Debswana Diamond Company, a joint venture between the Botswana government and Anglo American’s De Beers, said on Friday that its new business strategy adopted last year should enable it to create at least ten-billion pula ($924-million) in additional revenue over the next four years.

The five-year strategy, adopted at the beginning of 2020, includes restructuring of mines and is aimed at improving efficiencies throughout the group's operations.

It is being accelerated after Debswana was hit hard by the coronavirus pandemic. Earnings almost halved last year as sales and production were hampered by domestic and global shutdowns and restrictions on movement.

The new plan has already seen the company close one of its smaller low-grade mines, while a 47 year-old processing plant was decommissioned at another mine.

In 2021 the company plans to make savings of at least 2-billion pula through the restructuring of parts of the organisation, its head of transformation and innovation Thabo Balopi told a briefing with investors and media.

Debswana's parent company De Beers last year adopted a new business transformation model which sought to restructure mines, expand in jewellery and overhaul diamond sales.

As mines get deeper and costlier to run, Debswana is looking to convert its flagship Jwaneng mine into an underground mine.

Preparations are already underway to prepare the company and its workforce for the transformation after 50 years of open cast mining.

Under the current "Cut 9" open-cast expansion project, Jwaneng’s lifespan is being extended to 2034, with underground mining expected to start thereafter.

"The shift to underground is expected to produce about nine-million carats annually and extend the mine’s lifespan by a further 20 years," Balopi said.

"Early access is expected by 2023 with full production from 2034. At full operation, Jwaneng will be the world's largest underground mine with a more than 360 km of tunnel network," Balopi said.

Initial costs of converting the mine to underground are estimated at 65-billion pula.

Debswana plans to increase output by 38% this year to pre-pandemic levels of 23 million carats, a company official told Reuters in February, as the global diamond market recovers with the easing of travel restrictions and jewellers reopen after lockdowns.