Miner Cromwell is a level 60 quest giver located in the Valley of Spirits in the orcish city of Orgrimmar.
He starts the quest [60] The Horde Needs Copper Bars! (Ahn'Qiraj War Effort)
NOTE: He is only available during the Ahn'Qiraj War Effort world event.
See List of Orgrimmar NPCs.