An open pit coal mine in Germany?????? WTH?
It is SLATED to become and OPEN PIT but has not yet been so designated.
Right now is is merely some "Sort" of a pit, mine shaft, open hole or simple an excavation.
Remember that Bureaucrats twist and turn in their descriptions of things and in the process, their legal jargon just confuses the actual issue. If only they just use clear, concise wording and not legal jargon.
I "suspect" that it is merely a cave where our cave dwelling ancestors lived and often buried their dead. Germany has many such caves.