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.
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.