Gaborone: De Beers’ joint venture in Namibia will shut four diamond mines in the country by 2022 due to dwindling resources, Reuters reported.

Namdeb, a 50:50 project with the nation’s government, will close the Elizabeth Bay mine at the end of 2018, the Daberas deposit at the end of 2019, Sendelingsdrif in 2020 and the main asset, Southern Coastal, in 2022, Reuters said, citing a statement in the local media by a senior union figure.

The Elizabeth Bay and Daberas mines are “well beyond their original planned life of mine,” Namdeb corporate-affairs manager Pauline Thomas said in a statement to Rapaport News.

“The next few years will remain challenging, mainly due to subdued world economic growth, which negatively impacts forecast exchange rates and other indices,” Thomas explained. “We are constantly investigating new mining opportunities, however it is equally important that we plan responsibly for the possible closure of operations that reach the end of their economic life span.”

Namdeb’s operations include land-based mines, as well as Debmarine Namibia, which searches for diamonds offshore. Land-based production amounted to 404,000 carats in 2016, while output at Debmarine — which includes five vessels that mine diamonds from the ocean floor — stood at 1.2 million carats.

Production in the country saw a shift toward the offshore assets this year. In the first nine months of 2017, Debmarine’s production surged 22% to 1.1 million carats, while land-based output declined 7% to 267,000 carats.