During storage of bulk material in mammoth silos, compression occurs. In previous research by the authors, the homogenization effect of mammoth silos was investigated, but compression was left out of consideration. Large-scale homogenization can, for example, be achieved by using a horizontal stacking method and an inclined reclaiming method. The main objective of this paper is to quantify the influence of compression on large-scale homogenization of bulk material in mammoth silos. This was established by using the vertical compression relation of Terzaghi. The results indicate that the homogenization obtained by compression alone is of a different order of magnitude than the homogenization resulting from a change of reclaiming method. It can be concluded that compression alone is an indicator of small-scale homogenization only, and has therefore no significant contribution to large-scale homogenization in general. (C) 2004 Elsevier B.V. All rights reserved.