The Origins of Coal
Coal, essentially, is stored solar energy. During the Carboniferous period, earth was covered predominantly by plant life. When that period ended, the massive forests of primitive plants such as
were encased in earth in anaerobic environments. Lepidodendron was a very pithy plant with a scaly bark; as such, it was largely kept erect by the pressure of water against its cellular walls. When water resources became too few, the plants collapsed, dehydrated, and died. As these giant, 175 foot-tall ferns decomposed, they retained much of their energetic capacity (in the form of carbon) while losing most of the rest of their matter (water). As centuries passed, these giant trees of the past and their kin became the fossil fuels of today. What variety of coal each became, and where it is found, is largely then a matter of plate tectonics and pressure: the plants became scattered as Pangaea fractured, leaving deposits in various places around the world. Furthermore, the geological processes accompanying these tectonic shifts exerted their own influence on the composition of the coal as well.
Coal can be found in three basic forms: lignite, bituminous coal, and anthracite. While different gradations exist within these three categories, the major difference between them is a function of pressure. Coal is a sedimentary rock; the particulate matter that results from the decomposition of plant and animal life is crushed and compacted over time to form one of these varieties. American anthracite coal is found mostly in Western Pennsylvania, where it was forged in the pressure cooker of the Appalachian mountain chain approximately 200 million years ago. Eastern bituminous coal, found most plentifully in West Virginia and Illinois, was also formed during this time period. This contrasts greatly with western coal, found mostly in Wyoming. This coal was formed roughly 70 million years ago.6
The fact that the United States was, in its early existence as a continent, the home of a shallow inland sea full of plants probably has much to do with the vast quantities of coal that we can tout as a natural resource. Considering the fact that each foot of a coal seam “represents the accumulation of about 10,000 years of plant remains,”7 it is fascinating to imagine the prehistoric landscape of the North American continent. How many centuries of swamps and forests came and went, adding layer upon layer of biomass that would eventually leave 290 billion tons of coal: enough coal to last three centuries. For this reason, during the oil-induced energy crisis of the 1970’s, the coal industry dubbed the United States “The Saudi Arabia of Coal.” In fact, coal deposits cover about 13% of the surface area of the United States. That is an area larger than California and Texas combined.
Americans must thank coal for 58 percent of the United States’ electrical energy generation. For the most part, the United States’ coal reserves lie in West Virginia, Pennsylvania, the Ohio River Valley, and the Northern Great Plains. Thus, coal extraction has been a major industry in these areas since the Civil War Era or earlier. But how does one harvest coal? The work of a coal miner is perhaps one of the most dangerous jobs in the industrialized world.
Types of Coal Mines
There are two major types of coal mines: shaft mines and strip mines. Strip mines are exactly what they sound like. Large areas of land are “stripped,” layer by layer, and the coal is removed. Sometimes known as drift mines, these mines destroy the surface of the earth, leaving either large empty pits similar to rock quarries, or unnaturally flat stretches of land. In this method, no one goes underground, and the major activities undertaken by miners are the demolition of exposed coal seams and the use of shovels and construction vehicles to accumulate and move the coal. The other method, shaft mining, is the variety most people are familiar with. A tunnel, or shaft, is bored straight into the coal seam (slope mines), and miners go into the shaft to the exposed coal (known as the face) and remove the coal with tools. Depending on the topography of the area the coal seam is found in, shafts can either descend vertically into the ground, or horizontally into the side of a hill or mountain. In shaft mines, the networks of tunnels that branch off of the main shaft can stretch for miles in every direction, following the seams of coal. Furthermore, if coal is found in several layers--as is often the case--there can be any number of “floors” in the coal mine. This can result in a series of layers that, while only four to 15 feet in thickness, can cover thousands of square miles.s.8
The most basic tool for mining has long been the pickaxe. While different types of pickaxes have been used throughout the history of mining, it was long the integral part of the mining process. Before the invention of the battery operated lamp, the miner would use a candle stuck to the brim of his helmet and his pickaxe. Because of the presence of methane gas in the mines (exuded from coal), this was an extremely dangerous situation.
