Board Thread:Suggestions forum/@comment-27587913-20160226054057/@comment-26116279-20160226225730

AlatarOfGram wrote: Thorin Stonehelm wrote: I'd have to agree with speg, the grey mountains were abandoned long before erebor was even taken by smaug, the only things living in them are dragons and maybe a few orcs we can safely imply that after erebor was taken back, the dwarves there might try to take back the greys, they have the power, and it will make sense that they went on the offensive somewhat. It could be like the dwarf frontier biome, something they don't have.

The dwarves never retook Ered mithrin, they didn't have the power to take them from the dragons before they lost erebor and there was never an attempt to try again after erebor was recovered in lore, mainly because they tried to retake moria.