Buzwagi is shear-hosted quartz-veined deposit hosted in porphyritic granite. It is found in Nzega belt in the lower portion of the Nyanzian system. This belt is composed of basalt and intermediate volcanic intruded by granitoid masses which is dominated by deep-seated structure.

The granite that hosts the majority (85%) of the Buzwagi deposit is a medium to coarse feldspar granite with zone orthoclase crystals up to 4cm. This is predominantly underlain by medium- to coarse-grained granite intruding mafic flow and pillow flow basalts, within which there are two other distinctive units, including a tonalite silt-like body, which is occasionally mineralised with quartz veining, sericite alteration and sulphide mineralisation. Rock units dip to the east at c 60° in the southern portion of the lease area and 65-75° in the northern portion.

Several faults traverse the Buzwagi area. The most significant orientation of faulting is northwestsouth-east, parallel or sub-parallel to the Nzega shear (and probably related to it).

The Buzwagi deposit is hosted within or near a north-south brittle-fracture shear corridor that is up to 450m wide and includes two ore types: shear-hosted, porphyry-hosted.

As such, Buzwagi has been separated into 12 structural domains, within which mineralisation is segregated.

Domain 1 (which accounts for up to 50% of Buzwagi’s in-situ gold) is up to 1,000m long and 30m wide (subject to pinching and swelling), with a consistent gold grade (averaging 2.69g/t) along its entire strike length. The gold mineralisation in this domain is associated with quartz veins and/or quartz stockwork, reflecting dilatant zones within the north-south structural corridor. By contrast, mineralisation in Domain 6 extends over a wider area than Domain 1 (>30m) and is characterised by more stockwork and less shearing. All other mineralised domains are similar to Domain 6, except that they are generally less than 10m wide. The gold mineralisation in all domains plunges 30° to the south.

The Buzwagi site is located in north-western Tanzania, East Africa. Buzwagi is the second largest mining operation in Tanzania and the largest single open pit in the country, which is one of the fastest emerging gold producers in Africa and the continent’s third-largest gold producer after South Africa and Ghana.

Buzwagi will continue to process stockpiles until mid-2021. Following completion of the mining of the final cut at the bottom of the pit in the first quarter of 2019, the mill feed will be exclusively from stockpiles.

An owner-operated fleet is used in mining. There are three excavators, fifteen 150-tonne haul trucks and three blast hole rigs.

The process plant treats oxide ore by crushing, grinding, gravity separation and carbon-in-leach (CIL) and produces gold in the form of gold dore and a copper/gold concentrate to be transported for further refining. The flotation tailings are then processed by CIL, followed by electro-winning and smelting to doré on site.

The process plant is designed with a throughput capacity of 12,000 tonnes of ore per day (c. 4.4 million tonnes per year) and produces both doré (approximately 45% of production) and a gold/copper concentrate (approximately 55% of production).