Second quarter iron ore output was still 9 percent higher than the same quarter of 2014 at 79.7 million tonnes and 7 percent above the first quarter of 2015, data released by the Anglo-Australian company showed.
The result was as in line with analysts expectations of around 80 million tonnes, including Rio Tinto's partners in some mines.
Read MoreWhat iron ore's 10% rebound means
"We have maintained our emphasis on efficiency and protecting returns, which is reflected in this solid production performance, "Chief Executive Sam Walsh said in a statement.
Iron ore staged a modest recovery in June but tumbled to a decade low near $44 a tonne last week, as inventories at Chinese ports swelled and demand from Chinese steel mills waned.
Amid lower margins, Rio and rival BHP Billiton have been producing at full tilt to boost profits, but are facing a fightback from Brazil's Vale, the world's biggest producer.