Processing
Mining at Golden Grove targets sphalerite, chalcopyrite, pyrite and galena minerals to extract zinc, copper and lead ores.
Two ore types are processed at Golden Grove:
- zinc ore which produces a high precious metal (HPM) concentrate and a zinc concentrate; and
- copper ore, which produces copper concentrate.
The processing of ore at Golden Grove begins at the run-of-mine (ROM) pad where the ore is fed into a mechanism called the crusher. Here the ore is crushed from approximately 300mm down to pieces of approximately 100mm.
Crusher at Golden Grove.
From there the ore is carried along a conveyor and stockpiled. Ore from the stockpile is then taken to the mill where it is broken down further using a two-stage grinding circuit that includes a primary semi-autogenous grinding (SAG) mill and secondary ball mill, cyclone cluster and a pebble crusher to treat oversize material from the SAG mill. This circuit grinds the ore into a fine powder.
Ore stockpile, conveyor and SAG mill.
The ore then undergoes a flotation process which separates the valuable minerals from the unwanted material. The valuable minerals attach themselves to air bubbles.
Flotation circuit at Golden Grove.
The concentrate is then thickened into a slurry form which resembles a thick liquid or paste, of about 35% solids.
This then goes through a dewatering process where water is removed from the solids so that what remains is the metal concentrate which appears in a powder form.
The concentrates are stored at Golden Grove prior to being transported via truck to the Geraldton Port. At the Geraldton Port, transfer of the concentrate occurs within an enclosed storage shed prior to ship loading and consequent export.
Golden Grove concentrate.