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In one way or another, coal has been receiving a great amount of attention lately. And, for good reason. We are becoming very concious of our massive imports of fuel from overseas with all of the implications that this can have. You may recall the series of advertisements in which two quizical Arabs were looking at a sign that read, 'We have more coal than the Arabs have oil, let's use it.' But, depending upon one's background, the thought of returning to massive amounts of coal consumption can raise specters of doubt.
Most of us have had some exposure to the effects of wanton exploitation of our natural resources. Even if it were only through newspapers and TV we have seen the devestation of uncontrolled strip mining or the darkness at noon from poor combustion in large boilers. We do not wish to return to these conditions and we do not need to if we will but take the time and effort to avoid such consequences. There are no easy answers, however, only logical choices. And in order to make these choices we need to be informed.
That is just what I would like to do now. First, though, let me say that I am not an 'expert' on the uses of coal. You know what an 'expert' is don't you. A guy with a two sandwich size briefcase more than a hundred miles from home. Rather, I have had to work with some of these problems and therefore set out to bring together some background information which I would like to share with you.
Let us begin by taking a look at just what coal deposits we have and where they are located. For this it is convenient to look at a map of the 'lower 48' of these United States. We will check out Alaska later. Our deposits can be placed in four locations or 'provinces'; eastern, western, central and gulf coast. If we add up everything over which the Stars and Stripes fly we have coal deposits that have been estimated to be about two and a half million-million tons. That's a big number. Try it this way: 2,500,000,000,000. In fact it is so big that I am not going to try to differentiate between the various qualifications; that is, estimated, or proven, or metric or short tons. Its a lot of coal.
Of all of these vast deposits it can be said that the eastern coals generally represent quality and the western ones make up for it in quantity. For example, in the Fort Union region of Wyoming, Montana and the Dakotas we find the largest single deposit of coal. It is estimated to be a bit over a million-million tons. The Green River basin has something around seven hundred thousand-million tons and Appalachia comes in third with about five hundred thousand-million.
To me the western deposits as typified by those in Wyoming are simply breath taking. I remember an incident that brings this home to me so forcefully. Recently I had the opportunity of visiting a mining operation in the Kemerer, Wyoming area. I drove out over an area that was being cleared by earth moving equipment. When I stepped out of the car I was on black crumbly material to which I exclaimed, 'This is coal!' 'Yup,' said the tactern foreman, 'about 90 feet of it.' A seam 90' thick and as far as the eye could see and you can see a long way in Wyoming!
There is about another 100,000,000,000 tons that has been delineated in Alaska. It has about the same variation in quality as the deposits in the lower 48 states. Much of it is susceptible to surface mining techniques. Which reminds me of my first encounter with these deposits. I was on a mission in the Wainwright area on the shores of the Arctic Ocean looking for gravel deposits with which to build a possible marine terminal for large tankers. This day I was hiking along the shore line just outside of Wainwright and stumbling along on a pebble beach. Bending down to sample the stones I picked up a handful. To my surprise these were not stones at all but COAL. It had been washed from an outcropping some 20' above the waterline.
This very good coal is regularly gleaned by the local people, of Eskimo and Aluet anscestory, for their winter fuel supply. What a nice warm fire it makes. How good it felt that day in November with the outside temperature at minus 20.
With apologies to Gertrude Stein who said, 'A rose is a rose is a rose' not all coal is the same. It is rather like the mail order catalog with its good-better-best ratings. As we all know, coal was derived from woody plants buried for eons in prehistoric swamps. From this vegetal matter all of our coal has sprung. Trouble is some of it didn't spring far enough.
Let us define quality with the terms of the 'proximate' analysis. These are moisture, ash, volatile matter and fixed carbon. Since moisture and ash are of no use to us then let us rearrange the analysis into just volatile and fixed carbon. The volatile matter is that gaseous part that comes from the coal when it is heated and which is so important for ignition. The fixed carbon is what is left and it is a mixture of carbon along with carbon compounds of high enough molecular weight that they remain a solid upon heating or at least a sticky mass. We can do this for the various coals in our country and make a bar-graph that will show us how they compare.
This has been done in the 'Diagram Progressive Change From Vegetal Matter To Coal.' The volatile in each of the coals is shown as the solid black bar and right above it we find the corresponding fixed carbon. Note that as we read from left to right the volatile decreases and of course the fixed carbon increases to make up the 100%. But, more important you should note that as the volatile decreases there is a marked increase in the heating value until the conversion has reached anthracite. All of these are good fuels it is just that some are better than others.
