Slow Burn

Reporter / by Joseph Calamia /

Since 1962, a coal fire has been raging beneath Centralia, Pennsylvania, and it may continue burning for centuries. When the very ground beneath your feet catches fire, how can you extinguish the blaze?

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Credit: Joseph Calamia

Tourists drive for hours to Columbia County, hoping to find in a former mining town scenes of hell incarnate. They are disappointed.

In 1962, a small community in rural Pennsylvania prepared for a Memorial Day celebration. On the town’s edge, near the Odd Fellows Cemetery, sat an old mining pit turned municipal landfill. To control its smell and vermin, the story goes, volunteer firefighters set a small fire in the trash, let it burn for a few hours, and, after dousing the flames with water, left a smoking pit. Today, on what was once Route 61 just outside town, appears a spray-painted greeting:  “Welcome to Graffiti Highway.” About twenty feet down the road, smoke rises, almost imperceptibly, from a buckle in the paved sea of heart-encircled initials and crossed-out phone numbers. Some believe that Memorial Day trash fire ignited a seam of coal, the Buck Mountain vein, and started an underground inferno that still burns. If no one stops it—and no one plans to—some geologists estimate that it could continue burning for another two centuries.

The vestige of Centralia’s downtown is a broken web of dead end streets—abandoned in 1984 when the United States Congress spent $42 million to relocate those who wished to leave. Most street signs have disappeared, perhaps stolen by the same visitors who declared their love with blacktop and paint. Fewer than 20 of Centralia’s original 1,100 residents still live on these nameless streets. When they look out their windows, they don’t see flames and smoke, but overgrown brush, litter, and sinking concrete.

Though this town is famous, many mine fires are not. A map from the Pennsylvania Department of Environmental Protection shows over thirty of them speckled across the state’s northeast anthracite and southwest bituminous coal regions. Others, unknown or thought extinguished, may also be burning. One fire started in a city dump, in the town of Carbondale not far from Scranton, was thought extinguished in 1974. About a decade later, strange patterns formed in a perfect blanket of snow, footprints of the advancing fire below. Mine fires extend beyond Pennsylvania’s borders; they are common in the United States’ coal regions and other coalmining industrial nations including India, China, Russia, and Australia. Even when they don’t threaten homes, they waste a valuable natural resource and emit harmful gases. Since the mid-1980s, the US Department of Energy has invested over $3 billion in power plant “clean coal technologies,” but mine fires burn on, venting carbon monoxide, carbon dioxide, and methane in a wind poisonous to humans and the environment.

“I used to work in industry, now I’m paying for my sins,” said Martin Edwards, a geologist at the Pennsylvania Department of Environmental Protection, Bureau of Abandoned Mine Reclamation. Just because a mine is abandoned, Edwards explained, doesn’t mean it lacks coal to burn. As miners dig deep into the hidden seam, they leave about half of the coal in thick columns—to support their tunnels as they descend. Other mines have coal deposits weaved with less-valuable rock, making it economically infeasible to extract the fuel. From Edwards’ experience, underground fires most often start at the surface. Lightning can strike the ground, a forest fire can reach the area near an open pit, or, as is most often the case, someone can set some trash on fire.  Edwards spends days putting out refuse fires like the one that started the Centralia blaze. Other times these fires can start from inside the mine itself. In “the old days,” as Edwards described it, miners would purposely set fires underground. Cooler denser air rushed in under the fire’s lighter warmer surroundings. For the early miners, this convection current provided an effective circulation system, and sometimes, when the fire grew out of control, a disaster.

Though not purposely set, underground fires can still start today. Alex Smith, a geologist at the National Institute of Occupational Safety and Health, Pittsburgh Research Laboratory, studies these fires as threats to active miners. “Somebody doesn’t follow the usual precautions,” Smith said, “the sparks fly, you don’t see them, and they get embedded in a pile of coal. You think everything is good, until you walk away and the coal pile catches on fire.” Most of these fires result from the realities of the miner’s daily work:  electrical shorts or arcing, cutting and welding, and conveyor belt friction. The mine is a factory with electric and diesel-run power plants, cutting machinery, and conveyor belts to transport the newly freed chunks of fuel. “The belts run for miles,” Smith said, “If one becomes misaligned, eventually the friction can catch the coal on fire, which then catches the whole belt on fire.”

Smith explained another, more fantastic possibility:  spontaneous combustion. As freshly mined coal absorbs oxygen, it gives off small amounts of heat. Insulated by the mounds of coal surrounding it, the heat from this exothermic reaction grows. Moist, low-oxygen content coals, like the bituminous type near Pittsburgh, can start themselves burning as they dry, eventually igniting the seam.

In the United States, active mine accidents rarely cause disasters. “Usually those fires are able to be handled,” Smith said, describing current mandates for extinguishers and automatic suppression systems. “It’s pretty rare that a fire will actually get out of control and cause evacuation and loss of the mine.”

Instead, as in Centralia, many of the mines still burning were abandoned long before they went up in smoke.

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