A comprehensive 3D numerical investigation of hydrodynamics of particles flowing through a horizontal pipe loop consisting of four bends has been modeled. The multiphase mixture model available in Fluent 6.1  is used in this study. In this numerical simulation five different particles have been used as secondary phases to calculate real multiphase effect in which inter-particle interaction has been accounted. The deposition of particles, along the periphery of the wall around bends has been investigated. The effect of bend and fluid velocity on particle deposition has also been investigated. The maximum particle deposition is at the bottom wall in the pipe before entering the bends conversely, downstream of bends the maximum deposition is not at the bottom - as seen upstream of the bends - rather it occurs at an angle of 600 toward the inner side from the bottom. The larger particles clearly showed deposition near the bottom of the wall except downstream of the bends. As expected, the smaller particles showed less tendency of deposition and this is more pronounced at higher velocity. This numerical investigation showed good agreement with the experimental results conducted by CSIRO team .