random quarry
Maybe you'll need to find the save file outside of the game to delete it.
On an Android device, the file directory is: Internal storage → Android → data → com.bethsoft.falloutshelter → files
Regular vaults: Vault1.sav, Vault2.sav, Vault3.sav (depending on which slots have save files)
Seasonal vault (experimental vault): Vault4.sav
Newer versions of Android requires connecting to and operate through PC to access.