Fires: A Burning Global Recipe for Catastrophe
Glenn B. Stracher
I first contacted Anupma Prakash a couple of years ago to learn more about
coal fires around the world and their associated health and environmental impacts.
Problematic coal fires refer to the combustion of coal in underground seams,
in culm banks (where miners pile coal refuse from their excavations) or in storage
Prakash, who is an associate professor of geology at the University of Alaska-Fairbanks, took photographs of flames leaping into the air from coal fires in India and China that dramatically illustrate how newly exposed coal seams can ignite to dangerous levels. Such flames show up only when there is a sudden fresh collapse of the coal seam or a new coal surface is exposed while opencast mining is in progress, Prakash tells me.
But such flames are rare, she says. Coal fires frequently burn beneath the surface, and the damage they wreak on the environment and to human health is the result of sulfur and other toxins condensing onto soil, entering streams and groundwater or transferring into the atmosphere. And while the damage is extensive and often includes land subsidence from the underground burning, too often little is done to understand and prevent coal fire catastrophes from devastating forests and threatening or destroying communities.
A surface coal seam in an opencast mining area in the Rujigou coalfield in China collapses due to fires. The coal seam consisting of tens of meters of high quality bituminous to anthracite coal reduces to centimeters of ash and rubble on being burnt. Image courtesy of Anupma Prakash
I earned my doctorate in structural geology, focusing on the engineering aspects of stress and strain. I wanted to understand rock mechanics and how rocks deform and break. I didnt think of coal fires as contributing to such problems until I began my first teaching job, at Bloomsburg State University in Pennsylvania, near the coal fire burning beneath Centralia (Geotimes, October 2000). While I had heard about the Centralia fire and how the towns decision to burn landfill trash had ignited the Buck anthracite seam years earlier, I had never visited the site. When the geology department took a field trip to Centralia, I saw cracks in the road and valleys billowing with smoke. Sulfur and coal ash covered entire forested areas. The community had evacuated in response to the dangers of poisonous gas and subsidence. This was a geological catastrophe in action induced originally by people but prohibitive cost and difficulties meant little was being done to extinguish the fire.
The Centralia fire continues to burn today as do many other coal fires around the world. While coal fires have occurred naturally in the past during the Pleistocene and the Tertiary, millions of years before opencast and deep coal mining, human activity has promoted the proliferation and severity of these fires since the industrual revolution.
Ive been following coal fires ever since my visit to Centralia. Except for a small, brave group of dedicated people around the globe, some of whom I have noted in this article, it is a problem few others are studying. The work is dangerous and not without difficulties. Once started, coal fires can burn for years before cannibalizing their source of fuel. But there are many ways to fight such fires. Understanding the threat is the first step.
Northern China on fire
Coal production in China meets the fuel demands for about three-fourths of
the countrys energy requirements, but not without cost to the environment
and people. Coal fires, some burning for centuries, plague Ningxia, Xinjiang
and numerous provinces across northern China from Heilongjiang in the east to
Qinghai in the west. The Ningxia Hui and Xinjiang Uygur autonomous regions in
north-central and northwest China, respectively, contain most of Chinas
coal reserves. Lightning, spontaneous combustion, and legal and illegal mining
operations on all scales are responsible for most of the fires.
Andries Rosema of the Environmental Analysis and Remote Sensing (EARS) firm in the Netherlands worked with colleagues using satellite and airplane data to analyze the damage uncontrolled fires caused in China. The team found that the fires released up to 360 million metric tons of carbon dioxide 2 to 3 percent of worldwide production per year from burning fossil fuels, an amount equivalent to that emitted per year from all automobiles and light trucks in the United States. The economic loss of coal from these fires is as high as US$125 million to US$250 million, estimates Zhang Xiangmin of the International Institute for Geo-Information Science and Earth Observation (ITC) in the Netherlands.
Reports from the World Bank, World Resources Institute, and United Nations Development Program confirm that Chinas atmospheric pollution, primarily from coal combustion, is among the highest in the world. Coal gas and particulate matter are responsible for acid rain and human disease in more than 100 Chinese cities and the problems have spilled into other countries including Japan, Korea, the Philippines and Taiwan. Lung cancer, bronchitis, stroke, pulmonary heart disease, and chronic obstructive pulmonary disease which accounts for up to 26 percent of all deaths in China are on the rise. In some cases, such health effects are directly linked to coal emissions from indoor cooking and heating (Geotimes, November 2001).
Modern technology is assisting fire fighters in China. Optical and thermal images help in determining the location, size, depth, burning intensity, temperature, propagation direction and coal consumption of a fire. The Beijing Remote Sensing Corp., working with ITC, EARS and the Netherlands Institute of Applied Geo-Science, is integrating numerical modeling with geographic information systems software to generate fire-fighting maps and images of subsurface fires and to plan fire-fighting activities in the field.
Unfortunately, numerous fires are cost-prohibitive to extinguish and are allowed to burn unchecked, Prakash says.
Colorados tribal concerns
In the United States, fires have burned for decades in numerous coal-producing
states. According to the Office of Surface Mining of the U.S. Department of
the Interior, more than $651 million is needed to control these fires in abandoned
underground workings alone.
