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The 'How to Grow a Planet' team embarked on an ambitious mission: to extract ancient oxygen from the famous 'iron bands' of South Africa. With the help of the Sishen iron mine (Kumba Iron Ore), we succeeded!

This was the oldest oxygen ever released, and it was breathed in by our presenter, Professor Iain Stewart.

The iron bands of South Africa and Australia are believed to have formed during the 'Great Oxidation Event' between two and a half and three billion years ago.

The 'Great Oxidation Event' was the most important event in the evolution of life, after the first formation of life; it was when the early ancestors of plants, the cyanobacteria, began to release large amounts of oxygen.

The first tranche of oxygen was largely absorbed by the iron in the ocean (forming the iron oxide bands at the bottom of the sea) but eventually there was so much oxygen that this was released into the air, forming the first breathable atmosphere. This was to fundamentally alter the course of evolution on Earth.

The Sishen mine is an enormous iron mine that normally extracts the rock rich in iron oxide to make iron, but Kumba Iron Ore kindly agreed to co-operate with us on this project.

Kumba Vreugdenburg, a Geologist at the mine, designed the unique method. One kilogram of lumpy iron ore was placed in a reactor. 99% pure hydrogen was pumped over the iron ore as it was heated to over 900 degrees Celsius. The hydrogen combined with the oxygen from the iron oxide to form water (as steam). This steam was condensed to form water. This was repeated until 600 ml of water was collected.

Then, using straightforward electrolysis with a car battery, the water was split into hydrogen and oxygen. Professor Iain Stewart collected a test-tube of this oxygen, believed to be the oldest oxygen ever released from ancient rock. As part of our filming, Iain took several inhalations of the ancient oxygen. This is a world first!

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