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Real Coal BTU and analysis

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Let's start a thread on coal BTU and analysis so we can compare numbers. We need the analysis, the coal seam, the mine, and the date.

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).

Ash: impurities consisting of silica, iron, alumina, and other incombustible matter, left over when coal is burned.

Low Sulfur: sulfurs typically analyzed are Pyritic, Sulfate, and Organic

BTU: the heating value, determined in terms of Btu both on an as received basis (including moisture) and on a dry basis.

Calorific value: expressed in Btu/lb on a dry basis

Good coal for blacksmithing 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. Available analysis shows ash content of coals listed from 3.7% to 22.4% ash, sulfur from 0.4% to 3.3% , and BTU's from 8,467 BTU's to 15,500 BTU's Calorific Value.

Analysis from one sample of this coal from the Penn State coal sample database.

Type : Low Volatile Bituminous (lvb) State: WV Ash : 7.44% Sulfur: 0.64% BTU :14542 Volatile : 15.70% Carbon: 92.42% Reflectance: 1.8

Seam : Pocahontas No. 3,


There is a Pocahontas No. 3 in Virginia that has 15,006 BTU, and a Pocahontas No. 3 in West Virginia that has 13,953. Pocahontas No. 3 coal is not all the same due to the way it was formed. You have to look at the analysis to be sure what you are getting, is what you want. The analysis is usually available from the coal company when buying coal.

BP0051 Good Coal

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From the Pocahontas #3 seam, mined in SE West Virginia. 2008

As Received Specs:
Size: Pea 1 x 3/8 or Nut 2"
Moisture: 1.48%
Ash: 7.12%
Sulfur: .75%
BTU/lb: 14,373
BTU/lb: 15,724 (dry, ash-free)
Volatile Matter: 18.63%
Fixed Carbon: 79.62% (dry ash-free)
Free Swelling Index (Coke Button): 9
Lbs sulfur per million BTU: 0.52
Coal analysis report by Geochemical Testing, Somerset, PA.

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Anthracite blacksmithing coal from eastern PA 2008

Dry Specs:
Size: Pea 3/16 x 9/16 or Nut
Moisture: 5.49% (as received)
Ash: 9.58%
Sulfur: .59%
BTU/lb: 13,451
BTU/lb: 14,876 (dry, ash-free)
Volatile Matter: 4.36%
Fixed Carbon: 95.17% (dry, ash-free)
Ash Fusion Temp: 2,700 F
Lbs sulfur per million BTU's: 0.44

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This test is from Horizon Laboratories in Price, Utah.
Date Sampled: 3/17-3/23 of 2008
Sample Identification: BYU Stoker at Wildcat.
Analysis Report #: 69383

As Received Basis:
% Moisture 3.33
% Ash 9.87
% Sulfur 0.45
BTU/Lb 12717

Dry Basis:
% Moisture -----
% Ash 10.21
% Sulfur 0.47
BTU/Lb 13155

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Low ash vs high ash. As a blacksmith, you want the BTU value in heat from the fire otherwise your paying for rocks. I do not know the acceptable values.

I can tell you that good coal produces only a small amount of ash and clinker at the bottom of the fire. Other coals produce clinker, goo, rocks, etc that choke the fire to the point you must clean out the fire pot and rebuild the fire, sometimes on a regular basis. One good measure of the percent ash, is the amount and quality of ash in the ash bucket after a weeks forging.

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I get my coal in Monroe, Oregon from John Turkington at Farrier Supply. He sells very good quality blacksmith coal that burns hot, cokes well and leaves very little clinker.

Here is the Analysis:

Cumberland/Elkhorn Coal and Coke
Louisville, KY 502-589-5300

Seam : Sewell
State: WV
Ash : 4.0 %
Sulfur: 0.8%
BTU :14500 +
Volatile : 28.0%
Size: 1 1/4 x 1/4 minus

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