Methods and systems are described for tracking material through a production chain or operational process chain in which the material is transferred via a plurality of spatially distinct lumped masses of material (12, 14, 16, 18). A dynamic state space (430) is maintained descriptive of the plurality of spatially distinct lumped masses of material, wherein a quantity of entries in the dynamic state space is augmented or diminished dependent on a quantity of spatially distinct lumped masses being tracked. Measurements relating to an observed lumped mass of material are fused into the dynamic state space and a dynamic covariance matrix to provide an updated estimate of material in the plurality of spatially distinct lumped masses of material.