Mechanized excavation digging deeper into Chile’s infra, mining sectors

Mechanized excavation methods such as tunneling boring machines (TBMs) and shaft boring machines (SBMs) are taking on increased importance in Chile’s infrastructure and mining industries, and technological innovations are poised to intensify their usage further, according to executives from German firm Herrenknecht. 

TBMs have been used in Chilean mines before, such as El Teniente and Chuquicamata, while one of these machines will be used for the first time in the expansion of the Santiago subway system, albeit on only one section of the 26km line No. 7, currently under construction.

Local authorities have stated that TBMs will not be a fit-all solution for every new metro line, as the soil of the capital is considered too soft, but Herrenknecht’s head of business development and geotechnics and consulting, Karin Bäppler, has a different view. 

“Variable-density TBM could also be applied to ground conditions in Santiago. There are comparable projects in Latin America in similar conditions – the Lima metro for example,” she said in response to a question from BNamericas during a mechanized excavation seminar organized by the German firm and Chile's public-private tunnel and subterranean spaces organization CTES.

Variable-density TBMs can be adapted to changing ground conditions through a conversion system, allowing them to tunnel through softer or harder surfaces.

During her presentation, Bäppler highlighted the example of line B of the metro system in Lyon, France, where a variable-density TBM was used despite the high permeability of the soil.

Mechanized solutions are also undergoing innovations in the mining industry, as operations start to go deeper into the ground in search of higher-grade ore. 

“We're not cancelling jobs, we're transferring them to a higher skill set,” Herrenknecht’s product manager for mining, Patrick Rennkamp, told BNamericas at the same event, highlighting the use of TBMs in the sector.

He pointed out that mechanized excavation is also faster than drilling and blasting, as the latter methods only provide an average daily advance of one to two meters, compared to three to four meters per day using solutions such as TBMs.

When asked by BNamericas about the impact of shaft boring machines in civil works, such as on line No. 7 of the Santiago metro, where a projected excavation in a city park was cancelled following protests by local residents, he stated that Herrenknecht is working to reduce the impact of mechanized excavation on the surrounding terrain. 

“In general, we have vertical shaft machines, which have optimized footprints,” he said. 

Herrenknecht has provided mechanized excavation solutions for big projects such as line No. 2 of the Lima metro in Peru, the Riachuelo sub-fluvial tunnel in Argentine capital Buenos Aires and line No. 1 of Panama City’s metro.

Last year, Chile’s state-owned copper firm Codelco and Japanese equipment provider Komatsu sealed an agreement to test out a new TBM at the Chuquicamata copper mine in 2024. The machine is equipped with new technologies that enable it to adapt to small curves, reverse and pass intersections in hard rock tunnel excavations.