The objective of this investigation was to develop optimal designs for lightweight roof supports for use in underground coal mines. A load capacity of 196 kn (22 tons) and a height adjustable between 1.829 M (72 inches) and 2.438 M (96 inches) were taken as the design parameters; the design goal was a unit weighing less than 22.3 Kg (50 lb). Three alternative design concepts were explored: namely, mechanical, hydraulic, and hydromechanical, and 13 designs were analyzed in detail. Steel, aluminum alloy, and composites were the main potential construction materials investigated for suitability from structural, life, safety, and other considerations. It is shown that by using realistic mathematical models for stress and deflection calculations that it is possible to reduce prop weight to the design goal. The analysis presented for all-hydraulic props is applicable to hydraulic cylinders on all mining equipment and similar equipment. This report includes the computer program and user's guide for analyzing hydraulic cylinders as well as a bibliography on structural composites.