Currently, iron accounts for about 95% of the metals consumed worldwide every year. It can be said that iron is the "skeleton" supporting modern society, and without iron, there would be no modern civilization. Where does iron come from? Iron ores are divided into two main categories: one is sedimentary deposits formed on the surface of the earth - most of the global iron reserves come from this source; the other is endogenous deposits formed by magma and hydrothermal fluids in the earth's interior. Large and super-large iron mines are often associated with banded magnetite. Banded magnetite, also known as silica-iron formations, was formed mostly 2.0 billion years ago and is of a very large scale. A single deposit can be hundreds of meters thick, thousands of meters wide, and hundreds of thousands of meters long. This type of iron ore is composed of banded quartz and magnetite, with an iron content typically exceeding 15%, but it is not a high-grade iron ore, meaning it cannot be directly smelted without sorting. Banded magnetite can be further enriched through weathering, reaction with fluids such as water, and metamorphism, forming high-grade iron ores that can be directly smelted. Most of Australia's high-grade iron ores come from this process. The reason why Australia's iron ore is of such high quality can be simply summarized in four words: ancient and stable.
2.3 billion years ago, the oxygen content in the Earth's atmosphere was much lower than it is today, and the sulfur content in seawater was also very low. Therefore, iron existed mainly in the form of ferrous ions in seawater. Around 2.3 billion years ago, the oxygen content in the Earth's atmosphere rose to about half of its current level. At this time, ferrous ions were no longer stable and instead precipitated with silica, carbonates, etc., forming banded magnetite. Moreover, with the process of surface weathering, a large amount of iron was transported to the ocean, so the iron content in nearshore and lake waters is often higher than that in the open ocean, which is more conducive to mineralization. Australia is an ancient continent. Currently, the oldest minerals found worldwide come from Jack Hills in Western Australia. At the same time, Australia's continental crust is very stable. In the early stages of Earth's evolution, it was long in a shallow marine environment, receiving sediments from the continent and forming rich banded magnetite. Through long-term geological processes, the banded magnetite was further enriched, forming a series of super-large high-grade iron ores. Due to geological stability and the absence of large-scale mountain-building movements, these high-grade iron ores have been well preserved for billions of years. The famous Panawonika in Australia is a giant high-grade iron ore formed by the weathering of banded magnetite. The entire deposit is distributed along ancient river channels and exposed to the surface, making it easy to mine. The iron ore is very pure and can be directly smelted.
Speaking of Australia's iron ore, there is an interesting story. Australia is currently the world's largest iron ore exporter, with total reserves estimated at around 100 billion tons. However, before the 1950s, Australians always believed that their iron ore resources were very scarce and therefore prohibited iron ore exports. In 1952, Hancock and his wife, who were a farmer from Australia, took a private plane to Perth, the capital of Western Australia. During the flight, they encountered a heavy rainstorm and accidentally entered a huge canyon, where they unexpectedly found that the cliffs on both sides of the canyon were like rust. As a result, they discovered the world's largest iron ore deposit to date, which completely changed the pattern of iron ore in Australia and the world.
Australia has such favorable geological conditions that, in addition to iron ore, its uranium resources are also very rich. The uranium reserves at Olympic Dam alone account for about 40% of the total proven uranium reserves worldwide. In addition, Australia also has many bauxite deposits, which are also sedimentary deposits. On the flat plains, just a few meters of overburden can reveal high-quality bauxite. Australia's diamond reserves are also among the top in the world.