Abstract: An electric power actuated rubber tired carriage having a height profile substantially that of the tires on the wheels includes machinery for universally positioning in three separate degrees of motion a rotatable auger for drilling holes into mine tunnel walls. The drill rig comprises a square boom of variable length with a reciprocating auger mount with motor journalled thereabout to extend a parallel disposed drill of substantially the same length from the end of the boom into the drill hole. A power line retraction feature prevents fowling with drill rig movement. The rig carriage is short enough in length for transverse positioning across a tunnel width to drill holes at an acute angle to the ceiling wall for example, and bracing is mounted in these holes for supporting the ceiling. The drill is anchored in the tunnel floor.