HOHHOT -- Six university students drowned on Wednesday after falling into a flotation cell during a study visit at a copper-molybdenum ore-dressing plant in North China's Inner Mongolia autonomous region, local emergency authorities have said.

The accident occurred at approximately 10:20 am Wednesday at the plant, which is operated by a mining company under China National Gold Group Co, Ltd in Hulunbuir, according to the municipal emergency management bureau. The students, all of whom attended Northeastern University, were observing flotation processes when a grid plate collapsed, causing them to plunge into the flotation cell.

All six were rescued from the cell but later pronounced dead by medical personnel. A teacher was also injured in the incident.

Post-incident handling is underway.