Sahih al-Bukhari, Hadith 2355 ⓘ
Narrated Abu Huraira: Allah's Messenger said, "No bloodmoney will be charged if somebody dies in a mine or in a well or is killed by an animal; and if somebody finds a treasure in his land he has to give one-fifth of it to the Government."
حَدَّثَنَا مَحْمُودٌ، أَخْبَرَنَا عُبَيْدُ اللَّهِ، عَنْ إِسْرَائِيلَ، عَنْ أَبِي حَصِينٍ، عَنْ أَبِي صَالِحٍ، عَنْ أَبِي هُرَيْرَةَ ـ رضى الله عنه ـ قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " الْمَعْدِنُ جُبَارٌ، وَالْبِئْرُ جُبَارٌ، وَالْعَجْمَاءُ جُبَارٌ، وَفِي الرِّكَازِ الْخُمُسُ " .
also referenced under: Book 42, Hadith 5 (In-Book) & Volume 3, Book 40, Hadith 545 (USC-MSA)