Abstract: A drilling rig for drilling an underground borehole (5) into a seam (4) uses coiled metal tubing (8) fed by a tractor unit (11) from a drum (7) to provide a thrust force to a drilling head. The drilling head has a bent-sub assembly giving an angle of deviation which is controlled by rotating the coiled metal tubing in the borehole by way of rotation of the drum (7) in the frame (12) about the axis of the tube in the borehole (5).

Abstract: A drilling rig for drilling an underground borehole (5) into a seam (4) uses coiled metal tubing (8) fed by a tractor unit (11) from a drum (7) to provide a thrust force to a drilling head. The drilling head has a bent-sub assembly giving an angle of deviation which is controlled by rotating the coiled metal tubing in the borehole by way of rotation of the drum (7) in the frame (12) about the axis of the tube in the borehole (5).

Abstract: An erectable arm assembly for use in a borehole, the erectable arm assembly comprising a main body and an arm member, the arm member being able to move between a collapsed position in which the assembly can be removed from the borehole and an erected position, the erectable arm assembly being adapted to house a fluid drilling assembly comprising a fluid cutting device and a flexible hose drill string such that the arm member during erection can contain at least part of the fluid drilling assembly, and when in the erected position the arm member is able to guide the fluid cutting device towards the borehole wall, the assembly further including at least one sensor for monitoring the arm member or the fluid drilling assembly.

Abstract: A method of steering a fluid drilling head in an underground borehole drilling situation is provided by rotating the flexible hose through which high pressure is provided to the drilling head and providing a biasing force on the drilling head. The hose can be rotated from a remote surface mounted situation by rotating the entire surface rig (13) in a horizontal plane about a turntable (24) causing the vertically orientated portion of the hose (11) to rotate about its longitudinal axis. The biasing force can be provided in a number of different ways but typically results from the use of an asymmetrical gauging ring on the fluid drilling head.

Abstract: A fluid drilling head has a plurality of nozzles (3, 4, 5, 6) in a rotatable nozzle assembly (2) to provide high pressure cutting jets (7). The head is provided with a gauging ring (10) having an annular clearance (11) to the rotatable nozzle assembly (2) to provide for the passage of rock particles eroded by the cutting action of the jets (7) while regulating the progress of the drilling head in the borehole and controlling drill stalling. A stepped rotatable nozzle assembly having a smaller diameter portion (8) and a larger diameter portion (9) to extend the cutting zone of a reaming jet closer to the outer diameter of the gauging ring (10) is also described and claimed.

Abstract: A self-advancing drilling system comprising a drilling apparatus, the drilling apparatus having at least one leading fluid cutting nozzle, an advancing device on the drilling apparatus to provide forward movement to the drilling apparatus, the drilling system further comprising a drill string formed from recoverable flexible hose and a steering device having at least one jet nozzle.

Abstract: A self-advancing drilling system comprising a drilling apparatus, the drilling apparatus, the drilling apparatus having at least one leading fluid cutting nozzle, means on the drilling apparatus to provide forward movement to the drilling apparatus, the drilling system further comprising a drill string formed from recoverable flexible hose.

Abstract: A self-advancing drilling system comprising a drilling apparatus, the drilling apparatus having at least one leading fluid cutting nozzle, means on the drilling apparatus to provide forward movement to the drilling apparatus, the drilling system further comprising a drill string formed from a recoverable flexible hose.

Abstract: An erectable arm assembly for use in a borehole, the erectable arm assembly comprising a main body and an arm member, the arm member being able to move between a collapsed position in which the assembly can be removed from the borehole and an erected position, the erectable arm assembly being adapted to house a fluid drilling assembly comprising a fluid cutting device and a flexible hose drill string such that the arm member during erection can contain at least part of the fluid drilling assembly, and when in the erected position the arm member is able to guide the fluid cutting device towards the borehole wall, the assembly further including at least one sensor for monitoring the arm member or the fluid drilling assembly.

Abstract: A self-advancing drilling system comprising a drilling apparatus, the drilling apparatus, the drilling apparatus having at least one leading fluid cutting nozzle, means on the drilling apparatus to provide forward movement to the drilling apparatus, the drilling system further comprising a drill string formed from recoverable flexible hose.