Environment & Safety

In 2016, Cameco's McArthur River mine was awarded the Canadian Institute of Mining, Metallurgy and Petroleum's prestigious John T. Ryan National Safety Trophy for the third consecutive year.

In 2015, McArthur employees and contractors worked 1.86 million hours without a lost-time injury.

Safety

The McArthur River mine and the Key Lake mill are among Canada's safest mining operations. Each operation has a systematic program to identify, evaluate and mitigate risks and engage all workers and managers in development of a strong safety culture. These programs follow the international OHSAS 18001 model and have delivered excellent safety performance.

Full-time equivalent dose

(mSv/yr)
  2020
McArthur River 0.6
Key Lake 1.0

Radiation Protection

Radiation risks are effectively managed at McArthur River and Key Lake. Each operation has a formal radiation protection program and dedicated personnel who ensure that doses to workers are as low as reasonably achievable. The programs require that radiation protection is considered in the physical design of all facilities and operating procedures. They also provide for systematic monitoring of radiation in work areas and track exposures of individual workers using a combination of monitoring devices and health testing. Radiation exposures at McArthur River and Key Lake are far below below the regulated limits.

Environmental Protection

Environmental protection at the McArthur River and Key Lake operations is assured through ISO 14001-certified environmental management systems. These programs systematically identify, control and monitor environmental aspects associated with the facilities.

Environmental Monitoring

Comprehensive monitoring programs are in place at the McArthur River and Key Lake operations to help ensure that the surrounding environment is protected. Samples of water, air, soil, plants and fish are collected from numerous locations around the sites and tested to confirm that environmental protection systems are effective. Monitoring results are submitted to federal and provincial regulatory authorities for review. Cameco also supports independent regional monitoring downstream of its Saskatchewan operations to ensure there are no cumulative effects on the regional watershed. The extensive monitoring undertaken at McArthur River and Key Lake has identified no significant impact on the surrounding environment.

McArthur River Monitoring Results

Treated Water Quality — Arsenic
  Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20 Dec-20 Jan-21 Feb-21 Mar-21
Metal Mining Regulations Limit (mg/L) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5
McArthur River Level (mg/L) 0.00009 0.00009 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001

0.0001

0.0001

0.0001

 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001

Key Lake Monitoring Results

Treated Water Quality — Arsenic
  Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20 Dec-20 Jan-21 Feb-21 Mar-21
Metal Mining Regulations Limit (mg/L) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5
Key Lake Level (mg/L) 0.0048 0.0132 0.0108 0.0097 0.0015 0.0026 0.0149 0.0278 0.0029 0.0011 0.0009 0.0001

0.0007

 0.0298

0.0108

 0.0169 0.0175 0.0180 0.0160 0.0139 0.0118 0.0066 0.0066 0.0064

McArthur River Monitoring Results

Treated Water Quality — Copper
  Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20 Dec-20 Jan-21 Feb-21 Mar-21
Metal Mining Regulations Limit (mg/L) 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3
McArthur River Level (mg/L) 0.0002 0.0002 0.0003 0.0005 0.0008 0.0007 0.0005 0.0008 0.0005 0.0007 0.0005 0.0002

0.0004

0.0006

0.0007

 0.0012 0.0006 0.0005 0.0004 0.0009 0.0010 0.0006 0.0004 0.0004

Key Lake Monitoring Results

Treated Water Quality — Copper
  Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20 Dec-20 Jan-21 Feb-21 Mar-21
Metal Mining Regulations Limit  0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3
Key Lake Level (mg/L) 0.0009 0.0009 0.0013 0.0012 0.0009 0.0037 0.0024 0.0013 0.0010 0.0008 0.0010 0.0009

0.0014

0.0005

0.0005

 0.0003 0.004 0.0034 0.0017 0.0011 0.0010 0.0008 0.0005 0.0004

McArthur River Monitoring Results

Treated Water Quality — Lead
  Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20 Dec-20 Jan-21 Feb-21 Mar-21
Metal Mining Regulations Lead 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2
McArthur River Level (mg/L) 0.00009 0.00009 0.00009 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001

0.0001

0.0001

0.0001

 0.0002 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001

Key Lake Monitoring Results

Treated Water Quality — Lead
  Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20 Dec-20 Jan-21 Feb-21 Mar-21
Metal Mining Regulations Lead 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2
Key Lake Level (mg/L) 0.0001 0.0002 0.0004 0.0002 0.0001 0.0001 0.0003 0.0001 0.0001 0.0001 0.0002 0.0001

