Obtaining the Quest
Kill Black Blood of Draenor, sludge enemies found in the mines underneath Netherwing Ledge, and collect Sludge-Covered Objects. Opening these objects will eventually reveal the Murkblood Escape Plans: right-click on the plans in your inventory to obtain a quest called "The Great Murkblood Revolt." Deliver this quest to the Mistress of the Mines, a demonic creature standing at the entrance to the mines, to obtain 350 Netherwing reputation and the "Seeker of Truth" follow-up quest.
Questioning the Overseer
Locate a Murkblood Overseer within the mines. They are friendly to you, unlike the other Murkblood, and can be found hiding behind machines and in corners. Speak with the Overseer to question him and learn that the Murkblood have been deliberately sabotaging the mines; at the end of the conversation, the Overseer will willingly cut off his hand and give it to you, fulfilling the objective of your quest.
Completing the Quest
Once you have obtained the hand of the Overseer, return to the Mistress of the Mines and deliver the quest to her. Your character will not reveal any information about the Murkblood to her, and she will express rage at this fact. Completing the quest will reward you with 500 Netherwing reputation.
Continuing the Netherwing Quests
After delivering the hand of the Overseer to the Mistress of the Mines, the quest chain is over; there will be no more references to the Murkblood revolt or the situation in the mines. Continue completing other quests to increase your Netherwing reputation.