Water management – Mining sector

Water plays a crucial role in mining processes, from extraction to ore processing. The Ministry of the Environment, the Fight against Climate Change, Wildlife and Parks (MELCCFP) has therefore drafted Directive 019 on the mining industry, to prevent the contamination of watercourses by discharges to the environment. These regulations aim to minimize the environmental impact of mining activities by imposing strict water management standards. This is prompting mining companies to re-evaluate their practices and optimize their water management.

Challenges

The mining industry presents unique challenges in terms of water management, both from underground and surface water. Under Directive 019, mining companies must commit to maximizing the reuse of wastewater, while minimizing discharges. The use of fresh water must therefore be kept to a minimum. A strategic water management plan is therefore necessary to optimize the use and recirculation of water on a mining site.

Another major challenge for the industry is water quality. Mining operations can generate large quantities of contaminants, such as heavy metals, suspended solids and chemicals. These contaminants can have harmful impacts on the biodiversity of local ecosystems. Environmental discharge points are standardized on several parameters to limit these impacts.

What is a water balance?

A water balance is a comprehensive analysis of water use, consumption and discharge for all mining operations on a site. The quantities of water required for all types of use must be inventoried, from ore extraction to concentrator processing, not forgetting the sanitary water needs for the employees on site (showers, bathrooms, etc.).

Water on the mine site can come from several sources: surface water (water from precipitation, rivers and lakes) and groundwater (infiltration of water percolating through rock walls). The balance must also consider water recirculated on site, losses through evaporation and discharges to the environment.

The management plan is based on the water balance and describes water recirculation and storage strategies. Among other things, it makes it possible to assess the volumes of water to be managed from the mine site’s watersheds.

Stages in the water balance process

1) Data collection

In collaboration with the client’s team, GCM Enviro identifies the information required to assess inflows and outflows. This information can be gathered through historical data collection, sampling and flow measurement campaigns.

2) Assumptions and management plan

Through working sessions, GCM Enviro works with the customer to establish project assumptions and desired objectives. Subsequently, management plan scenarios for the various types of water are proposed.

3) Report and water balance

GCM Enviro will draw up a water management report to provide an overview of the chosen strategy, based on the water balance. This report includes the team’s limitations and recommendations based on site-specific needs and capabilities. A water quality assessment may be added to the exercise. This will help define the specific treatment requirements for the various water flows in order to comply with applicable environmental discharge standards.

Conclusion

The water balance is therefore a key element in optimizing water management at a mine site. With an effective water management plan, mining companies can reduce their environmental footprint and promote the sustainable development of their operations.

GCM Enviro Synergies would be delighted to assist you in this process!

Camille Duquet, CEP – Industrial Water Treatment