Afghan police stand guard near the scene where the coal miners were killed. (SAYED MUSTAFA/EPA)

At least 24 Afghan miners were killed Saturday when a coal mine collapsed in northern Afghanistan, according to local officials.

The miners had been complaining about dangerous working conditions on the morning of the incident, said Sediq Azizi, a spokesman for the governor of Samangan province, where the mine is located.

The mine’s supervisor did not heed the workers’ concerns, Azizi said, and fled after the men were killed.

The incident is a cautionary tale in a country that soon expects to increase its mining operations exponentially, filling a financial the gap that will be left when foreign troops withdraw from Afghanistan. Chinese, Indian and Canadian companies all have invested in extracting the country’s mineral wealth.

Still, many mines, like the one in Samangan, are locally owned and operated, with limited safeguards for workers.