"The mine produces lower quality diamonds which makes it expensive to dig during this period when the market is depressed," he was quoted as saying by Reuters.
The mine produces an average annual output of 500,000 carats, 2.5% of Debswana's total production.
However, Damtshaa's diamonds are said to be of lower value than those produced at Jwaneng and Orapa mines.
Meanwhile, Debswana will also close a processing plant at Orapa Mine for an indefinite period.
At least 500 jobs are at risk from the closures.
Debswana produced 12.3 million carats in the first nine months of the year, down 29% compared to the same period of 2019.
Mathew Nyaungwa, Editor in Chief of the African Bureau, Rough&Polished