This paper analyzes the causes leading to the sliding of the support seat of the the belt veranda in a concentrator stockpile field. A rigid model is established for the pile foundation. Comparison of the model-based calculation results with field test results indicates that consideration must be given to the adverse influence of the run-off water on the stockpile field as well as to the adverse influence of large scale heaping and loading on the displacement of the pile foundation. It is proposed that cluster piles should be designed and reinforcement should be considered based on the horizontal loading of the piles.