Musnad Ahmad 1070:1

'Abd al-Rahman narrated to us, from Sufyan, from Zayd—meaning Ibn Aslam—from a man from Banu Sulaym, from his grandfather: That he brought silver to the Prophet, peace and blessings of Allah be upon him, and said, "This is from a mine of ours." The Prophet, peace and blessings of Allah be upon him, said, "There will be mines that the most evil of people will attend."