This report presents the results of a technical, economic, and environmental feasibility study of phosphate ore recovery by the hydraulic borehole mining method. The experiments resulted in the recovery of 1,696 tons of ore from three boreholes during a 65-hour operating period. The experiments were conducted with the hydraulic borehole mining tool operating submerged in borehole 1, in air in borehole 2, and submerged again but with an air-shielded cutting jet in borehole 3. A continuous monitoring program was conducted throughout the mining operation and for a period of 2 months after completion to assess the impact of the hydraulic borehole mining method on the environment. Environmental impact was assessed in terms of site ground subsidence changes in ground water quality, and changes in radiological profile. The study indicated in-air mining to be technically feasible but not economically viable owing to the incidence of cavity roof failure. Submerged mining was shown to be both technically and economically feasible, particularly with the tool in the air-shielded cutting jet. The environmental monitoring program demonstrated hydraulic borehole mining to have a minor effect on the environment.