I visited some time ago together with my wife before her operation these cobolt mines about three hours away from home. A day out so to speak for her, me and a girlfriend of hers. Now slag means in English; "
stony waste matter separated from metals during the
smelting or
refining of ore." Not necessary coal, but could have been. The mines are no longer active.
On top of the slags in my text, means only that the two girls seen up there on this heap, are on top of the slags. Nothing more intriguing. No Rob, we do not use coal, but in Germany they still do. I hope this is a satisfying answer to any bewilderment. Today, it is a museum and in connection with Haugsfoss falls as I have shown previously. Thank you for your interest and comments.