It is very dangerous to assume or extrapolate anything when it comes to bulk material properties and behaviour. Traditional methods for flow prediction, such as hand calculation or even just relying on past experience, require assumptions to be made about the bulk material properties and flow. Although these materials may have generic names and possess similar properties (e.g. coal, iron ore), they can all behave quite differently under dynamic conditions. What we end up designing for one part of the plant may be quite different to what is needed in another part of the plant, which may be handling or processing a different size fraction, say. The consequences of making too many assumptions can be quite serious as illustrated by flow blockages in handling and processing operations, such as conveyor transfers, chutes, ship loading, etc. A common concern when applying DEM to bulk flow problems is determining how you set the material, interaction and geometric properties of your particle elements to provide you with accurate results. DEM, like with all forms of modelling, is a mathematical representation of the real world. A real material can consist of many millions/billions of individual elements, each one with its own shape. The big question is how can you go from your real material to a DEM element equivalent; such that the bulk properties and behaviour observed in the simulation sufficiently represent that seen in the real world? Figure 1 shows how this is to be achieved.