The dwarves of the Dolven-view wish to mark the Lonely Span as a passageway owned now by dwarves, and no other creature of Moria.
'Have you seen the Lonely Span yet? It is a bridge that connects the Great Delving to the Twenty-first Hall in Zelem-melek, and it is a vital checkpoint in our expedition.
'If it is safe, you should plant a banner of the dwarves there. As long as it stands, we will know that the Lonely Span is held for the dwarves of Khazad-dûm!'
The Lonely Span can be found by following the east path past the Cooling Chamber from the Dolven-view camp.
You should head to the Lonely Span and plant a banner of the dwarves there.
Sót is in the Dolven-view in the Great Delving of Moria.
You should return to Sót now that the bridge to the Twenty-first Hall has been claimed by the dwarf-expedition.