Abstract: Shipping costs incurred in the shipping of particulate material in bulk may be reduced through the use of a vibratory compaction unit that settles the bulk material within the container during the loading process enabling a greater quantity of the particulate material to be loaded into a container of a given volume. The vibratory compaction unit includes a clamping deck 40 having a generally vertical face 44 together with spaced contact blocks 96 located on the clamping deck 40 and extending from the face 44. Clamping hooks 94 are located on the clamping deck 40 for engaging lifting pockets 16, 18, of a universal shipping container 14 or the like to firmly clamp the container 14 against the contact blocks 16. An exciter mass 52 is spaced from but adjacent to the clamping deck 40 and a vibration imparting motors 64, 66, 68 are located on the exciter mass 52. Amplification springs 60 interconnect the clamping deck 40 and the exciter mass 52.