Classification criteria:
1.G & gt85, and then use y value or b value to distinguish fat coal, gas fat coal and other coals, when y >; 25.0mm, should be divided into fat coal or gas coal, such as Y "25 mm", according to the size of its Vdaf is divided into other coal reactions.
According to the classification of B value, VDAF "is 28%, tentatively b> 150% is fat coal, VDAF >: 28%, tentatively b & gt220% is fat coal or gas fat coal. If there is any contradiction between the categories divided by B value and Y value, the category divided by Y value shall prevail.
2.Vdaf & gt37%, g < 5 > coal, and then distinguish it as long flame coal or lignite by light transmittance PM.
3.Vdaf & gt37%, PM & GTFor 30%-50% coal, measure Qgr and maf again, if their values are greater than; 24MJ/kg(5739cal/g) should belong to long-flame coal.
National Standard for Coal Classification in China (GB575 1-86)