The lack of light and presence of methane limited the size of mines until the invention of the safety lamp in 1815. This lamp allowed for the dissipation of the temperature around the burning wick of the lamp, which kept the methane gas from reaching its flash point. However, when methane was present, the flame changed colors. This served as a useful warning for miners. Another benefit of the lamp was that it could detect carbon monoxide--fatal to miners because it could cause asphyxiation. When a miner wanted to check for one of these two lethal gases, he would put the lamp on a pole and extend it into the shaft before him. If the lamp changed blue, he knew methane was present, and took the necessary steps to remain safe: either hurry out of the mine, or pump in air to dissipate the methane. This was necessary because if the methane mixed with coal dust, it could explode. (The dangers of coal dust will be explored with an all-too-real example later in this paper.) If carbon monoxide was present, the miner would know because he would put the lamp close to the floor of the shaft where this gas accumulated, and it would go out.
As time passed, and technology improved, the tools available to miners improved. In fact, the use of coal allowed steam engines to become much more effective means of performing work, and therefore improved the means of extracting coal. Two illustrations of these symbiotic technological developments were the mine pump and the pneumatic drill. Because most mines are below the water table, moisture seepage could render a mine unusable. The steam engine-powered pump enabled the miners to pump greater quantities of water from mines at a greater depth than the use of humans or beasts of burden, thus improving the profitability of mining (machines being cheaper than people), and the strength of the pump. Also, by using pneumatic drills, miners were more productive. Using a pickaxe while lying on ones back, chipping away at the ceiling of a mine, was slow, dangerous work. Using the pneumatic drill made this work faster and less awkward.
The most dangerous tool used in coal mines was dynamite. In order to speed the process of extracting coal, miners used dynamite to loosen coal from the face. However, the obvious dangers of using explosives while in a flammable room led to the cautious use of dynamite. Oddly, it was not the coal face that posed an explosion danger, but the dust. Coal lumps do not explode because they don’t have enough surface area to do so; the temperatures necessary to ignite the coal face aren’t present enough to burn the face itself when there is a detonation. However, the coal dust is an entirely different matter. Once the coal is suspended in the air in particulate form, it is highly flammable and explosive. In fact, this is the preferred manner of burning coal in power plants today--as dust. Coal miners had to cover the mine floor, walls, and ceilings with a solution of rock dust and moisture in order to dilute the coal dust to the point of safety.
New Technologies in Mining
In the 1930’s, mining became more and more mechanized. While this led to some safety increases, it had the related consequences of making miners less necessary, driving down wages and reducing jobs. As a result, miners were forced to either find jobs that paid substantially less, or to deal with workplace pressures that made the ability to replace them much more dangerous. For example, if a mine operator did not want to modernize his equipment because of high capitalization costs, he could keep miners under control with the threat of replacing them with other miners or machines. This was a challenge for miners in the first half of the twentieth century. One can also speculate that, because the United Mine Workers were so effective in lobbying to improve the conditions of their labor, they accelerated the loss of much of their power by forcing companies’ hands in developing mechanized mining to minimize human loss in mine accidents and financial loss in wages, breaks in productivity due to strikes, and other financial outlays such as wage increases.
Coal-Driven Power Generation
Currently, coal is most useful for generating electrical energy. As previously stated, coal is burnt to generate approximately 58 percent of the United States’ electrical energy. Those states that do not use coal to generate electricity divide their production between the three next-largest producers of electricity: oil, natural gas (our other two fossil fuels), and nuclear power. One ton of coal, however, produces four times as many British Thermal Units (BTUs) as the next productive fuel. It can produce 24,050,000 BTUs per ton, while fuel oil only produces 6,287,000 BTUs. This fact further underscores the United States’ potential energy advantage over other nations, and further highlights the reasons for reticence to embrace climate change treaties such as the Kyoto Protocols.
