Abu Dawud Book 13, Hadith Number 3055.

Narated By Rabi’ah ibn AbuAbdurRahman : Rabi’ah reported on the authority of more than one person saying: The Apostle of Allah (PBUH) assigned as a fief to Bilal ibn al-Harith al-Muzani the mines of al-Qabaliyyah which is in the neighbourhood of al-Fur’, and only zakat is levied on those mines up to the present day.