BHP Billiton on Wednesday reported strong production of copper and petroleum products in the first quarter of the financial year, but only a slight boost to iron ore output.
"The release of latent capacity and robust operating performance across our diversified portfolio continues to underpin strong growth in our high margin businesses," it said in its quarterly activities report.
The world's biggest miner said its production of iron ore -- a key steelmaking commodity -- rose one percent on-year to 39.77 million tonnes in the three months to September 30.
But shipments were down three percent on the June quarter with the company saying production was impacted by a planned shutdown related to harbour expansion work at its flagship west Australia operations.
Production of metallurgical coal -- another key ingredient for making steel -- dropped four percent to 8.94 million tonnes from the same period last year but was up 10 percent on the June quarter.
The Melbourne-based company posted a significant rise in production of petroleum products, which were up 19 percent from the previous corresponding period, including a 30 percent surge in gas output.
Copper output was also strong, jumping 24 percent on the September quarter last year, reflected by higher grade ore at its Escondida mine in Chile and record quarterly production at Antamina in Peru.
Zinc production was up 11 percent from the previous September quarter, uranium up four percent, silver production was steady while lead output dropped six percent.