Coal analysis
WEBJan 1, 2013 · The abrasion index (AI) is a measure of the wear caused by the mineral matter in coal. A 2 kg sample of − mm sample is placed in a mill in which four standard metal blades rotate at 1500 r/min for a duration of 12 000 revolutions. The AI is calculated from the loss in mass of the four blades during the test.