Delivering a copper mine in extreme terrain

This spectacularly located and complex project traversed rugged mountainsides and extreme elevations to double copper mining capacity in the Los Bronces district for our customer, Anglo American.

Within months of completion in late 2011, 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. 

Inside the project

We carved one job site, Confluencia, from a tiny, steep pinnacle 2 miles (3.5 kilometers) above sea level, while we tucked another into a hillside far below. In order to transport ore between the sites, we managed construction of a slurry pipeline that plunges more than 8,700 feet (2,652 meters) over rough terrain, through hard-rock tunnels, and via bridges over deep canyons.

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

Image gallery

An interesting challenge

And if the aforementioned challenges were not enough, we built the Las Tortolas flotation plant on a former military target range peppered with unexploded ordnance that required a painstaking sweep before work could begin.


We brought everything—and everyone—great distances to some of the most inhospitable places on the planet. We provisioned our men and women with shelter, food, and other requirements hauled up tortuous mountain roads, where snow could pile up to 13 feet (4 meters) high. Our 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.  ​

A reclamation system—important to water management and sustainability in this arid region—recovers and pumps slurry water to the concentrator for reuse.

How a mine works

After processing units grind crushed ore into finer and finer particles, the material enters flotation cells in which foaming agents and injected air renders a bubbly froth. A chemical agent causes lighter mineral content to attach itself to bubbles and rise toward the surface, where it is skimmed off or otherwise captured.

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 our unwavering commitment to health and safety, all workers had to pass strict medical exams; some even adopted special diets to lose weight and reduce their blood pressure before they could start work.

Thanks to the team's steadfast commitment, in 2012, an independent local safety agency called Los Bronces the safest of any major Chilean mining construction project in a decade.