USGS Bulletin 1823 Preparation of Coal for Analysis
Crushing and Grinding. The coal sample, as received from the field, consists of 3 to 15 kg of material that first is reduced to a particle size of 2 to 4 mm (5 to 10 mesh) in a jaw crusher. This crushed material is then divided into three splits. The first split is forwarded to a laboratory for standard ultimate and proximate analyses.