Consultancy assists mines in sustainable water programme

With climate change posing a serious and immediate risk to the quality and quantity of a mine’s water resource, a water stewardship programme can help a mine build resilience in relation to its water use and discharge, according to mining consultancy SRK Consulting principal environmental geologist Lindsay Shand.

With South Africa’s growing demand for water, and the impact of climate change on rainfall variability and water supply security, the need for a systematic approach to water stewardship in mining has never been greater, she notes.

“A primary risk of climate change is access to fresh water. In recent years, drought, floods and other water-related risks have threatened the sustainability of businesses, demanding a strategic and systemic approach to the management of water needs and sources,” says Shand.

However, many of the systemic water risks faced by businesses cannot be sufficiently solved through company measures alone, requiring the assistance of an independent consultancy.

SRK Consulting has been providing focused advice and solutions to clients, mainly in the mining and related industries, since 1974.

The concept of water stewardship, whereby companies work collaboratively with other partners to manage shared water resources, is proposed as an effective response mechanism to these risks. She explains that water stewardship promotes and fosters the sustainable and equitable management of freshwater resources.

Water stewardship practices range from water use efficiency at an organisation’s own operations and engagement with suppliers, to long-term multi-stakeholder river basin projects, and beyond.

Such endeavours help ensure that water users not only manage their own risks and seize opportunities related to water, but also ensure businesses have the water they need to continue production processes and promote long-term water security for all.

Water management has long been a focus in the mining sector, with Shand highlighting this by pointing to 2014 when the International Council on Mining and Metals’ water stewardship framework outlined a standardised approach for mining companies, recognising that water connects an operation to the surrounding landscape and communities.

“In our past work with mining clients, projects were often only intended to address a particular challenge or project, rather than taking a broader view,” she highlights.

Shand adds that currently, however, there is a growing recognition that a high-level, concerted approach to water stewardship is not only the environmentally-responsible route to take, but also contributes to building the resilience of the mining operation.

SRK Consulting senior engineer Jennifer Meneghelli says many mines have over the years significantly reduced the amount of water that they draw from external sources, and this often involves making better use of on-site water that is pumped from pits.

“An important element of this is to separate clean and dirty water streams, to facilitate more recycling and optimising the volumes of water requiring treatment,” she says.

However, Meneghelli cautions that dewatering needs to be done with the environment in mind, especially where water entering mined voids becomes contaminated owing to contact with the exposed rock faces, as it has in South Africa’s gold mines and coal fields.

“Mine dewatering also presents a further contamination risk, by creating a localised drawdown cone of depression, which can draw in surface and subsurface contamination into the deeper groundwater aquifer units,” she explains.

Further, Meneghelli adds that the cessation of dewatering activities during mine closure and post-closure could result in the flooding of the formerly-mined area, with the resultant contamination of groundwater. This, she says, needs to be managed to prevent the closed mine having a negative impact on the receiving environment.

Meanwhile, with a consequence of dewatering being the potential lowering of the water table below the existing borehole depth of other users, mines may have to drill deeper, or elsewhere to regain their groundwater access, if even possible.

“Where resources are not available to invest in deepening boreholes, or if underground aquifers are under significant strain, there could be serious consequences for community health, livelihoods and even employment opportunities,” warns SRK Consulting principal environmental scientist Wouter Jordaan.

He says water discharge from mines is another consequence requiring careful consideration, as large volumes of groundwater pumped from mines into river systems can result in the water level of rivers rising. “This . . . present[s] a significant risk for subsistence agricultural activity, which is often conducted as close to a water source as possible.”

There is also the possibility of fine material from mined material accumulating and impacting the soil quality of arable land.

Meanwhile, SRK Consulting reports that it recently worked closely with a mine and the responsible water authority to ensure that the quality of naturally-occurring saline groundwater from an openpit was an acceptable quality before being discharged from site.

“This strategy was guided by the presence of sensitive farming activity downstream of the mine and was made possible by taking the broader water stewardship approach,” concludes Shand.