On February 5, a surface crown pillar collapsed, trapping 87 workers inside the mine. At the same time, a container on the surface converted into an office was swallowed by the resultant sinkhole. The miners were soon freed without loss of life or significant injury, but three clerical employees remain trapped in the container now below ground.

Lily is owned by the Australian company Vantage Gold, and is located in Mpumalanga province, east of Johannesburg. Rescue efforts were halted about a week in, after subsequent falls of ground made the site unsafe.

Management now plans an operation similar to what was used to rescue 33 Chilean miners in 2010, using a drill to create a rescue shaft to where the container is thought to be. “The drill rig is capable of drilling a 660 millimeter diameter hole 80 meters deep, which will allow access to Level 5,” the company said in a statement. However, it will be at least three weeks before the site is stable enough to proceed, the company warned.

Initial rescue efforts at one point came as close as 10 m to the trapped container, and signs of life were detected. Since then the container has slid further into the sinkhole, and contact was lost. The three workers were reported to be without food or water, and the availability of oxygen is uncertain.

The accident comes at a time when the South African mining industry has achieved its lowest casualty rate in decades—75 fatalities reported last year, out of a workforce of nearly half a million.