A retaining wall collapsed at the Armijos tailings station, located in the Camilo Ponce Enriquez area in southern Ecuador, the Energy and Mines Ministry said. Nobody was injured.

"One of the immediate measures in the area will be ... to prohibit mining activities at that plant," the Ministry said in a statement, without providing details on the incident.

The ministry said it opened an investigation to determine how the company could be sanctioned.

Ecuador this month is expected to release guidelines for the management of tailings dams, partly in response to high profile accidents including a 2019 dam collapse in Brazil that killed more than 250 people.

Local authorities in Camilo Ponce Enriquez, a traditional mining zone, said the company had not complied with the protocols and the collapse caused sediment pollution in the river.

"There was a collapse ... and all this material, about 50 tons, went down the mountain until it reached the Tenguel river," city commissioner Cristian Tomala told reporters.

Ecuador has been developing large-scale mining since last year and has been exporting gold and copper from its two largest mines.