The unrest has spread to other gold and platinum mines, rippling across one of the most important sectors in South Africa, which has Africa’s biggest economy, and raising concerns that South Africa is headed for a long period of labor unrest more severe than anything since the end of apartheid in 1994. Many South Africans have described the killing of the miners as a massacre, and investigations by local journalists suggest that at least some of the miners were trying to flee when they were shot. President Jacob Zuma created a panel of inquiry with broad powers to investigate.

Workers at Lonmin went on strike more than a month ago, demanding that the company increase their take-home pay to about $1,500 a month, roughly double or triple what most miners now earn. Many of the striking workers are members of a radical, breakaway union that has pledged to get higher wages for miners. Talks between workers and the companies have thus far failed to reach an agreement to get the miners back to work.