The following research is on the subject of the advantages and disadvantages of the use of coal and of nuclear fuels in the production of electricity. The mineral and fuel reserves of this planet are not limitless, and the future will require the discovery of new resources and sources for the production of energy. Coal is one replacement for the use of oil in the production of electricity, and nuclear fuels are under consideration as well. However, nuclear fuels in particular are under fire from environmental groups fearful of the possibility of a melt-down in a nuclear reactor, which could conceivably spread death and destruction over a wide area. Coal and nuclear fuels each have a place in the future of energy production, and each also has certain drawbacks which limit their use to certain areas.
I. MINING AND PROCESSING OF THE FUEL
A single electrical generating plant producing 380,000-kw requires a total of one million gallons of oil per day; a large 1.2 million-kw coal-fired plant uses fuel at the rate of 8000 tons of coal — or about one hundred railroad cars full — every day.
Coal beds are no longer sought, for most of them have been located and only need to be explored further to determine their rank, ash content, continuity, thickness and depth over an area where mining is contemplated. Advances in the mining of coal have been considerable in recent years. In most underground mines today continuous mining machines are used. These use draglines with buckets that will hold more than three hundred tons of rock, stripping shovels that can take 270 tons of rock at a bite, and trucks of 240-ton capacity. In Turkey and Europe, bucket-wheel excavators are used that can dig as much as 300,000 tons a day.
Basically, coal is mined by three methods. Underground mines are entered by a vertical or inclined shaft leading from the surface; the shaft intersects a coal bed of minable thickness and quality, and at that point lateral openings are driven into it and extraction begins. Coal mining once required much human labor. Holes were drilled into the face of the coal seam and loaded with black powder or dynamite, and the explosions spewed up broken coal which was then loaded by hand-shovel into a small car. When full, this was pushed by men or pulled by a mule along a track to a loading pocket adjacent to the shaft. The coal was then loaded into other cars or buckets and hoisted to the surface. New technology has changed this picture. The continuous mining machines are powered by electricity, and they cut out the coal instead of blasting, break it, and convey it continuously into waiting cars for transport to the hoisting shaft. Such mines are rarely three thousand feet deep; they range from a few tons of daily production to ten thousand tons; and they employ one to two thousand men in individual mines.
Another form of mine is the strip mine, created by stripping the overlaying material, called overburden, from a minable coal seam. Draglines or large electric shovels are used for this purpose; in either case, the overburden is stacked behind the current operations on the recently mined-out area of the pit so that it can be leveled or landscaped again. The coal bed is blasted to break it for shoveling. Drill holes are now made a foot in diameter and the explosive material, ammonium nitrate, is chemically and physically more like fertilizer than dynamite. A shovel or front-loader is used to place the broken coal on trucks. Most such mines are less than two hundred feet deep, and they may produce as much as fifteen thousand tons of coal a day, employing as many as seven hundred men in a single mine. More than half the coal produced in the United States is produced from strip mines.
The third method produces very little coal in the United States — auger mining, which is carried out by means of large horizontal augers that bore into a coal bed exposed on the side of a hill; the auger pushes out the coal as it rotates.
Nuclear energy as a source of electrical energy on a commercial basis began a little over a decade ago. By 1974, the United States produced about thirteen million kilowatts of nuclear power on-line, representing less than 1% of the electric generating capacity of the country. This figure is expected to jump to 150 million kilowatt by 1980, and to double again in five years. By 1990, it is expected this source will account for some 500 million kilowatts. This method does not produce energy by the familiar combustion processes associated with the use of fossil fuels; instead, nuclear energy is derived from the conversion of relatively small amounts of matter. Vast amounts of ores containing these nuclear fuels are available, but the challenge is to recover this material economically and convert it into energy.
Coal is formed from the remains of trees, and most of the world’s coal beds seem to represent accumulations of plant material in swamps near the shores of ancient seas. The ebb and flow of these seas, caused by the instability of the continental margins under crustal stress, first allowed the creation of the swamps in which the fallen trees rotted slowly, and second the burial of the matted remains by beach sands laid down during the ensuring transgression. Most coal fields have many coal layers and seams, indicating repeated alternations of living swamp and sedimentary burial. The coal seams lie on what are called underclays, which is a very fine material deposited by the sluggish streams of a subsiding coastal area immediately before the creation of a coastal swamp.
Bituminous coal is the most abundant and widespread coal in the United States, and it is the coal most commonly used for industrial, electric power, and heating purposes. Coal is found in beds ranging from those less than an inch thick to those many feet deep. Many beds may be found in a single sedimentary sequence or depositional basin. In West Virginia there are 117 coal beds important enough to be named and there are also hundreds of smaller beds. The lower boundaries of coal seams are sharp contacts with the underclay, while the upper boundary may be either well defined or gradational to sandstone or shale. Certain geologic periods have been more conducive to the production of coal than others. The late Paleozoic age has coal beds as a distinctive feature, and this geologic time scale is called the Carboniferous. Coal beds are also important among rocks of Cretaceous and early Tertiary beds in some parts of the world. Coal beds can be buried deeply, or they may be exposed at the surface. The United States production of coal has exceeded the consumption by about 10% since World War II.
