the atmosphere made precision engineering difficult, and the tunnels between caverns, some no more than 1.5 m wide, made it difficult to make connections between workshops. After the RAF raid on the rocket-making centre at Peenemunde in East Prussia on 17-18 August 1943, some of its facilities were moved to Bleicherode, and most of its scientists, led by the pioneer of rocket science, Dr Wernher von Braun, were there in the early months of 1945. The district was first occupied by the United States army who in due course ceded it to USSR forces. While von Braun went to the United States, the Russian authorities brought together at Bleicherode large numbers of German rocket specialists, but in 1947 transferred all the work to distant parts of the USSR, where the research was ultimately applied to the rockets that launched the Sputnik in 1957.
The potash mines closed in 1990, and parts of the mines and the processing complex have been declared industrial monuments.