Shares in Rio Tinto Ltd (LSE:RIO, ASX:RIO, OTC:RTNTF) and Antofagasta PLC (LSE:ANTO) both rose 2% after the giant miners posted operational updates for the second quarter.
A day after announcing that iron ore chief Simon Trott will take over as CEO next month, Rio's current boss hailed "excellent" performance from the group's mines.
Highlights of the report included record production from the bauxite business and from the massive copper-gold deposit Oyu Tolgoi in Mongolia.
There was no change to guidance, but copper and bauxite are now expected to be at the upper end of the range, with costs at the lower end due to progress on the Oyu Tolgoi ramp-up, the performance of partly owned Escondida in Chile, and higher-than-expected gold prices also driving net costs down.
Rio noted that copper prices rebounded in Q2 amid easing trade tensions and a weaker dollar, with US CME prices 10% higher than in London due to US tariff risks, while market tightness deepened as Chinese smelters ramped up output despite falling treatment and refining charges.
Analysts at Panmure Liberum noted that iron ore had rebounded from a weak start and was the highest Q2 production since 2018.
For lithium, while global EV sales up 29% yoy in April-May, but the market was still seen as oversupplied, with a lack of cuts and new supply coming on.
As for Chilean copper specialist ANTO, chief executive Iván Arriagada pointed to increased production from its two largest mining districts, Los Pelambres and Centinela, with group production increasing 3% compared to the first quarter and 11% compared to the prior year.
Net cash costs fell 27%, or 32% compared to the prior year, benefiting from gold and molybdenum by-products.
"Guidance for the year remains unchanged with copper production for the full year expected to be in the range of 660-700,000 tonnes and net cash costs towards the lower end of the guidance range of $1.45-1.65/lb," he said.
Production is expected to increase quarter-on-quarter for the remainder of the year, following maintenance activities completed in the first half.
He noted that the supply-side is "becoming increasingly constrained".
Analyst Peter Mallin-Jones at Peel Hunt said copper production for the quarter was "a slight miss" compared to expectations, but unit costs were lower than expected.
Copper output of 160kt was slightly below his 163kt estimate, gold output of 48koz was lower than his 59koz estimate, while molybdenum output was a beat at 4.4kt versus 3.9kt.
"Despite the slightly lower volumes, gross cash costs were lower than we expected, aided by the super low copper TC/RCs [treatment and refining charges] at present."
The unit cost position "looks very promising" for the coming second half performance, Mallin-Jones added, "given the expectations for rising volumes through 3Q and 4Q, and we suspect this will more than offset minor concerns over the lower-than-expected output at Zaldivar".