Injection fluids formed of reverse emulsions and related methods of forming and using reverse emulsions for cavity control in solution mining. The reverse emulsion can reduce the volume of oil required to create an oil pad at the roof of a solution mining cavern in order to prevent vertical leaching and cavern collapse. The reverse emulsion can be formed from an emulsifier, a brine solution and oil. The emulsifier concentration can range from about 1% to about 5% by weight of the reverse emulsion. The emulsifier and the oil can be combined to form an oil/emulsifier mixture, wherein the oil/emulsifier mixture is combined with the brine solution to form the reverse emulsion. The oil/emulsifier mixture can be from about 1% to about 5% by weight of the reverse emulsion.