Table 6. Comparison of Economic Indexes of Flotation, High-Intensity Magnetic Separation, and Gravity Separation Methods.
| beneficiation method | flotation | high-intensity magnetic separation | gravity separation |
|---|---|---|---|
| annual production (tons) | 10,000 | 10,000 | 10,000 |
| manganese content (%) | 30% | 30% | 30% |
| manganese ore price (per ton) | 100 | 100 | 100 |
| mining cost (million) | 10 | 10 | 10 |
| shipping cost (million) | 5 | 5 | 5 |
| processing cost (million) | 3 | 4 | 2 |
| equipment maintenance cost (million) | 2 | 2 | 2 |
| manpower cost (million) | 1.5 | 1.5 | 1.5 |
| environmental cost (million) | 0.5 | 0.5 | 0.5 |
| investment discount rate | 10% | 10% | 10% |
| net present value (NPV) (million) | 11.75 | 7.24 | 10.47 |
| internal rate of return (IRR) | 14.09% | 11.34% | 15.73% |
| payback period (PBP) (years) | 3 | 4 | 3 |