Los Bronces Copper Mine Expansion - Chile

Sustainability and innovation to deliver a copper mine in extreme terrain

Anglo American approved this spectacularly located and complex project, which traversed rugged mountainsides and extreme elevations, in order to double copper mining capacity in the Los Bronces district near Chile’s capital, Santiago.

Thanks to a strong focus on using innovative solutions to protect the environment, the various sites that comprise the concentrator expansion project had already begun to blend back into the dramatic landscape along the western face of the Chilean Andes within months of completion in late 2011. 

Inside the project

Various innovative and safe solutions were applied to carry out the excavations between the complicated geographical conditions and the rich natural environment nearby, which includes protected areas and glaciers.

This coordinated work with our customer allowed us to establish a job site, Confluencia, on a tiny, steep pinnacle 10,500 feet (3,200 meters) above sea level, while also installing another one in a hillside far below.

Caring for nearby water sources and controlling emissions, two of the environmental priorities we share with our customer, were included in the design, leading to the construction of a slurry pipeline that descends more than 8,700 feet (2,652 meters) over rough terrain, through hard-rock tunnels, and via bridges over deep canyons to transport ore between the sites. A reclamation system—crucial for water management and sustainability in this arid region—recovers and pumps slurry water to the concentrator for reuse.

Throughout execution, the project encountered new risks, including snowfalls that could bury a truck, high winds, dramatic cliffs, and significant geotechnical challenges typical of mountain work. Furthermore, the project continued to advance despite the effects of the 8.8 magnitude earthquake that occurred on February 27, 2010, the sixth-largest ever recorded.

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Logistics for a remarkable challenge

Along with the aforementioned challenges, the great teamwork between Anglo American and Bechtel also helped overcome another challenge: the Las Tórtolas flotation plant was built on a former military target range encumbered with unexploded ordnance that required a thorough sweep before work could begin.

Remote locations and weather conditions required provisioning our team members with shelter, food, and other necessities that had to be hauled up mountain roads, where snow could pile up to 13 feet (4 meters) high. As a result, the winter emergency committee monitored these roads 24 hours a day for avalanches and other risks. As an extra precaution, truck drivers routinely drove practice runs without their loads prior to delivery.

Safety first

Altitude sickness, extreme weather, avalanches, and rough terrain pose constant risks for workers at high-altitude sites such as Los Bronces. In keeping with the unwavering commitment to health and safety instilled in both Anglo America and Bechtel, all workers had to pass strict medical exams before they could start work.

Thanks to the team's steadfast commitment, in 2012, the Chilean Chamber of Construction (Cámara Chilena de la Construcción) awarded Los Bronces a safety recognition for achieving 4 consecutive years without accidents.