Orelia is Archean gold mineralized deposit that is part of the Yandal Greenstone belt.

The stratigraphy dips approximately 60 degrees towards the west and strikes north south. The oldest and the most western unit is the ultramafic sequence, towards the east, the komatiite unit has a sharp contact with a 2-5m massive sulphide/breccia unit. This contact is the Calista shear. The stratigraphic sequence east of the Calista shear and massive sulphide unit consists of a series of basaltic units. This includes massive and pillowed tholeiitic basalt, basaltic lithic lapilli tuff, and interflow sedimentary rocks. In the middle of this sequence lies the Orelia dolerite that has been classified as an ophitic basalt. Further towards the east the next unit is a felsic zone dominated by sandstones, siltstones and mudstones with intercalations poorly sorted volcaniclastics tuffs of dacitic composition. This felsic unit is intruded by 2 dolerites Cumberland in the east and Lotus in the west. The whole Orelia stratigraphy is intruded by a suite of late intermediate dioritic to lamprophyre dykes ranging from 0.5m to 2-3m in width. The sequence appears to be upright with the older Ultramafic member thrusted over the basaltic and felsic units.

The main host rocks of mineralisation at Orelia-Cockburn are deformed and altered tholeiitic basalts, and intermediate to felsic volcaniclastic rocks. It appears that the structures in the main mineralised corridors exploit the rheolo ........

Ore from the Orelia pit at Bronzewing Operations was processed for the first time during Q4 2023.

The selected mining method for the Orelia deposit is of a bench mining open pit method. The proposed open pit cutback will be mined using conventional open pit mining methods (drill, blast, load and haul) utilising similar class excavators and trucks used in other NSR open pit mining operations.

A mining recovery factor of 95% has been applied reporting of Open pit Reserve physicals.

A minimum mining width down to 25 m for final pit extraction from the base of pit has been used.

The Orelia pit will be mined in two stages (1A and 1B). The Stage 1A pit will deepen the floor of the existing pit to target higher grade, lower strip ratio ore. The Stage 1B pit will include a cutback to the west and north walls as well as deepening below the Stage 1A floor.

MINING
All the defined Mineral Resource Estimates at the Yandal Gold Project are within an open pit mining environment and are a lode style of mineralisation requiring a degree of mining selectivity. The material to be excavated will be predominantly free dig from surface with blasting required deeper in the oxidation profile and into the fresh ore zones. Given these conditions, conventional open pit mining techniques using drill and blast with material movement by hydraulic excavator and trucks will be employed.

The project scale and selectivity would suit 120 t ........

The process consists of a double toggle jaw crusher followed by a SAG and Ball milling circuit.

Metso Outotec has been chosen to supply its Premier SAG Mill for Northern Star Resources’ Thunderbox gold mine expansion. The expansion should double the throughput of the Thunderbox operation.

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