Water management best practice at Hera Mine

Water use efficiency and availability at Hera Mine is a key risk given the local meteorological conditions.

To respond and prepare for drought, Aurelia has been on a campaign to improve water use efficiency. By the end of FY21, the Hera Mine achieved a 25% improvement in water consumption per tonne of ore processed (1.2m3/t in FY20 to 0.90 m³/t in FY21).

These improvements were largely driven by improved recovery of water in the process plant and adjustments (including process control and flocculation dosing) to the tailings thickener to increase the percent solids in the tailings stream.

This resulted in an approximate saving of 10m³ of water used per hour. Water availability was also improved through a number of programs including:

• cleaning and pump testing of bores to identify optimal operating conditions
• installation of variable speed drives on bores to operate within optimal ranges
• installation of additional bores within the existing bore field
• extension of the Project Boundary to encompass additional groundwater resources to the south of the Hera Mine and installation of new bores.