0.0009

0.0002

0.0001

 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0003 0.0001 0.0001

McArthur River Monitoring Results

Treated Water Quality — Nickel
  Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20 Dec-20 Jan-21 Feb-21 Mar-21
Metal Mining Regulations Limit (mg/L) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5
McArthur River Level (mg/L) 0.0019 0.0015 0.0015 0.0010 0.0016 0.0016 0.0016 0.0014 0.0018 0.0019 0.0014 0.0016

0.0014

0.0011

0.0011

 0.0013 0.0012 0.0013 0.0014 0.0014 0.0023 0.0024 0.0026 0.0027

Key Lake Monitoring Results

Treated Water Quality — Nickel
  Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20 Dec-20 Jan-21 Feb-21 Mar-21
Metal Mining Regulations Limit (mg/L) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5
Key Lake Level (mg/L) 0.1298 0.1436 0.1675 0.1594 0.1903 0.1740 0.0860 0.2175 0.1454 0.1685 0.1648 0.2176

0.2025

0.0993

0.0998

 0.2383 0.1447 0.1172 0.0708 0.0823 0.2142 0.1228 0.0935 0.0844

McArthur River Monitoring Results

Treated Water Quality — Zinc
  Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20 Dec-20 Jan-21 Feb-21 Mar-21
Metal Mining Regulations Limit (mg/L) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5
McArthur River Level (mg/L) 0.0057 0.0018 0.0016 0.0026 0.0042 0.0039 0.0026 0.0025 0.0034 0.0028 0.0031 0.0019

0.0016

0.0013

0.0016

 0.0024 0.0020 0.0016 0.0014 0.0018 0.0021 0.0032 0.0027 0.0050

Key Lake Monitoring Results

Treated Water Quality — Zinc
  Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20 Dec-20 Jan-21 Feb-21 Mar-21
Metal Mining Regulations Limit (mg/L) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5
Key Lake Level (mg/L) 0.0078 0.0056 0.0053 0.0039 0.0057 0.0078 0.0050 0.0091 0.0079 0.0110 0.0091 0.0113

0.0099

0.0034

0.0018

 0.0044 0.0020 0.0021 0.0028 0.0032 0.0080 0.0056 0.0043 0.0040

McArthur River Monitoring Results

Treated Water Quality — Suspended Solids
  Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20 Dec-20 Jan-21 Feb-21 Mar-21
Metal Mining Regulations Limit (mg/L) 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15
McArthur River Level (mg/L) 0.9 1.0 1.0 0.9 0.9 0.9 0.9 1.0 0.9 1.0 1.0 1.0 1.0 1.0 1.0 2.0 2.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0

Key Lake Monitoring Results

Treated Water Quality — Suspended Solids
  Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20 Dec-20 Jan-21 Feb-21 Mar-21
Metal Mining Regulations Limit (mg/L) 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15
Key Lake Level (mg/L) 3 2 2 1 3 1 2 3 2 2 3 4 2 2 2 3 4 2 0.9 2 3 4 1 2

McArthur River Monitoring Results

Treated Water Quality — Radium-226
  Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20 Dec-20 Jan-21 Feb-21 Mar-21
Metal Mining Regulations Limit (Bq/L) 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37
McArthur River Level (Bq/L) 0.044 0.065 0.053 0.046 0.048 0.043 0.056 0.075 0.066 0.068 0.055 0.048

0.048

0.045

0.058

 0.052 0.045 0.040 0.040 0.038 0.046 0.035 0.023 0.028

Key Lake Monitoring Results

Treated Water Quality — Radium-226
  Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20 Dec-20 Jan-21 Feb-21 Mar-21
Metal Mining Regulations Limit (Bq/L) 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37
Key Lake Level (Bq/L) 0.133 0.088 0.065 0.060 0.080 0.035 0.048 0.048 0.098 0.045 0.080 0.074

