A Glencore-owned copper mine in the Democratic Republic of Congo is embroiled in a row over royalties with local tax authorities.

The government body – known by its French acronym DGRAD – says that Kamoto Copper Co (KCC) owes the Congolese state a little over €800-million ($894-million), according to people familiar with the matter. After the unit’s local bank accounts were frozen earlier this year, the tax collection staff this week also briefly sealed off a warehouse where the company was storing metal, the people said, asking not to be named because the information wasn’t public.

Kamoto – in which the Swiss commodity giant holds a 75% interest – is one of the largest mines in Congo, exporting 200 000 tons of copper and 16 000 tons of cobalt in 2023, according to government data. Production of copper and cobalt at the mine has been unaffected by the dispute, the people said.

It produced 89 000 tons of copper and 11 700 tons of cobalt in the first half of the year. Glencore also operates a second copper-cobalt project in Congo.

A Glencore spokesperson declined to comment on the dispute. A spokesperson for the finance ministry, which oversees DGRAD, didn’t immediately respond to a request for comment. KCC’s total tax and royalty payments in Congo between 2021 and 2023 were $2.3-billion, according to information published by the company.

Agents from the tax agency visited the Kamoto warehouse in the mining hub of Kolwezi on Tuesday to close it off but the facility was unsealed the following day and operations returned to normal, the people said. The tax body opted to restrict bank accounts and seize property after discussions between the two sides didn’t lead to a resolution, they added.

Congo – whose copper exports have more than tripled since 2015 – recently overtook Peru to become the world’s second-largest producer of the metal that’s key to the green-energy transition. The country is also by far the biggest source of cobalt, accounting for about three-quarters of total global output last year.