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Kidd Mine, which has the world’s oldest pool of water

Kidd Mine Ontario: The World's Oldest Pool of Water

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In the depths of the earth there are discoveries being made that are revolutionizing our view of the world and even the nature of life. In a mine in Ontario there is a body of water that is probably the world’s oldest pool of water. It is believed that this pool could be over two billion years old. This body of water may not look much, but it is exciting scientists as it could contain information and even organisms that could change our view of life.

Its Northern Point Is the Nearest Point to the Center of the Earth

The two-billion-year-old pool of water is located in the Kidd Mine in Ontario near the city of Timmins. The mine is a base metal mine and it has one of the globe’s largest sulfide ore deposits in the world. It is up to 10,000 feet (3,300 meters) deep. One of the most remarkable facts about the mine is that its northern point is the nearest point to the center of the earth that is potentially accessible to humans. This makes it very important to scientists.

Scientist testing the world’s oldest pool of water (Photo by Barbara Sherwood Lollar)

Scientist testing the world’s oldest pool of water (Photo by Barbara Sherwood Lollar)

History of the World’s Oldest Pool

Experts from the University of Toronto were drawn to the mine because it was so deep. They decided to explore it and they went deeper into the site than any previous team, using a drill to look for evidence of water.

In 2013 they discovered a pool of water that was 1.5 billion-years-old and this encouraged the team to explore further in the hope of finding even older reservoirs. The team of experts continued to dig further into the mine, some 2 miles (3 kilometers) beneath the surface of the earth.  This was made easier by the fact that the mine is continuing to go deeper and deeper.  Then at just over 3 miles (4.8km) underground, they found what they had been looking for - a pool of flowing water.  What surprised them was the extent of the pool and the high volume of flowing water.

Groundwater usually flows slowly when compared to surface water. It can only move about three feet (1 meter) per year. However, when tapped by drills using boreholes, it can flow much faster, approximately 2 liters every minute.

Gas bubbles in the water rising to the surface (Photo Credit: University of Toronto)

Gas bubbles in the water rising to the surface (Photo Credit: University of Toronto )

The experts from the University of Toronto took samples from the pool and subjected them to chemical analyses, testing the gases that had been dissolved in the ancient pool of water. They found traces of helium, argon, and neon and this enabled them to date the water. At two billion years old, it’s the oldest water found in the history of the world. This is a geochemistry record and at present samples from the pool are being independently tested to verify the findings.

Researchers have established that these ancient pools of water deep in the earth have the capability to support life. Therefore the oldest pool could potentially be a unique ecosystem which may have been sustaining life for two billion years or even more. The discovery of the pool proves that life can theoretically emerge even miles under the earth, although no microbes or organisms have been found in the pool of water so far.

What is really exciting is that the conditions in the mine are comparable to the surface of other uninhabitable planets.  Therefore, the processes that could, in theory, produce and sustain life underground, could also occur on the surface of planets such as Mars.

The find is encouraging experts in Canada and all over the globe to further explore for pools of water in the depths of the earth which could help us understand if and how life can develop in areas which once were thought to be uninhabitable.

Recent testing on one sample of water is apparently demonstrating that the world’s oldest pool of water is even older than first thought.

The Kidd mine is currently nearing the end of its working life as it’s due for closure in 2020. It is not known if research can be conducted beyond this date.

Kidd Mine is not accessible to tourists

Visiting the mine is unfortunately not possible. It is a restricted area and only staff members and those with special permission are allowed on site.

Top image: Kidd Mine, which has the world’s oldest pool of water  Source: (Public Domain)

By Ed Whelan


Dockrill, Peter (2016) The World's Oldest Water Is Even More Ancient Than We Realised

Available from

Nisbet, E.G. and Sleep, N.H., 2001. The habitat and nature of early life. Nature, 409(6823), p.1083. Available from

Sussman, R., 2014. The oldest living things in the world. University of Chicago Press.

Ed Whelan's picture


My name is Edward Whelan and I graduated with a PhD in history in 2008. Between 2010-2012 I worked in the Limerick City Archives. I have written a book and several peer reviewed journal articles. At present I am a... Read More

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