0.058

0.031

0.016

 0.056 0.025 0.011 0.009 0.009 0.005 0.006 0.006 0.010

McArthur River Monitoring Results

Treated Water Quality — pH
  Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20 Dec-20 Jan-21 Feb-21 Mar-21
Authorized Maximum pH 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5
McArthur River Level pH 7.5 7.4 7.5 7.5 7.4 7.4 7.5 7.4 7.5 7.5 7.4 7.5 7.5 7.5 7.5 7.6 7.6 7.5 7.4 7.5 7.4 7.4 7.4 7.4
Authorized Minimum pH 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0

Key Lake Monitoring Results

Treated Water Quality — pH
  Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20 Dec-20 Jan-21 Feb-21 Mar-21
Authorized Maximum pH 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5
Key Lake Level pH 6.7 6.6 6.7 6.7 6.6 6.7 6.5 6.6 6.6 6.5 6.5 6.6 6.6 6.6 6.7 6.6 6.5 6.7 6.8 6.9 6.8 7.0 7.1 7.2
Authorized Minimum pH 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0

McArthur River Monitoring Results

Treated Water Quality — Selenium
  Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20 Dec-20 Jan-21 Feb-21 Mar-21
Saskatchewan Ministry of Environment Limit (mg/L) 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6
McArthur River Level (mg/L) 0.0002 0.0002 0.0003 0.0002 0.0004 0.0003 0.0006 0.0003 0.0002 0.0002 0.0002 0.0002

0.0002

0.0002

0.0004

 0.0005 0.0004 0.0004 0.0003 0.0002 0.0003 0.0003 0.0002 0.0002

Key Lake Monitoring Results

Treated Water Quality — Selenium
  Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20 Dec-20 Jan-21 Feb-21 Mar-21
Saskatchewan Ministry of Environment Limit (mg/L) 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6
Key Lake Level (mg/L) 0.0084 0.0093 0.0098 0.0092 0.0103 0.0113 0.0093 0.0113 0.0115 0.0108 0.0100 0.0099

0.0094

0.0091

0.0102

 0.0124 0.0093 0.0089 0.0110 0.0110 0.0140 0.0105 0.0104 0.0097

McArthur River Monitoring Results

Treated Water Quality — Uranium
  Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20 Dec-20 Jan-21 Feb-21 Mar-21
Saskatchewan Ministry of Environment Limit (mg/L) 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5
McArthur River Level (mg/L) 0.0088 0.0054 0.0068 0.0067 0.0076 0.0069 0.0099 0.0146 0.0100 0.0106 0.0126 0.0085

0.0072

0.0066

0.0069

 0.0047 0.0075 0.0071 0.0066 0.0124 0.0110 0.0117 0.0078 0.0064

Key Lake Monitoring Results

Treated Water Quality — Uranium
  Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20 Dec-20 Jan-21 Feb-21 Mar-21
Saskatchewan Ministry of Environment Limit (mg/L) 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5
Key Lake Level (mg/L) 0.0165 0.0162 0.0398 0.0414 0.0383 0.0350 0.0330 0.0258 0.0158 0.0278 0.0258 0.0372

0.0248

0.0190

0.0232

 0.0236 0.0148 0.0168 0.0172 0.0195 0.0504 0.0286 0.0420 0.0208

McArthur River Monitoring Results

Treated Water Quality — Molybdenum
  Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20 Dec-20 Jan-21 Feb-21 Mar-21
McArthur River Level (mg/L) 0.0066 0.0064 0.0273 0.0130 0.0283 0.0200 0.0109 0.0052 0.0031 0.0036 0.0036 0.0031

0.0032

0.0070

0.0188

 0.0160 0.0183 0.0168 0.0115 0.0074 0.0053 0.0040 0.0028 0.0025

Key Lake Monitoring Results

Treated Water Quality — Molybdenum

 

 Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20 Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20 Dec-20 Jan-21 Feb-21 Mar-21
Key Lake Level (mg/L) 0.0021 0.1580 0.0827 0.0558 0.0265 0.0550 0.1146 0.0503 0.0128 0.0033 0.0028 0.0026

0.0028

0.1362

0.0724

 0.0510 0.1190 0.1150 0.0840 0.0628 0.0330 0.0212 0.244 0.0145

McArthur River Monitoring Results

Ambient Air Quality – Annual Average Total Suspended Particulate (TSP)    
NOTE - Regulations replaced and standard revised on June 1, 2015; however for consistency, the old value is referenced for the 2015 reporting year. Reporting against the new value began in Q1 2016.
  2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 Q1
Saskatchewan Ministry of Environment Standard - see note (µg/m³) 70 70 70 70 60 60 60 60 60 60
Annual Average (µg/m³) 7.2 4.9 4.2 4.2 2.3 3.2 1.7 1.4 1.1 0.9

