Abstract: A down remaining apparatus has an upper stabilizer which supports the down reaming apparatus in the bored hole. A plurality of wheel assemblies are radially attached to the hub of the upper stabilizer. Each of the wheel assemblies has rotatable tires oriented against the bored hole wall, and a rotatable overload wheel which contacts the tunnel wall upon compression of the tires. A weight assembly comprising a plurality of stacked plates is secured to the frame of the down reaming apparatus and has manways therethrough which allow passage of workers. A lower stabilizer provides additional support for the down reaming apparatus. A plurality of wheel assemblies are radially attached to the hub of the lower stabilizer. Each of the wheel assemblies has a rotatable wheel pivotally attached to the lower stabilizer hub and spaced therefrom by a compressible bumper which reacts against the bored hole wall to stabilize the down reaming apparatus.