Approvals process for metal mines impoundment areas

Streamlining the approvals process for metal mines with tailings impoundment areas


This document provides information to proponents of metal mining projects, interested stakeholders and Indigenous groups.  The document describes the approved approach to streamline timelines for Governor in Council decisions for authorizing the use of natural water bodies frequented by fish and which may also fall under the Navigable Waters Protection Act as tailings impoundment areas (TIA) for qualifying metal mines.


In this paper, a TIA is the use of a natural water body that is frequented by fish, to dispose of mine waste by a metal mine.

Authorization of a TIA requires a regulatory amendment to list the water body on Schedule 2 of the Metal and Diamond Mining Effluent Regulations (MDMER). An environmental assessment (EA) is conducted prior to the regulatory amendment process. More information on the MDMER is provided in Annex 1.

A Proclamation of exemption under section 23 of the Navigable Waters Protection Act (NWPA) may also be required. Section 23 allows for any water or any part of which are navigable or that flow into any navigable water to be exempted in whole or in part from the operation of sections 21 and 22 of the NWPA, which prohibit the throwing or depositing of material in any navigable water. An Order in Council (OIC) must first be approved for a Proclamation of exemption to be issued. More information on the NWPA is provided in Annex 2.

Shorter process

TIA authorizations for proposed metal mines that meet the conditions for exemption described in this document will be submitted to Treasury Board for publication in Part II of the Canada Gazette. If Treasury Board approves, this means that the regulatory amendment to list the water body on Schedule 2 of the MDMER and the OIC under section 23 of the NWPA, are exempted from the consultation step of pre-publication in Part 1 of the Canada Gazette.

This approach does not diminish environmental protection. It provides for a more efficient regulatory system for project reviews, and aims to shorten the approval time to 5 to 6 months for publication in the Canada Gazette, Part II (from the conclusion of the EA) for projects meeting the identified conditions of exemption.


Canada Gazette, Part I is used to make public the text of proposed regulations and the associated regulatory impact analysis statement, providing an opportunity for the public to comment on both.

In the case of TIAs, since the regulatory amendments consist only of the name of a water body to be listed in Schedule 2 of the MDMER and/or the water body to be exempted from the operation of sections 21 and 22 of the NWPA, there is no regulatory text to be reviewed by stakeholders. In addition, under this streamlined approach, the costs and benefits of the regulatory elements, which are typically presented in Canada Gazette, Part I, will be presented during the EA and regulatory consultation processes, with the opportunity for public comment.

A regulatory impact analysis statement will still be prepared and published in Canada Gazette, Part II, including details on the public consultations that took place.

Conditions for exemption

In order to recommend exemption from pre-publication in Canada Gazette, Part I for an amendment to Schedule 2 of the MDMER and an OIC under s. 23 of the NWPA, the following conditions must be met :

  1. The environmental assessment considered:

    • public and stakeholder comments on the water body listed
    • an assessment of alternatives to the proposed TIA, including costs and public comments
    • consultations on the fish habitat compensation plan
    • any other information considered relevant to facilitate the regulatory process under NWPAand
    • consultation with Indigenous Peoples (to meet all obligations that may exist in relation to Aboriginal rights or Treaty rights protected by section 35 of the Constitution Act, 1982)
  2. The federal government has determined, based on the environmental assessment, that, taking into account the implementation of appropriate mitigation measures, the project is not likely to cause significant adverse environmental effects
  3. Consultations on the MDMER amendment and NWPA Proclamation of exemption have met the Treasury Board guidelines for effective regulatory consultations.

    Note: The consultation guidelines are available on the Treasury Board web site.

  4. Supporting documents provided demonstrate that the public interest will not be injuriously affected by a Governor in Council Proclamation of exemption declaring the subject waters exempt from the operation of sections 21 and/or 22 of the NWPA.

What does this mean for the environmental assessment

Proposed TIA authorizations that meet all the conditions for exemption may move directly to Canada Gazette, Part II.  To ensure that proposed TIA authorizations are well positioned to meet the conditions, a number of operational steps need to take place as part of, or concurrently, with the EA process.  Some of these steps are the responsibility of government, some of the project proponent.


The federal government and Northern co-management boards will undertake the following activities during the EA phase:

  1. Regulatory consultations

  2. Indigenous consultations as required under section 35 of the Constitution Act, 1982

  3. Lay out the expectations and regulatory requirements early in the process

  4. Lay out the process and conditions for exemption from Canada Gazette, Part I and

  5. Gather information for the regulatory impact analysis statement

The federal government will make its information needs clearly known to project proponents early on.  Northern co-management boards will be encouraged to make their information needs clearly known to project proponents early on.

In addition, the federal government will work collaboratively with provincial governments and Northern co-management boards to ensure that federal interests, such as navigation issues, are addressed during harmonized federal-provincial EA processes.

Project proponent

Before or during the EA, project proponents will need to provide all the necessary information requested by governments, including:

Having all the necessary information for the MDMER regulatory amendment package, and, where applicable, the NWPA Proclamation of exemption package, by the time the EA process is complete allows government to initiate the regulatory review process within optimum time periods, including consideration of seasonal variances.  It also enables government to complete the MDMER and NWPA packages in unison, in a timely fashion.