There are other qualities that go to define an acceptable coal; ash fusion temperature, grindability and sulfur content to name a few. To go into all of these is beyond the scope of this article. However, we should have a word about sulfur since it is such a currently popular item. Sulfur dioxide in flue gas is under strict government control and it is growing in its intensity. At present the regulations generally restrict a user to not more than 0.8 pounds of sulfur in the flue gas per million heat units (Btu).
Let's pick three coals all with 0.8% sulfur showing in the analysis. These will be a Texas lignite, a West Virginia low volatile bituminus and a Pennsylvania anthracite. Each of these has a different heating value so when we figure out how much sulfur we are going to put into the air from the stack we find that the bituminus from West Virginia and the anthracite put in less sulfur than the lignite. Similar comparisons can be made with the western coals. Some of the Wyoming coal is as low as 0.4% sulfur but it is not high in heating value so there is a trade-off.
The way things are going in the regulatory field, though, I have the feeling that all large users of coal are going to be required to install flue gas scrubbing equipment. There are, fortunately, processes that have been proven that can be used to scrub out the sulfurous gasses. One of the better ones uses a water slurry of lime or limestone and makes a gypsum like solid when mixed with the fly ash. These are expensive operations. Its like adding a few dollars a ton to the cost of the coal. There has been a lot of tonnage thrown through the fire doors of innumerable steam engines and fixed boilers. But, today most of the coal used is in the pulverized form. Depending upon volatile and other considerations it is first crushed to minus ' and then fed to pulverizers of a variety of design. Here it is ground to a size where 70% and 80% will pass through a 200 mesh screen. This is a 0.0029' aperture. That's fine stuff. It is swept out of the pulverizers by directing a portion of the combustion air through the machine and that which is fine enough will be picked up by the air stream while the larger particles remain to get further attention. It is carried on into the furnace and burns in a cloud.
Stripping shovel operator's view of pit, Sinclair Mine, Peabody Coal Company, Ky. Dipper of big shovel holds 125 cubic yards of earch and rock. Loading shovel in background scoops coal into 135-ton trucks.
If one examines the coal-air mixture as it travels around the boiler room in pipes like it was a liquid it is inevitable that a conclusion will be drawn that this could be used directly in an internal combustion engine.
Theoretically it can. However, a number of groups have been working on the problem and the erosiveness of the ash has so far made the approach impractical. The Bureau of Mines at its experiment station in Morgantown, West Virginia, worked for several years on the problem and finally concluded that a better approach would be to liquify the coal and then burn the coal derived liquid fuel in the engines. That seems to be where the problem resides at the moment.
That brings us to the question of fueling all of our thousands and thousands of farming tractors. We need plenty of gasoline and diesel fuel to keep bread on the table. We can direct our diminishing supplies of petroleum into these fields after we have re-established coal in the industrial and power plant fields. But there comes a day when maybe that is not enough. Well, we do know how to make these liquid fuels from coal. It just takes money. The synthetic fuels business is a very capital intensive business.
What do I mean by 'capital intensive?' Take the auto industry for example. They require an investment of something like 50 for every dollar of annual sales. The oil industry requires about a dollar of plant investment to support each dollar of annual sales. An electric power utility takes a lot of investment. They need about $5.00 invested for each dollar that they get from us each year. The synthetic fuel industry is somewhat like the power company in its ability to soak up money. So, yes, we can make these fuels from coal and yes there is a lot of work going on to improve the processes but it all ends up costing a whole lot more than we are accustomed to paying to say to the guy at the pump, 'Filler up, please.' I suppose we could go on and talk about nuclear and about solar and maybe geothermal energy. But the truth is, we have a lot of coal in the ground that we can use first. So let us get on with learning how to use it without asphyxiating ourselves while we are drowning in our own garbage. And, let us learn how to fix up the land after we have dug out the coal and we can do this for I have seen the handy work of those that care. And, let us get our priorities organized, that is let us use coal where it can be used to advantage and save our petroleum and our natural gas for where they can best be used ... .in our vehicles and in our homes. And, let us tell our representatives in the Congress how we feel. I have. Have you?
A giant bulldozer with an experimental 40' blade works at leveling mined land in southeastern Kansas. A helper bulldozer lends a tow by cable. The big blade, set at a 40 degree angle, can move 7,000 cubic yards of earth and rock per hour, more than 10 times the rate for an ordinary bulldozer.
A herd of Charola is cattle graze on reclaimed strip mined land in the Midwest.
It's apple blossom time in the coal mines. This commercial orchard blooms on land reclaimed after strip mining at the Fidelity Mine of The United Electric Coal Companies, subsidiary of General Dynamics, at DuQuoin, Illinois. The company reports the trees grow faster on reclaimed land, are more resistant to disease and bear better fruit because mining brings to the surface trace elements which were depleted in the original top soil.