The DRC has reintroduced its ban on copper and cobalt concentrate exports, which expired on April 12, and Ivanhoe said it was aware of the order issued to customs officials by a provincial director in Katanga.

However the company said it was also aware of a subsequent letter confirming companies with an exemption from the mines minister would be allowed to export concentrates.

"Kamoa Copper has filed the necessary application materials and we have had constructive discussions with the Minister of Mines on obtaining a derogation for Kamoa-Kakula given current limitations on smelting capacity in-country," Ivanhoe Mines president and CFO Marna Cloete said on Friday.

The joint venture with Zijin Mining started its phase one 3.8 million tonne per annum production last Tuesday, with Ivanhoe announcing the news a day later, the same day DRC president Felix Tshisekedi welcomed the start on Twitter.

"The start of production of copper concentrate at the Kamoa-Kakula mine indicates that the DRC is open for business and investment," Tshisekedi said in a joint statement.

However mining companies are likely to be on edge given Tshisekedi's recent plans to renegotiate mining contracts.

The DRC was rated the riskiest jurisdiction in the world in Mining Journal Intelligence's World Risk Report 2020.

Cloete said Ivanhoe fully intended to utilise local smelter capacity "to the extent possible".

"Furthermore, as we announced in March, Ivanhoe Mines, together with our joint venture partner Zijin Mining, is assessing the construction of a smelting complex at Kamoa-Kakula for the production of blister and anode copper," she said.

"This is all part of our intention to operate responsibly in the DRC for generations to come, and for the benefit of all of our stakeholders, including the government of DRC who are our 20% partner in Kamoa Copper."

Phase one is expected to produce 200,000t of copper per year and the planned expansion to 19Mtpa is expected to make it the world's second-largest copper mining complex with peak production of more than 800,000tpa.

Its start marked a new era of commercial copper production for Ivanhoe, which is also redeveloping Kipushi in the DRC and its Platreef discovery in South Africa.

Ivanhoe shares (TSX: IVN), which reached an all-time peak of C$9.74 earlier this month, fell 4.3% in Toronto on Friday to $8.88 to value it at $10.7 billion (US$8.9 billion).