The Southern Ute Indian Nations Department of Energy in Ignacio, Colo., is playing a major role in trying to cool down and control the spread of subsurface coal fires endangering forests and fauna. The underground heat sources are promoting subsidence and accelerating erosion in the Cinder Buttes area of La Plata County. Dick Baughman, the tribal geologist, is responsible for reconnaissance surveys and temperature measurements in the field. Part of my job is to protect the forest, Baughman says.
Subsurface burning is responsible
for subsidence in parts of LaPlata County, Colo. Here the pre-burn surface was
originally at the elevation at the top of the photo. Dick Baughman is standing
on rock chemically weathered from coal-fire gas, also responsible for killing
vegetation. The coal bed in the foreground dips approximately 12 degrees into
the hillside. Photo by G. Stracher.
I had collected some condensation products from a vent in the area in May of 2001, and was careful to have colleagues watch me as I held my breath to keep from inhaling the fumes. In August, Baughman told me that a vent 30 feet away measured concentrations of hydrogen sulfide that could kill a person with a single gulp of air. When Baughman works with colleagues to take temperature measurements, he hangs a gas detector over the vent that measures the concentration of hydrogen sulfide.
When they need to extinguish a fire, each person wears a hydrogen sulfide gas detector. During mitigation attempts a safety person watches, and when anyones hydrogen sulfide gas detector sounds the alarm he makes sure everyone is evacuated to a safe area, Baughman says. If a vent was exhausting high hydrogen sulfide concentrations during normal field reconnaissance, I would just stay away from it.
To help extinguish the fires, Baughman directs fire fighters to problematic surface vents and fissures: the external manifestation of the ires below. The fire fighters, wearing protective gear, venture near explosive levels of methane and extremely toxic concentrations of hydrogen sulfide and sulfur dioxide to pump a grout consisting of fly-ash concrete and Thermocell coolant into the orifices. The grout starves the fires of oxygen and cools the fire down, but sometimes the sealant cracks. Results have left Baughman skeptical that the fires can be extinguished. The fires may cool down and stop encroaching into an undesirable area, but vents and fissures with temperatures as high as 1400 degrees Fahrenheit constantly reappear.
Working with Baughman this summer, I saw just how dangerous these fires can be as I watched a grout-filled vent-fissure system develop a crack and, within a day, release sulfur that had condensed from the exhaled gas. Such fast reaction kinetics enable toxic materials to quickly get into the groundwater, soil or streams. If the condensed sulfur mixes with rain or water, it turns into sulfuric acid which washes into the soil.
Vents in Indonesia emit toxic gases that form a green condensation of sulfur. Alfred E. Whitehouse et al.
Indias coal fires displacing people
In 1894, commercial mining began in Indias largest coalfield the
Jharia coalfield (JCF) north of the Damodar River in the state of Bihar. Coal
production in India supplies two-thirds of the countrys energy requirements
but, as in China, not without cost to the environment and Indias people.
Historical documents from Bharat Coaking Coal Limited (BCCL) in Bihar reveal
that the first fire broke out in 1916 and that by the 1960s fires had spread
throughout the entire coalfield. BCCL reports that most fires began by spontaneous
combustion before opencast or strip mining; or by deep, underground mining because
of exploitation without fire-prevention codes, now in place. In addition, some
JCF fires began in abandoned deep mines used as hideouts for the illegal distillation
of alcohol, Prakash says. Currently, about 37 million tons of coal are
lost to JCF fires.
Many large communities of people have relocated from the Jharia region to escape land subsidence and high concentrations of toxic coal gas and particulate matter. But the move is made difficult because of inoperable rail lines. The Government of India and Ministry of Coal are assisting with relocation funds. Regardless, the pollution is still causing people to suffer from asthma, chronic bronchitis, skin diseases and lung diseases.
Although fire-fighting techniques ranging from trenching for surface fires to inert gas injection for subsurface fires are used to combat the coal fires, BCCL reports that many large fires rage on because of inaccessible deep mines and the risk of subsidence.
The Asian Brown Haze
According to recent findings released in August by scientists with the United Nations Environment Programme (UNEP) including Nobel laureate Paul Crutzen of the Max-Planck Institute for Chemistry in Germany, Ashesh P. Mitra of the National Physical Laboratory in India, and Veerabhadran Ramanathan of the Scripps Institution of Oceanography in the United States burning fossil fuels in Asia are contributing to the expanding, three-kilometer thick Asian Brown Haze.
This cloud of particulate matter, acids and aerosols stretches across South Asia from Afghanistan to Sri Lanka. In the first half of the 1990s it contributed an estimated 60,000 human respiratory fatalities in India alone. It is responsible for crop failures induced by acid rain and for a 10 to 15 percent reduction in sunlight reaching the surface in South Asia, thereby altering weather patterns from drought in Pakistan to flooding in Bangladesh. Preliminary UNEP findings indicate the haze problem may be worse over China.
This cloud has the potential to coalesce with others around the world generated by coal fires and other sources of atmospheric pollution. The potential global consequences are frightening.
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