The revision by the US Geological Survey (USGS) came after Vietnamese authorities arrested in October corporate executives that were partnering with Western companies to develop rare earths mining projects in Vietnam. There is no clear link between the USGS revision and the arrests.

The USGS did not immediately reply to a request for comment about its new estimates.

Despite having the world’s second-largest deposits of rare earths, estimated at around 22 million tonnes of rare earths oxide (REO) equivalent, Vietnam extracted only 1,200 tonnes in 2022, the statistics from the USGS show.

The agency had earlier estimated that Vietnam mined 4,300 tonnes in 2022. In its new forecast, it estimates output fell to just 600 tonnes of REO equivalent last year.

Rare earths are used in multiple industries, including electric vehicles, auto batteries and renewables, and have several applications in electronic and military products.

Before the arrests, Vietnam was planning new tenders for mining concession at its largest rare earths mine, which is still largely untapped, Reuters reported in September citing an executive at Australia’s mining company Blackstone Minerals Ltd.

Blackstone was planning to bid together with one of the two Vietnamese companies accused of illegally trading rare earths and whose executives were later arrested.

Blackstone and Vietnam’s environment ministry, which is in charge of mining projects, did not immediately reply to requests for comment about whether the tenders were still planned for rare earths mines.

The US has agreed to boost cooperation on rare earths with Vietnam, whose large untapped resources are seen as an alternative source of the minerals. China has the world’s largest deposits of rare earths and dominates the extraction and processing of the critical minerals.

The US embassy in Hanoi did not immediately respond to an emailed request for comment.