It is narrated from Sayyiduna Abyad bin Hammal (may Allah be pleased with him) that he came as a delegate to the Prophet (peace and blessings be upon him), and he (peace and blessings be upon him) granted him the salt (mine) as a land grant. When he turned to leave, a man said: "O Messenger of Allah! Do you know what you have given him? You have given him nothing but flowing water." The narrator said: So he (peace and blessings be upon him) took it back. The narrator said: And I asked him (peace and blessings be upon him) how much of the arak is protected. He (peace and blessings be upon him) said: "Whatever the feet of the camels do not reach."
Hadith Referenceالمعجم الكبير للطبراني / باب الألف / 806