Going Underground

The companies and technologies enabling Chile’s transition from open-pit to underground mining

Declining ore grades in Chile have caused a steady decrease in total factor productivity (TFP), which is driving the country’s mining sector underground. The poster child for such developments is Codelco’s Chuquicamata, where the State-run mining company is spending over US$5.6 billion on to transition the century-old mine from one of the world's largest open-pit mines (by excavated volume) to an underground operation to maintain production rates and extend the life of mine by over 40 years.

The large copper-gold porphyry systems scattered across the Andes often start with an oxides layer on top of a higher-grade sulfide level at depth. The development to transition large-scale mines from open pit to underground operations usually involves large capex, which offers opportunities for companies involved in the raise boring and tunneling space.

Furthermore, raise boring’s importance for ventilation of the exhaust of diesel-operated equipment within mines make it a necessary expense for older operations such as El Teniente, the largest underground mine in the world.

Master Drilling, a vertical development specialist and leader in raise boring and blind hole boring (a mechanized alternative for conventional methods which allows for the development of block caving) has contracts at both Chuquicamata and El Teniente.

Fernando Vivanco, Master Drilling’s general manager for Chile, discussed the company’s new technology called MTB (mobile tunnel borer) for mechanized horizontal development, which is currently in South Africa undergoing tests. “We have had preliminary conversations with Codelco to test the machine in Chile, and they are interested in going to South Africa to see the machine and establish if there is a possibility to bring it to this country for testing,” he revealed.

Elaborating on the technology, Vivanco explained how MTB is like a TBM (tunnel borer machine), but mainly focused on mining. “Whereas traditional tunnel borers are focused on civil works, the MTB is a bespoke machine for mining to allow for horizontal mechanical excavation for underground mining development and can operate on a 12-degree incline or decline development,” he said, noting that the machine can be utilised to excavate a variety of tunnels, including tunnels to underground ore bodies such as declines, portals, haulages, inclines, ramps, ring roads and connecting tunnels.

American company Robbins is one of the pioneers in the TBM market, celebrating its 70thanniversary in 2022. Lok Home, president and CEO, provided details of how the company’s Mine Development Machine (MDM) 5000 is specifically designed for underground mechanical excavation, like a TBM, but for mining applications.

“Historically, 99% of TBMs have made a round tunnel which is not a good shape in the mining industry as miners use vehicles to extract the ore. Robbins’ aim was to give miners access tunnels using mechanical boring means, but with a flat floor and good ground support,” he explained, adding that the MDM can make a tunnel much faster than what can be accomplished with mechanical drill and blast.

Emphasizing the importance of mechanization in the drive towards automation, Home observed that mining companies are starting to realize that the only way to go to mechanized mining underground is to accept mechanical excavation.

“We are already seeing more demand coming from industry rather than us trying to chase them,” he revealed, continuing: “We also foresee that in the next 10 years we will actually be mechanically excavating ore bodies. Although this trend might be slow to take off, we expect huge demand in the future. Environmental consciousness is also driving the trend towards underground mining and mechanical excavation as nobody wants to see big open pits and piles of tailings.”

With underground tunneling comes a myriad of challenges such as space constraints, difficult ground conditions, unmovable underground structures, and work that must be done in an environment where it is difficult to deploy reliable network systems. Rajant’s private wireless network enables tunneling operators to overcome these inherent networking challenges.”

Sagar Chandra, Vice President Business Development – Americas, Rajant

Technological advancements

Some of Chile’s most important mining operations are also the oldest. Mining at El Teniente, for example, is reported to have started as early as 1819. Introducing technology at operations that have operated in a certain way for many years can be a challenge, but State-run mining company Codelco has invested heavily in modernizing its operations. Speaking at the World Copper Conference, CEO Octavio Aranedo underlined the company’s focus on digital transformation.

César Ortega, founder and general manager of Chilean company Telemining, worked at Codelco for 34 years and became director of telecommunications, information and automation technologies for all divisions before founding Telemining in 2011. Telemining provides digital services, installations, automatization and access control systems for underground mining settings, and Ortega emphasized the importance of installing the requisite digital infrastructure to support autonomous operations. “Today a 1 GB network is too small; you need at least 10 GB to communicate between camps,” he stated, noting that the demand for communication networks has never been higher. “Broadband communication is a must, because shovels and trucks are now automatic. That is the tendency of the future where mining will become completely automated; all the operations will be driven and managed from control rooms through broadband communication networks.”

Telemining has worked with Rajant at El Teniente, a US-based company focused on enabling wireless communications in real time. Sagar Chandra, vice president business development Americas at Rajant, explained that with underground tunneling comes a myriad of challenges such as space constraints, difficult ground conditions, unmovable underground structures, and work that must be done in an environment where it is difficult to deploy reliable network systems. He described how Rajant’s private wireless network enables tunneling operators to overcome the networking challenges inherent in enabling communications, and improves productivity inside tunnels: “Our Kinetic Mesh network comprises compact, lightweight BreadCrumb nodes that can be flexibly deployed throughout the tunnel, on both fixed infrastructure and moving equipment, to form a robust mesh network underground.”

In July 2021, one of big four global OEMs, Sandvik, completed its acquisition of DSI Underground, with DSI becoming part of Sandvik’s Mining and Rock Technology division. Carlos Leigh, DSI Underground’s regional CEO for Latin America, affirmed that the integration of the companies had progressed as planned, and that DSI will maintain its operational independence, but now with the weight of a major OEM behind it.

Leigh highlighted Codelco’s PMCH (Proyecto Mina Chuquicamata Subterránea) as one of DSI’s most important projects, where the company supplies underground support and ventilation products. Ventilation is one of the biggest costs in underground operations, and Leigh spoke about how DSI’s joint venture with ABC Technology Group is optimizing this process: “One of the most important innovations (of the DSI-ABC JV) is HardLine, a new duct made with a high resistance semi-rigid plastic that replaces steel ducting in some cases,” he said, adding that it is easy to install, has much better ventilation capabilities than steel, and will soon be produced locally in Chile, reducing extra costs related to freight and improving delivery times considerably, a critical issue for customers.

Image courtesy of DSI Underground