An apparatus for bursting pipe is preferably adapted to receive rotational
energy from the inner member of a dual-member drill string. In a
preferred embodiment, a plurality of pipe-bursting members, driven by the
interconnected inner members, cut or burst a subterranean pipe. In
another preferred embodiment, a plurality of screw drives move the
pipe-bursting members between an expanded position and a retracted
position in response to rotation of the interconnected inner members.