In this study, the flowability of two biomass feedstocks, corn stover and Douglas Fir, will be examined with the Mohr-Coulomb model.  Two types of triaxial tests, i.e. hydrostatic triaxial compression and conventional triaxial compression, will be conducted with a Cubical Triaxial Tester. Triaxial test results will be used in determining the Mohr-Coulomb model parameters. The determined flowability will be compared with existing studies.