Colombia issues new Hidroituango alert

Colombian authorities activated emergency measures on Thursday after a vast sinkhole was discovered near the troubled Hidroituango mega-dam project.

Workers identified a 40m-deep underground cavity while drilling the ground to check its stability ahead of the planned closure of the project's turbine rooms, according to local officials.

Antioquia department president Luis Pérez said project owner EPM had been given 72 hours to present a report outlining risks to local communities and consequences for the project's future.

He said new flood alerts were issued for communities located downstream from the project along the Cauca river in northwestern Colombia.

"What I would recommend to the [engineers] is to avoid situations that could cause the sinkhole to grow," Pérez told reporters. "We became aware of the situation yesterday and decisions were taken after talks involving the president [Iván Duque] and the [Medellín] mayor [Federico Gutiérrez]."

EPM said its monitoring systems had not detected unusual movements or water filtrations.

The company had planned to close the turbine rooms' floodgates within weeks, describing the move as a major milestone in its bid to save the project. The rooms - which contain Hidroituango's key machinery and equipment - were purposefully flooded last May to prevent the dam from bursting its banks.

Construction work at Hidroituango was halted last April after serious structural damage prompted fears of catastrophic flooding.

Located around 170km northeast of Medellín, Hidroituango is the country's largest infrastructure project in investment terms. The 2.4GW facility will supply over 17% of Colombia's electricity when fully operational.

EPM has said the plant's operational startup will be postponed by at least three years to December 2021 in a best-case scenario.

It forecasts the total cost of the emergency will reach 7tn pesos (US$2.2bn), including US$1.3bn in lost energy sales, US$630mn in repair works and US$314mn in contingency expenses. The project had been budgeted at US$4bn before the construction problems began.