Ash – POTASH, that is. I first learned about this after driving around the Alsacian countryside and discovering this abandoned mine:
To make matters more interesting, it is located in a small town called Pulversheim,
After a bit of Internet research, it turns out the history is very interesting. Potash was discovered here in 1904 – and at the time, the only other source of potash was in Germany, leading to the Germans having a monopoly on the market. So naturally it was a huge benefit to have a second source. One good source for more information is this site, Les Mines.