Located far up near the northern tip of Sweden is the Aitik mine, the largest open pit copper mine in the country. There, enormous Caterpillar 795F mining trucks with tires 15 feet tall haul 310 ton loads of rocks up steep inclines 24 hours a day, 365 days a year. The bottom of the mine is 1,500 feet below the surface of the earth. Combined, a fleet of 30 trucks moves 70 million tons of earth each year. From that total, 97,500 tons of copper are obtained, along with 2.9 tons of gold and 62 tons of silver.
The mining trucks are marvels of modern engineering, but they have one drawback. Each one consumes over 100 gallons an hour of diesel fuel, according to a report from TU. To address that issue, Caterpillar is converting some of the trucks to run exclusively on electric power taken from overhead wires. Batteries large enough to supply the enormous amount of power needed would simply be too large and heavy to work on individual trucks, but putting the energy needed into overhead wires solves the problem.
The overhead wiring is being constructed by ABB and Eitech, two companies with lots of experience building electrified railways and tram systems. The work is supported by a grant of $1.2 million from the Swedish Energy Agency. A similar system for trucks carrying cargo from ports to inland distribution terminals has been constructed in Southern California. The Caterpillar 795F mining trucks are already powered by diesel electric powertrains, so converting them to exclusively electric power will be fairly straightforward and Caterpillar has already started on the conversions.
