Modular flexible conveyor ducts can transport regolith horizontally, on inclines, or vertically, and can be designed to operate at any gravity level. Conveying efficiency improves as gravity is reduced . Each module is comprised of a thin outer duct, containing a novel light-weight flexible conveyor core. Transport is totally enclosed and dust-free. The design is robust and tolerant of occasional oversize particles. Minimal maintenance is required, and distances of many 10's of meters could be traversed with no back-and-forth driving of rovers, no dust generation, and consistent steady delivery of material. Beneficiation modules with screen-wire sieves are also possible. For larger operations or longer distances, multiple units could be daisy chained together. Various (ultrasonic or percussion) cutter-drill-heads or feeders could be employed to allow efficient extraction of material at depth. With additional development of drill-head feeder designs, extraction from depths of multiple meters could be achieved. The light-weight flexible nature of the novel conveying-core designs proposed for these regolith transport ducts may be suitable for many conventional bulk material transport operations. The light-weight duct-walls for space applications may need to be replaced with heavier, more robust tube walls for long duration continuous-use terrestrial applications. Also the overall distances for screw-conveyor transport that make economic sense under terrestrial gravity, are shorter than would be the case under reduced gravity. Since the mode of flow in these proposed flexible-ducts is significantly different than that used in most conventional screw conveyors, the range of potential applications may cover a wider variety of configurations than are used by conventional rigid screw conveyors. Many terrestrial solids transfer applications where pneumatic transport is currently the best option, may be candidates for the mechanically fluidized flow in the proposed flexible duct conveyors.