EFFECTIVENESS OF OXYGEN BARRIERS UNDER CLIMATE CHANGE: DEFINITION OF A DROUGHT INDEX

Transcription

1 EFFECTIVENESS OF OXYGEN BARRIERS UNDER CLIMATE CHANGE: DEFINITION OF A DROUGHT INDEX Émilie Bresson 1, Isabelle Demers 1, Yann Chavaillaz 2,3, Philippe Roy 2, Thomas Pabst 4 1 Research Institute of Mines and Environment (RIME), Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda,QC, Canada; 2 Ouranos Inc., Montréal, QC, Canada; 3 Concordia university, Montréal, QC, Canada; 4 Research Institute of Mines and Environment (RIME), Polytechnique-Montréal, Montréal, QC, Canada; QC, Canada 2018 TAILINGS AND MINE WASTE CONFERENCE

2 Introduction Mines industry in Quebec (Canada) Present in the whole Quebec Different ores: gold, iron, copper, graphite, lithium, nickel Most active region: Abitibi-Témiscamingue Quebec mining activity (MERN)

3 Introduction Reclamation methods in southern Quebec AMD 1 formation: Sulfides + O 2 + H 2 O AMD 1 Acid Mine Drainage

4 Introduction Reclamation methods in southern Quebec AMD 1 formation: Humid continental climate Sulfides + O 2 + H 2 O AMD 1 Acid Mine Drainage

5 Introduction Reclamation methods in southern Quebec AMD 1 formation: Sulfides + O 2 + H 2 O AMD Humid continental climate Most frequent reclamation methods: oxygen barriers Tailings/MRL degree of saturation S r 85% Water cover Elevated water table CCBE 2 Oxygen barriers examples 1 Acid Mine Drainage 2 Cover with Capillarity Barrier Effect

6 Introduction Climate vulnerabilities Oxygen barrier climate vulnerability: Desaturation due to drought S r < 85%

7 Introduction Climate vulnerabilities Oxygen barrier climate vulnerability: Desaturation due to drought S r < 85% Climate change (CC) in this region, among others: Longer periods without precipitation Temperature increase More intense droughts

8 Introduction Climate vulnerabilities Oxygen barrier climate vulnerability: Desaturation due to drought S r < 85% Climate change (CC) in this region, among others: Longer periods without precipitation Temperature increase More intense droughts Are the reclamation cover designs adapted to CC?

9 Introduction Objective Develop a drought index adapted to oxygen barrier evolving with CC

10 Description of the drought index features Step 1: Select period with unfrozen soil

11 Description of the drought index features Step 1: Select period with unfrozen soil

12 Description of the drought index features Step 1: Select period with unfrozen soil Dry month: P-E < β

13 Description of the drought index features Step 1: Select period with unfrozen soil Dry month: P-E < β β

14 Description of the drought index features Step 1: Step 2: Duration: days with P < 1mm Severity: 1/(Precipitation before event)

15 More details about the Lorraine site: G. Hotton presentation Session 2D Studied site: Lorraine Picture and scheme of the CCBE. (Photo: É. Bresson)

16 Observed drought duration and severity Different patterns for severity and duration characteristics Example of duration and severity for all dry events observed for Lorraine site

17 Observed drought duration and severity Example of duration and severity for all dry events observed for Lorraine site

18 Observed drought duration and severity Does one of the features have more weight on drought impact? Example of duration and severity for all dry events observed for Lorraine site

19 Sensitivity to duration and severity Numerical sensitivity experiments on Lorraine site Duration (days) Severity (10-3 mm -1 ) 4, 10, 15, 16, 17, 18, 19, 20, 25, 30, 45, 60, 90 Low (maximum precipitation amount), Median (median precipitation amount), High (minimum precipitation amount)

