To evaluate operational problems in evaporite deposit utilization associated with brine, halite, sylvinite, and carnallitic ore were creep tested under unconfined conditions, both with and without added brine. Axial deformation and dissolution chemistry where observed throughout the tests. In both the sylvinite and carnallitic ore tests, selective dissolution of sylvite and carnallite minerals was associated with the precipitation of halite. The nature of this process was dependent on temperature and initial brine and ore composition. Generally, the presence of brine caused a decrease in the resistance to creep deformation. It is suggested that observed weakening in evaporites under dilatant conditions and in the presence of brine is due primarily to the enhancement of fracture mechanics processes through selective dissolution from stressed areas in the rock, such as fracture-process zones and asperities acting as barriers to slip. Correlation of results with a variety of practical environments, including brine inflow problems, waste salt backfilling practices, and underground storage facilities, was possible. Since there is always inherent brine in salt rock deposits, the results also add to the existing body of knowledge regarding advanced evaporite rock mechanics in general.Key words: evaporite, potash, salt, brine, creep, mining.