After more than a century of steady copper excavation, the El Teniente mine features some 2,400 kilometres of tunnels sprawling below the Rancagua region in central Chile, about 80 kilometres from Santiago, the country’s capital. If stretched out in a continuous line, the tunnels could reach nearly to São Paulo, Brazil, on South America’s east coast. Since the start of organized mining in 1904, nearly 1.5 billion tonnes of copper ore have been extracted from the mine. The owner, Chilean state-owned mining company Codelco, aims to maintain fine copper production of more than 430,000 tonnes a year over the long term.

But the mine’s huge size has become the biggest challenge for its owners. After delving eight levels below the surface, the mine faces a growing challenge in maintaining the speed of production. When a ninth level is opened, distances to the surface will reach as long as 10 kilometres, making it more crucial to step up productivity in order to reach output goals. This far below the surface, the hardness level of the ore is much greater than at higher levels and it is more difficult to extract the copper.

“To maintain performance levels, El Teniente must implement new technology and adhere to best practices as a means of mitigating the low productivity created by these conditions and other issues associated with a low-grade ore deposit,” says Ricardo Álvarez, general manager of El Teniente.

El Teniente management has worked closely with Sandvik to find ways to keep up productivity in the face of the challenges it faces in the near future. El Teniente recently adopted Sandvik’s automated ore transportation system AutoMine, which will allow the mine to make another leap in productivity. Sandvik also supplies El Teniente with LHDs, trucks and other production equipment such as drilling and bolting machines, along with crushers and hydraulic hammers. All this technology is part of a package offered by Sandvik to add value and improve El Teniente’s efficiency and profitability.

“The AutoMine system has allowed us to increase the number of hours worked by nearly 30 percent over the use of an operator on board, and this marks a major shift in continuous mining operations,” says André Sougarret, mine manager at El Teniente.

“One of the units, Pipa Norte, produces 10,000 tonnes a day with only 36 workers. One operator might work with four LHDs, while an onboard system requires one operator for each LHD. A single person, the transit operator, is responsible for introducing or removing equipment.”

The mine develops around 27 kilometres of tunnels each year to move an average of 137,000 tonnes of ore daily, or almost 48 million tonnes a year. Around 400,000 tonnes per year of fine copper is recovered from the ore, either as refined ingots or as copper cathodes. As a result of ore processing, nearly 5,000 tonnes of molybdenum are recovered as a by-product.

“The introduction of new equipment has allowed us to significantly increase the overall productivity in the mine, and changes in the quality of the surrounding rock have allowed us to enlarge the dimensions of the drifts,” says Álvarez, the general manager. “The larger working space enables the use of larger equipment like 17-metric-tonne payload and 80-tonne trucks.”

André Sougarret, the mine manager, says El Teniente relies heavily on LHDs for its underground operations. “Sandvik has been supplying more and more equipment to cover that need,” he says. “In fact, most of the LHDs at El Teniente have been provided by Sandvik. Their LHDs have helped to improve the reliability of the mining processes we require to meet our commitments.”

The new equipment has also helped improve safety for the operators in the mine. “In terms of safety, the system has helped us to have an excellent performance,” says André Sougarret. “We’ve gone six years without an accident, mainly because we have very few staff members in operational areas.”