Contractors
Chile’s mines tunnel themselves into the country’s mountains
As open-pit mines mature, the cost of waste removal increases, making the transition to underground operations, where higher-grade ore can be accessed with less overburden removal, more economically viable. The migration from open pit to underground mining operations has taken the Chilean mining sphere by force. Following Chuquicamata’s pioneering efforts, beginning underground operations in 2022, the trend has surfaced, and gone underground, everywhere. Major surface mining operations, such as Los Bronces Integrado, Collahuasi, Ministro Hales, and Escondida, are migrating and/or evaluating migration to underground mining. With these migrations, 40% of the total number of mining operations in Chile would be underground operations.
Such migrations have provided Chile’s underground construction firms with an opportunity. “The future of mining in the underground sector looks promising. We anticipate a significant increase in underground projects, driven by environmental considerations and the need to address low-grade deposits,” said Andrés Llona Tagle, administration and finance manager at Mas Errázuriz.
The benefits of underground mining operations are immense, said Juan Pablo Merello, general manager at Skava Consulting: “Economically speaking, underground mining emerges as the most profitable option. Tunnels offer a superior solution with less environmental impact than surface alternatives, allowing surrounding areas to continue functioning during construction and operation.”
The lower environmental impact is pronounced: “The volume of earth moved is typically about 10 to 20 times lower compared to open-pit mining,” said Adolfo Sicilia, general manager at OSSA.
Underground mining, however, is not a new concept, emphasized José Miguel Galera, CEO at Systra Subterra: “It was prevalent at the end of the 19th and the first half of the 20th centuries before the shift to open-pit mining in the 1960s. We are returning to underground mining, equipped with advanced technological resources and knowledge that we did not have 50 years ago.”
“The mining industry needs to build confidence with the public, stakeholders, communities and governments by delivering sustainable projects that protect watercourses and natural habitats, address stakeholder and community needs, and leave a lasting skills legacy.”
Ailie MacAdam, President, Mining & Metals, Bechtel
An example of the advanced technological resources includes the use of robots within operations. OSSA is testing intelligent mobile robots in underground environments. “The UNDERAIBOT project aims at the experimental development of a deployable kit for inspecting and exploring underground environments in construction - such as mining galleries, tunnels under construction, hydroelectric galleries - and rescue and emergency situations - like fires - in conditions of low visibility and without connectivity using mobile robots capable of being equipped with artificial intelligence,” Sicilia elaborated.
Robots have been used within the Chilean mining industry for many years. Sigdo Koppers Ingeniería y Construcción employs EVA, a robot developed by Boston Dynamics, for engineering tasks. “Capable of conducting 3D surveys of project progress, EVA represents a pioneering technology in Chile. Another advantage of this robot is its ability to enter confined spaces and undertake repetitive tasks in hazardous environments. We are harnessing this potential through our Special Maneuvers Unit (UME),” said Caroline Vender, the firm’s CEO.
TBMs as the future
One of the greatest recent advances within the tunneling circuit is the use of mechanized cutting. This has been supported using tunnel boring machines (TBMs), which were brought to the mining industry from industrial tunnel construction settings, like the metro line construction. “The growing attention towards TBM technology suggests a shift towards mechanized excavation in the mining industry in the coming years,” said Merello. “TBMs offer significant improvements in safety and construction speed.”
“EVA is a robot developed by Boston Dynamics with enormous potential in engineering applications. Capable of conducting 3D surveys of project progress, EVA represents a pioneering technology in Chile. Another advantage is its ability to enter confined spaces and undertake repetitive tasks in hazardous environments.”
Caroline Vender, CEO, Sigdo Koppers Ingeniería y Construcción
They also improve productivity, said Fernando Vivanco, general manager at Master Drilling: “Mechanical cutting revolutionizes mining with its unique advantages over traditional drill and blast methods. It enables continuous mining operations, multitasking by excavating, mapping, and supporting tunnel walls simultaneously. This boosts productivity significantly, targeting around 200-300 meters of tunnel per month compared to 60-80 meters with traditional methods.”
Given their primary use is for road infrastructure TBMs have present size and height limitations in the mining environment. “We are looking to develop technologies akin to TBMs but tailored specifically for mining applications, forming a significant focus area for the upcoming year,” Vivanco continued.
The transition to underground operations also benefits ventilations companies. Such companies are innovating to create ducts that provide clients with the most benefit. DSI Underground has been successful: “DSI Ventilation stands out for manufacturing semi-rigid products of special plastic, which offer impact resistance and low friction, resulting in significant energy savings. Recently, we tested our locally produced HardlineTM duct in a mine in northern Chile, which reduced the time needed to improve air quality by 33%, simply by changing the type of duct,” said Carlos Leigh, regional CEO LATAM and CEO DSI Ventilation Systems.
The transition to underground mining is not merely a return to past practices but a forward-looking move, leveraging cutting-edge technology and improved knowledge to secure the future of mining in Chile. As the industry adapts to these changes, it exemplifies resilience and innovation, ensuring that mining remains a cornerstone of Chile's economy for years to come.
Article header image courtesy of Sigdo Koppers