Two South African gold mining companies have reported workers' deaths.

AngloGold Ashanti Ltd., the country's largest gold producer, said Thursday a worker died in a falling ground accident, according to IOL Business.

The accident could have been a result of seismic activity that occurred during drilling.

The South African Department of Mineral Resources was said to be investigating the accident and production was halted.

Harmony Gold Mining Co., the country's third-largest gold producer, said an employee died after a mud rush accident on Thursday.

Mining companies have long been criticized for dangerous conditions that have led to worker deaths. Susan Shabangu, South African mining minister, said in August that high gold and platinum prices could be leading companies to drill in deeper and more dangerous areas, leading to more fatalities in a pursuit of profits.

However, the statistical evidence paints a more complex situation. For example, the number of workers killed in gold mines fell to 63 in 2010, down 22 percent from 81 in 2009, according to the Department of Mineral Resources. Figures for 2011 have not been released.

The Department of Mineral Resources is seeking to bring safety levels to international benchmarks by 2013.