Index of compressibility, susceptibility to compressibility as well as compactibility were detd. for lignite biomass mixts. (Belchatow mine) contg. 30% by mass of biomass and for lignite (moisture content 18.6-27.9%) and compared. The decrease in moisture content resulted in decreasing the compressibility index and increasing the ability for merge. The strength of the briquettes increased with increasing pressure and decreasing moisture contents.