Diamond miner De Beers Group on Friday said it was "shocked and saddened" by the sudden death of Debswana MD Albert Milton.
Milton had become unwell while in Johannesburg on Thursday evening. He had been admitted to hospital, but died early on Friday morning.
"We extend our deepest condolences to Albert’s family, relatives and friends. Our thoughts are with them at this most difficult time," the group said.
Milton had joined Debswana, a 50:50 joint venture between De Beers and the government of Botswna, in 1992. He held various positions throughout his career across the company’s mining operations and in leadership positions.
He was appointed Debswana MD in December 2018.
Debswana CFO Lynette Armstrong has been appointed acting MD.