Notice

On June 29, 2012, the Fisheries Act was amended. Policy and regulations are now being developed to support the new fisheries protection provisions of the Act (which are not yet in force). The existing guidance and policies continue to apply. For more information, see Changes to the Fisheries Act.

Metal Mining Effluent Regulations

Mining is an important part of the Canadian economy, generating billions of dollars and hundreds of thousands of jobs. Like any activity, it has an impact on the environment. Government's job is to ensure that mining's environmental impacts are as minimal as possible.

There has been considerable research and development work in Canada to understand mining waste management methods and their impacts on the environment. This research has clearly shown that often the most effective way to dispose of mining waste is under water, either through an artificial impoundment or a natural water body.

On-land storage requires large areas in which to contain tailings, plus it is generally more difficult on land to control the potential for negative impacts to the environment.

Natural lakes can provide a long-term, stable environment for storing mining waste. They have a small risk of failure when compared to artificial impoundment areas if no dams are required. Artificial impoundments may use large areas of land and often require dams be built to contain the water needed to submerge the tailings. They are more likely to fail because of the need for dams.

Fisheries and Oceans Canada plays an important role in ensuring that tailings from metal mines are managed in accordance with the Fisheries Act and the policy principle of no net loss of fish habitat.

The Metal Mining Effluent Regulations (MMER), enacted in 2002, were developed under section 36 of the Fisheries Act to regulate the deposit of mine tailings and other waste matter produced during mining operations into natural fish bearing waters. These regulations, administered by Environment Canada, are for both new and existing mines. They are among the most comprehensive and stringent national standards for mining effluents in the world.

If a developer proposes to use a natural fish bearing water body for tailings management, DFO ensures that a thorough environmental assessment is done to determine the impacts. There is public consultation related to the potential use of the water body, and DFO approves a fish habitat compensation plan to ensure no net loss of fish habitat results from the use of this water body.

In plain language, if a pond is going to be used to store tailings, then companies need to compensate by recreating the lost habitat. In the past, compensation plans have improved salmon and trout habitat in waters that have been harmed by industrial activities and other users, to the benefit of fish populations.

DFO monitors the implementation of the compensation plan and the effectiveness of measures to compensate for the loss of any fish habitat associated with a mine development.

DFO, Environment Canada and Natural Resources Canada work closely to conduct a thorough analysis of tailings management options by the developer. This ensures that if a tailings impoundment area option is selected, it is the most environmentally and socio-economically sensible approach.