A study to evaluate physical beneficiation processes was undertaken to assess the efficiency of beneficiating oil shale, and to measure its impact on the economics of shale oil production. This study evaluated the effect of crusher types and degree of crushing on beneficiation of oil shales, the natural beneficiation that occurs due to particle size distribution, different beneficiation techniques (heavy liquid sink-float, heavy media cyclones, and froth flotation), and the costs associated with beneficiating low grade oil shales. Every effort was made to incorporate all test available in published reports for both the Green River and Eastern Oil Shales. Results of beneficiation tests show that within the scatter in data, there is no effect of shale particle size (between 45 microns to -3''), method of beneficiation, grade of feed material (13 to 3/GPT), or type of crusher used on oil recovery. The geochemical nature of the oil shale clearly shows that maximum separation of kerogen and inorganic materials occur at particle size below 20 microns. This was verified when the froth flotation technique was used on these fine particle sizes; the oil recovery increased dramatically with much lower oil losses. Analysis of the data shows that froth flotation is the preferred technique for beneficiating oil shales as opposed to heavy media separation. 17 refs., 31 figs., 42 tabs.