Vanadium mineralisation occurs in vanadium-bearing titaniferous magnetite-rich layers that occur within the Upper Zone of the Rustenburg Layered Suite of the Bushveld Complex. The magnetiterich layers are part of the layered sequence and are concordant, continuous along strike and down-dip, although thickness variability occurs.

The Bushveld Complex intruded Pretoria Group meta-sedimentary rocks of the Transvaal Supergroup approximately 2,060 million years ago. The layered sequence of mafic rocks, known as the Rustenburg Layered Suite, comprises five distinct zones.

• the Marginal Zone,
• the Lower Zone,
• the Critical Zone,
• the Main Zone, and
• the Upper Zone.

Project Geology
Both the Main Zone (Pyramid Gabbronorites) and the Upper Zone (Bierkraal Magnetite Gabbros) occur on the Vametco Mining Right Area (MRA). Underlying the northern regions of the Vametco MRA are the Bierkraal Magnetite Gabbros, whilst the southern part of the Vametco MRA is underlain by Pyramid Gabbro-Norites. The mafic layers are east-west striking and north dipping, with an average dip of 19°. The lithologies associated with the Main Zone (Pyramid GabbroNorite) are gabbro-norite, and locally anorthosite and pyroxenite bands. The lithologies in the Upper Zone (Bierkraal Magnetite Gabbro), that occurs on the northern part of the Property, include magnetite–bearing gabbro, olivine-diorite and some anorthosite and magnetite layers. The well-developed magnetite seams in the lower portion of the Upper Zone are currently being mined at Vametco for their vanadium content.

At Vametco, the magnetite bearing layers are grouped into three seams, namely the Upper, Intermediate and Lower seams, all of which dip to the north at approximately 19°. The seams occur just above the lower contact of the Upper Zone with the Main Zone and the Lower Seam rests on a prominent anorthosite layer.

The magnetite layers are mostly covered by a black organic soil and outcrops are not common in the pre-mining area. The weathering has destroyed the original structure of the mafic rocks for a couple of metres below the surface where after the weathering is seen as calcium and silica fill in fractures.

Structure and intrusions
At least five faults have been identified, one of which, towards the far east of the Vametco MRA, has a significant throw and forms the eastern limit of the open pit mine. The faults have been exposed by mining.

Linear intrusions in the form of dolerite dykes are present within the Vametco MRA. The dolerite dykes were intersected in drillholes VMB-11, VMB-13 and VMB-14. The dolerite is younger than and intruded into the lithologies of the RLS (JMA, 2015).

Slumps/potholes occur in the stratigraphy have been exposed during open-pit mining. These are of several tens of metres in extent and the magnetite layers are preserved within them.

Vanadium Mineralisation
Vanadium-rich magnetite bearing layers occur at the base of the Upper Zone and have a cumulative thickness of over 125 m. According to the magnetite content, the layers of magnetitebearing rocks have been classified into five major units, then further subdivided into 22 seams.

At Vametco the Seam sub-division was simplified to the Seam Zones for ease of reference and mine planning. All Mineral Resource estimates are based on the Seam Zones. The Upper Seam as determined for the Mineral Resource comprises US-1.

Geological Models
The long history of mining platinum group elements and chrome from the Bushveld Complex has led to thorough understanding of the geology. The origin of the concordant magnetite layers is a subject of debate with the currently most widely accepted theory being as follows:
• introduction of magma to the magma chamber resetting the crystallisation phase;
• decrease in the magma chamber pressure;
• settling and sorting of crystals through gravity; and
• change in oxygen content of the chamber.

Although their genesis is not fully understood, the occurrence of these magnetite layers in the same stratigraphic units is well documented throughout the Bushveld Complex.

Nature of Deposits on the Property
The magnetite layers are continuous over large distances. However, the Intermediate Seam pinches out in some parts of the property. The layers strike in an east-west direction for 3.3 km and dip northwards at 19° within the Project area. The lower layers have been intersected at a depth of 270 m below surface, which equates to 830 m down-dip from outcrop on the plane of mineralisation.

