Coal macerals moisture

Moisture loss can (and often does) occur during grinding and/or pulverization and is believed to be related to the types and amounts of banded (maceral) ingredients in the coal. Losses are least for vitrain and increase in order of vapor pressures for moisture (e.g., vitrain < clarain < durain < fusain). 

Coal is a sedimentary rock composed of three categories of substances (1) organic carbonaceous matter—macerals, (2) inorganic (mainly crystalline) minerals, and (3) fluids. The latter occur in pores within and between the other two solid constituents. The fluids in coal prior to mining are mainly moisture and methane. Applied to coal, the term mineral matter is an inclusive term that refers to the mineralogical phases as well as to all other inorganic elements in coal, that is, the elements that are bonded in various ways to the organic (C, H, O, N, S) components. 

Surface moisture water held on the surface of coal particles or macerals... 

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