Managing water as a finite and at-risk resource
Water is a valuable and often scarce shared resource that has high environmental, social and economic value. We are acutely aware of the need to conserve and closely manage our consumption of water while ensuring adverse water quality impacts on local and regional water resources are avoided.
Effective water stewardship in mining encompasses monitoring and measuring water withdrawal, water discharge and water reuse to allow for periodic review and revision of water management processes and systems, underpinning transparent water governance.
Managing water responsibly and seeking to ensure that adverse impacts on local and regional water resources are avoided is a key consideration for our operations.
Our Water Management Standard mandates the comprehensive understanding of water risks within and beyond the mine site and the implementation of tailored management and monitoring plans, that at site level are supported by context-specific water objectives and targets.
Our management standard commits us to:
- Ensuring that reliable information regarding potential and actual water quality impacts on local and regional water resources is generated, analysed and acted upon at an appropriate spatial scale. This must allow for effective water quality management by our sites
- Seeking to ensure our operations are able to optimise their consumptive water use and achieve their water quality objectives via a robust water balance model. This model must also support forecasting the potential water management impacts of mine design changes on local and regional water resources
- Seeking to ensure that actual and potential impacts arising from water resource use are avoided where possible, or managed according to mandatory host government requirements, reasonable community expectations and our values
Core objectives for operational water management are to:
- Set site-specific targets for minimising new water withdrawals from the ground and surface water bodies while seeking to maximise the reuse of water
- Prevent contamination of water resources by either maintaining zero water discharge on sites, or by treating and releasing excess water from the process circuit, which is typically the case for high rainfall areas
Wherever possible we actively participate in catchment management efforts:
As an example, we work with other stakeholders in a number of water forums in Brazil focused on managing community-level water resources for the common good. Our operations in the state of Minas Gerais, which include the Cuiabá Complex and the Córrego do Sítio mines collaborate on joint water stewardship through state and regional water basin committees; establishing water consumption reduction targets, and conducting water quality monitoring and spring preservation.
Progress in 2022
The increasing water withdrawal trend continued, which to some extent was due to production-related demand increases, but also because of drier periods at high water demand operations.
Two of the three significant environmental incidents over 2022 related to impacts of water resources (see the <ESGD> for further details).
During 2022, we progressed the following water-related initiatives:
- Iduapriem, Ghana: The mine’s primary water treatment capability was expanded in 2021 to accommodate larger water volumes expected to be managed and potentially released from the process water inventory during construction and the ramp-up of the new Beposo TSF. Primary treatment entails water clarification, pH adjustment and cyanide detoxification. Although the additional treatment capacity was not required by the mine in 2022, it proved useful for the storage and reuse of additional treated water.
- Geita, Tanzania: The in-situ groundwater bioremediation project in Tanzania progressed in 2022 with the joint venture partnership between Sensatec Tanzania and a German-based technology provider. In phase one of the project, which spans a 100m target area downstream of the Geita TSF, seven injection boreholes were installed in addition to upstream and downstream monitoring bores. The first round of reagent injection was completed and initial process monitoring showed promising reductions in targeted parameters.
- Geita mine continued to reduce its water withdrawals from external lakes and dams, with water harvested from the site’s pits and sumps constituting more than 50% of its new water withdrawals during the year.
- AGA Mineração, Brazil: The progression to filtered tailing stacking in Brazil was completed. Water flow analysis indicates that this transition has contributed to increased water withdrawals at these operations as the water pools on TSFs, which also acted as reservoirs to store and attenuate harvested rainwater, and which was then used into dry periods, have effectively been eliminated.
OUR INTERACTIONS WITH WATER IN 2022
- An assessment to ascertain whether a second phase of enhanced treatment might be required at Iduapriem mine, was initiated during 2022 and will be progressed in 2023
- The groundwater remediation project at Geita will continue with three additional phases of reagent injection and monitoring. These will inform the approach for further, targeted expansion of the interception gallery