The largest size of graded coal. The upper and lower size limits chosen depend upon market requirements. For example: 200mm to 100mm or 150mm to 75mm (generally called large cobbles); 100mm to 50mm (generally called cobbles).
The largest size of graded coal. The upper and lower size limits chosen depend upon market requirements. For example: 200mm to 100mm or 150mm to 75mm (generally called large cobbles); 100mm to 50mm (generally called cobbles).