Pump apparatus comprising a base or chassis, a power unit and a reel assembly each operatively mounted to the base or chassis, a flexible conveyor conduit and flexible service line adapted to be payed out from the reel assembly and a work head including a pump operatively connected to the conveyor conduit. The work head comprises a pump having an outlet which is operatively connected to a conveying conduit, a support frame to which the pump is mounted and a powered traction drive assembly operatively mounted to the support frame. The reel assembly comprises a reel rotatably mounted to the base or chassis, a conveying conduit and a flexible service line, each being adapted to be wound thereon and payed out therefrom.