Abdul Muhari, spokesman for the national disaster mitigation agency, or BNPB, said the floodwaters hit a camp used by miners

"The floodwaters from upstream hit a temporary housing area of traditional gold miners at around 9:00 pm (1200 GMT), sweeping away their tents and equipment," Muhari said in a statement

He said four people were injured and had received initial treatment from locals but no other major damage had been reported

"To date, no significant physical or material losses have been found. In addition, no residents were displaced due to this incident," Muhari said

Unlicensed mines are common across the mineral-rich Southeast Asian archipelago, where abandoned sites attract locals who hunt for leftover gold ore without proper safety equipment