El Teniente Copper Mine Expansion

Fluor provided design, procurement and construction for an expansion of El Teniente, an existing underground copper mine and ore haulage complex high in the Chilean Andes that was the world’s largest such complex at the time.

The project increased ore production from 35,000 to 62,500 tons per day by expanding transfer and haulage facilities in the north and central areas of the mine and opening new ore blocks in the southern portion of the vast deposit.

Client's Challenge

First mined in the early 1900s, the El Teniente mine developed through the years into a block-caving re-tram system of horizontal and vertical passageways that totaled 340 miles in length in the late 1960s.

The El Teniente mine is located inside a precipitous mountain 90 miles southeast of Santiago. Due to the remote location and high altitude, the project site was only accessible by single-line, narrow-gauge railroad during the first 30 months of construction.

Fluor's Solution

Fluor's scope of work required the construction of 30 miles of new underground labyrinth. Thirteen miles of tunnels, drifts, cross-cuts and connections were driven horizontally, and 11 miles of finger raises, ore passes, shafts and inclines were raised and sunk vertically. Fluor also constructed the six-mile-long Teniente 8 railway tunnel. Nearly 850,000 cubic yards of rock were excavated.

Fluor engineered and constructed two large-bore “elevator” shafts and installed hoisting equipment in a third. The Sewell Shaft transported workers and material from the Teniente 8 railroad tunnel. It was estimated that approximately 100 million tons of ore, 100 tons of freight and 900,000 passenger round trips were carried by the Teniente railroad annually.

Project success relied heavily on Fluor’s mining expertise. The project team conducted computer studies covering piston effect, horsepower requirements and high-density traffic patterns to select optimum tunnel section and gradients and the size and speeds of the several types of trains to be used.

Conclusion

Fluor also overcame extreme weather conditions during construction. Logistics to provide supplies for the workers were slowed by snow, and driving the railroad tunnel was delayed by a flood that caused more than 6,500 cubic yards of debris to fall into the hole. Despite the logistical challenges presented by the site location and weather, Fluor completed the mine expansion in 1979.