Metal and diamond mining effluent quality

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The effects of untreated mining effluent could be highly damaging to aquatic environments. The Metal and Diamond Mining Effluent Regulations are designed to protect fish and fish habitat by governing the discharge of mining effluent into water frequented by fish. The indicator summarizes the test results observed since the regulations came into effect in 2002. In 2018 the regulations were amended to include diamond mines, to strengthen effluent limits and to improve the monitoring of environmental effects.Footnote 1

Results

Key results

Between 2003 and 2018, for reported results,

  • fish toxicity test results varied up to 2017 to reach 98.6% compliance and then declined to 91.6% compliance in 2018
  • the percentage of mining operations meeting regulatory standards for total suspended solids increased from 92.1% to 97.8%
  • test results for all other deleterious substances and pH levels ranged from 97.7% to 100% compliance

Percentage of regulatory data submitted by metal and diamond mines within authorized limits,Footnote 2  Canada, 2003 to 2018

Percentage of regulatory data submitted by metal mines within authorized limits, Canada, 2003 to 2016 (see data table below for the long description)
Data table for the long description
Percentage of regulatory data submitted by metal and diamond mines within authorized limits, Canada, 2003 to 2018
Year Arsenic
(percentage)
Copper
(percentage)
Cyanide
(percentage)
Lead
(percentage)
Nickel
(percentage)
Radium 226
(percentage)
Zinc
(percentage)
Total suspended solids
(percentage)
pH low
(percentage)
pH high
(percentage)
Fish toxicity
(percentage)
2003 99.8 99.8 100.0 99.9 99.6 99.0 99.8 92.1 99.7 99.5 95.0
2004 99.7 99.6 100.0 100.0 99.2 100.0 99.9 95.3 99.7 99.4 91.7
2005 99.5 99.7 100.0 100.0 98.6 99.8 99.1 91.8 99.2 99.6 97.8
2006 99.8 100.0 100.0 100.0 98.3 100.0 99.8 95.4 99.6 99.7 97.7
2007 99.8 99.9 100.0 100.0 98.5 100.0 99.8 93.7 99.6 99.7 97.0
2008 99.8 99.7 99.2 100.0 99.2 99.1 99.7 93.8 99.2 99.3 95.5
2009 100.0 99.5 100.0 100.0 99.5 100.0 99.7 94.5 99.5 99.7 96.2
2010 99.9 99.9 100.0 100.0 99.2 99.7 99.7 95.6 99.8 99.8 97.3
2011 99.8 99.9 99.7 100.0 99.6 99.9 99.7 96.1 99.7 99.8 97.5
2012 99.8 99.8 98.6 100.0 99.6 99.9 99.7 96.3 99.9 99.9 98.8
2013 99.8 99.7 99.3 100.0 99.8 99.2 99.8 97.9 99.8 99.9 96.8
2014 99.9 99.7 99.8 100.0 99.3 99.5 99.6 97.6 99.3 99.8 99.0
2015 100.0 99.9 99.8 100.0 99.8 99.4 100.0 98.0 99.3 99.9 99.6
2016 100.0 99.9 100.0 100.0 99.9 99.3 99.9 98.0 99.3 99.9 95.7
2017 100.0 100.0 100.0 100.0 99.9 99.8 99.9 98.0 99.8 100.0 98.6
2018 100.0 100.0 99.8 100.0 99.5 100.0 99.4 97.8 97.7 100.0 91.6
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How this indicator was calculated

Note: Deleterious substances listed in the Metal and Diamond Mining Effluent Regulations include arsenic, copper, cyanide, lead, nickel, zinc, total suspended solids, and radium 226. The regulations set a minimum (pH low) and maximum (pH high) level for the pH of effluent released. Fish toxicity refers to tests of effluent on rainbow trout mortality rate.
Source: Environment and Climate Change Canada (2020) Mining and Processing Division.

In 2018, the first year diamond mines reported under the amended Metal and Diamond Mining Effluent Regulations, 5 diamond mining facilities and 140 metal mining facilities in Canada were subject to the regulations. Compared to the previous year, the percentage of mining operations meeting regulatory standards for deleterious substances, pH levels and fish toxicity decreased or remained at the same level, except for Radium 226, which increased to 100% compliance. A high number of failed tests at a mine located in Quebec contributed to the overall decline in reported compliance for fish toxicity test results between 2017 and 2018. For deleterious substances, compliance was 100% for 4 substances and above 99% for the remaining substances, except for total suspended solids which had a compliance rate of 97.8%. 

About the indicator

About the indicator

What the indicator measures

The Metal and diamond mining effluent quality indicator presents the annual percentage of reported test results for all metal and diamond mines that are within authorized limits for deleterious substances, pH levels and fish toxicity from 2003 to 2018. The indicator helps Environment and Climate Change Canada evaluate the degree of compliance with the Metal and Diamond Mining Effluent Regulations and the effectiveness of pollution prevention and control technologies, practices and programs within the metal and diamond mining sectors. This indicator summarizes the results achieved since the regulations came into effect in June 2002.

