Flow Diagram

Flow Diagram
Project map

Flow Diagram

The Hinda Phosphate project features a pilot-plant proven flowsheet that focuses on simplicity, reliability and ease of maintenance over recovery

The Project consists of four functional areas:

  • An open pit, free dig mine;
  • Phosphate beneficiation and flotation plant;
  • Product slurry pipeline system for transporting product to the coast, and
  • A drying, storage and ship loading facility at the coast.

1. Truck and Shovel Operation: The mining operation is a conventional open-pit truck and shovel, with in-pit crushing and conveying (IPCC) for both free dig Ore and after 5 years, overburden. The pit will be mined to full depth of economic mineralisation and then advanced northwest along strike, allowing for continual backfill and rehabilitation.

2. In-pit Sizer: The haul trucks tip the Ore into an in-pit primary crusher (mineral sizer) which breaks the material up so it can be conveyed.

3. Overland Conveyor: An overland conveyor transports the crushed Ore from the mine site to the beneficiation plant.

4. Primary Ore Stockpile:   After the Ore is conveyed to the beneficiation plant site it is stacked on a large horseshoe stockpile by a luffing, telescoping stacker. The stockpile acts a buffer between the mine site and the plant site and allows for blending and grade control.

5. Secondary Sizer:   Ore reclaimed from the primary crushed Ore stockpile is secondary crushed using a quad-roll mineral sizer.

6. Secondary Crushed Ore Stockpile: Once the Ore has been secondary crushed it is dry stacked before being reclaimed using at slot feeder under the stockpile. This provides a buffer to allow continuous operation of the grinding circuit.

7. Primary Wet Screen: This pre-screening step is used to cost effectively remove gangue mineral species, whilst upgrading the phosphate content, and evening out mill feed grade. Two double deck screens remove oversized material that is then attrition scrubbed. A high proportion of magnesia (>70%) reports to these coarse and fines rejects, together with some silica and most of the iron. The phosphate grade of the resulting mid-fraction is upgraded from a LOM average of 11.0% mined to a mill feed averaging 21.7% P205. Importantly also, this mid fraction is less variable with respect to grade than that of the run-of mine material, which assists control of the downstream flotation process.

8. Attritioner: The oversized ore from the primary wet screen is attritioned in order to further break the material up.

9. Coarse Removal Screen: The attritioned material is screened again to remove the oversize “coarse rejects” with the undersized material returned to the plant. Hydrocyclones reject the “fines” fraction from the resulting product.

10. HyrdroCyclone:   As the fines component of the Ore is barren in phosphate as well as being high in carbonates it is separated from the screened ore by a hydrocyclone and sent to the tailings dam.

11. Ball Mill: A single 7.5 MW ball mill grinds the pre-screened Ore mid-fraction, liberating the minerals whilst maintaining the particle size required for efficient float concentration.

12. Mill Classification:   Convention Hydraulic Sizers are used to classify the ore in the milling circuit. Hydraulic sizes are cheap to operate and offer a superior cut-point efficiency over cyclones.

13. Desliming Hydrocyclones: The milled Ore is deslimed before the flotation circuit to remove slimes which compromise float concentration.

14. Reverse Rougher Flotation: Three stages of conditioning with a phosphate depressant and carbonate and silica collectors is followed by a Reverse Rougher float to reject the gangue minerals. The roughers produce a sink product of approximately 30% P205.

15. Reverse Cleaner Flotation:   The reverse rougher sink product is processed in a reverse cleaner float stage to achieve a grade of 32% P205 and 0.7% MgO.

16. Concentrate Thickener:   densifies the concentrate to 65% w/w solids for storage in the header tanks, prior to pumping to the slurry pipeline.

18. Buried Slurry Pipeline: The Concentrate slurry Product is pumped along a 42km slurry pipeline over the coastal plain to Pointe Indienne.

19. Receival Tanks: Once the Slurry Concentrate reached the port site it is stored in large buffer tanks ahead of the drying plant, to allow for continuous operation.

20. Pressure filtration: dewaters the 60% solids slurry that is stored in the receival tanks to 10% moisture.

21. Concentrate Dryer: A gas-fired flash dryer reduces the moisture content to a target level of 3-7% moisture.

22. Concentrate Storage: A covered stockpile with stacker and reclaimer provides approximately 200kt storage of dried concentrate prior to ship loading.

23. Jetty and Shiploader:   A trestle jetty and shiploader is used to load ships up to 65,000 t Ultramax size at a rate of 4,000 t/h.