At the town's peak in 1960, some 16,000 people lived here. After the government acquired a majority interest in the mine, and even more so after copper mining was nationalized in 1971, the government company moved workers into the valley. It built the Copper Highway to provide commuting access for them to the mine and related operations. While some buildings were demolished in the 1980s, others have now been renovated for contract workers, and restored as part of preservation of this historic site. The Chilean government designated it in 1998 as a National Monument.