Glück auf
Glückauf (alternative spelling Glück auf; also, as an exclamation: Glück auf!) is the traditional German miners' greeting. It describes the hope of the miners: "es mögen sich Erzgänge auftun" ("may lodes [of ore] be opened") which is short for "Ich wünsche Dir Glück, tu einen neuen Gang auf" ("I wish you luck, open a new lode"), because, when mining for ore, without prospecting, no-one could predict with certainty whether the miners' work would lead to a reward. The greeting also expressed the desire that miners would return safely from the mine after their shift.
Today it is still a common form of greeting in the Ore Mountains region of eastern Germany and in the Ruhr area, specifically Bochum, which is home to the German Mining Museum (Deutsches Bergbau-Museum).