The Anaconda Company, headquartered in Montana, had built its fortune on copper extraction across the Americas. El Salvador was its answer to a declining asset, a replacement mine designed to maintain output as Potrerillos wound down. But the political ground in Chile was shifting faster than Anaconda's geologists could drill. In 1971, President Salvador Allende nationalized the Chilean copper industry, transferring ownership of El Salvador and every other major mine to the newly formed state corporation Codelco. Anaconda and Kennecott Copper Corporation lost their Chilean holdings overnight. When Augusto Pinochet seized power in a military coup two years later, the mines stayed nationalized — one of the few Allende-era policies the military government left intact. Chile eventually reimbursed the American companies for part of their losses, but the copper remained Chilean.

El Salvador occupies an unenviable position within Codelco's portfolio: it is the company's smallest mine and its most expensive to operate. In 2005, producing a pound of copper at El Salvador cost $0.72, compared to the company-wide average of $0.44. Declining ore grades — the geological reality that had already killed Potrerillos — continued their steady erosion. That year, Codelco announced plans to shut the mine down by 2011. The closure never came. Instead, the company extended El Salvador's life by fifteen to twenty years, a decision driven less by the mine's economics than by the town that depended on it. El Salvador the mine sits next to El Salvador the company town, and closing one means emptying the other. Geologically, the deposit marks the southernmost point of the giant porphyry copper districts of the Atacama Desert, where Paleocene volcanic rocks host mineralization induced by Eocene dacite intrusions.

The history of El Salvador is punctuated by labor disputes that reflect Chile's broader political struggles. In 1983, during Pinochet's military rule, roughly 13,000 workers across three Codelco mines voted to strike indefinitely after a union leader was arrested for calling for an end to the dictatorship. At least 3,300 workers and 37 labor leaders were fired. The mine struck again in 1989. But the most significant confrontations came in 2007 and 2008, when contract workers — the mine's lower-paid, lower-benefit workforce — shut El Salvador down. They blocked roads, preventing company employees from reaching production areas, and demanded the same bonuses, healthcare, housing, and education benefits that direct hires received. An agreement was reached in July 2007, but when Codelco failed to honor its terms, the contract workers walked out again in April 2008.

The 2008 strike escalated beyond picket lines. Striking workers damaged underground infrastructure, and loads left on support columns not designed to bear weight for extended periods created unstable conditions that an external consulting firm confirmed as dangerous. Electrical and water supply equipment was set on fire in acts of sabotage that threatened the distribution of power and drinking water not just to the mine but to the surrounding community. Codelco reported losing roughly 1,000 tons of copper production against a planned 8,000 tons for the month of July. The episode exposed the tension at the heart of company-town mining: the workers whose labor extracts the copper also hold the power to stop everything, and when they feel that the wealth flowing from the ground is not flowing to them, the consequences can be severe. El Salvador continues to operate as Codelco's smallest division, producing 5.7 thousand tons of copper in 2024 — a fraction of the company's 1,428.7 thousand-ton total, but enough to keep The Savior alive.