The Los Lagos and Aysén regions are the two remaining terrestrial stretches of the Fibra Óptica Austral public-private partnership to connect Chile's far south via fiber.
Brazil's federal audit court, however, suspended the sale of transmission subsidiary Intesa.
Capital markets must complement the role of BNDES, wrote a former head of the development bank.
The Brazilian conglomerate plans to pay off some US$800mn in debt over 22 years.
OAS will appeal the ruling and is negotiating a leniency agreement with authorities.
According to the magnate, using local construction materials instead of imported ones for building the Mexico City airport would significantly reduce the project's costs.
The concessionaire in charge of the US$938mn project had claimed that two recently opened tunnels were incompatible with the project's design.
Brazil's development bank hired a consortium to explore commercial options for the best use of the river's water.