BHP said its Escondida copper mine, the world’s largest, was operating at a “reduced rate” after union workers walked off the job for part of the day on Tuesday in solidarity with the anti-government protest movement across Chile. Chile, the world’s top copper producer, has long been one of the region’s most prosperous and stable free-market economies. But entrenched inequality and spiraling costs of living ignited massive, and sometimes violent, protests last week.

Riots, arson and looting have led to at least 18 deaths, resulted in more than 7,000 arrests and caused upwards of $1.4 billion in losses to Chilean businesses.