potassium A visit or working day into the potash mine of K +S KALI in Merkers always ends with the ‘Glück auf’ greeting (‘so glad to be up again’) greeting. After having been down 800 metres, it may not be such a bad idea to think about this potash mine. We also went down recently into the deep German potash mines to see where the quality mineral – so valuable for potato growing – lies hidden and how it is extracted. Fortunately, our descent was also followed by our ascent again. The breaker makes short shrift of the large rocks and grinds them into transportable grit. approximately 4.5 hour’s drive from our cathedral city of Utrecht. Potassium chloride has been extracted from the deep layers of the earth here for over a hundred years now. K+S is the owner of this enormous mine near Merkers. You can see the high entrance of the lift shaft from miles away. It is here that the miners are taken down to a space 540 metres deep in the ground. It is in this space that the working day of every miner starts. Not, as in coal mines, in stuffy, dark and blackdusted rooms, but in spacious corridors where you can drive around in big pickup trucks or small lorries. The dust swirling around the mine is even good for the lungs, according to our German guide Herr Golle. ‘We don’t have dust lungs here, as was often the case in coal mines.’ And driving around the mines can take you at least a few weeks, if you wish to see all the corridors. With a maximum speed of 20 miles an hour, we are rushing along, as it seems in the dark, through the system of corridors that has a total length of more than 2,800 miles. ‘That is eight times up and down from Berlin to Munich’ says the guide, who mostly takes German visitors around apparently. A Dutch example then: ten times up and down from Maastricht to Den Helder. T Millions of years ago There are various theories circulating that are supposed to explain the origin of the potash mines. The most plausible explanation is that the salt layers must have formed 200 million years ago in an enormous inland salt sea. Like a pot on a stove, the water very slowly evaporated over many millions of years leaving the salt behind. Even today there are still inland salt seas, the Dead Sea in Israel, for example. Over the many millions of years, earth slides have pushed the salt layers up in some places and down in others. That is clearly noticeable when we drive around in the dark corridors. One moment our car goes steeply down, and the next moment we go steeply up again. After a 15-minute drive, we arrive at the active mining area. Enormous shovels are in the process of lifting big chunks of potassium chloride. These chunks are the result of dynamite explosions 7 metres deep in the hard potash wall. Each explosion loosens about 350 tons of potassium chloride in big chunks. The shovel can move 17 tons of this debris in one go. If you would want to fill a potato trailer with this machine, you could do it in two goes. These shovels move the potassium chloride into one enormous mountain near an impressive breaker. This machine makes short shrift of the enormous lumps and grinds them into transportable pieces. Via long conveyor belts, the finely-ground potassium chloride is taken to the plant to be processed. There is a total of 160 km of conveyor belts underground. Once arrived inside the plant, the potassium chloride is subjected to a number of processes resulting in various wellknown potash products: Potash-60, Korn-Potash and Potassium Sulphate. After having observed the impressive spectacle of the miners and their machinery, together with the he German village of Merkers, in former East Germany, lies Potato World 2009 • number 2 19 Pagina 18
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