The stratigraphy covered by the KCGM tenements consists of a basal ultramafic unit called the Hannan Lake Serpentinite. This ultramafic unit is overlain successively by the high magnesian Devon Consols Basalt, Kapai Slate, tholeiitic Paringa Basalt and the Black Flag sediments. Differentiated zones of dolerite and gabbro texture occur within the mafic sequence. The Golden Mile Dolerite, hosting the bulk of the Golden Mile and Mount Charlotte gold mineralisation, is a strongly differentiated layered gabbro, approximately 700m in thickness. The Golden Mile Dolerite is situated conformably between the Paringa Basalt and the Black Flag sediments. This entire stratigraphic sequence is intruded by numerous porphyry dykes of intermediate to felsic composition.

The Mt Charlotte style gold mineralisation is hosted within the Golden Mile Dolerite and is predominantly associated with pyrite in carbonate alteration haloes around quartz veins, with a minor proportion as relatively coarse free gold within the veins, commonly close to their margins. The veins vary in width from a few millimetres to a maximum of about two metres but are commonly between two centimetres and 50 cm wide. The vein spacing varies from 20 cm to tens of metres but is typically from 50 cm to two metres in areas mined as ore. Quartz is the dominant vein-fill mineral; accessory vein minerals include calcite, ankerite, scheelite, pyrite, pyrrhotite, and gold.

The Hidden Secret style gold mineralisation is hosted within the Williamstown Dolerite at the contact with the Kapai Slate and Devon Consols Basalt and spatially associated with a porphyritic intrusion and the Towns Fault. Gold is hosted in deformed a quartz vein 2- 20cm wide. Vein minerals include pyrite, telluride, silica, carbonate and fuchsite.

Kal East is a narrow, high-grade Fimiston-style lode lying 250m to the east of existing infrastructure at the Mt Charlotte mine. Infill resource definition drilling has identified more complexity than expected, defining a series of hangingwall and footwall structures. Mineralisation is hosted primarily within Williamstown Dolerite and the highest grade is constrained within a steeply dipping southerly plunging shoot. Internal zones within the Williamstown Dolerite are important in controlling the distribution of gold.

Belgravia is a series of mineralised lodes lying 100m north of existing infrastructure at the Mt Charlotte mine. Mineralisation is hosted within pillowed and variolitic Devon Consols Basalt in proximity to the Hannans Lake Serpentinite, the contact of which is intruded by felsic porphyritic rocks. Infill resource definition drilling has identified eight separate NNW- striking lodes with en échelon geometry. The lodes are overprinted by stockwork mineralisation, with veins dipping to the north similar to the Mt Charlotte-style stockwork orientations.

Mt Charlotte Underground Mine
The Mt Charlotte underground mine is accessed via a portal within the Fimiston Pit (Super Pit) and the Cassidy Shaft. Production in Mt Charlotte is carried out utilising a combination of remnant Sublevel caving, modified Avoca and conventional longhole open stoping. In most cases, active and historic stopes are backfilled with development waste to save haulage costs.

The main Mt Charlotte orebodies are worked by sub-level caving; the dimensions and ground support for the mill-holes and access drives are determined using the rock mass Q value and structural information. Hidden Secret is mined using a combination of modified Avoca and Avoca mining methods; stope dimensions and backfilling requirements are determined using hydraulic radius and Q value, modified by location of major structures and rock mass changes.

Underground operations at Mt Charlotte are subject to mine seismicity. The mechanisms for seismic activity are well understood, and a combination of careful extraction sequencing and appropriate ground support in access drives is used to limit stress build-up (and thus event magnitude) and minimise damage from those seismic events which do occur.

Dilution factors are updated when there is sufficient data to do so and are based on the historical performance of each mining block and evaluation of the geotechnical block model. Average stope dilution specific to mining method and ranges from 10% to 20%.

The recovery factor is reviewed and updated as required based on historical recovery at the site. Average stope recovery is currently 85%.

A minimum stope mining width of 2.8m has been used. This considers a minimum stope width of 1.8m +0.5m dilution in the Hangingwall and +0.5m dilution in the Footwall.

The Mt Charlotte mine infrastructure is developed and in place and includes mine dewatering pumps, compressed air supply and mine ventilation. The main access decline connects the mine to a portal in the north end of the Fimiston Pit. The decline and pit ramp are well maintained. There is a radio communication system throughout the mine.

KCGM has an existing (operating) ore processing facility that has successfully treated refractory gold ores from the Fimiston Open Pit and Mt Charlotte underground operation for over 30 years. The original Fimiston plant was constructed in 1989, comprising what is now known as the Mt Charlotte milling circuit (but which is not dedicated to processing Mt Charlotte underground ores alone). A largeexpansion in 1995 saw the addition of the Fimiston milling circuit, which brought to it broadly to its current configuration. At the time this expansion incorporated the largest SAG mill in Australia.

In 2015, the Gidji roasters were decommissioned and the processing of a gold-rich, flotation sulphide concentrate moved from roasting to ultrafine grinding (UFG). The Gidji processing site remains in operation, where the largest two of the three UFG mills are located. Various debottlenecking and expansion projects have been undertaken over the years to achieve the current production rate ........