Adds an area around Moria that would have mithril generate in slightly higher rates and higher levels. In the books, Moria is described as prosperous and full of mithril, a feeling I did not get while grinding for mithril in the Misty Mountains. To offset this, and to represent the fall of Moria, Gundabad Uruks would spawn and invade the region frequently. Also, in deeper levels, Utumno mobs would spawn regardless of light levels.
This would prevent new players from trying to rush getting lots of mithril like at Meneltarma. Also, it would not prevent high level high level players from getting this mithril, though with difficulty, So, a player would have to have good gear to take advantage of this cheaper mithril, still making it an end game item.