Abstract: There is provided a process for recovery of metal values from an ore body containing sulfide minerals. The ore body is fractured for increasing its permeability. The fractured ore body is then roasted in situ to increase the permeability and porosity of ore body to liquid leach solutions. The roasted sulfide minerals in the ore body are thereafter contacted with a leach solution to extract metal values therefrom and the extracted metal values are recovered.

Abstract: A subterranean formation containing oil shale is prepared for in situ retorting by initially excavating a void in a lower portion of a retort site. A primary sub-round of explosive is placed in a portion of formation within the retort site above the void, and a secondary sub-round of explosive is also placed in unfragmented formation above the void. In one embodiment, the primary sub-round comprises explosive placed in separate pairs of longitudinally spaced apart upwardly converging blasting holes. Explosive in the primary sub-round is detonated for fracturing unfragmented formation along a boundary defined by the upwardly converging blasting holes to separate a portion of formation from adjacent unfragmented formation for forming at least one new face above the separated portion of formation.