Dwalin, Master of Thorin's Hall, has agreed to help you forge the key, but there are some vital components missing.
'That we can forge this key, I have no doubt, but there are some items we will need before we can begin. Master Elrond's instructions say that we need mithril, but there is none to be had in the Blue Mountains. Also, we will need something to cast a mould from.
'Now, one of the gifts Bilbo took back from the Lonely Mountain was a nugget of mithril. I doubt he understood its value, so he probably left it behind when he returned to Rivendell. However, he may have given it to the Mathom-house in Michel Delving. Perhaps the Keeper of the Mathom-house can help you with that.
'As for the casting, Atli Spiderbane sent word that the Archet guards found a ruined key among the bodies of the Blackwolds. Jon Brackenbrook may still have it. If their leader was from Angmar, as I have heard, it may be that key is just what we need to cast the mould.'
Keeper Brombard Foxtail is at the Mathom-house in Michel Delving in the western part of the Shire. Jon Brackenbrook is in the town of Archet, north-east of Bree-town.
Dwalin informed you that he needs a mithril nugget, which might be in the keeping of the Mathom-house in the Shire, and a key to cast a mould from, which might be obtained from Jon Brackenbrook, the new Captain of Archet.
Dwalin can be found in Thorin's Hall in Ered Luin.
Dwalin sent you to get a mithril nugget from the Mathom-house in the Shire and a key to help in casting a mould from Jon Brackenbrook in Archet.
Litli can be found by the forge near the throne of Thorin's Hall.
Now that you have recovered the mithril and Éogan's key, Litli, one of Dwalin's smiths, can begin work on the key.
Dwalin can be found in Thorin's Hall in Ered Luin.
Litli took the mithril from you and began heating it. However, he mentioned that shaping the mithril will be a problem, one that perhaps Dwalin can solve.