A pump storage system (PSS) is introduced to the coal preparation dense medium cyclone (DMC) plants
to improve their energy efficiency while maintaining the required medium supply. The DMC processes
are very energy intensive and inefficient because the medium supply pumps are constantly over-pumping.
The PSS presented is to reduce energy consumption and cost by introducing an addition medium circulation
loop. The corresponding pump operation optimization problem in the PSS scheme under timebased
electricity tariff is formulated and solved, based on which the financial benefits of the design is
investigated using life cycle cost analysis. A case study based on the operation status of a South African
coal mine is carried out to verify the effectiveness of the proposed approach. It is demonstrated that the
energy cost can be reduced by more than 50% in the studied case by introducing a 160 m3 storage tank.
According to life cycle analysis, the PSS Option 1 yields an annual 38% reduction of the overall cost for the
beneficiation plant with a payback period of 2.68 years.