Key Lake Monitoring Results

Ambient Air Quality – Annual Average Total Suspended Particulate (TSP)  
NOTE - Regulations replaced and standard revised on June 1, 2015; however for consistency, the old value is referenced for the 2015 reporting year. Reporting against the new value began in Q1 2016.
  2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 Q1
Saskatchewan Ministry of Environment Standard - see note (µg/m³) 70 70 70 70 60 60 60 60 60 60
Annual Average (µg/m³) 11.5 10.4 10.3 10.0 10.8 12.2 8.8 6.7 5.9 4.0

 

Key Lake Monitoring Results

Ambient Air Quality – Annual Average Ambient Sulfur Dioxide (SO₂) 
NOTE - Regulations replaced and standard revised on June 1, 2015; however for consistency, the old value is referenced for the 2015 reporting year. Reporting against the new value began in Q1 2016.              During Care and Maintenance, the plant is shut down, therefore no emissions are reported.
  2012 2013 2014 2015 2016 2017 2018 2019 2020
Saskatchewan Ministry of Environment Standard (ppb) 10 10 10 10 8 8 8 8 8
Annual Average (ppb) 7.7 6.7 7.3 9.1 0.5 0.4 0 0 0

Key Lake and McArthur River entered into a safe state of Care and Maintenance in January 2018.

Environmental Incidents and Other Events

Environmental incidents and other events are reported to regulatory agencies as required by federal and provincial regulations.

Latest incidents or events:

McArthur River

Date May 10, 2021
Incident

Reportable release
Details

An increase in outdoor temperatures caused snow meltwater to accumulate within utilidor sump #7 and approximately 2,000 liters of meltwater overflowed the sump onto the ground. This event is classified as a reportable release.
Corrective Action

An alternative pumping system has been set up. Provincial and federal regulators were notified.
Environmental Effect 1

Past reporting

McArthur River

Date May 10, 2021
Incident

Reportable release
Details

An increase in outdoor temperatures caused snow meltwater to accumulate within utilidor sump #7 and approximately 2,000 liters of meltwater overflowed the sump onto the ground. This event is classified as a reportable release.
Corrective Action

An alternative pumping system has been set up. Provincial and federal regulators were notified.
Environmental Effect 1

 

Date March 12, 2021
Incident

Fire alarm system activation
Details

The Emergency Response Team (ERT) responded to a fire alarm activation on the third floor east wing of the permanent camp.The Emergency Response Team (ERT) responded to a fire alarm activation on the third floor east wing of the permanent camp.
Corrective Action

The ERT team swept the area and determined the fire alarm activation was due to steam. Area was cleared to allow tradespeople to mitigate issue with assistance of ERT team members.  Federal regulators were informed.
Environmental Effect N/A

 

Date February 8, 2021
Incident

Fire alarm system activation
Details

At approximately 12:30 p.m. the fire alarm system in the main camp was activated as a result of light smoke detected in the E-wing. In accordance with emergency procedures, camp residents reported to the designated muster point and the emergency response team (ERT) responded and verified that there was no fire. The cause of the observed smoke was determined to be a damaged belt on the air handling unit.
Corrective Action

The camp wing was ventilated and the belt was replaced. Once the area was verified as safe, the alarm system was reset. The CNSC has been notified and follow-up reporting will take place.
Environmental Effect N/A

 

Date September 18, 2020
Incident

Fire alarm system activation
Details

At approximately 12:30 p.m. a fire alarm was activated underground near the material delivery chute on the 640 level. The emergency response team (ERT) responded in accordance with emergency procedures and verified that there was no fire.
Corrective Action

An investigation into the cause of the false alarm is underway. The CNSC has been notified.
Environmental Effect N/A

 

Date July 29, 2020
Incident

Fire system activation
Details

The emergency response team (ERT), responded to fire system activation in the north-ex refuge station (530 level) underground. The ERT responded in accordance with emergency procedures and verified that there was no fire or smoke.
Corrective Action

Investigation indicated that high humidity levels caused a smoke detector to go into alarm. The CNSC was notified.
Environmental Effect N/A

