The accident occurred at about 9.30am, near wall 34 of an old iron mine, Truong Van Hoa, vice-president of the people's committee of Chau Hong Commune, said yesterday.
Nguyen Van Trong (born in 1984 in Thai Nguyen) was entering the mine's tunnel with three friends to look for iron ore, when a 2cu.m rock suddenly fell on him from the tunnel's ceiling and killed him instantly.
His terrified friends survived the incident.
"We rushed 10 people, including policemen, to the mine to bring Trong's body out. The mining equipment and a flashlight were still in his hands when we found his body, and the light was still on," Vi Duc Tien, deputy chief of police of the commune, said.
"He has got two children. His family is very poor," he said.
Sam Ngoc Phong, police chief of the commune, said the police office handed over Trong's body to his family early yesterday morning, and also reported the accident to the police in Quy Hop Ward.
"We had advised households not to enter the old mines as they are very dangerous. However, some poor families still come and illegally look for ore in the hope of improving their living standards," he said.
The mine, where the accident took place, previously belonged to gemstone company Phủ Quỳ, Trương Văn Hoa said.
The company handed the area over to the local authority when its mining contract expired.