The Agua Negra Pass (Spanish: Paso de Agua Negra) is a pass over the Andes Mountains which connects Argentina and Chile. The highest point of this pass is at AMSL.
To improve trade between Chile and Argentina, a 14 km, three-bore vehicular tunnel (two for traffic and one for ventilation) below the pass is planned, which will allow year-round traffic. (The pass is closed for much of the winter.)
In March 2015, Argentina officially approved the project. It is awaiting ratification from Chile.
In 2018, the bidding contest for the tunnel project between construction companies took place. The whole project was budgeted at 1.5 billion dollars.
Also planned for the deepest part of the tunnel is the Agua Negra Deep Experiment Site (ANDES) (ANDES): an underground laboratory. Because all currently operating deep underground laboratories are located in the Northern Hemisphere, a Southern Hemisphere site would have some unique benefits:
ANDES is not expected to be ready before 2027.
In 2020, the Chilean government under President Sebastián Piñera rejected the IADB loan for the tunnel, halting the project.