☙
Anthracite is the form of coal containing the highest percentage of carbon. Three classes are distinguished:
| Name | Fixed Carbon (percent) |
Volatile Matter (percent) |
|---|---|---|
| meta-anthracite | >98% | <2% |
| anthracite | 92–98% | 2–8% |
| semianthracite | 86–92% | 8–14% |
United States sizes, according to the Anthracite Committee. Effective July 28 1947, and amended July 20, 1953.
| Name | Round Test Mesh (inches) |
Undersize¹ | Maximum Impurities² | Uses (some purely historic) |
|||
|---|---|---|---|---|---|---|---|
| Max- imum |
Min- imum |
Slate3 | Bone4 | Ash5 | |||
| Broken | through 4 3⁄8 | — | — | 1½% | 2% | 11% | hand-fired residential furnaces, gas producers |
| over 3¼ to 3 | 15% | 7½% | — | — | — | ||
| Egg | through 3¼ to 3 | — | — | 1½% | 2% | 11% | ditto |
| over 2 7⁄16 | 15% | 7½% | — | — | 11% | ||
| Stove | through 2 7⁄16 | — | — | 2% | 3% | 11% | ditto |
| over 1 5⁄8 | 15% | 7½% | — | — | — | ||
| Chestnut | through 1 5⁄8 | — | — | 3% | 4% | 11% | ditto |
| over 13⁄16 | 15% | 7½% | — | — | — | ||
| Pea | through 13⁄16 | — | — | 4% | 5% | 12% | ditto |
| over 9⁄16 | 15% | 7½% | — | — | — | ||
| Buckwheat #1 | through 9⁄16 | — | — | — | — | 13% | residential stokers, hand-fired steam boilers |
| over 5⁄16 | 15% | 7½% | — | — | — | ||
| Buckwheat #2 (Rice) | through 5⁄16 | — | — | — | — | 13% | ditto |
| over 3⁄16 | 17% | 7½% | — | — | — | ||
| Buckwheat #3 (Barley) | through 3⁄16 | — | — | — | — | 15% | traveling grate stokers |
| over 3⁄32 | 20% | 10% | — | — | — | ||
| Buckwheat #4 | through 3⁄32 |
— | — | — | — | 15% | traveling grate stokers, pulverized |
| over 3⁄64 | 30% | 10% | — | — | — | ||
| Buckwheat #5 | through 3⁄64 | no limit | — | — | 16% | ||
Notes
1. A tolerance of 1% is allowed on maximum percentage of undersize. Maximum percentage of undersized is as measured at the preparation plant.
2.When slate content in sizes from broken through chestnut is below the maximum allowed, bone content may be increased by 1.5 times the decrease in slate content.
3. Slate is defined as any material having less than 40 percent fixed carbon.
4. Bone is defined as any material that has 40 percent or more fixed carbon, but less than 75 percent.
5. Ash is determined dry. A tolerance of 1% is allowed on maximum ash content.
Energy Information Adminstration.
Coal Data: A Reference.
Washington, DC: U.S.G.P.O, 1982.
Page 60.
These values differ somewhat from earlier sources:
| Size | Screen sizes, inches (through and over) |
|---|---|
| egg | 2.5 to 1.75 |
| stove | 1.75 to 1.25 |
| chestnut | 1.25 to 0.75 |
| peas | 0.75 to 0.50 |
| buckwheat | 0.50 to 0.25 |
*Steam: Its Generation and Use. 34th edition.
New York: Babcock and Wilcock, 1911.
Page 52.
| Name | passes through | passes over round holes | square mesh |
|---|---|---|---|
| lump | |||
| steamboat | |||
| cupola | |||
| broken | 4½ | 3 7/16 | over 2 ¾ |
| egg | 3 7/16 | 2½ | 2¾ |
| No. 2 | 2½ | 1 9/16 | |
| large stove (No. 3) | 2 to 2¼ | 1 7/8 to 1½ | |
| small stove (No. 4) | 1 7/8 to 1 3/8 | 1 1/8 to 1 | |
| stove (replaced above 2 sizes by 1928) | 2 inch square | 1 3/8 inch square | |
| nut (short for chestnut) | 1 9/16 | 1 1/16 | |
| pea | 1 1/16 | ½ | |
| buckwheat No. 1 | ½ | ¼ | ½ |
| ¼ | |||
| buckwheat No. 2 (or rice) | ¼ | 3/16 | |
| buckwheat No. 3 (or barley) | 3/16 | 3/32 to 1/16 | |
| buckwheat No. 4 | |||
| dust |
E. N. Zern, editor.
Coal Miner's Pocketbook. 12th edition.
New York: McGraw-Hill, 1928.
Pages 919, 924, 1209, 1212, 1218, 1244 and others. The descriptions of the sizes in this book are inconsistent, which apparently reflects company to company differences in practices at that time.
Sorry. No information on contributors is available for this page.
home | tools index | search |
contact 
|
contributors |
help | privacy | terms of use
Copyright © 2000 Sizes, Inc. All rights reserved.
Last revised: 8 November 2003.