It is narrated from Hazrat Abu Hurairah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: The wound caused by a beast is without liability, the blood of one who dies by falling into a well is without liability, the blood of one who dies in a mine is also without liability, and for buried treasure (found by someone), one-fifth (khums) is obligatory.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 7457
Hadith Gradingحکم دارالسلام:إسناده صحيح، خ: 6913، م: 1710، ابن جريج ثقة لكنه يدلس، وقد صرح هنا بالسماع.