Why this indicator is important

Mining is an important sector for the Canadian economy. In 2018, the metal ore and diamond mining industries combined employed 49 785 persons,Footnote 3  and accounted for about 1% (21 182 million dollars) of Canada's gross domestic product.Footnote 4  Canada ranks among the top 5 countries in terms of the production of diamonds and a number of major metals.Footnote 5

Without adequate regulations, metal and diamond mining could have harmful impacts on the environment. For example, the effects of untreated mining effluent could be highly damaging to aquatic environments, as well as fish and fish habitat. Proper management regimes can mitigate these impacts. These regulations are designed to protect fish and fish habitat by setting standards for effluent released from metal and diamond mines into water frequented by fish. Specifically, the regulations prohibit discharge of effluent that is acutely lethal to fish and set limits for pH of effluent and concentrations of arsenic, copper, cyanide, lead, nickel, zinc, radium 226 and total suspended solids.

FSDS icon: Pristine lakes and rivers

Pristine lakes and rivers

This indicator supports the measurement of progress towards the following 2019 to 2022 Federal Sustainable Development Strategy long-term goal: Clean and healthy lakes and rivers support economic prosperity and the well-being of Canadians. 

It is used to assess progress towards the short-term milestone: Maintain high compliance rates with Fisheries Act regulations to reduce risks from metal mining and pulp and paper effluent.

In addition, the indicator contributes to the Sustainable Development Goals of the 2030 Agenda for Sustainable Development. It is linked to the 2030 Agenda's Goal 6: Clean water and sanitation and Target 6.3: "By 2030, improve water quality by reducing pollution, eliminating dumping and minimizing release of hazardous chemicals and materials, halving the proportion of untreated wastewater and substantially increasing recycling and safe reuse globally."

Related indicator

The Pulp and paper effluent quality indicator summarizes the degree of compliance achieved since 1985 under the Pulp and Paper Effluent Regulations.

Data sources and methods

Data sources and methods

Data sources

This indicator uses compliance data provided by metal and diamond mines to Environment and Climate Change Canada under section 22 of the Metal and Diamond Mining Effluent Regulations (the regulations).

More information

In 2018, the Metal Mining Effluent Regulations were amended to include diamond mines, becoming the Metal and Diamond Mining Effluent Regulations. This indicator uses data from all mines subject to the regulations that came into effect in June 2002 for metal mines and in June 2018 for diamond mines. They apply to all Canadian metal and diamond mines that have an effluent flow rate exceeding 50 cubic metres per day, and that deposit a deleterious substance in any water or place defined in the regulations.

The regulations define metal mines as any work or undertaking that is designed or is used, or has been used, in connection with a mining, milling or hydrometallurgical activity to produce a metal or a metal concentrate or an ore from which a metal or a metal concentrate may be produced, as well as any cleared or disturbed area that is adjacent to such a work or undertaking. It includes any work or undertaking, such as a smelter, pelletizing plant, sintering plant, refinery or acid plant, if its effluent is combined with the effluent from a mining, milling or hydrometallurgical activity whose purpose is to produce a metal or a metal concentrate or an ore from which a metal or a metal concentrate may be produced. Table 1 presents the number of metal mines subject to the regulations by province and territory from 2003 to 2018.

The regulations define diamond mines as any work or undertaking that is designed or is used, or has been used, in connection with a mining or milling activity to produce a diamond or an ore from which a diamond may be produced. It includes any cleared or disturbed area that is adjacent to such a work or undertaking. Table 2 presents the number of diamond mines subject to the regulations by province and territory for 2018.

The indicator uses the quarterly and annual reports of metal and diamond mining effluent discharges submitted to Environment and Climate Change Canada under the regulations.

Table 1: Number of metal mines subject to the regulations by province and territory, 2003 to 2018
Province or territory 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018
Newfoundland and Labrador 3 3 5 5 5 6 6 6 8 9 10 10 11 11 11 11
Prince Edward Island 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Nova Scotia 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 2
New Brunswick 1 1 1 1 3 3 3 3 3 3 3 3 3 3 3 2
Quebec 20 21 21 26 28 30 31 28 28 31 32 32 34 35 35 36
Ontario 21 21 22 25 28 29 31 34 37 38 40 40 45 46 46 47
Manitoba 9 9 9 8 9 10 10 10 11 10 10 10 10 10 10 10
Saskatchewan 8 8 8 8 8 8 8 7 7 9 9 9 8 8 8 8
Alberta 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
British Columbia 5 5 5 5 6 6 8 9 10 8 8 12 11 13 13 13
Yukon 0 0 0 1 1 1 2 2 3 3 3 3 3 3 3 3
Northwest Territories 3 3 3 3 3 3 3 3 2 3 3 3 3 3 3 3
Nunavut 3 3 3 3 2 1 1 2 2 2 2 2 3 4 4 5
Canada 73 74 77 85 94 98 104 105 112 117 121 125 132 137 137 140

Source: Environment and Climate Change Canada (2020) Mining and Processing Division.