The world’s reserves of uranium are concentrated in a few countries, principally the United States, Canada, South Africa, the U.S.S.R., France and Australia. Information on the uranium deposits in Russia is not available, but there are believed to be large deposits in the Fergana area of central Asia, as well as in northern Siberia and the central area of Kamchatka.
Thorium is now becoming another source of nuclear energy. The first thorium-cycle reactor designed for commercial use began operation near Platterville, Colorado, in 1973. Many countries outside the United States have meager supplies of fossil fuels or uranium, but they do have an adequate supply of thorium.
Unit trains are used in the United States to transport bituminous coal 10,000 tons at a time from Montana and Wyoming to points as far away as Indiana and Texas. Coal is also trans-ported as a slurry through pipelines from northeast Arizona to the Mohave power plant near Las Vegas, Nevada. In America, most coal is transported by rail, unless it is to be used at or near the mine in fuel power plants. It is also transported by barge, but this necessitates the route between the large coal deposit and centers of use to be crossed by waterways. The efficiency limits of hauling coal by unit trains have not been reached, and there ar hauls of more than one thousand miles now planned. If construction and maintenance energy costs of a railroad are to be charged largely or mainly to coal haulage, the coal slurry pipeline is a more efficient system of transportation, comparable to the natural gas pipeline. Such pipeline transport costs between 60 and 70% of the price of unit-train haulage.
The amounts of fissionable materials needed for nuclear power are much smaller, and they can be transported by rail or by truck, generally specially-shielded if there is any danger of radiation.
Coal is seen as having a great potential for contributing to the needs of high energy society. It is more versatile today as a fuel source than when it was the mainstay of power in the world during the Industrial Revolution. Coal can be converted into gaseous or liquid fuels that can be transported by tanker and pipeline or used near the conversion plants. It can be burned in power plants near the mine, and the resultant electricity can be transmitted hundreds of miles over ultra-high voltage lines. It can also provide benefits by operating in place of the rapidly depleting reserves of oil and gas. Unfortunately, the tendency to ignore coal over the past few years is now causing problems, though the coal reserves of the United States are enormous — 1.5 trillion tons, which at current or even accelerated rates should burn for several hundred years. However, the technology for recovery, combustion and conversion of coal into other, more convenient forms is archaic. Also, much of the coal is of limited usefulness because it is either too high in sulfur or too low in energy
value to be worth the cst of transporting to distant users.
Nuclear power is valuable as a replacement for supplementation of depleted fossil fuels, the cessation of the air and water pollution problems associated with the use of fossil fuels, and the provision of electricity for nations and regions that have little or no access to cheap fossil fuels. Nuclear power plants produce no carbon dioxide, and thus they do not contribute to accumulation of that in the atmosphere, which some scientists regard as a long-range threat to life on earth. The higher cost of energy produced by fossil fuels has increased interest in the use of nuclear power.
6. PERSONAL SAFETY
The dangers to the men in the coal mines are several, though some — usually the more visible — tend to be exaggerated. There are accidents and disease, such as “black lung,” which affects only underground coal miners. From 1965 to 1972, there were 1,412 lives lost in underground coal mining in the United States, a rate of 0.61 deaths per million tons of coal. This is more than five times the death rate for surface or strip-mining of coal.
Any exposure to radioactivity, whether natural background or man-made, is harmful to humans. Background radiation is low at sea level on or near the ocean and high in elevated regions, particularly if the rocks are granitic. Such radiation may have little or no somatic or direct effect on exposed individuals, but it is almost certainly responsible for some “natural” deformities and cancer by induced mutagenesis. In contemporary high-energy society, the largest exposure to radiation comes from the medical use of x-rays. This is followed by natural and background radiation. Finally, nuclear power is a very minor source. The proliferation of nuclear power plants and their satellite plants for fuel enrichment and fabrication and for reprocessing the spent fuel, on the other hand, has the possibility of increasing radioactivity on local levels that could range from small regional increase in the incidence of cancer and birth defects a catastrophic level. Also, the small quantities of dangerously radioactive waste now produced will increase with the growth of nuclear power. These waste materials must be kept out of the biological environment for between six hundred and one thousand years, making this a serious threat.
7. ENVIRONMENTAL DANGERS
In the ore-producing states of the Rocky Mountains and the Southwest, digging large holes to extract ores causes little disturbance in the environment in such an area because the surrounding countryside is already barren, dry, and starkly eroded. In the humid, forested East, however, the disturbance is very destructive. A few years ago, strip-mined land was abandoned. When the coal was gone, what was left was a desolation of steep piles of discarded earth or overburden alternating with the trenches from which the coal has been removed. The soil was often acidic from minerals leached from the piles of overburden, and very few plants could grow. Most states now have strict laws requiring the backfilling of the trenches, recontouring the ground surface to some semblance of its original state, and the planting of trees. Even in soil with a great acidity, red pine or hybrid poplars can usually survive and even do well.
