[en] This study of resuspension of soil containing minute amounts of plutonium (Pu-239) has been in progress at the Rocky Flats (RF) Plant since 1978. It is one of several studies initiated after wind relocated small amounts of soil-borne Pu-239 during cleanup of an outdoor storage area. The Pu-239-settled field is now sparsely covered with prairie grass typical of the area. Past studies were limited to comparisons of bulk soil activity with total activity in the airborne dust. This work covers the physics of the particle resuspension process. This report covers the following: (1) Pu-239 resuspension rate versus wind speed, (2) mechanisms of soil particle resuspension, (3) vertical concentration profile of Pu-239 particles, (4) Pu-239 and host particle size distribution and activity concentration. 5 references, 1 table