According to embodiments described in the specification, an exemplary method is disclosed for hydraulically hoisting potash (or other evaporite ore) ‘fines’ material from an underground mine. The method includes mining an ore deposit using a boring machine to generate Run-of-Mine (ROM) material at a mine face, conveying the generated ROM material to an underground ore screening plant, screening the ROM material relative to a threshold size wherein the threshold size is a feed size of one or more flotation cells at a surface processing plant, mixing ‘fines’ material, comprising ROM material that is below the threshold size, with a saturated brine to create a slurry mixture wherein the saturated brine prevents the ‘fines’ material from dissolving into the slurry mixture, and pumping the slurry mixture to a surface location via one of a shaft and a borehole to the surface product separation plant.