No matter what rhetoric is spouted by the grinning German reps at the UN, if Germany has closed down all of their deep "black" coal mines they must know that you cannot reopen them, that coal has gone forever, gravity will win out there.The tunnels, or "gates" need constant maintenance or there's no circulation of air, assuming the ventiltion fans have been kept running, the coal faces will have collapsed and methane (the explosive gas) will seep out from them. Without a pit being worked and maintained daily and forever by teams of colliers, gravity will close it permanantly. You cannot re-open a closed deep mine.