London - Glencore, the mining and commodities company led by billionaire Ivan Glasenberg, reported a 9-percent decline in copper production after ore grades fell and a Chilean mine shut for maintenance.

Output of copper from mines in Africa, Australia and South America was 350 700 metric tons in the first quarter, the Baar, Switzerland-based company said on Tuesday in a statement. That compared with 385 600 tons a year earlier.

Ore grades declined at the Alumbrera mine in Argentina and the Antamina mine in Peru, while planned work at the Collahuasi operation in Chile also reduced volumes of the metal used in pipes and wires.

Glencore, the world’s biggest exporter of power-station coal, said output of the commodity increased 4 percent to 35.6 million tons. The company has said it will trim Australian production by 15 million tons this year and is considering shutting operations in South Africa after prices slumped to near the lowest since 2007.

Production of zinc rose 16 percent to 356 200 tons, lead decreased 4 percent to 75 800 tons and nickel gained 7 percent to 23 800 tons.