 

Date December 13, 2019
Incident

Fire system activation
Details

At 5:40 pm the McArthur River emergency response team (ERT), responded to fire system activation in B Wing of the permanent camp. The ERT responded in accordance with emergency procedures, cleared the area and verified that there was no fire or smoke.
Corrective Action

The ERT found that activation of the fire system was due to a broken sprinkler line in upper B Wing. The team secured the area and assisted in repairing and rearming the system. The CNSC was notified.
Environmental Effect N/A

 

Date November 4, 2019
Incident

Smoke alarm
Details

At approximately 2:30 am a smoke alarm registered at the main freeze plant. The emergency response team (ERT) responded in accordance with emergency procedures and verified that it was a false alarm.
Corrective Action

The ERT determined the alarm was due to the start-up of a heater. The system was put back into service and the CNSC was notified.
Environmental Effect N/A

 

Date July 15, 2019
Incident

Fire alarm
Details

At 0:47 the McArthur River emergency response team (ERT), responded to a camp fire alarm in A Wing Attic. The ERT responded in accordance with emergency procedures, cleared the area and verified that there was no fire or smoke.
Corrective Action

ERT investigation indicates a pressure switch failure in a compressor caused loss of pressure in the A Wing’s dry sprinkler system, triggering an alarm. Provincial and federal regulators were notified.
Environmental Effect N/A

 

Date June 22, 2019
Incident

Smoke underground
Details

During attempts to reset power to the underground, workers reported smoke on the 530 level of the mine. Workers reported to surface and the emergency response team (ERT) responded in accordance with emergency procedures. The ERT investigated and confirmed there was no active fire.
Corrective Action

Once the area was declared safe, electricians confirmed the source of the smoke as a 600V cable that appears to have shorted to ground. Federal and provincial regulators were notified. An investigation to determine the cause of the short is ongoing.
Environmental Effect N/A

 

Date March 31, 2019
Incident

Reportable Discharge
Details

Approximately 3,200 cubic metres of treated water was released from two liner tears in monitoring pond #4 between the dates of March 18 to March 29, 2019. Lab analysis shows the treated water was of good quality and met regulatory limits for release.
Corrective Action

The pond was taken offline and drained. It will remain offline until an inspection and repairs can be completed. The cause is being investigated. Provincial and federal regulators were notified.
Environmental Effect 1

 

Date March 25, 2019
Incident

Smoke underground
Details

During an attempt to reset power to the underground, two employees reported smoke on the 640 level of the mine. The area was evacuated and the emergency response team (ERT) responded in accordance with emergency procedures. The ERT investigated, confirmed that there was no active fire and identified the source of the smoke as being two damaged electrical cables that feed the 640 level substation. 
Corrective Action

Electricians isolated damaged electrical lines and restored power to the underground. Federal and provincial regulators were notified.  An investigation to determine the cause of the damaged cables is ongoing.
Environmental Effect N/A

 

Date February 2, 2019
Incident

Release of treated water
Details

Approximately 800 cubic metres of treated water was released from a possible liner tear in pond 3 from January 29 to February 2, 2019. Lab analysis shows the treated water was of good quality and met regulatory limits for release.
Corrective Action

The pond was taken offline and drained. It will remain offline until an inspection and repairs can be completed. It is expected that surface ice and changing water levels caused the tear. Provincial and federal regulators were notified.
Environmental Effect 1

 

Date January 31, 2019
Incident

Reportable release
Details

A liquid propane leak at the propane vapourizer building was observed by employees, and following monitoring by the safety officer, the plumber initiated work to repair the valve. The supply line was isolated and underground work was not started while the heating was inoperable.
Corrective Action

It is expected that the incident was caused by a rapid change in extreme temperatures. Repairs were completed by the site plumber. Provincial and federal regulators have been notified.
Environmental Effect 1

 

Date November 20, 2018
Incident

Equipment recertification
Details

On November 20th, an employee identified that required paperwork for extending the use of hoist ropes had not been submitted to the Ministry of Labour Relations and Workplace Safety. The necessary inspections had been completed but were not submitted on time for recertification.
Corrective Action

The applicable equipment has been taken out of service until approval from the Ministry is received. The oversight is under investigation. Provincial and federal regulators were notified.
Environmental Effect N/A

 

