Rio Tinto Group, the world’s second-biggest mining company, may have found "huge" deposits of iron ore in southern Botswana, according to the CEO of the country’s chamber of mines.

The discovery in an area called Werda is thought to be an extension of South Africa’s Sishen deposits, which are mined by Anglo American Kumba Iron Ore, chamber CEO Charles Siwawa said on Wednesday in an interview in Walvis Bay, Namibia.

"From the presentations they made to the Botswana government, there are huge iron-ore deposits," Mr Siwawa said. "They might have found a second Sishen."

Rio Tinto, which has been working in Werda, near Botswana’s border with South Africa, for the past three years, will continue exploration work, Mr Siwawa said. Kumba’s Sishen mine produced almost 31-million metric tons of iron ore last year.

Rio Tinto was doing early stage iron-ore exploration in Botswana, the company said in its fourth-quarter operations review in January. A spokesman for the London-based company declined to comment further on Thursday.

Future output from Rio Tinto’s find and Tsodilo Resources’ Xaudum project in Ngamiland had the potential to surpass production from Botswana’s diamond-mining industry, Mr Siwawa said.

"The future of Botswana mining is going to be the coal and iron-ore resources and, of course, diamonds," he said.