To address the difficulties of solid-liquid partitioning in mine drainage, this research introduces a tandem hydrocyclone integrated with an overflow cap configuration. The design leverages the synergistic interaction between a wide-angle primary cone and a narrow-angle secondary stage to bolster the classification of fine particulates. Through a combination of computational fluid dynamics (CFD) and empirical validation, the sensitivity of hydrodynamic profiles and sorting efficiency to both geometric and operational variables was scrutinized. Findings reveal that a refined overflow cap geometry stabilizes the inflow environment for the downstream stage while mitigating manometric head loss in the lead unit, thereby facilitating mine water purification. Furthermore, elevated inlet pressures trigger a reduction in overflow solids recovery and a contraction of the separation cut-off point, which collectively sharpen the classification precision. Consequently, the strategic adjustment of structural and feed parameters is vital for maximizing the separation proficiency of the serial hydrocyclone system.