An apparatus is provided for the drilling of a borehole and its
simultaneous lining with cement or the like by the same apparatus. The
apparatus comprises a combination spray head and reamer head, a means to
drive the reamer head through a borehole and a means for delivering
cement to the spray head. Cement is fed to a rotatable spray disc or arms
of the spray head, which is arranged to distribute the cement
substantially evenly over the internal surface of the borehole created by
the reamer head. The apparatus uses lined drill rods, as well as a lined
reamer core with a double walled plastic tube. An air transfer assembly
is used to connect an internal air source to an air passage contained in
the plastic tube, such that the external air source remains stationary
during rotation of the lined drill rods and attached reamer and spray
heads.