Jharia coal fires may burn hotter, emit more greenhouse gases

Editorial Lens

"A recent study published in 'Communications Earth and Environment' has fundamentally revised our understanding of the Jharia coalfield fires in Jharkhand. The research reveals that these subsurface fires are far more intense and ecologically damaging than previously understood, with temperatures potentially reaching 4,000°C. This extreme heat facilitates unique geological phenomena, such as the formation of 'birianiite'—a type of paralava where rock is melted and re-solidified into a fused, glass-enveloped structure. Beyond the localized geological impact, the study highlights a massive, overlooked dimension of the climate crisis: the fugitive emissions from these fires. The numerical modeling suggests the Jharia fires could contribute up to 748.72 million tonnes of carbon dioxide equivalent per year to global warming. The mechanism involves mining-induced oxygen exposure triggering spontaneous oxidation, which subsequently causes structural collapses that act as 'chimneys,' venting toxic gases and heat directly into the atmosphere, representing a significant challenge for both environmental management and global climate mitigation strategies."

Context and Overview

A groundbreaking scientific study published on May 18 in the international journal Communications Earth and Environment has revealed that the decades-old underground coal fires in the Jharia coalfields of Jharkhand burn significantly hotter and release far more greenhouse gases than previously estimated. Conducted by a collaborative team of researchers from the United Kingdom and India, including the Council of Scientific and Industrial Research Central Institute of Mining and Fuel Research, the study highlights a major overlooked challenge in global climate policy and environmental management.

The Mechanism of Subsurface Coal Fires

Subsurface coal fires are ignited when mining activities expose deep coal seams to atmospheric oxygen. This exposure triggers spontaneous natural oxidation reactions, causing the coal to smoulder continuously deep underground for years or even decades.

As the fires consume the subsurface coal seams, they destabilize the overlying rock layers, leading to structural collapse. These resulting collapse structures can reach up to ten meters in width and stretch vertically for more than one hundred meters through the earth. They essentially function as giant chimneys, venting toxic gases, heat, and smoke directly into the atmosphere.

Major Findings of the Research

1. Extreme Temperatures: Utilizing a combination of advanced computer modeling and direct field observations at the Ena, Bastacolla, and Tisera collieries, the researchers simulated heat flow and gas dynamics. They discovered that large, isolated collapse structures could reach temperatures approaching four thousand degrees Celsius under specific conditions. This is vastly higher than any conventional thermal estimates typically associated with underground coal fires.
2. Discovery of Birianiite: Due to the extreme thermal environment, researchers discovered instances of paralava, which is rock that has been completely melted and re-solidified by intense heat. At the Ena and Tisera collieries, they identified a unique type of fused, glass-enveloped rock. The team nicknamed this material birianiite, a nod to its highly heterogeneous geological composition and layered physical resemblance to the popular Indian rice dish, biryani.
3. Massive Scale of Fugitive Emissions: The numerical modeling estimates that the total global warming potential of the Jharia coal fires could be as high as 748.72 million tonnes of carbon dioxide equivalent per year.