Brennender Berg, Germany
Brennender Berg in English is “Burning Mountain,” although it is more of a gorge than a mountain. It refers to an area of Germany between the towns of Dudweiler and Sulzbach-Neuweiler, under which a seam of coal has been burning since around 1668 – more than 350 years.
In 1688, the tale goes, a shepherd started a wood fire on a tree stump, which burned to the roots and ignited the coal seam; more likely, this was a case of spontaneous combustion linked to early coal workings.
The burning coal seam is now evidenced mainly by warm rock, glowing embers, and sulfurous smoke rather than open flames as in the past. The area is less dangerous than it was in previous centuries and is open for visitors, but fumes and uneven ground still warrant caution; a hike is best on cooler days or after rain when the smoke is less intense.
Smoking Hills, Canada
The Smoking Hills of Canada are located near Franklin Bay on the Arctic Ocean in the Northwest Territories of Canada. The uninhabited hills (the nearest community is about 65 miles away) lie above the Arctic Circle. Discovered by explorer John Franklin in 1826, the hills are notable for exuding constant smoke from burning sulfur- and lignite-rich shales underground.
The mountains contain large deposits of lignite (brown coal), sulfur, and oil shales. A reaction between sulfur minerals, oxygen, and lignite leads to spontaneous combustion, and it is believed that the deposits have been burning for hundreds of years.
The smoke and runoff are highly acidic, and nearby ponds and lakes can reach pH values below 2, meaning they are habitable only by species that thrive in acid environments. In 1850, Robert McClure’s expedition collected a specimen of the burning minerals that later burned a hole through the captain’s mahogany desk, and today the various chemicals in the burning rock and smoke have left bright stripes of color along the hills.
Burning Mountain, Australia
Officially named Mount Wingen, Burning Mountain is located about 139 miles north of Sydney, Australia, and is part of the Burning Mountain Nature Reserve. The mountain was first thought to be a volcano because of vents spewing sulfurous smoke, but later investigation showed there is a burning coal seam running underneath.
The traditional story told by the Indigenous people centres on a woman whose husband did not come home from battle; wanting to die, she climbed the mountain and was turned into a stone that cried tears of fire, which rolled down the mountain and set it aflame. Today, scientists think the fire started either after a lightning strike or by spontaneous combustion.
The mountain’s coal seam is about two meters thick and roughly 30 meters below the surface. Recent estimates suggest the fire has been burning for approximately 5,500–6,000 years, making it one of the oldest known coal fires on Earth.
Centralia, Pennsylvania, USA
Coal-rich Pennsylvania has endured many coal seam fires, but most eventually are extinguished or burn themselves out. Not so in the town of Centralia. Deep mining left passageways underground as strip mining tore up the surface above. In 1962, volunteer firefighters ignited a fire to clean out one pit-turned-landfill in order to make room for more garbage.
The fire was doused with water that night, but was found to be burning the next day. More attempts to put the fire out were unsuccessful, and it was discovered that a hole in the pit led to a mine passage, which let the fire reach a coal seam and stymied all attempts to extinguish it; some locals still argue the seam fire may have started earlier.
The underground fire reached downtown by 1979, when a gas station owner (who was also the mayor) measured his gasoline storage tank at 172 degrees. In 1981, a 12-year-old boy fell into a sinkhole venting hot gases; he was pulled out by his cousin and survived. Residents accepted government buyouts beginning in 1984 and gradually relocated, and Centralia was officially condemned in 1992.
A handful of residents remained for decades, but recent census and demographic estimates now put the official population at between 1 and 4 people, effectively making it a near-ghost town. The mine fire has now been burning for more than 60 years and is expected to continue for many decades, possibly centuries, if left alone.
eMalahleni, South Africa
Coal mining in the Mpumalanga province (formerly Eastern Transvaal) of South Africa centres around the city of eMalahleni, which means “place of coal.” It was formerly known under its Afrikaans name, Witbank. The extensive Transvaal and Delagoa Bay Collieries were abandoned in 1953 without reclamation, and parts of the mines have been on fire ever since.
Witbank coalfield mines typically had a low coal recovery ratio, and the pillars of coal left behind spontaneously combusted in contact with oxygen.
The abandoned underground mine passages collapse unexpectedly, and have injured and killed people occasionally over the years, either from the collapse or the burning coal underneath. Ongoing research and satellite monitoring continue to map active fires and subsidence zones in the eMalahleni coalfield, highlighting how long-term environmental and safety problems can persist long after mines are closed.
These are not the only long-burning coal seam fires. They’ve happened throughout history and sometimes burn for centuries or even millennia. There are other underground coal fires burning today as well, all over the world, contributing to land degradation, local air pollution, and greenhouse gas emissions.