The use of rock boxes within conveyor transfers is not new, however, there is little published in the literature to aid in the design and implementation of rock boxes; instead mainly relying on prior knowledge and rules-of-thumb. A benefit of a rock box over other transfer types (e.g. soft loading chutes and impact plates) is their ability to capture material in such a way that it is only the initial feed of material which contacts chute walls or liners, with build-up of material creating a dominance of particle-particle interactions, thus reducing wear of the system and hence cost. This paper presents the preliminary results from an experimental rock box test program using polyethylene pellets, conducted on the variable geometry conveyor transfer research facility at the University of Wollongong. The position of the rock box, along with the belt speed and feed rate of material were varied to obtain a range of visual as well as quantifiable data. This paper also presents a series of discrete element modelling (DEM) simulations designed to predict the very same particle/bulk characteristics seen in the experimental test program in a view to determining whether accurate simulated predictions can be obtained. This simulation work involved the use of calibrated material models to ensure accuracy of all particle-particle and particle-geometry interactions. Initial minor discrepancies between the experimental and simulated results were investigated via input parameter adjustment to determine the root cause of the variations. The final comparisons still show some variation, however, investigations are ongoing.
Hastie, D. B. (2013). An experimental and simulated investigation of particle flow through a conveyor rock box. ICBMH 2013 - 11th International Conference on Bulk Materials Storage, Handling and Transportation