The 2-billion-year-old (Archean) Phalaborwa Carbonatite Complex contains apatite-bearing zones, the primary source of South African phosphate production. Phalaborwa carbonatite contains two types of apatite ores: foskorite and pyroxenite.

The manufacture of phosphoric acid from phosphate concentrate produced a phosphogypsum waste which has been deposited on 2 large stacks. The REE in the phosphate ore reports primarily to the phosphate concentrate delivered to the PA plants.

The two stacks are situated to the West of the Phalaborwa mining complex. The residue stacks were deposited on a relatively flat base, consisting of soil and gravel, which was intersected in some of the drill holes.

Stack A, the largest of the 2 stacks, with an approximate basal dimensions of 1,200 m x 700 m, has a higher surface elevation and steeper slopes. An acidic water pond (with a depth of c.4 m at its deepest central part) covers most of the top centre of the stack. Some gypsum has been mined for agriculture purposes has been removed from the NE corner of stack A.

Stack B, with an approximate basal surface of 800 m x 650 m, is lower and has gentler slopes than stack A. The acid pond on top is smaller, but with a depth virtually the same as for stack A. Some gypsum quarrying and mining has taken place in the SE and SW corners of stack B.

In both stacks, the material is made of white, fine-grained, friable phosphogypsum which is indurated/ceme ........

Two stacks (Stack A and Stack B) comprising of phosphogypsum residue from a chemical phosphoric acid production process have been identified as the target of reclamation operations.

With no need for hard rock mining, crushing, and milling, the phosphogypsum will be hydraulically reclaimed from the stacks and pumped into the processing facility.

Reclamation Methodology
The main input parameters for this reclamation design are based on delivering a design material flow of 312 t/h to the processing plant at an average solids’ concentration of 25 to 35 %w/w and with a single monitor cannon being able to produce 7,000 tonnes/day. The number of monitor cannons required will be 2 x operating 24/7 with two complete standby units connected to ensure flexibility and continuity of supply to the process plant.

The proposed methodology for the reclamation of the RRE Bosveld resource is to hydraulically reclaim both stacks – starting with Stack B and then moving over to Stack A once B has been depleted. The top-down method in 8 to 10 m benches will be used on both stacks. This is determined by the material's behaviour and considering the high moisture content on the facilities.

Large amounts of water are currently stored on both residue storage facilities. This water will need to be decanted from the facilities to allow the material to consolidate before reclamation. The material at the face will be reclaimed using a 150 mm track-mounted rem ........

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