TAR SANDS TREATMENT

摘要

A method of mining deposits of discrete materials such as oil bearing sands disposed between an overburden and an underlying competent rock stratum in which at least one pilot hole is vertically drilled from the surface through the overburden and through the formation of discrete solids into the underlying competent rock stratum, an access drift or tunnel is driven in the competent rock stratum to intersect the vertical pilot hole, a sump is formed in the drift or tunnel below the pilot hole, the pilot hole drill bit is removed and a mechanical-hydraulic excavator head is attached to the drill string, a collection raise is excavated upwardly from the drift or tunnel concentric with the pilot hole to the bottom of the formation of discrete solids, and a liquid under high pressure is jetted radially from said mechanical-hydraulic excavator head into the discrete material commencing at the bottom of the formation of discrete material and continuing upwardly towards the top of the said formation to progressively upwardly undercut the said formation and to disintegrate the discrete material whereby the discrete material is flushed by the high pressure liquid downwardly through the collection raise into the sump for removal. A mechanical excavator is used in combination with the hydraulic head for enlarging the pilot hole to enhance operation of the hydraulic head and to provide support for the roof of the stope above the mechanical excavator to minimize undesired caving of the stope roof and to create an air chamber in which the mechanical-hydraulic excavator head can operate.