PETER WILLE Innovative water stewardship must focus on reducing water loss by reducing evaporation, maximising re-use and recycling and extending the lifecycle of mine water
While water stewardship is not a well-known term, according to global organisation the United Nations Industrial Development Organisation, it has been simply defined as “the use of water in a socially equitable manner, that is environmentally sustainable and economically beneficial”.
Consulting engineers WSP in Africa water treatment team leader Peter Wille states that this is especially true in the mining sector, where water stewardship has become a “hot-button topic that has proven challenging to put into practice”.
According to the South African government, “the current situation of widespread national water deficits creates an untenable scenario that requires all sectors be efficient and effective in the use of water. It is therefore essential to improve the current level of water-use efficiency and to implement water conservation and water demand management (WC/WDM) measures as a vital aspect of norms and codes of good practice in water management by all sectors”
Wille states that, while mining CEOs have taken this to heart and want to apply water stewardship across the operations of their companies, with some even setting large targets to reduce freshwater abstraction by up to 50% in water-scarce regions, this is easier said than done.
Several initiatives, driven mostly by mining organisation the International Council on Mining and Metals, such as the raw water savings targets, have been designed to focus on understanding the fundamentals of water.
For instance, what makes clean water, what is dirty water, and where water use is highest. At the core of these is the need to have a proper inside-out monitoring programme in place.
This monitoring programme must be capable of drawing data and highlighting the engineering of the right solutions to accomplish these goals. Solutions include the building of new pumps and dams, or improving targeted water treatment for reuse in the optimal application.
As water stewardship is a complex topic, there is no single way to accomplish it. Instead, it requires a multidisciplinary approach where time, effort, resources and significant leadership are paramount, he points out.
It begins by understanding the unique context of the mine and building awareness to help engagement with stakeholders. Following from there, the mining company must develop partnerships that can creatively deliver large-scale water solutions. By working with local communities, these partnerships can be achieved as well as more realistic targets set to benefit business, communities and the environment.
The Cycle of Water
Much of the process of effective water stewardship links to the life cycle of water within the mine. The development of any mine is dependent on having access to water resources. Part of this is permitting extraction and discharges from the facility into the surrounding environment.
“Water has an intrinsic value to it, and every person has the right to access clean water as well. This is where catchment studies come into play – by looking at the broader picture of society, water needs, and water access. Innovative solutions around water stewardship, therefore, must focus on reducing water loss by reducing evaporation, maximising reuse and recycling and extending the life cycle of mine water. These solutions require environmental planning.”
Other innovative solutions include building treatment plants. Unfortunately, active treatment plans are expensive and energy intensive, giving rise to other concerns. This has seen preference given to passive and semi-passive treatments, as these reduce the load discharged into the rivers. Passive and semi-passive treatments are defined as treatments that use no or few chemicals and mechanical equipment, making the process more economical and less environmentally harmful.
The use of passive or semi-passive treatments, particularly for mine closing, fits well with the life cycle of mine water approach to water stewardship as it allows water to become a functional resource in another sector.
Beyond this, he stresses that it becomes critical to ensure that treated water is used more beneficially. This requires the involvement of the community to explore likely options such as agriculture, phytoremediation and agroforestry, for example.
One of the more effective ways of thinking differently about water stewardship is moving from short-term strategies to longer term ones. This change in thinking to long-term strategies includes not only the short-term deadlines and day-to-day operational constraints, but also the end-of-life and closure of the mine.
In long-term planning, the quick identification of closure implications of the mine allows for the implemented water strategies and management during the operational period to be adapted accordingly. This response may help in the mine achieving goals of water stewardship during operations, but also minimise post-closure cost and liabilities which may outweigh the operational adaption cost.
“While no change in strategy may be easy to achieve and undertake, if mines are serious about water stewardship, then they need this long-term perspective as the design-life and ongoing needs of other water users may well exceed the life of the mine,” he concludes.