Surface drilling apparatus

A surface drilling apparatus for drilling large diameter holes in soft to medium-hard earth formations includes a cylindrical casing defined by a stationary upper section and a lower section rotatable relative to the upper section; a plurality of circular rows of cutting discs rotatably mounted on the base of the lower section for cutting material beneath the apparatus; a transfer pipe in the center of the base of the lower section for receiving cut material from the cutting discs and feeding the cut material upwardly through a discharge pipe for carrying the material upwardly to the surface; and an annular, upwardly inclined slot in the discharge pipe at the top of the upper section through which air is fed under pressure into the discharge pipe to induce the cut material upwardly from the transfer pipe and blow the material upwardly.