Date September 8, 2018
Incident

Release of treated water
Details

Inspection of recent liner repairs in the storage ponds that are part of the water treatment system at the McArthur River operation led to the discovery of water leakage. Approximately 1,200 cubic metres of treated water was released from this pond.
Corrective Action

The storage pond was taken out of service, drained and repairs initiated. Provincial and federal regulators were notified.
Environmental Effect 1

 

Date August 25, 2018
Incident

Ammonia release
Details

A refrigeration mechanic entered the Module 1 freeze plant at about 2:15 p.m. and noticed the smell of ammonia. The mechanic identified that a small amount of ammonia had leaked from a cracked sight glass on a vessel. None of the ammonia detectors in the plant were in alarm.
Corrective Action

The vessel has been taken out of service pending repair, and the cause is being investigated. Provincial and federal regulators were notified.
Environmental Effect 1

 

Date August 6, 2018
Incident

Release of treated water
Details

Inspection of the storage ponds that are part of the water treatment system at the McArthur River operation led to the discovery that approximately 8,000 cubic metres of treated water had been discharged from these ponds.
Corrective Action

The storage ponds were taken out of service, drained and repairs initiated. Provincial and federal regulators were notified.
Environmental Effect 1

 

Cameco Environmental Effect Rating

  • Level 1 - no measurable impact to the environment
  • Level 2 - negligible impact
  • Level 3 - short-term, seasonal impact
  • Level 4 - mortality of some species, but not affecting ecosystem function
  • Level 5 - impairment of ecosystem function
  • N/A - not applicable

Key Lake

Date June 22, 2021
Incident

Reportable release
Details

Examination of 2020 and 2021 groundwater sampling results from new monitoring wells indicated elevated levels of parameters such as ammonia and sulfate below the mill terrace area.
Corrective Action

An assessment indicates the source is likely a release of water contaminated with barren strip solution. The release is believed to have occurred prior to the operation being placed into care and maintenance in 2018, as tests have indicated there is not an active discharge occurring.

Further investigation is underway. Additional drilling and sampling will be completed to further assess groundwater conditions in this area. Inspections and repairs will be completed prior to resumption of production.

Provincial and federal regulators were notified.
Environmental Effect 2

Past reporting

Key Lake

Date June 22, 2021 
Incident

Reportable release
Details

Examination of 2020 and 2021 groundwater sampling results from new monitoring wells indicated elevated levels of parameters such as ammonia and sulfate below the mill terrace area.
Corrective Action

An assessment indicates the source is likely a release of water contaminated with barren strip solution. The release is believed to have occurred prior to the operation being placed into care and maintenance in 2018, as tests have indicated there is not an active discharge occurring.

Further investigation is underway. Additional drilling and sampling will be completed to further assess groundwater conditions in this area. Inspections and repairs will be completed prior to resumption of production.

Provincial and federal regulators were notified.
Environmental Effect 2

 

Date April 18, 2021 
Incident

Dangerous occurrence
Details

While decommissioning electrical cables in the packaging area, a 120V energized wire was inadvertently cut. This caused the breaker to trip and no injuries occurred.
Corrective Action

The electrical wire was repaired and an investigation is underway.  Provincial and federal regulators were notified.
Environmental Effect N/A

 

Date February 12, 2021
Incident

Reportable release
Details

At around 8:15 a.m., a leak detection alarm in Valve Shelter #1 was activated after a damaged 3-inch pipe released approximately 3m3 of water to the floor of the shelter and outside the doorway. Upon investigation, it was determined that freezing temperatures had caused the pipe to split.
Corrective Action

A lateral valve in the shelter was closed, which stopped the release. The material was cleaned up utilizing a vacuum truck. The damaged pipe is being repaired. Provincial and federal regulators were notified.
Environmental Effect 1

 

Date October 27, 2020
Incident

Reportable release
Details

At approximately 6:15 a.m., workers noted that a water supply line valve in the wash bay had been left open overnight resulting in the release of approximately 12,000 litres of water onto the frozen ground outside the building.
Corrective Action

Workers shut off the water supply valve. Water samples were collected for analysis and the slush/ice build-up on the frozen ground was removed for transfer to the Phase IV Ore Pad.  Provincial and federal regulators were notified.
Environmental Effect 1

 

