Musannaf Ibn Abi Shayba 1:1722

'Abbad ibn al-'Awwam narrated to us, from Sa'id ibn Abi 'Aruba, from Qatada, from Ibn 'Abbas, that a Zanj (an Ethiopian/black man) fell into Zamzam and died. He said: "Lower a man down to him and take him out." Then he said: "Drain what is in it of water." Then he said to the one in the well: "Place your bucket from the side of the spring that is adjacent to the House (the Ka'bah) or the Corner (the Black Stone), for it is one of the springs of Paradise."