  Systems for transport and processing of granular media are challenging to
analyse, operate and optimise. In the mining and mineral processing industries
these systems are chains of processes with complex interplay between the
equipment, control, and the processed material. The material properties have
natural variations that are usually only known at certain locations. Therefore,
we explore a material-oriented approach to digital twins with a particle
representation of the granular media. In digital form, the material is treated
as pseudo-particles, each representing a large collection of real particles of
various sizes, shapes and, mineral properties. Movements and changes in the
state of the material are determined by the combined data from control systems,
sensors, vehicle telematics, and simulation models at locations where no real
sensors can see. The particle-based representation enables material tracking
along the chain of processes. Each digital particle can act as a carrier of
observational data generated by the equipment as it interacts with the real
material. This makes it possible to better learn material properties from
process observations, and to predict the effect on downstream processes. We
test the technique on a mining simulator and demonstrate analysis that can be
performed using data from cross-system material tracking.
