Methods and apparatuses for producing a planar cavern are provided. The planar cavern is formed by first creating a continuous bore that extends through a subsurface resource deposit. The continuous bore can be formed by connecting first and second bores at a point within the subsurface resource deposit. After the continuous bore has been formed, a sawing assembly is placed within the continuous bore. The sawing assembly is then moved, in a continuous or in a reciprocating fashion, within the continuous bore. As the sawing assembly is moved, it is maintained under tension, to create a planar cavern. By thus exposing a large area of the resource deposit, a relatively large amount of the resource deposit can be dissolved in a solvent introduced to the planar cavern per unit time. Saturated solution can then be pumped from the planar cavern, and the resource recovered from the saturated solution by evaporation.