By staff reporter Zhu Tao and intern reporter Wang Jing

China’s top law enforcement body has launched an investigation into a landslide at an illegal mining site in northern China that killed at least 128 people and left several hundred missing.

The disaster began early September 8 when sludge from an iron ore tailings pond spilled into a village of about 1,000 in Xiangfen County, Shanxi Province. The pond’s banks burst after heavy rains.

China’s Supreme People’s Procuratorate dispatched a senior official to the scene to oversee an investigation.

Rescue officials said nine people linked to the operation of Tashan Mine have been detained by the local public security officers. In addition, Xiangfeng County authorities have punished several officials for lax work safety supervision.

A Caijing reporter in Xiangfen said that, by the afternoon of September 10, authorities had confirmed 128 deaths and 35 injuries. But rescue efforts were continuing.

The death toll could rise into the hundreds, as the number of missing victims buried in the waste remained unclear.

Wang Jun, head of the State Administration for Work Safety, was quoted by the official China Daily newspaper as saying that “there is almost no hope of their survival for those still trapped.”

“They have been buried for three days under two meters of sludge,” said Wang.

A preliminary investigation determined the incident was caused by illegal mining at Tashan, where iron ore tailings surpassed the capacity of the holding pond, according to rescue officials.