Date March 17, 2020
Incident

Reportable release
Details

At approximately 2:30 p.m. in the reverse osmosis (RO) facility, the automated shutdown of water pumps failed resulting in the release of approximately 3,000 litres of dewatering water to the ground.
Corrective Action

All wells providing water to the RO plant were shut down. Released water, which froze in place on the ground, was removed and placed on the Gaertner special waste pad. Preliminary investigation indicates a system communication power loss, from a UPS failure during maintenance testing, resulted in loss of signal between the high water level alarm and automated pump shutdown system. Provincial and federal regulators were notified.
Environmental Effect 1

 

Date March 8, 2020
Incident

Emergency response team (ERT) activation
Details

At 12:24 p.m., the emergency response team (ERT) responded to a burst fire system water line in the stairwell of the mine shop.
Corrective Action

Water was isolated and the line was repaired. ERT investigation revealed the line had frozen and burst due to cold weather and heating failure. Federal regulators were notified.
Environmental Effect N/A

 

Date November 16, 2019
Incident

Reportable release
Details

At approximately 7:15 am, a pressure relief valve failed on the mill terrace propane vaporizer #2, resulting in the release of about 198m3 of propane gas. There was no effect on the environment or health and safety of personnel.
Corrective Action

The propane line was isolated, area restricted and nearby equipment shut down. An investigation is under way. Provincial and federal regulators have been notified.
Environmental Effect 1

 

Date September 11, 2019
Incident

Gas detection alarm
Details

At approximately 5:20 pm the Key Lake emergency response team (ERT), responded to an alarm at the chemistry lab that hydrogen levels were high. The ERT responded in accordance with emergency procedures, and confirmed it was a false alarm.
Corrective Action

All gas valves were closed, the area was ventilated and the ERT confirmed that it was a false alarm. The CNSC was notified.
Environmental Effect N/A

 

Date August 28, 2019
Incident

Fire alarm
Details

At approximately 9:00 am the Key Lake emergency response team (ERT), responded to a fire alarm at the electrical substation. The ERT responded in accordance with emergency procedures, and found smoke but no fire present.
Corrective Action

The area was ventilated and electricians isolated a damaged transformer. The CNSC was notified.
Environmental Effect N/A

 

Date August 10, 2019
Incident

Fire alarm
Details

At approximately 2:00 am the Key Lake emergency response team (ERT), responded to a camp fire alarm. The ERT responded in accordance with emergency procedures, and confirmed that the sprinkler system had activated. Camp was temporarily evacuated.
Corrective Action

ERT investigation indicates that the sauna malfunctioned causing excessive heat. The area was isolated and cleared for workers to re-enter camp. Provincial and federal regulators were notified.
Environmental Effect N/A

 

Date July 9, 2019
Incident

Reportable release
Details

A small release from a propane regulator was detected in the mill terrace vaporizer building. No measureable decrease was detected in propane tank volumes indicating that the release volume was negligible.  There was no effect on the environment or health and safety of personnel.
Corrective Action

The propane line was isolated, area restricted and ventilation was increased.  An investigation is under way. Provincial and federal regulators have been notified.
Environmental Effect 1

 

Date March 3, 2019
Incident

Reportable release
Details

At 9:30 am a liquid propane distribution hose at the Acid Plant Propane Tank Farm was visually inspected and found to be leaking. Release volume is considered negligible as consumption of propane remained consistent with routine operation during the period.
Corrective Action

It is expected that the line deteriorated over time. Repairs were completed by the site plumber. Provincial and federal regulators have been notified.
Environmental Effect 1

 

Date January 8, 2019
Incident

Ammonia release
Details

A minor leak was discovered on an ammonia storage tank by the solvent extraction facility at approximately 3:00 pm. The area was isolated and maintenance staff notified.
Corrective Action

It is expected that a valve on the tank has deteriorated as it was due to be replaced in 2019. Provincial and federal regulators were notified.
Environmental Effect 1

 

Date December 3, 2018
Incident

Reportable release
Details

During a review of groundwater monitoring data it was noted that a sampling well adjacent to the mill building was showing an increasing trend in uranium concentration. Following further sampling, early indications show that a nearby sump area within the mill has released an estimated 50 m3 of water over the course of the year.
Corrective Action

Further investigation is underway and the area will be pumped dry and inspected. Provincial and federal regulators have been notified.
Environmental Effect 2