Coal fired power plants are basically very efficient steam engines. The coal is delivered to the power plant and dumped into a hopper. It is pulverized into coal dust--the same dust so dangerous to the miners--and mixed with air and blown into the boiler for combustion. The coal then combusts, generating extreme heat that superheats pipes lining the perimeter of the boiler. The water flowing through these pipes converts to highly pressurized steam, which shoots through the blades of a turbine, generating the rotation necessary to turn a generator and create a current. After passing through the turbine and losing much of its energy, the steam condenses into water in a condenser tank and begins the process over again. The water in the condenser is released from the plant.t.9
The basic elements of this process have not changed in decades. However, the issues that arise from the use of coal have focused much attention on improving the efficiency and reducing the environmental costs of each of the separate steps in this process. For, if coal is to remain a viable source of energy, it is imperative that it clean up its act.
Coal and Environmental Concerns
Air Quality Pollution Resulting from Coal Consumption and its Costs
The political power of coal and its masters is both a blessing and a curse. Both England (the first nation to utilize coal as its primary energy source) and the United States rose to world dominance on the back of a coal-powered economy. King Coal, as it has been known at times in its history, was the provider of blessed industrial might to the many, and industrial woe to those who had to remove it from the ground for a living. However, contemporary environmental concerns have lent King Coal a new mantle: chief polluter and environmental bogeyman.
No matter what variety of coal one uses, it is the dirtiest fossil fuel. Soft coal is replete with SO2 , and even the hardest varieties of coal can have this noxious pollutant in large amounts. Human and animal deaths can be attributed to this compound.10 In June of 2004, the AP reported that fully one third of the United States population lived in counties (243 in total, most of which were east of the Mississippi river) in which the level of microscopic soot was above acceptable levels. In an ironic twist, the considerably smaller concentrations of SO2 in coal found in Wyoming have made it a champion of tighter environmental controls on coal--Wyoming’s coal industry benefits from any regulations that place limits on Eastern Coal. Also, the lack of coal elsewhere in the Midwest has resulted in cleaner air in the Midwest..11
Any environmentally sound policy, however, comes with significant political risks and costs. A case in point: in the 2000 presidential election, which was eventually decided by a Supreme Court decision, West Virginia voted against its strongly democratic tradition when it delivered its electoral votes to fossil-fuel friendly Republican candidate George Bush over the more environmentally conscious--and presumably anti-fossil fuel--Democrat Al Gore. As we know, the Bush presidency resulted in the deposition of Saddam Hussein in Iraq, a situation that promised to liberalize Middle Eastern oil production. However, at the time of this writing, the primary result has been instability in the world’s oil markets caused by resultant political instability in Iraq and unrelated, but exacerbating complications in the Russian oil industry. Because of coal-related decision making, coal, one could conclude, has a disproportionately far-reaching impact on America’s energy destiny: perhaps a history-altering one. John Kerry, Gore’s successor in running for the Democratic Party, in an effort to return the party to the White House, has made clean coal technology a key point in his plan for energy independence: a decision that could help him do well at the polls in West Virginia and Wyoming, but which may not allow Americans to breathe any easier in the long run. .
Global Warming, Nuclear Radiation, and Coal
Because coal requires combustion, it emits Carbon Dioxide (CO2). In fact, it emits more CO2 per kilogram of fuel than any other fossil fuel.12 Furthermore, uranium and thorium are found in significant amounts in coal. The resultant radiation from these plants, then, makes them more radioactive than nuclear power plants because these fissionable materials escape through the smokestacks of the plants. In fact, the amount of fissionable materials released through coal smokestacks could theoretically provide more energy than the amount of coal consumed!13 While there does not seem to be any immediate danger to people through this radioactive material, this further underscores the dirtiness of coal.
Cleaning Up Coal
Clean Coal Technology relies on many complicated processes, but is beyond the purview of our project here. Suffice it to say that “clean coal” in the modern era of global warming is a phrase roughly the equivalent of “safe sex” in the era of HIV/AIDS. However, the impetus for continuing to clean up coal is economic: the cleaner we can burn coal, the longer we will be able to maintain a disproportionate rate of energy consumption relative to the rest of the world. According to The Economist (Sept. 2002), “[C]lean-coal technologies fall into three categories: pre-combustion processing of coal; combustion processes that burn coal more cleanly; and post-combustion processes that scrub the exhausts.” These processes are highly technical in nature, and are therefore best discovered directly from the source materials. While students would most likely be able to learn about these processes, a shared exploration of source documents would be most effective for teachers interested in these processes.