 

Table 2: Number of diamond mines subject to the regulations by province and territory, 2018
Province or territory 2018
Newfoundland and Labrador 0
Prince Edward Island 0
Nova Scotia 0
New Brunswick 0
Quebec 1
Ontario 1
Manitoba 0
Saskatchewan 0
Alberta 0
British Columbia 0
Yukon 0
Northwest Territories 3
Nunavut 0
Canada 5

Source: Environment and Climate Change Canada (2020) Mining and Processing Division.

 

Methods

The indicator is calculated by measuring the percentage of reported test results for all metal and diamond mines that are within authorized limits for deleterious substances, pH levels and fish toxicity. For each substance, this is done by dividing the number of monthly mean results that meet the authorized limits by the total number of monthly mean results reported in a given year. For pH, this is done by dividing the number of pH measurements that are within the allowable pH range by the total number of pH measurements reported in a given year. For fish toxicity, this is done by dividing the number of non lethal fish toxicity test results by the total number of fish toxicity test results reported in a given year.

More information

The regulations include provisions to allow the discharge of metal and diamond mine effluent into water frequented by fish, subject to certain requirements. Mines that are subject to the regulations may deposit an effluent that contains a deleterious substance if:

  • the concentration of the deleterious substance in the effluent does not exceed the authorized limits
  • the pH of the effluent is equal to, or greater than, 6.0 but is not greater than 9.5
  • the effluent is not acutely lethal (an effluent is deemed non-acutely lethal if it kills less than or equal to 50% of the rainbow trout subjected to it at 100% concentration over a 96-hour period)

For deleterious substances, individual test results for each substance are compared with the maximum authorized concentration in a grab or composite sample set out in the regulations. All the test results in a month for each substance are used to calculate monthly mean concentrations for each final discharge point. These monthly means are compared to the maximum authorized monthly mean concentration limits set out in the regulations. Table 3 summarizes the maximum authorized monthly mean concentrations, in milligrams per litre or in becquerels per litre, for the deleterious substances listed in the regulations.

The frequency of test measurements varies depending on the individual mine and its performance. Under the regulations, operators are required to test the effluent at each discharge point weekly for deleterious substances and monthly for acute lethality (fish toxicity) and to record the results of all tests.

The frequency of testing can be reduced to once per quarter in the following instances:

  • for arsenic, copper, cyanide, lead, nickel and zinc: if the concentration of the substance from a discharge point is less than 10% of the regulations monthly mean concentration limit for that substance over a period of 12 consecutive months
  • for radium 226 from a mine, other than uranium mines: if the concentration of radium 226 is less than 0.037 becquerel per litre in 10 consecutive weeks of testing
  • for fish toxicity: if the effluent is determined not to be acutely lethal over a period of 12 consecutive months
Table 3. Authorized limits for deleterious substances
Substances Maximum authorized monthly mean concentration
Arsenic 0.50 milligram per litre
Copper 0.30 milligram per litre
Cyanide 1.00 milligram per litre
Lead 0.20 milligram per litre
Nickel 0.50 milligram per litre
Zinc 0.50 milligram per litre
Total suspended solids 15.00 milligrams per litre
Radium 226 0.37 becquerel per litre

Note: Concentration limits are 1 of the 3 types of limits included in the regulations, the others being the maximum authorized concentration in a composite sample and the maximum authorized concentration in a grab sample. More information about these limits is available in Schedule 4 of the regulations.
Source: Metal and Diamond Mining Effluent Regulations.

Recent changes

The indicator now provides compliance information related to diamond mines. The Metal Mining Effluent Regulations were amended in 2018 to include diamond mines, requiring diamond mines to report monitoring results as of 2018. 

Caveats and limitations

The 2018 data were compiled by Environment and Climate Change Canada officials using the effluent quality information provided by the metal and diamond mines in their annual and quarterly reports.

In 2018, it was determined that 93 mining facilities subject to the regulations (64%) provided complete effluent monitoring information. Of the remaining 52 facilities, 7 did not submit any reports and 45 facilities submitted incomplete reports. Of the incomplete reports, the majority of reporting issues were related to missing acute lethality and radium-226 test results. The compliance statistics used for the indicator were compiled on the basis of the information provided in the quarterly and annual report submissions.

The indicator includes all Canadian metal and diamond mines subject to the Metal and Diamond Mining Effluent Regulations, which came into effect for metal mines on June 6, 2002 and diamond mines on June 1, 2018. Mining operations that are not captured under the regulations include placer mines,Footnote 6  coal mines, quarries, and other non-metallic mineral mining facilities.

Resources

Resources

References

Environment and Climate Change Canada (2020) Mining and Processing Division. Metal and Diamond Mining Effluent Regulations, SOR/2002-222.

Related information

Assessment of the Aquatic Effects of Mining in Canada: AQUAMIN Final Report

National assessment of phase 1 data from the Metal Mining Environmental Effects Monitoring Program

Regulations Amending the Metal Mining Effluent Regulations

Second national assessment of environmental effects monitoring data from metal mines

Third National Assessment of Environmental Effects Monitoring Information from Metal Mines Subject to the Metal Mining Effluent Regulations

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