The current mining cycle for the Project is conventional drill, blast, load and haul with the opportunity of free-dig in some areas of weathered material.

Prior to mining in a particular area, all vegetation cover and useable soil is removed and placed on a separate soil stockpile. Waste rock and ore are blasted at irregular intervals and removed to waste rock dumps or the primary crusher, respectively. Material is loaded onto 20- or 40-tonne haul trucks using hydraulic shovels and front-end loaders. The mining is not a constraint and there is potential to increase the ore production in excess of 2.6 Mtpa (if required) based on the strike length, dip and orientation of the orebody. Due to the stratified nature of the ore deposit, Bushveld Vametco uses a combination of strip mining and open pit mining.

The open pit mining approach can be typified as bench mining where faces are opened up in one area through overburden and waste stripping. The exposed ore is mined and transported to the plant by a fleet of trucks and shovels. A pit optimisation study was done to generate different pit shells in order to identify the pit shell which should render the optimal value based on practical technical constraints over the Life of Mine (“LOM”).

Vametco uses a series of contractors to perform the mining. There are currently four contractors operating at Vametco.

Crushing
The primary crusher operates on an eleven shift fortnight basis, whilst the remainder of the plant is operated on a 24/7 basis. RoM ore is delivered by tipper truck either directly to the oscillatory cone primary crusher, or to a RoM stockpile from where it is reclaimed to the primary crusher by an excavator and dump trucks. A stockpile of approximately 130,000 t was evident during the site inspection (27-28 May 2019), representing approximately 30 days of throughput at present (2019) treatment rates.

The primary crusher reduces the ore top size from 1,000 mm to 150 mm. The crusher discharge grizzly cuts the stream at 40 mm, with the coarse fraction being transferred to the secondary crusher feed stockpile (approximately 70,000 t). The sub- 40 mm fraction is combined with the output of the secondary and tertiary crushers and is transferred to the tertiary crusher screen feed bins.

The oversize material is drawn from the secondary crusher feed stockpile by three vibratory feeders and is transferred to a single secondary Simons cone crusher where it is reduced to a nominal top size of 38 mm before being combined with the primary crusher undersize and transferred into five screen bins. The crushed material is drawn from the bins by vibratory feeders to five polydeck vibrating screens where it is screened at 10 mm. The oversize from the five screens proceeds to the two tertiary crusher feed bins, each bin feeding a tertiary Simons crusher via a vibrating feeder. The material is crushed to 10 mm before being returned to the five screen bins. The sub- 10 mm screen undersize is directed to two silos ahead of the primary ball mill circuit.

Milling
The primary milling circuit consists of three ball mills which reduce the particle size to 70 % < 150 µm.

The mills are operated in closed circuit with cyclones with magnetic separators on the cyclone overflow streams. The combined primary mill magnetic fractions are directed to the single secondary mill. The primary mill non-magnetic fractions are cycloned, with the cyclone overflow being directed to the tailings thickener. The cyclone underflow is magnetically scavenged.

Vametco’s processing plant receives ore from the co-located Vametco mine. Vametco employs the standard salt roast and leach process to produce a steel-alloying vanadium carbon nitride product called Nitrovan.

The processing plant has historically performed satisfactorily with a recent annual production history of around 2,600 mtV p.a. NitrovanTM. A study as to the current indicated sectional maximum throughputs indicates that some of the sections could become limiting at an annual tonnage throughput of 1.5 Mtpa for a production of around 3,400 mtV p.a. NitrovanTM.

Measures to increase the hourly throughput, improve thermal efficiencies and limit downtime in the kiln section are currently being considered.

Process Summary
The mills are operated in closed circuit with cyclones with magnetic separators on the cyclone
overflow streams.

The secondary mill is operated in closed circuit with a cyclone to produce a grind of 80 % < 106 µm ........