At least 20 mine employees perished in a road accident in South Africa

Sunday, local officials reported that at least 20 employees of mining giant De Beers were killed in a road accident in South Africa.

A transport official in the northern province of Limpopo stated that the involved bus was transporting employees from one of the country's largest diamond mines, the Venetia mine.

According to Vongani Chauke, the bus collided with a truck.

Chauke told AFP that the incident occurred at approximately 1600 GMT, 25 kilometers (15 miles) from the mine, in the village of Musian, which is located on the border with Zimbabwe.

It has not been determined what caused the accident.

South Africa has one of the most developed road networks on the African continent, but one of the worst road safety records.

The Venetia mine, located near the borders of Botswana and Zimbabwe, has been operated by the De Beers group for more than three decades.

It accounts for more than 40 percent of the country's annual diamond output and employs more than 4,300 people, including a significant number of locals.

It was the country's largest open-pit mine before De Beers invested $2 billion in a major underground project to gain access to less accessible diamonds. The organization's annual production goal is four million carats.

In July, De Beers announced the start of underground diamond production from the newly exposed seams beneath the open-pit mine.