Procedure for applying the conditions for exemption

  1. Following the environmental assessment, Environment and Climate Change Canada (ECCC), DFO, and Transport Canada (where implicated) will jointly review the EA process, the EA decision and the consultation process to

    • determine if the conditions have been met; and
    • make a recommendation about going directly to Canada Gazette, Part II publication.
  2. Governor in Council (Treasury Board) will review the recommendation and make the final decision on whether to exempt from pre-publication in Canada Gazette, Part I. Projects that are not exempted will go through the Canada Gazette, Parts I and II process with a target of 8 months from the date of the EA decision.


Annex 1: Metal and Diamond Mining Effluent Regulations

Annex 2: Navigable Waters Protection Act

Annex 1: Metal and Diamond 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. There are legal requirements in place to minimize the environmental effects from mining.

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. Submerging tailings under a water cover is a proven technique to prevent oxygen from reaching the reactive sulfide material and prevents the formation of acid rock drainage.

The objectives of tailings management are to prevent the generation of acid rock drainage and to confine the mine tailings in order to provide for the safe, long-term disposal of mine waste. In some instances, engineered impoundments can be built above ground to submerge mine tailings under water covers rather than a TIA using natural water bodies. Above ground tailings management facilities may require significant space and are prone to engineering and long-term maintenance challenges. Engineered depressions or large dams for tailings impoundment in mountainous areas or areas prone to earthquakes and flash floods introduce their own set of environmental disturbances, costs and risks. If properly evaluated and implemented on a site-specific basis, the storage of mine tailings in natural water bodies can offer the best environmental and engineering practice.

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

The Metal and Diamond Mining Effluent Regulations (MDMER), enacted in 2002, were developed under section 36 of the Fisheries Act to regulate the deposit of mine effluent and of waste rock and tailings into natural fish bearing waters. These regulations, administered by ECCC, apply to both new and existing mines.

If a mine developer proposes to use a natural fish bearing water body for tailings management, an environmental assessment is done to determine the impacts. There is public consultation related to the potential use of the water body and the proposed fish habitat compensation plan.

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

DFO, ECCC and Natural Resources Canada work closely to analyze the tailings management options identified by the mine developer in order that the selected TIA option would be the appropriate technical, environmentally and socio-economically sensible approach.

The MDMER are among the most stringent mining effluent standards in the world, and apply to all sources of effluent at the mine site, including any tailings storage or impoundment areas.  The Regulations impose limits on releases of arsenic, copper, cyanide, lead, nickel, zinc, radium-226 and total suspended solids, and prohibit the release of effluent that is acutely lethal to fish. Mines must monitor effluent quality and report the findings to ECCC, as well as conduct studies to determine if the effluent is affecting fish or fish habitat.

Annex 2: Navigable Waters Protection Act

The Navigable Waters Protection Act (NWPA) is the responsibility of the Minister of Transport.

Purpose of the Navigable Waters Protection Act (NWPA)

In Canada there exists a common law public right of navigation. This right provides that if the waters are navigable the public has the right to navigate these waters. Only Parliament may restrict or remove this right of navigation through an Act of Parliament. The NWPA is one of those legislative acts. The NWPA provides a balance between the public right of navigation and the need to build works, such as bridges, dams or docks for example, in navigable waters. The NWPA prohibits the construction or placement of works in navigable waters, unless the work, its site and plans, have been approved (prior to construction or placement) by the Minister of Transport - on such terms and conditions as he deems fit. In addition, the Act provides for approval of some works after commencement and has measures regarding removal of wreck or other obstacles to navigation and for the prohibition to throw or deposit any material in navigable waters.

Navigable waters

The NWPA has a definition in section 2 that reads "… includes a canal and any other body of water created or altered as a result of the construction of any work".  Although not precisely defined in law, the courts generally consider that navigable waters include all waters that may be navigated by any type of vessel (ranging from commercial cargo ships to canoes and kayaks).

Sections 21 and 22 of the NWPA prohibit throwing and depositing of material that is liable to interfere with navigation (for example sawdust, edging, slabs, bark) or that is likely to sink (for example stone, gravel, earth, cinder, ashes) where there are not at least 20 fathoms (approximately 36.6 metres) of water depth at all times.  However, section 23 of the NWPA allows for any water or any part of which are navigable or that flow into any navigable water to be exempted in whole or in part from the operation of sections 21 and 22 of the NWPA.

An Order in Council must be approved for a Proclamation of exemption to be issued under section 23 of the NWPA.  Through this process, the waters themselves are declared exempt from the operation of sections 21 and 22 of the NWPA.

For applicants seeking a Proclamation of exemption, the significant language in section 23 is:"when it is shown to the satisfaction of the Governor in Council that the public interest would not be injuriously affected."  The information that demonstrates the public interest components may include the completion of an EA, public and Indigenous consultations, economic impacts and health and safety considerations.  The Proclamation of exemption timeline is approximately 9 to 12 months - which includes the Order in Council process.

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