A Tuesday inspection by environmental officials found a design flaw at the Sao Mai reservoir responsible for the death of 49-year-old miner Tran Cao Vinh on Monday. He was buried in sand as the wall of the mine collapsed.

On September 26, Sao Mai opened three pits to conduct pre-extraction inspection. A pit is 40 meters wide and 24 - 27 meters deep. However, its diagonal slope was above 50 degrees, in contravention of the approved design.

The remaining two open pits operated by the company also had the same slope flaw. In addition, the company failed to comply with guidelines mentioned in the environmental impact report, especially those related to workplace hygiene.

The province's environment inspectors filed a report and suspended all mining activities. The company has to follow all guidelines in the environmental impact report, employ safety measures, and report back to the authorities who will consider if the suspension can be revoked, they said.

In 2016, pit collapse at two titanium reservoirs in Binh Thuan had caused an environmental disaster with hazardous red mud spilling, halting traffic and damaging residential property.

There are currently four firms licensed to mine titanium in the area. The 350ha Sao Mai titanium reservoir was licensed by the Ministry of Natural Resources and Environment for a duration of nine years, starting from 2019.