(Bloomberg) -- First Quantum Minerals Ltd. has offered to buy the Zambian government’s 20 percent stake in Africa’s biggest copper mine for as much as $700 million, according to two people familiar with the transaction.

Vancouver-based First Quantum already owns 80 percent of the Kansanshi mine in Zambia’s North-Western Province, while state-owned ZCCM Investments Holdings Plc holds the rest. The proposal, which was submitted last year, includes $300 million to $400 million in cash, and an equal amount in special royalties, over more than 10 years, said the people, who asked not to be identified because they’re not authorized to comment.

First Quantum spokesman John Gladston declined to comment. Amos Chanda, Zambian President Edgar Lungu’s spokesman, didn’t immediately respond to a call and message seeking comment, and neither did a spokeswoman for ZCCM-IH.

The deal would also include ZCCM-IH dropping a $1.4 billion legal claim against First Quantum over a loan the company received from Kansanshi, the people said. The government is still considering the proposal, according to one of the people.

First Quantum and the government have been at loggerheads over other issues too. The country’s revenue authority handed it a $7.9 billion tax bill last year, while an increase in royalties this year prompted First Quantum to announce plans to fire 2,500 workers. The company has since backtracked on the proposal.

Kansanshi is First Quantum’s biggest mine, and accounted for more than half the company’s revenue in 2017.

To contact the reporters on this story: Matthew Hill in Maputo at mhill58@bloomberg.net;Taonga Clifford Mitimingi in Lusaka at tmitimingi@bloomberg.net

To contact the editors responsible for this story: Antony Sguazzin at asguazzin@bloomberg.net, Hilton Shone, Gordon Bell

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