TORONTO - Chinese copper miner Jiangxi Copper Co has increased its stake in Canadian miner First Quantum Minerals (FQM) to 18.5% from 18.3%, after buying a total of 1.35-million shares, according to a public filing in Canada on Wednesday.

FQM shares have been under pressure since the Panama government moved to revoke the contract for the Canadian miner's flagship copper mine in the Central American country.

Jiangxi Copper, which already is the largest shareholder of FQM, made the purchases over three trading days starting November 3, taking its total shares in the Canadian company to 128.2-million shares, or about 18.5%, according to Reuters calculations.

In 2020, FQM adopted a poison pill takeover defense that prevents the Chinese company from buying more than 20% stake, under a standstill agreement.

FQM did not offer an immediate comment when reached by Reuters on Jiangxi Copper's decision to raise its stake. Jiangxi Copper was not immediately reachable for comment.

Earlier this week, brokerage firm Barclays cut the target price for FQM to C$17 from C$25.

Shares of FQM at the Toronto Stock Exchange closed 8% higher at C$16.84 on Thursday after trading up as much 8.9% on the Jiangxi Copper news.

Still, its shares are down about 40% since the Panama government proposed a referendum to decided whether the Cobre Panama mining licence should be canceled after massive protests against the government awarding the contract to FQM and lack of transparency while signing the contract.

Panama's top court will decide the validity of the contract, though a date for the ruling is not known yet.

Despite the protests, FQM's Panama operations are continuing.

Two sources familiar with the matter told Reuters that FQM remains on track to meet its production for the next fiscal year.

The mine, which accounts for approximately 5% of the Panama's GDP and supports more than 49 000 direct and indirect jobs, is the country's second-largest revenue source after the Panama Canal.

The Cobre Panama mine is one of the newest copper mines and was built at a cost of $11-billion over nearly two decades.