Water is integral to our operations, and water stewardship is a key part of our ongoing social licence to operate. We recognise the need to manage our water requirements with the shared needs and demands of the environment, local communities and other stakeholders in water catchments. Consideration of the impact that climate change may have on water availability and quality is integral to effective management.
Each operation maintains water management plans and site-wide water balances to guide responsible water use throughout the mine lifecycle and in the context of the local catchment. Water-related activities are regulated by relevant legislation in each jurisdiction and are subject to set quality and quantity thresholds.
Total water withdrawn increased in FY21. The increase in water withdrawn was due to the inclusion of Red Lake and an increase in water withdrawn at the Mt Rawdon and Mt Carlton operations. Mt Rawdon experienced an unseasonably dry FY21 and had to supplement with raw water.
Our aim is to maximise the reuse of mine affected water (MAW) to reduce the demand for external raw water supply which reduces competition for agricultural and other industries and communities. No Evolution operations are in high to extremely high baseline water stress areas according to definitions set in the WBC SD Global Water Tool, WRI Aqueduct Global Water Tool or Water Footprint Network.
Total water reuse increased by 25% between FY20 and FY21. Notable increases in water reuse were recorded at Cowal (30%) and Mt Carlton (>200%), demonstrating the increased focus and planning associated with water reuse at our operations. With the commissioning of the IWL during FY21, descaling of pipework and upgrade of pumps, Cowal was able to increase daily return of water from the IWL from a previous average of 8-12ML to >17ML to meet the daily demand of ~24ML.
Water Reuse FY18-FY21
In FY21, the water withdrawn intensity per tonne of ore processed increased by 11% which is attributed to the inclusion of Red Lake in the water intensity measure (excluding Red Lake, the intensity figure would have decreased by 20%). This is a whole of site water demand measured as per dry tonne milled. Red Lake has a relatively high-water intensity of 5.15 kL/tonne, noting that this is the only Evolution site to operate an Autoclave and be undertaking extensive reclamation activities in the treatment of legacy Arsenic Trioxide materials from underground workings. Our future efforts in water management will include continued focus on water security – mitigation of the effects of extreme weather events (drought and flood) through a reduction of total water demand, increase in water reuse, water storage and stormwater, sediment and erosion control best practice.
Integrated Waste Landform at Cowal.