 

Date November 22, 2018
Incident

Reportable release
Details

An employee noticed the smell of propane at 10:40 am on November 22nd and the source was determined to be the reverse osmosis propane tank. Tank levels did not indicate any change, so it is expected that the release volume was very small. Corrective Action: Repairs were completed by the site plumber. Provincial and federal regulators have been notified.
Corrective Action

Repairs were completed by the site plumber. Provincial and federal regulators have been notified.
Environmental Effect 1

 

Date October 12, 2018
Incident

Reportable release
Details

At 8:00 a.m., automated monitoring in the reverse osmosis facility at the Key Lake Operation measured high pH readings. In accordance with the facility’s design, the flow of treated water was redirected. Approximately 10 cubic metres of water that was above the high pH regulatory limit was released from the reverse osmosis facility into Horsefly Lake.
Corrective Action

Treated water from the reverse osmosis facility was redirected until the pH was back to normal operating range. The incident is being investigated to prevent recurrence. Provincial and federal regulators were notified.
Environmental Effect 1

 

Date August 30, 2018
Incident

Fire alarm system activation
Details

The Key Lake permanent camp fire alarm system was activated at approximately 6:00 a.m.. The emergency response team (ERT) responded in accordance with emergency procedures and verified that it was a false alarm.
Corrective Action

The cause of the false alarm is under investigation and the CNSC was notified.
Environmental Effect N/A

 

Date August 27, 2018
Incident

Ventilation Ducting Support Failure
Details

A clean-air supply ventilation duct in the Key Lake mill separated at one location causing a section of duct to drop and rest on pipes below. 
Corrective Action

The area was restricted and the incident is being investigated. Provincial and federal regulators were notified.
Environmental Effect 1

 

Cameco Environmental Effect Rating

  • Level 1 - no measurable impact to the environment
  • Level 2 - negligible impact
  • Level 3 - short-term, seasonal impact
  • Level 4 - mortality of some species, but not affecting ecosystem function
  • Level 5 - impairment of ecosystem function
  • N/A - not applicable

Decommissioning

Detailed plans and financial guarantees are in place to provide for decommissioning of the McArthur River and Key Lake sites when operations end. Decommissioning will include removal of all buildings and equipment and landscaping and re-vegetation of disturbed areas. All underground workings and other mine and mill facilities will be sealed off and secured. A monitoring program will be in place to ensure the sites remain in a secure and stable state for the long-term. For more information, see Preliminary Decommissioning Plan - Summary - McArthur River Operation or Preliminary Decomissioning Plan - Summary - Key Lake Operation.

Environmental Assessment

All new mining developments and significant changes to existing operations may be subject to environmental assessments to identify potential effects on the environment. An environmental assessment of plans to increase the annual production and tailings capacity of the Key Lake was concluded and approved in mid-2014. Additional information is available from our Northern Saskatchewan website.

Tailings Management

Tailings, or what remains of the ore after the uranium has been removed at the Key Lake mill, is placed in the Deilmann tailings management facility. Commissioned in 1996, the facility is built into the mined out Deilmann pit and is designed to safely contain the tailings during continuing operations and after decommissioning. Tailings are placed in the pit under a water cover. During operations, groundwater is collected from a series of wells around the facility and is treated prior to release to the environment. When operations cease, the tailings will become a solid dense mass and groundwater will flow around the tailings, rather than through them, to minimize environmental impact.

Prior to 1996, tailings from the Key Lake mill were deposited in a surface tailings management facility approximately 600 metres by 600 metres and 15 metres deep. The facility was constructed five metres above the groundwater table and used a modified bentonite liner to isolate the tailings from the surrounding soil.

Regulatory Oversight

The primary regulator for the McArthur River and Key Lake operations is the Canadian Nuclear Safety Commission (CNSC). These operations are also subject to regulatory oversight from several other federal and provincial agencies including Saskatchewan Ministry of Environment. Federal and provincial regulators conduct regular site inspections and audits to verify that people and the environment are protected. Uranium mining and milling operations in Canada are licensed by the CNSC.

Sustainability at Cameco

When measuring the sustainability and ethical impact of a company, environmental, social and governance (ESG) are key factors considered by the public and investors. Sustainability and ESG matters have been an important focus at Cameco for many years and we have a strong performance record.

Learn more