The miner, whose second-quarter results included a $45 million loss from copper hedging, said it aims to ensure a level of cash flow for its $6.3 billion Cobre Panama project ahead of commercial production.
The Toronto-based company said it has 25,000 tonnes of copper under forward sales contracts, at an average price of $3.15 per pound, maturing out to December 2018. A further 98,000 tonnes, at average prices of $3.04-$3.45 per pound, mature out to June 2019.
"We continue to sell all of our production into a market where there is excess demand," said Chief Executive Philip Pascall in a statement.
"Nevertheless, in light of current conditions, we think it is prudent to extend our copper sales hedge program on a limited basis. The intent is to ensure a certain level of cash flow during Cobre Panama's commissioning and ramp-up phases that precede commercial operations."
Cobre Panama, with proven reserves of 3.18 billion tonnes and a 40-year mine life, is 80 percent owned by First Quantum and 20 percent owned by Korea Panama Mining Corp, a partnership of Korea Resources Corp [KOREC.UL] and LS-Nikko Copper.
Mine commissioning is starting this year with operations ramping up over 2019. In 2020, the mine is expected to process 85 million tonnes of ore.
First Quantum, primarily a copper miner that also produces nickel and gold, reported second-quarter earnings of $128 million, or 19 cents per share, slightly lagging analysts' expectations for a profit of 21 cents a share, on average, according to Thomson Reuters I/B/E/S.
Copper prices are down about 15 percent from a mid-June peak as uncertainty over tariffs and trade wars rattles markets.
First Quantum also said it had filed documents with the Zambia Revenue Authority challenging an $8 billion tax fine imposed in March, while it continues to work with the agency.
(Reporting by Susan Taylor)
By Susan Taylor