20 Sr minimum (%) Courtesy to G. Hotton (presentation Session 2D) Minimum hydraulic head (m) Sensitivity to duration and severity Degree of saturation and minimum hydraulic head depending on duration and severity Duration (days) Severity (10-3 mm -1 ) 4, 10, 15, 16, 17, 18, 19, 20, 25, 30, 45, 60, 90 Low, Median, High High intensity Median intensity Low intensity Limit CCBE Sand & gravel MRL Sand , Duration (days) Tailings 30-days precipitation (mm) 15 jours 16 jours 17 jours 18 jours 19 jours 20 jours 25 jours 30 jours 45 jours 60 jours 90 jours Initial level 4 jours 10 jours

21 definition and use DS = duration severity

22 definition and use for the x th percentile and the p period DS = duration severity p,x = DS p,x DS hist,50 DS index for the xth percentile and the p period DS index for the 50 th percentile (median) and the historical period

23 definition and use for the x th percentile and the p period DS = duration severity p,x = DS p,x DS hist,50 1 hist,75 hist,50 hist,25 Historical period time

24 definition and use for the x th percentile and the p period DS = duration severity p,x = DS p,x DS hist, , ,50 1 hist,75 hist,50 hist, ,25 Historical period period time

25 definition and use for the x th percentile and the p period DS = duration severity p,x = DS p,x DS hist, , , , , ,25 1 hist,75 hist, ,25 hist,25 Historical period period period time

26 definition and use for the x th percentile and the p period DS = duration severity p,x = DS p,x DS hist, , , , , ,25 1 hist,75 hist, ,25 hist,25 Historical period period period time

27 definition and use for the x th percentile and the p period DS = duration severity p,x = DS p,x DS hist, , , , , ,25 1 hist,75 hist, ,25 hist,25 Historical period period period time

28 definition and use for the x th percentile and the p period DS = duration severity p,x = DS p,x DS hist,50 Duration and severity for one specific drought duration severity

29 definition and use Sensitivity experiments for the x th percentile and the p period DS = duration severity p,x = DS p,x DS hist,50 Duration and severity for one specific drought duration severity Lab/numerical tests

30 Minimum hydraulic head (m) definition and use Sensitivity experiments for the x th percentile and the p period DS = duration severity p,x = DS p,x DS hist, Duration and severity for one specific drought duration severity Lab/numerical tests days precipitation (mm) 15 jours 16 jours 17 jours 18 jours 19 jours 20 jours 25 jours 30 jours 45 jours 60 jours 90 jours Initial level 4 jours 10 jours

31 Minimum hydraulic head (m) definition and use Sensitivity experiments for the x th percentile and the p period DS = duration severity p,x = DS p,x DS hist, Duration and severity for one specific drought duration severity Lab/numerical tests days precipitation (mm) 15 jours 16 jours 17 jours 18 jours 19 jours 20 jours 25 jours 30 jours 45 jours 60 jours 90 jours Initial level 4 jours 10 jours

32 Climate data Earth climate system Earth climate system (source NCAR)

33 Climate data Climate models Global and regional climate models Global climate model Regional climate model

34 Climate data Climate scenarios Greenhouse gas emission scenarios Radiative forcing for the 4 RCP (van Vuuren et al, 2011 ; source : IPCC)

35 Climate data Climate scenarios Greenhouse gas emission scenarios Biais correction Δ (OBS SIM) Radiative forcing for the 4 RCP (van Vuuren et al, 2011 ; source : IPCC) Simulation Observations Time Biais correction Time

36 Climate data Climate scenarios Greenhouse gas emission scenarios Biais correction Radiative forcing for the 4 RCP (van Vuuren et al, 2011 ; source : IPCC) Simulation Observations Δ (OBS SIM) Time Biais correction Climate scenario data used for drought index calculation Time

37 Conclusion Take-home messages Different types of droughts simple and adapted to oxygen barrier reclamation designs Introduction of coherent set of climate data for climate change impact investigation

38 Conclusion Future work Two other points to study Frequency Distribution of 30-days prior drought precipitation Is the 30-day period long enough? Experiments with other sites with oxygen barrier reclamation design

39 Thank you for your attention

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