Underground mining can cause subsidence, acid mine drainage, and fires. Subsidence is when rock collapses into the openings of abandoned mines. Acid mine drainage occurs where groundwater flows through the shattered coal that remains underground after the cessation of mining and takes sulfur from pyrite into solution. This leaves the mine as dilute sulfuric acid, toxic to plants and fish alike. Uncontrolled fires can occur both underground and in abandoned mines and surface waste piles. They damage health, property, and the environment. In 1969, the Bureau of Mines reported 110 underground fires and 460 burning coal-refuse banks in seven states. Most of these were in Pennsylvania and West Virginia. Such fires also cause accumulations of carbon monoxide in buildings, and this is a health hazard.
Strip-mining, if the area is left unclaimed, can lead to heavy erosion, which adds to long delays in the reestablishment of vegetative cover and to downstream siltation and acidification. This is not an insoluble problem, of course, and reclaimed land in the flatlands of Illinois and Indiana support heavier crops now than before mining.
The hazard of a catastrophic reactor accident, thermal pollution from power plants, perpetual surveillance of high-level radioactive waste materials, and the “plutonium peril,” are all major concerns to the environment involved in the use of nuclear power. The hazards to human health re somatic (meaning the individual is directly and immediately affected by being exposed to damaging doses of radioactivity), carcinogenic (which means cancer can be caused in exposed individuals after a delay of between five and twenty years), and genetic (which affects adversely the descendants of the individuals exposed).
Long-lived radioactive materials are included in the category of persistent pollutants. They degrade, but at very slow rates. Radioactive wastes are a product of the generation of power by nuclear fission. Periodically, such fuels are separated by chemical processes to recover plutonium or prevent waste products from “poisoning” the reactor and reducing its efficiency. This atomic waste is a great danger to the environment unless it is disposed of properly.
8. LONG TERM OUTLOOK AS COMPARED TO THE SHORT TERM OUTLOOK
Coal, as noted before, is abundant in the United States today. The need has also been noted for greater technology to solve the various problems of dealing with the coal, but it is probable that coal could be used for energy production for many hundreds of years even at accelerated rates of use. In the short term, the production of coal is not adequate to fill the needs of the country for energy, and there are also environmental problems from burning this substance, just as there are for other fossil fuels.
Coal has been in use the longest of all the fossil fuels. It
made the Industrial Revolution possible, and produced the urbanization that accompanied it. The environmental price was high, and any use of coal must first address this question of the environment. After World War II, the hope was for nuclear power, but this ran into snags and the nations of the world turned back to coal.
Coal can be ground into a granular powder, treated with steam and oxygen, then the resultant gas can be purified. This produces high-energy methane, free of sulfur, carbon monoxide, or free hydrogen. The process is simple in outline, but the details are more complex and the cost at the present time is too expensive.
Nuclear fuel is much more economical in the long-run though in the short term the creation of nuclear power plants is very expensive. The fears of this kind of energy production are the main reasons preventing the full implementation of this energy source. The energy content of uranium used in the breeder reactors is sixty times that used in light-water reactors.
9. WASTE DISPOSAL
The problems of waste disposal in coal mining have been delineated. the abandoned mining operations which do not bother to reclaim the land leave behind heaps of overburden and other effluents from beneath the ground.
The problem of waste disposal in the generation of nuclear energy is a much greater problem. The waste material produced by these reactors is expected to increase in amount as the use of nuclear power increases, but there is no truly efficient or permanent method for disposing of such wastes and protecting the populace and the environment. Safe and permanent disposal of nuclear waste involves a social cost that cannot as yet be measured. There have been proposals made for disposal in the deep ocean, under the Antarctic ice cap, and in natural underground salt formations. This last idea received a great deal of attention in the United States, where a permanent repository was identified in Kansas but was abandoned when the site was shown to be defective. The idea is still under consideration if a suitable site can be found, however.
It is likely that both these energy sources will be tapped for different purposes in the years ahead. In any case, other fossil fuels are reaching a depletion level and must be supplemented by whatever means are shown to be economically and ecologically feasible. Nuclear plants receive the most opposition because the dangers appear to be the greatest, at least in the case of a catastrophic occurrence. The impact of nuclear waste is another reason for much of this opposition, and until this problem is solved such opposition is likely to continue.
There are also hazards associated with the burning of coal, most especially air pollution problems and other forms of effluents sent into the environment. Coal is certain to become the major source of energy in developing nations and other regions lacking the technology or the capital to introduce nuclear power in the near future. Both coal and nuclear power are likely the future sources of energy in the United States.
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