The Liqhobong Mine lease area contains a cluster of at least five diamondiferous kimberlite bodies; namely the Main Pipe, Satellite Pipe, Discovery Blow, the Blow and a NW-SE striking dyke that is traceable from the perimeters of both the Main and Satellite Pipes (Figure 2). The surface areas of these pipes and blows are ~8.5 hectares, 1.6 hectares, 0.15 hectares and 0.1m hectares respectively. All the currently known five diamondiferous kimberlites of the Liqhobong cluster are within a strike length of at least 2.5 km (Leroux, 2010). Both blows and the Satellite Pipe are generously endowed with kimberlite indicator minerals (KIMs) occurring as xenocrysts. The main pipe is comparatively less enriched in the kimberlite indicator minerals but has abundant olivine macrocrysts and mantle xenoliths, the latter which commonly bear the KIMs.

The mining process at LMDC will be a conventional open-pit operation consisting of drill, blast, load and haul activities which will be carried out by a mining contractor. The pit design has been based on a split shell concept largely to defer waste stripping as much as possible while at the same time providing a double ramp system to mitigate the risk of ramp failure. The pit layout incorporates a concentric cut 1 which has been designed around the existing exposed pit bottom. This cut provides three and a quarter’s years of ore supply. Four successive split shell cuts follow, namely Cut 2 South, Cut 2 North, Cut 3 South and Cut 3 North. Each split shell cut will have its own ramp system, however once the north cut meets up with its respective south cut, the ramps join to become a concentric system.

The waste and ore mining fleet is planned to commence with 40 tonne ADT’s with a matching excavator. As waste tonnes increase from year five, a CAT 777 (90 tonne) truck or equivalent will be phased in. Haul roads in the pit have been designed at a width of 25m to accommodate the larger trucks and will be at a gradient of 1:10. The ADT ore fleet will continue throughout the LoM and ramp widths in the kimberlite zones will be 17m.

All kimberlite ore will be trucked and tipped into the primary crusher located 560m from the edge of the current pit. The front-end arrangement allows for direct tipping into a crusher tipping bin fitted with an 800mm aperture grizzley and rock- breaker. The crusher bin has a live capacity of 180m3 or approximately 320 tonnes. The ore will then be fed with an apron feeder into the primary crusher and onto the treatment plant. A RoM stockpile area adjacent to the tipping bin will provide 30,000 tonnes of capacity or approximately three days of production. Building a larger stockpile area proved prohibitive due to the steep terrain in the area. The tipping strategy will be to direct tip into the crusher bin during normal production operations. When the mining fleet is not operational due to a shift change or blasting activities, re-handling from the stockpile will take place using a dedicated front end loader.

The ROM ore will be processed through a plant with a top cut-off size of 40mm, and bottom cut-off size of 1.25mm, comprising of the following unit processes:

- Ore receiving and primary crushing
- Scrubbing and screening
- Secondary crushing
- Coarse DMS
- Fines DMS
- Tertiary crushing
- Final recovery and sort-house
- De-gritting and slimes thickening/process water reclamation
- Tailings disposal.

Primary Crushing will utilise a jaw crusher with a gap setting of 120mm, and will be located midway between the pit and the plant, with crushed material conveyed 290m to the plant. A crushed ROM stockpile could also be created as an operational buffer in the future and allowance has been made in the design of the front end to accommodate this .

Primary Washing and Screening will be in two parallel scrubbers with sizing screens directing the >40mm oversize to the secondary crusher bin conveyor, the 4-40mm material discharges onto the Coarse DMS feed bin conveyor, and the <4mm material to the Scrubber De-sliming Screens.

Secondary Crushing will utilize two cone crushers and will operate dry and in closed circuit, choke fed and utilising surge pan feeders so as to optimise crushing efficiency and minimise diamond breakage. Oversize reports back to the feed bins, whilst +4-40mm material is conveyed to the Coarse DMS surge bin and fines (<4mm) are pumped to the scrubber desliming screens.

DMS Feed Preparation Section collects the <4mm material as well as the +1.25-10mm Tertiary Crusher product and feeds this to the Fines DMS Surge Bins.

Coarse DMS consists of two identical DMS modules that treat the high value +4-40mm material and operates as an open circuit, with the floats drained, washed and >10mm oversize conveyed to the Tertiary Crusher. +1.25-10mm float material is conveyed to the tailings system. The product is discharged onto the double deck sinks drain, rinse and sizing screen before being sized into three size fractions namely middles (4-8mm), coarse (8- 16mm) and extra coarse (16-40mm) for processing through the Coarse DMS Recovery Module.

The fines DMS operates as above with two DMS modules, producing three size fractions namely fines (1.25-3mm), coarse (3-6mm) and extra coarse (6-12mm) fractions for processing through the Fine DMS Recovery Module.

The tertiary crushing section treats the nominally >10mm material from the Floats Screens top deck oversize of the Coarse DMS Modules, as a closed loop, with the +1.25-10mm material discharged to the fine DMS surge bin and oversize is re-crushed.

The two coarse recovery modules makes use of a dedicated middles X-ray machine, whilst the coarse/extra coarse X-ray machine operates alternatively on each concentrate feed, fed by a tube feeder. The X-ray machines are double pass, operated wet and require filtered water. Concentrate and tailings are dewatered and the concentrates report to relevant glove boxes by tube feeders, whilst the tailings report to the coarse recovery tailings conveyor.

The two fines recovery modules operate similarly, with the distinction that fines fraction concentrate from both modules is treated through an extra single pass wet recon X-ray Machine for further concentration before reporting to the drier and glove boxes.

The sort-house has four glove boxes dedicated to fines fraction, two to the middles/coarse fractions from the fines recovery modules, and one glove box for middles and one for coarse/extra coarse from the Coarse Recovery Modules. A dedicated glove box is used to defalsify as well as size and weigh the product from the other glove boxes.

The Degrit and Thickener circuit receives the underflow from the Tertiary Crusher Sizing Screen and the Scrubber De-sliming Screens and pressure- feeds it to the Degrit cyclones. Underflow from the cyclones is dewatered with screen oversize reporting to tailings and undersize to the Thickener Feed Box for flocculent addition. Overflow from the thickener reports to the Process Water Dam, with underflow to Slimes Disposal Sump for pumping to the slimes dam.

Tailings disposal operations make use of tailings from the coarse and fine DMS circuits in the construction of the slimes dam wall. Recovery tailings are stockpiled.