All known mineralisation in the area is epigenetic “Cobar” style. Deposits are structurally controlled quartz + sulphide matrix breccias grading to massive sulphide.

The deposits are located in high strain zones. Metal ratios are variable but there is a general tendency for separate Pb+Zn+Ag±Au±Cu and Cu+Ag±Au ore bodies. These are often in close association with the Pb+Zn lenses lying to the west of the Cu lenses. At Hera Zn is usually more abundant than Pb.

Formation temperatures are moderate to high. At Hera the presence of Fe-rich sphalerite, nonmagnetic pyrrhotite and cubanite indicates formation temperatures between 350°C and 400°C. Recognised at Hera are quartz + K-feldspar veins, scheelite, and minor skarn mineralogy which suggest a possible magmatic input. Deposit timing is enigmatic. The main mineralisation occurs as brittle sulphide matrix breccias with silicification grading to ductile massive sulphides that crosscut both bedding and cleavage. Recent age dating on micas and galena gives an age of ~385Ma for the Hera deposit.

The mineralisation at Hera, indicated by elevated gold, silver, lead, zinc and sulphur grades, appears to be structurally controlled and is associated with shearing, brecciation and quartz veining.

The twelve solid wireframes representing mineralised domains were treated as hard boundaries during estimation of all elements except arsenic. This means that blocks inside a particular domain were estimated using only data from inside that domain. Blocks and data that lie outside of all of the mineralised domain wireframes were treated as a single additional domain. Variogram models were produced for each of the domains with sufficient data and search ellipse orientations were defined for each domain individually.

A fault, observable in underground developments, cross cuts the deposit at the southern end of Main North and is interpreted to off-set Main South by about 25 m to the west.

The reported resources at Hera span a length of around 800 m and consist of seven en echelon volumes that dip steeply to the west-southwest. The plan width of the resource varies from 2 m to 70 m (including internal low grade zones) with individual stopes reaching up to 25 m wide. The upper limit of the reported estimates occurs at a depth of around 230 m from surface and the lower limit of the resource extends to a depth of 630 m below the surface.

Hera is an underground mine utilising long-hole open stoping in a combination of bottom-up and top-down directions. The stopes are backfilled with cemented rock fill (CRF), waste rock fill or a combination of both.

The orebody is accessed from a decline located in the hangingwall. The decline has a gradient of 1:7 and production levels are nominally 25 m apart.

Mining for the period was undertaken using conventional bench stoping mining techniques. Stope voids are backfilled with waste rock material from concurrent underground development and, if required, additional waste rock material is transported from the WRE Area on the surface.

The Hera Process Plant processes ore from the Hera Mine to produce gold-silver doré bars and a ‘bulk’ (lead+zinc) concentrate for sale.

The process flow sheet in summary, consists of:
- Primary, secondary and tertiary crushing circuit to produce a P100 of 2.36mm.
- A gravity gold circuit consisting on an Inline Pressure Jig (IPJ), 2 x inline spinners and a Falcon centrifugal concentrator. These devices produce a gravity concentrate that is leached with Inline Leach Reactor (ILR) producing a gold solution to the electrowinning cells to deliver gravity gold doré for sale.
- A VTM-400 vertimill to produce a sub 250 micron feed to the flotation circuit.
- A rougher and cleaner flotation circuit to produce a lead-zinc concentrate grading +50% lead + zinc.
- A gold leach circuit which leaches the cleaner concentrate to produce a gold-silver bearing leach liquor and a final concentrate for sale.
- The gold-silver bearing leach liquor is presented to a Merrill Crowe circuit to produce gold – silver doré for sale.