Chile is rich in mineral resources, among which are the largest known copper deposits in the world. In the mid-1910s, copper was extracted electrolytically for the first time at Chuquicamata, the world’s biggest copper mine. The requisite power generation and transmission systems came from Siemens Schuckertwerke, which served as a general contractor for this major project. Equipment worth more than twelve million marks was delivered to Chile for the Chile Exploration Company.
Producing copper takes a lot of energy – Crushing, extraction, conversion
Chile is rich in mineral deposits, among which are the largest known copper deposits in the world. In the 19th century, exploitation of the country’s mineral resources, as well as its economic development, had been largely driven by Germany and Great Britain. But early in the 20th century U.S. companies also became increasingly active there, focusing in particular on the major copper-ore deposits in the north. Since the ore in the Antofagasta region had a relatively low copper content, industrial-scale methods and equipment were needed to mine copper cost-effectively at Chuquicamata.
To extract copper electrolytically from rock, the ore first had to be crushed into small pieces. Then dilute sulfuric acid was added, which dissolved the copper content. After several purification steps, direct current was used to extract the semi-purified metal from the solution as electrolytically pure copper. The plant in Chuquicamata was the first to produce copper by this process on a large scale.
Better than the competition – A major contract for more than 12 million marks
Plans for the first phase called for producing some 125 to 150 metric tons of electrolytically pure copper each day – which meant processing as much as 10,000 metric tons of ore. That in turn required about 24 megawatts of electricity. Since Chuquicamata is located in the Atacama Desert, neither hydroelectric power nor fossil fuel to generate electricity was available anywhere in the immediate vicinity. Given these conditions, the operators decided to build a power plant by the sea, and to transmit electricity from there to a receiving plant near the mine, at an elevation of more than 2,700 meters.
Thanks to Karl Georg Frank’s work as an intermediary – he headed the German electrical company’s “information bureau” in New York – Siemens won out over mighty competitors from North America and Great Britain. In May 1913, the Chile Exploration Company, a copper subsidiary of the Guggenheim & Sons bank in New York, awarded the contract to build the power plant and receiving plant to Siemens-Schuckertwerke, which acted as a general contractor to deliver more than twelve million marks’ worth of heavy-current equipment, including third-party materials, to Chile.
Crude oil delivered by ship – From the sea to the desert
After extended advance studies, the project planners decided to locate the power plant in the port city of Tocopilla, where the crude oil used for fuel could easily be shipped in. The receiving plant at the other end was built not far from the mine, 140 kilometers away. The electricity generated by the three-phase generators in Tocopilla was transmitted to the receiving plant in Chuquicamata via a 100,000 volt high-voltage line.
At the site, the three-phase current was transformed down to 5,000 volts. Most of the energy was then converted by machine transformers to direct current at an average of 235 volts, since the electrolysis equipment and the various motors ran on DC.
A long list of difficulties – Completion still on time
The ambitious project had to overcome a long list of difficulties. For one thing, the entire installation was being built in an earthquake zone. On top of that, transporting all the necessary materials across the inaccessible terrain was an arduous task. Another problem was that the climate in the Atacama Desert is extremely dry. So cooling water had to be obtained in Tocopilla by distilling seawater, while the receiving plant could draw on a high-pressure water line that passed nearby.
Political disputes also interfered with the work. Since almost all the construction took place during World War I, it was extremely complicated to transport the machinery from Germany to Chile. The last large shipments did not reach their destination until April 1915. Nevertheless, the first machines were commissioned just one month later. The country’s largest power plant to date was ready to run on schedule in February 1916.
Dr. Franz Hebestreit
You might also find this interestingFurther information on this topic
- Siemens-Schuckertwerke, Die Anlagen der Chile Exploration Company in Tocopilla und Chuquicamata (= SSW Druckschrift 909), Berlin 1921 [in German only]