San Francisco Tunnel Los Bronces Access Protection

The San Francisco River is one of the main tributaries of the Mapocho River that crosses the city of Santiago. This river originates and passes the surroundings of the mining site Los Bronces de Anglo American, located in the middle of the Andes Mountain Range. Within its route, the river crosses a tunnel that makes a bypass through the old tailings pond of the mining site.

In summer, this sector is prone to rainfall, producing landslides that block the entrance and exit portals of the tunnel, affecting the riverbed and generating a significant environmental impact when it comes into contact with the tailings pond material.

To protect the portals, a long-term plan has been designed. It begins with mitigation works for the landslides that occurred in the vicinity of the portal. For this purpose, an engineering project was initially developed to model the water flows in the streams and then implement a solution with multiple shallow landslide barriers protecting both portals of the tunnel. The barriers will avoid future environmental impacts due to the diversion of the river waters.