In New South Wales, Australia, a coal seam buried 98 feet (30 meters) below the surface of the Earth has been burning for thousands of years. Known as the Burning Mountain, it is known as the oldest combusting coal seam in the world.

Naturally Burning Coal Seam

The mysterious underground blaze has been continuously burning for at least 6,000 years, making it the oldest known fire on Earth. Some experts also believe that it may be far more ancient, even as old as 15,000 years.

The site is located under Mount Wingen, which literally means 'fire' in the local language to the Wanaruah people who originally owned the land. There is some evidence that the Burning Mountain was used by the Wanaruah people for cooking, manufacturing tools, and as a source of warmth in the winter months.

In its history, the Burning Mountain has covered a total area of 4.04 miles (6.5 kilometers), moving south at a speed of 3.2 feet (one meter) per year. It is just one of thousands of coal seams which burn at any one time around the globe.

According to fire science professor Guillermo Rein from the Imperial College London, no one knows the exact size of the fire under the Burning Mountain. Experts only infer that it measures 16-33 feet (5-10 meters) wide and reaches a temperature of 1,832 degrees Fahrenheit (1,000 degrees Celsius).

The area has been turned into a national park and is open to tourists. Visitors can witness some smoke and white ash, warm ground, discolored rocks, and a sulfur smell released as the subterranean fire cooks the minerals of the mountain.

Although the fire is almost invisible now, the path it has taken is visible upon closer inspection. It has burnt areas covered in ash and is devoid of plant life.

READ ALSO: Coal Waste In Australia May Be Putting The Country At Risk

How Did the Fire Start?

No one can tell who first ignited the underground fire in Mount Wingen. The first documented European to see the smoke was a farmhand named Smart, who discovered it in 1828. At first, he thought that he found a volcano in the region.

The following year, geologist Reverend CPN Wilton examined the area and thought that the alleged volcano was actually a coal seam fire. Aside from his investigation, no other official research has been done on the Burning Mountain at the time.

Once ignited, these underground fires are almost impossible to put out. They just slowly and intensely travel through the coal seam, a layer of coal which occurs naturally beneath the surface of the Earth.

Unlike a normal fire, a coal seam fire burns below the ground. It is smoldering, which means that there is no flame but is just more like embers in a barbecue. This makes coal seam fire different from the one emitted by coal seam gas which is known to set waterways on fire.

Many coal seam fires, like those found in the US, China, and India, are caused by human activities like coal mining. Below Centralia, Pennsylvania, a now-deserted town has been burning for almost 60 years.

Mount Wingen is far away enough from civilization to cause any danger. However, experts believe that coal seam fires can be more common due to climate change and may release large amounts of carbon dioxide and methane into the atmosphere.

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