1. Green Mining Conference Water Management and the Environment
Maria Story, P. Eng.
13 September 2018

2. Introduction

3. It became clear to me early in my career:
that water quality was COMPLICATED and CONTROVERSIAL
but
we had to start looking at every project HOLISTICALLY to make the best decisions for the ENVIRONMENT as a WHOLE
focussing on one environmental medium could have more negative impacts on other environmental media

6. Establishing PWQOs & CWQGs
PWQO is the concentration of water quality which is protective of all forms of aquatic life and all aspects of the aquatic life cycles during indefinite exposure to the water
(MOECC, 1994)
CWQGs is a concentration of water to protect all forms of aquatic life and all aspects of the aquatic life cycles, including the most sensitive life stage of the most sensitive species over the long term (CCME,1999)

7. 20 d very severe unfavourable effect
28-d LC50
7-d LOEC
14-d EC20 (growth)
21-d EC16 (reprod)
7-d LC80
14-d EC50 (growth)
20 d very severe unfavourable effect
EC50

8. Case Studies Historic Cobalt/Coleman Mining Camp
Unrealistic Effluent Limits
Cobalt Constructed Wetland

9. Historic Cobalt Mining Camp

11. 20 d very severe unfavourable effect
28-d LC50
7-d LOEC
14-d EC20 (growth)
21-d EC16 (reprod)
7-d LC80
14-d EC50 (growth)
20 d very severe unfavourable effect
EC50

12. Unrealistic Effluent Limits

13. threshold for sub-lethal effects (12 mon)
Published Chronic Toxicity Data for Unionized Ammonia
Daily Effluent Limit = 0.04 mg/L
Monthly Average Effluent Limit = 0.02 mg/L
62-d EC20
LOEC (4 mon)
30-d IC20 survival/growth
7-d IC20 for fry growth
threshold for sub-lethal effects (12 mon)
gill damage (6 wks)
7-d EC20
reduction develop

14. Conservatism when Establishing Effluent Limits
Lowest Flow in Receiver (7Q20 = 7 d in 7300 d)
Maximum Effluent Flows
Maximum Effluent Concentrations
Low Effluent Limits
Over Engineered Resource-Intensive Treatment Systems

15. Two Tiered Approach Low Effluent Concentration Limits
the original 0.02 and 0.04 mg/L
protective during low flow conditions
no flow monitoring requirements
Higher Effluent Concentration Limits
higher flow conditions
with receiver flow monitoring requirements to ensure a specific mixing ratio and adequate assimilative capacity

16. Cobalt Constructed Wetland (on Ferland Tailings)

18. Cobalt Constructed Wetland - Loadings

19. Cobalt Constructed Wetland - Concentrations

20. The 7 words to failure are: “We have always
Conclusions
The 7 words to failure are: “We have always
done it this way.”
It is time for change.

21. Acknowledgements
Thanks to: Agnico Eagle Mines Limited for sharing data from their surface water sampling program. and The Corporation of the Town of Cobalt for sharing data from their Industrial Sewage Works Constructed Wetland.
Maria Story, P.Eng. (SEI President)