The Jundee-Nimary gold is hosted within a 4km (long) and 2.5km (wide) sequence of Achaean basalts and weakly differentiated dolerite sills separated by sedimentary rocks (carbonaceous shales, cherts, and siltstone) and dacitic porphyries. Younger felsic and intermediate porphyries and dolerite dykes intrude the sequence. The mine sequence is bounded to the west by a thick succession of felsic volcanics and volcaniclastics, and mineralisation diminishes eastwards as the mafic package becomes more magnesium–rich to ultramafic in composition.

The age of the gold mineralisation is approximately 2,700 million years (Archaean), and is controlled by a series of complex brittle fractures. Over 70% of the gold is hosted within the more brittle dolerite units with the remaining 30% associated with the basalts. The field has undergone multiphase deformation – folds, thrusts, strike and oblique slip faults. The gold is hosted within narrow, discontinuous quartz +/- carbonate veins (typically <0.5m wide) which contain abundant visible gold.

Low grade mineralisation occurred with the first phase of faulting. This was followed by the emplacement of large dacitic intrusions which locked up the initial fault lines causing some abutment pressure – during the second faulting phase this abutment pressure prevented the faults from slipping as easily as before causing a “ripping” between the two fault lines fracturing the rock and causing a relatively large low pressure zone. Gold-rich fluids then flowed into these low pressure zones (main mineralization event). There is minor post mineralisation faulting which causes some minor offsets of the loads.

Currently all ore is sourced from Jundee underground operations which yield ~1.0M tonnes ore each year. There are three underground portals which provide access to the various underground lode structures – Barton, Gateway and Invicta portals. The Barton portal contains three actively working ore bodies (Nim3, Lyons and Westside) with Invicta consisting of the Invicta (remnants), Cardassian and Deakin ore bodies, while the Gateway and Gringotts ore bodies are mined from the Gateway portal.

Currently all ore is sourced from Jundee underground operations which yield ~1.0M tonnes ore each year. There are three underground portals which provide access to the various underground lode structures – Barton, Gateway and Invicta portals. The Barton portal contains three actively working ore bodies (Nim3, Lyons and Westside) with Invicta consisting of the Invicta (remnants), Cardassian and Deakin ore bodies, while the Gateway and Gringotts ore bodies are mined from the Gateway portal. The underground mining is being carried out by an up-hole long-hole open stoping sequence as its primary method. No backfill or paste is used.

The Jundee Processing circuit is a conventional CIL plant with a hard rock processing capacity in excess of 1.8M tonnes per annum. The current blend ratio is 100% underground ore.

The crushing circuit is two-stage consisting of a C125 jaw crusher and HP6 secondary crusher closed by a double deck banana screen with a nominal 400 tonne per hour crushing capacity. The crushing circuit can operate in either full secondary crush or partial secondary crush modes to suit milling requirements. The crushing circuit feeds a reclaim stockpile with a 25,000 tonne capacity. Three variable speed belt feeders below the reclaim feeders ensure steady and controlled grinding circuit feed.

The grinding circuit comprises of two mills. The 5.5m diameter x 8.2m EGL ANI SAG mill is low aspect with a 3,850 kilowatt motor. The SAG mill normally operates in open circuit, but has the capability to be operated in closed circuit SAG only configuration. The 4.3m diameter x 6.7m EGL Nordber ........