From my research, it seems to be BHP Billition and Rio Tinto. However, this answer needs further confirmation.
bhp
Vale is the world's largest producer of iron ore and pellets and the world's second largest diversified mining company and present in more than 30 countries.
Mostly domestic mining operations (who are heavily subsidized) which account for something like a third to half of the world's iron ore production. They also import immense quantities from Australia and I think Brazil, as well as other iron ore exporters.
China.
Brazil is the top producer of Iron Ore.
Iron ore is mined in Australia. Some of the largest iron ore deposits in the world are mind in Western Austalia, in the Pilbara region.
The countries that produce major iron ore in the world include China, Brazil, Australia, India, Russia, Canada and US. The type of iron ore found in these countries varies from each other. This factor forces or compels countries to import that kind of iron ore which is not found or is short in their country. Likewise they export the type of iron ore which is surplus one.
Iron ore is mined in many places around the world. South America, Australia, and Asia have some of the largest iron ore mines.
Minnesota is known to have the largest iron ore deposits in the United States, particularly in the Mesabi Iron Range. The state's iron ore is mainly used in steel production.
in the year 2009 unctad report say that 1) Australia is the biggest iron ore producing countries in the world. 2) Brazil 3) India 4) china
The countries with the largest reserves of iron ore are Australia, Brazil, and Russia. These countries have significant deposits of iron ore that are extracted and contribute to their global standing as major producers.