Mercury porosimetry was used to study changes in the pore structure of
three western Canadian low-rank coals treated in three different atmo
spheres (nitrogen, steam and combustion products) at temperatures up t
o 500-degrees-C. The intrusion curves are well described by two differ
ent power laws in the pressure range 0.1-200 MPa. Principal-component
analysis was performed to determine relations among the power-law expo
nents, equilibrium moisture and volatile matter.