Regionally mineralisation is hosted within early to mid-Ordovician turbidite sediments, forming part of the Girilambone Group. The Tritton mineralisation is hosted within greenschist facies, deformed pelitic to psammitic sediments, and sparse zones of coarser sandstones. The Tritton sulphide mineralisation is classified as a stratiform “Besshi style” volcanogenic massive sulphide (VMS) deposit.

Mineralisation is dominated by banded to stringer pyrite chalcopyrite, with a relatively consistent massive pyrite - chalcopyrite unit along the hanging wall contact. Alteration assemblages adjacent to mineralisation are characterised by an ankerite/chlorite footwall and silica sericite hanging wall. After mineralisation emplacement the stratigraphic package has been variably folded producing regional scale and micro scale fold patterns.

Murrawombie is a sulphide copper gold deposit located on ML1280 in central New South Wales (NSW), Australia. The deposit geology is described as a Besshi style volcanic associated massive sulphide occurrence. It contains economic grades of copper with minor gold and silver.

Regionally mineralisation is hosted within early to mid-Ordovician turbidite sediments, forming part of the Girilambone Group. Mineralisation is hosted within greenschist facies, deformed pelitic to psammitic sediments, and sparse zones of coarser sandstones.

The Larsens sulphide mineralisation is stratiform and is classified as a “Besshi style” volcanogenic massive sulphide. Mineralisation is dominated by massive pyrite – chalcopyrite, with minor banded to stringer pyrite – chalcopyrite, and sparse locally important magnetite chalcopyrite.

Structurally the Larsens sulphide mineralisation is hosted within a corridor of moderate to intense shearing related to a thrust fault observed in the east wall of the Eastern Shear of the Murrawombie Pit (Murrawombie pit is located approximately 4 km SW of the Larsens mineralisation). The shear corridor has been traced by Sirotem (geophysical exploration tool) to the north west of the Murrawombie pit, with the Larsens mineralisation sitting Hanging Wall to the Eastern Shear, in relatively un-deformed sediments.

The North East and Larsens Mines are located 5 km north of Murrawombie.

Copper mineralisation at the North East Mine is hosted by weakly chlorite altered and silicified schist in a massive to banded pyrite – chalcopyrite lens that dips moderately to the east.

A higher grade core to the mineralisation is continuous across strike and plunge having a strike approximately 100 m and a width of 10 m.

Economic mineralisation strike is in the order of 175 m with a horizontal width averaging 30 m. The deposit is open at depth and resources, limited only by drilling.

Copper sulphide mineralisation, primarily chalcocite, at the adjacent Larsens Mine is hosted by weakly chlorite altered schist in three discrete, massive to banded pyrite – chalcopyrite lenses that dip steeply to the east and plunge moderately to the south – east. The central lens is the largest defined to date and comprises two sub parallel lenses each several metres thick with strike lengths of 40m.

The mining method used at Tritton underground mine is sublevel open stoping. Transverse or longitudinal stope orientation is used depending on the geometry of the ore lenses. Transverse stopes are designed to have vertical walls between stopes, where there is sufficient width. In the wider areas of the deposit a number of stopes will be mined across the strike in a grid pattern. Stopes will frequently have two wall exposures of cemented backfill and a few stopes will have three exposures.

Stopes are backfilled with cemented paste fill made from mill tailing. Use of paste fill provides support of the ground around mined out stopes. Mineral Resource recovery has historically been over 80% since the introduction of paste fill.

The Murrawombie Deposit will be mined by a combination of underground and open pit methods. Underground mining will extract the majority of the ore. The open pit mining will be an expansion by a small push back of the south eastern wall of the existing pit to recover the remnant shallow resource. The pit expansion will be mined as the last stage of production from the deposit, to avoid complication of simultaneously working above an operating underground mine. No crown pillar will be left to separate open pit and underground workings.

Mining at the North East Decline is undertaken using longitudinal open stoping with partial rock fill, currently at a rate of 480,000 tpa. North East Decline ore is trucked to the processing plant at Tritton.

The crushing circuit comprises an ore bin with a fixed 800 mm aperture grizzly, feeding ore via a vibratory feeder to a Kemco S7N single toggle jaw crusher with a feed opening of 1.22 x 1.02 m.

Crushed ore of P80 100mm is conveyed to a 6,000 tonne stockpile where it is reclaimed via three vibrating feeders.

Grinding comprises an ANI Ruwolt fixed speed high aspect 6.7m dia X 2.13, 1500 kW SAG Mill, discharging via a trommel screen to the secondary grinding circuit. Lime is added at the SAG to target pH 10.5 for pyrite suppression.

Secondary grinding comprises a Marcy 3.81 m dia x 5.18 m 1250 kW ball mill operating in closed circuit with 500 mm dia Linatex hydrocyclones. Cyclone overflow discharges to two parallel Metso Vertimills (VTM800STD) installed as part of the TEP and shown in the foreground of the lower photo.

The grinding circuit produces a cyclone overflow product of P80 75 µm at 30 to 35% w/w solids.

The tertiary cyclone overflow feeds two 50 m³ Wemco tank cells (installed as part of the TEP) in series for primary rougher flotation.

Regrind is achieved by a 2.0 m dia x 3.4 m 150 kW ball mill in closed circuit with Cavex hydrocyclones. The underflow reports to regrind and overflow to scavenger cleaner, rougher cleaner and final conc.

The Tritton flotation circuit produces a copper concentrate typically with 25% Cu, <1 g/t gold and 30 g/t Ag from a mill feed of 2.1% Cu, 0.15 g/t Au and 6- 7 g/t Ag.

Copper is recovered by cementation from the residual acidic copper solutions circulating in the Girilambone heap leach pads.