Run of Mine ore is trucked from the open pit to the processing plant where it goes through three stages of crushing and screening, grinding, flotation and dewatering. The steps in this process are summarised as follows:

Crushing

The ore is crushed down to rock sizes of 11mm through a stand-alone jaw crusher, followed by secondary and tertiary crushing using cone crushers. 

Primary grinding

The ore then moves through a primary grinding circuit at a rate of around 280-320 tonnes per hour. This circuit consists of a SAG Mill in closed circuit with hydrocyclones, a Vertimill and two primary Isamills. Through this circuit, the ore is slurried and produces ground material at 70 microns. 

Flotation circuit

The slurried ore gravity flows to the flotation circuit. Here, various reagents are introduced which attach themselves to the ore (sulphide materials) and enable them to float. The zinc and lead bearing minerals are then recovered. 

Pre-cycloning

The rougher concentrate material is then pumped through a pre-cycloning stage to produce two products: fine and coarse material. The fine material is sent to the cleaning conditioner tanks and the coarse material is sent to the regrinding circuit.

Regrinding

The regrinding circuit consists of open circuit M10000 Isamills grinding the coarse precyclone underflow stream to 20 microns followed by four M3000 Isamills operating in closed circuit to produce a cleaner feed product of 7 microns

Final concentrate

The fine ground materials are then conditioned with reagents prior to passing to a seven stage cleaner circuit to produce a final zinc/lead bulk concentrate. The concentrate and tailings products are pumped to different thickening tanks. Thickened concentrate is then sent to storage tanks prior to filtering and stockpiling. 

Tailings removal

Thickened tailings are pumped to the tailings storage facility via a pipeline. The tailings storage facility is located west of the mine. It plays a key role in recycling water for use within the processing plant. 

At the end of this process, the bulk concentrate has a moisture content of around 13%, which reduces dust generation during handling. All trucking, loading and shipping operations are fully contained to protect against spillage and ensure environmental security.

More information

MRM Processing Diagram (0.6Mb)

Media releases

MRM expands concentrator capacity (0.1Mb)