The deposit is hosted in metamorphosed Neo- Proterazoic black carbonaceous shale and calcareous quartzite of the Oonah formation overlaid by Tertiary conglomerate, gravel and grit and subsequent Quaternary stream alluvium and swamp and marsh deposits. Mineralization occurs in the horizon of scarts with a magnetite strip associated with the layers, and tin is found as a supergene at a late stage, a low-temperature formation, that is, post-dating of skarn formation, and also (in the form of silicate) released during serpentinization. The horizon of the mineralized skarn extends approximately 50 meters long (north-south) and 15 meters wide (east-west).

The current pit crest dimensions are approximately 125 m long (60 m at base of pit), 45 m to 50 m (25 m to 30 m at base) wide at its maximum and 20 m deep. The proposed expansion will increase the length of the pit base to 90 m with no effective increase in pit width at the base. The footprint at the crest is expected to increase to about 180 m in length and 110 m wide, disrupting approximately 0.5ha of relatively undisturbed vegetation in the process. The final pit depth will be nominally 40 m from the crest of the footwall shale (western slope) and 60 m from the crest of the hanging-wall (eastern side). Based on the current pit slope performance, the western pit wall will follow the footwall shale down to final pit depth as a single height highwall.

Based on the geometry of the final pit, it is proposed that the expansion will occur as a single cutback to the final pit void to allow adequate room for equipment to safely operate during mining. This cutback will be taken from the eastern and southern extent of the pit, retreating from the south towards the north for each cut. Depending on ore supply a shallow drop cut may be taken initially to ensure constant feed for the plant.

A nominal ramp grade of 1V to 6.5H (15 percent) will be adopted for design, so for a pit depth of 35 m, assuming a 5 m deep goodbye cut, the ramp will need to have a horizontal length of approximately 230 m. A minimum ramp width of 11.5 m will be allowed based on 2.5 x the width of the largest vehicle (40t Moxy) with allowance for a safety berm that is half the height of the largest vehicle tyre.

The Granville Expansion will comprise the resumption of mining from the existing open cut (the Granville East Mine or GEM) of up to 40,000 tonnes of ore and 145,000 tonnes of waste material to provide stable geotechnical conditions. Waste rock from the extended open pit will be classified as Non Acid Forming (NAF) or Potentially Acid Forming (PAF) and stored in a new waste rock emplacement (WRE) east of the pit. Ore will be crushed at GEM and transported to the Granville Process Plant (GPP) approximately 8km from the mine along the Heemskirk Road. Ore will be processed using gravity, magnetic separation and flotation methods to produce a tin concentrate for export overseas. Tailings from the processing plant will be discharged to the proposed Tailings Storage Facility (proposed TSF). It is anticipated the Granville Expansion will run for 18 to 24 months.

Ore will be crushed at GEM to 6mm (P80) and stored on a new ROM / crushing pad with a capacity of up to 22,000 tonnes. During construction of the new ROM/crushing pad, measures will be implemented to reduce the likelihood of erosion and/or sedimentation, and will include an expansion of the existing sediment retention ponds and pre-treatment basin and diversion of surface water run-off from around the proposed ROM/Crusher pad and proposed WRE. Mobile crushing equipment will be employed on a campaign basis to crush 15,000 to 20,000 tonnes at a time, operating up to six days per week, 12 hours per day. Crushing equipment is anticipated to include one primary jaw crusher, two secondary/tertiary cone crushers and two vibrating screen decks.

Transported ore will be treated at the GPP up to 12 hours per day, six days per week. Ore will be initially screened (trommel) and treated through a jig, relying on specific gravity to separate the lighter waste or rejects from the heavier pre concentrate. Heavier minerals, including cassiterite, magnetite and sulphides will principally report to the pre-concentrate which will be delivered from the gravity concentrator to the dressing plant.