Integrated tactical continuous production planning of two blending systems sharing supply sources: the case of a phosphate supply chain

The tightening of compositional constraints by customers on merchantable phosphate ores (MOs) prevents the world's largest phosphate production site from continuing to plan its production with the current rules. This site extends over hundreds of km2, with several mines, several washing plants, and a drying plant, with MOs' shipment by rail or pipeline. MOs are obtained by blending ores (SOs) of varying compositions and volumes. Currently, the plants are managed quite independently, SOs are pre-assigned to the MOs, and the MO production routings in the washing plants are predetermined. We propose a model that ignores both SOs pre-allocation and routing’s choice. This blending production planning problem is neglected in the scientific literature but can be found in many mining production sites in most characteristics, offering perspectives on applying the proposal's approach. The numerous tests show that this model makes it possible to respect the composition constraints relating to several components, with a generalised use of the most economical routings and ensuring horizontal and vertical alignment of decisions.