Exploitation of the mechanical energy of the rock

[Obamot]

... is there still one who wants to make "The eel under rock?" Or we can close the mine

[chatelot16]

bin voila speaking of mine! descends the slag heaps in the coal mines it makes great heights

and in addition it will prevent mining collapses

[Obamot]

..."The collapse of great heights?" the long it took place remains only to clear