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BP0131 Coal, Coke, and Rocks
by Glenn Conner
Coal, to many people, is a black rock that sometimes can be burned. To a blacksmith, it is the fuel used in the forge to heat the metal, and comes in two varieties, good and bad. "Good coal" produces high heat, little ash, little clinkers (slag) and makes life so much easier. Bad coal is fussed at, cussed at, and generally returned to the earth as landfill (thrown away).
You will hear a lot about blacksmiths using Pocahontas Coal. Well, Pocahontas Coal is broken down into 10 seams of Pocahontas coals, numbered #1 - #9 and Poca #3 rider. Pocahontas #3,#5,#6,#9, and #3 Rider are the seams that have listed coal production. So when they say Pocahontas Coal, which Pocahontas Coal are they talking about? You have to ask, and if there is a question, ask to see the analysis of the coal. The analysis will usually list the Seam, Type, State it was mined, Ash, Sulfur, BTU, Volatiles, Carbon, Reflectance, and other properties
There are 117 named coal seams in West Virginia. Sixty-five seams are considered mineable. In the year 2000, coal was produced from 50 different coal seams.
This is some industrial coke that came from Pennsylvania.
It is gray in color, light weight, and about the size of your fist. That is a 2 pound hammer for size comparison.
When I put it into a regular coal forge, it had to have a constant air blast to keep burning, and needed to be about twice as deep as a soft coal fire. It gave off no smoke but the exhaust fumes from the open fire were invisible and gave me a trememdous headache. Second time I used it, I intentionally stayed out of the exhaust fumes from the open fire and no headache.
This is what is considered good coal for blacksmithing, it is low ash, low sulfur, high BTU coal of a usable size for the forge. The numbers suggested for good coal are less than 7% ash, less than 1% sulfur and above 14,000 Calorific Value in BTU's. These are not hard numbers but guidelines.
This coal will burn unattended in the forge for 4-6 hours with no additional air. With air it will produce "white hot" steel and with a little more air, burn steel with no problem. You can use air from an electric fan and adjust the air and almost hold a temperature while working several irons in the same fire.
This on the other hand is coal from the top or bottom of the seam and contains a lit of sediment, mud, rock or junk. The yellow sometimes looks like rust, but smells a lot more like sulfur when it is burned. Notice what looks like layers in the pieces.
This is another photo of the layering in the sample of "coal".
When you look closely sometimes you can sometimes see the layers coming apart.
They just fall apart or fracture on the layering lines. Some are 1/4 inch or thicker, and some are paper thin, it just depends on the layer.
The reason this is considered landfill for a blacksmith is because when it is burned, it produces much less heat as your heating up the junk which does not burn. The layers become more pronounced.
Coal is made up primarily of "organic" elements (carbon, hydrogen, oxygen and nitrogen) and "inorganic" elements (primarily silicon, aluminum, iron, calcium, magnesium, titanium, sodium, potassium, and sulfur). Organic elements comprise the combustible body of the coal, whereas the inorganic elements are present in coal in minerals that largely form the ash when the coal is burned. Inorganic elements (e.g. silicon and aluminum) are present in most West Virginia coals in the range of several percent or more in ash forming minerals, but other "inorganic" elements, such as sulfur, present in lesser amounts, may detrimentally impact the use of West Virginia coals. You can decide if this sample was more "organic" or more "inorganic" in nature.
Coal seams are fossilized accumulations of plants which lived and died in swamps that were so devoid of oxygen that few microbes or other critters could survive to feed on their remains. The first phase of coal known as "peat" thus developed. These swamps were interwoven with intricate, meandering river channels which eventually covered things with mud and silt. Subsequent deep burial by more sediments in succeeding geologic ages resulted in heat and pressure which transformed the peat into coal. Generally speaking, every 12 inches of coal thickness represents approximately 10,000 years of continuous peat accumulation. Coal seams in West Virginia average 3 feet in thickness, although they occasionally can be as thick as 25 feet.
When the swamp stretches across 2, 3, or more states, one part of the swamp can easily be different from the other, and form coal that, although in the same seam, is different in composition. That is why Poca 3 in Ky, WV and Va may give 3 different analysis results.
For the history buffs: The first reference to coal ( in what is today West Virginia) was in 1742, when John Peter Salley reported an outcropping of coal along a tributary of the Kanawha River. By 1817, coal began to replace charcoal as a fuel for the numerous Kanawha River salt furnaces.