Mining

Desalination is an increasingly key solution for scarcity of water, guaranteeing water supply even in periods or areas of drought. Combined with local presence and a worldwide network of experts, we ensure our clients the best possible solutions to supply high-quality water, manage brine concentrates, produce or recover energy, extract raw materials, and capitalize on by-products.

Our process water solutions are designed to meet the customer’s needs, producing high-quality process water from a range of feed water sources and significantly reducing water consumption. 

We are experienced in helping clients reduce their financial exposure and comply with discharge requirements and stringent environmental regulations regarding wastewater management. We understand the unique requirements of mining operations and our worldwide expertise in mine water issues allows us to offer specialized water treatment solutions that treat water and efficiently remove a wide range of contaminants such as heavy metals and minerals, arsenic, suspended solids, organics, iron, manganese, and specific ions that can impact the local environment.

Regardless of the source of the intake water, our mine water treatment technologies ensure there is a consistent supply of water to the facility.  

Our precoat filtration and vacuum deaeration technologies help gold and silver producers achieve maximum efficiency in their recovery operations for these precious minerals. By filtering the cyanide leach solution before zinc precipitation, precipitated impurities that could be carried over from the decantation steps are removed. No more than a trace of oxygen is left, minimizing zinc and cyanide consumption.

Veolia offers a unique combination of water and solid waste treatment capabilities, which enable us to tailor solutions to each mine’s tailings challenge. We ensure overflow compliance and water treatment, but we also look at the overall wastewater strategy. In particular, we investigate opportunities to treat wastewater at source point to reduce the load going to tailings and we see tailings as an opportunity for water and metals recovery to make the most from the available resources.

Operating mines, as well as abandoned mine sites, generate acid mine drainage which requires water treatment to prevent adverse impacts to rivers and streams. We have developed a proprietary process known as DenseSludge™ to reduce sludge management costs and improve the operating efficiency of treatment plants. The process utilizes conventional equipment combined with our process expertise in sludge recycling techniques to form a heavier, denser sludge. This solution reduces sludge volume in the clarifier by up to 90% and improves lime utilization, resulting in significant savings.

We provide the expertise required for several mining production processes. HPD® evaporation and crystallization systems are often a critical component in evaporites and solution mining, by-product recovery, and internal water process management for the mining industry.

There are three main elements of a mine water management program: water quantity, water quality and closure plans.

Water quantity
The quantity of water available at a mine site varies depending on the region. For example, in the western United States, water scarcity can play a role where the mine is reusing its pit water, but in parts of Canada, we are seeing the opposite where some mines have a positive water balance and have too much. Another thing to keep in mind is how climate change is going to impact the site’s water balance. This must be taken into account when determining the program. And finally, it is important to find the right balance between treatment capacity and storage needs: increased active treatment capacity reduces storage capacity and vice versa.

Water quality
What is the quality of the source water and how does the waste rock and tailings management impact the water quality? This along with the environmental regulations for effluent discharge are key in selecting the right technology for water treatment. It’s important to anticipate potential future regulations. For example, in British Columbia, Canada, regulations for selenium are becoming more and more stringent; mining companies are anticipating future regulations that may come into play in the near future, so they are already planning for these tighter regulations when developing their mine water treatment programs.

Closure plans
An often forgotten area when developing a mine water management program is to also keep in mind its closure plan. What is needed on a day-to-day basis for operations during the actual life of the mine is different from the actual post-closure operations.

Operating mines, as well as abandoned mine sites, generate acid mine drainage which requires water treatment to prevent adverse impacts to rivers and streams. Veolia has developed a proprietary process known as DenseSludge™ to reduce sludge management costs and improve the operating efficiency of treatment plants that have acid mine drainage. 
The DenseSludge™ recycle process forms particles that settle quickly, dewater readily, and hold little water. The result is a reduction in sludge generation by nearly 90% and production of a drier sludge, which reduces the volume of water that returns to the mine pool for re-treatment. The technology has enabled mining companies to extend the life of existing sludge storage facilities and reduce requirements for building of new storage.

The process of dealing with — or remediating — a closed mine site can come with several key issues and challenges, especially from a water treatment perspective. At the end of their productive working lives, it is vitally important to ensure that mines are managed in a manner that mitigates or eliminates any potentially adverse effects. In practice, this means that the owners of individual abandoned or closed mine sites often have a duty of care to protect the natural environment — both in and around the area. They need to make every effort to eliminate the possibility of any negative impacts, which can include contamination of the surrounding land and surface watercourses, as well as the pollution of local groundwater supplies and drinking water aquifers.

In doing so, the deployment of an effective water treatment strategy is likely to form a key component for effective mine closure and reclamation. Contaminated water at closed mine sites can contain a range of harmful and toxic substances and dangerous chemicals, as well as metals such as cadmium, nickel, iron, copper and zinc. Such materials will tend to vary depending on the nature and location of the mine site. Furthermore, water at abandoned mine sites can be highly acidic, which can pose a dangerous threat to human, animal and plant life.