About Quality of Coal: Abrasion Index
The higher the index the abrasive coal the higher the maintenance costs of the coal grinding equipment. A coal called abrasive when his abrasive index 400600, and referred not abrasive when his abrasive index lt; = 10. Coke has abrasive index in 2500 while having an abrasive sandstone index 1200. Desired coal buyers must have abrasive index lt; = 200.