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  • Record Number: 17100 Author, Monographic: Vigneault, B.//Campbell, P. G. C.//Tessier, A.//De Vitre, R.//Prémont, S. Author Role: Title, Monographic: Subaqueous disposal of reactive mine tailings - Louvicourt Mine Test Cells. Geochemical

    sampling and analysis final report Translated Title: Reprint Status: Edition: Author, Subsidiary: Author Role: Place of Publication: Québec Publisher Name: INRS-Eau Date of Publication: 2001 Original Publication Date: Février 2001 Volume Identification: Extent of Work: vii, 47 Packaging Method: pages incluant 2 annexes Series Editor: Series Editor Role: Series Title: INRS-Eau, rapport de recherche Series Volume ID: 547 Location/URL: ISBN: 2-89146-457-5 Notes: Rapport annuel 2000-2001 Abstract: Call Number: R000547 Keywords: rapport / ok/ dl

  • B. Vigneault P.G.C. Campbell A. Tessier R. De Vitre S. Prémont

    Subaqueous DisposaI of Reactive Mine Tailings

    t

    Louvicourt Mine Test Cells

    Geochemical Sampling and Analysis

    Final Report - February 2001

    INRS-Eau Report No. 547

    INRS-Eau C.P.7500 Ste-Foy Québec GIV 4C7

  • ii

    Table of contents

    Table of contents ii List of Tables Hi List of Figures III Summary ......................................................................................................................................... v

    Résumé ......................................................................................................................................•.•..•. vi

    1. INTRODUCTION ................................................................................ _ ................................ 8

    2. MATERIALS AND METHOnS ......................................................................................... 11

    2.1. Site description / Sampling ................................................................................................ 11

    2.2. Electrochemical micro-profiles of pH and DO .................................................................. 13

    2.3. Interstitial water analysis .................................................................................................... 14

    2.4. Diffusive fluxes across the tailings - overlying water interface .................................. ; ...... 16

    2.5. Solid phase analysis ........................................................................................................... 17

    2.6. Quality assurance - Quality control (QAlQC) ................................................................... 18

    2.7. Statistical analysis .............................................................................................................. 18

    3. RESUL TS ............................................................................................ ____ ....................... 19

    3.1. General observations .......................................................................................................... 19

    3.2. Electrochemical micro-profiles ofpH and DO .................................................................. 19

    3.3. Interstitial water analysis (peepers) - pH, anions, Fe, Mn ................................................. 20

    3.4. Interstitial water analysis (peepers) - trace metals ...............................•..•.......................... 22

    3.5. Solid phase analysis ................................................................................•......... ~ ................ 22

    4. DISCUSSION ................................................................................. _ ... _._ ... _ .................... 23

    4.1. DO consumption by the submerged tailings .......................................... .' ........................... 23

    4.2. Alteration of surficial tailings ............................................................................................ 24 t

    4.3. Trace metal mobilization ...............................................................................•.......•............ 25

    5. CONCLUSIONS .................................................................................... _ .. _ .................... 29

    6. A CKN 0 WLEDG MENTS ............................................................. _ ... __ ...... __ .......... 30

    7. REFERENCES ................................................................................ _ .................................. 30

  • III

    Appendix 1 Summary of findings from October 1996 sampling ........................................................... A 1-1

    Appendix2 Summary of findings from June 1997 sampling ................................................................ A2-1

    List of Tables

    Table 1. Sequential extraction of metals from surface tailings with (1) MgCh, (2) acetate buffer

    at pH 5, (3) NH20H'HCI at room temperature, (4) NH20H·HCI at 96 oC, (5) H202 and (6)

    HF, HN03 and HCI04. Value are mean ± SD, n = 3 (1996) and n = 4 (1998). The 1998 Cd

    analyses in fractions 5 and 6 were made by ETAAS (in fraction 5 of cell 1, only 1 out of 4

    replicates) ............................................................................................................................... 3 3

    Table 2. Calculated diffusive flux of ions across the tailings - overlying water interface in cell 2.

    Positive fluxes indicate ions which diffuse from the overlying water into the tailings,

    whereas negative fluxes correspond to diffusion out of the tailings into the overlying water.

    Value are mean± SD, n = 3 (1996 and 1997) and n = 4 (1998) ............................................ 35

    List of Figures

    Figure 1. Typical porewater DO concentrations (a) and pH (b) profiles measured with

    microelectrodes inserted in the tailings (1 mm vertical resolution). The horizontal broken

    line indicates the tailings - overlying water interface. Each curve is from one insertion of

    the micro electJ;ode in the tailings using a micromanipulator deployed from a sampling

    platform at the centre of the experimental cell ....................................................................... 36

    Figure 2. Porewater pH profiles sampled by in situ dialysis (1 cm vertical resolution). The

    horizontal broken line indicates the tailings - overlying water interface. Each curve is from

    an individual peeper inserted into the tailings in the experimental cell, n = 3 (1996 and 1997)

    and n = 4 (1998) ..................................................................................................................... 38

  • iv

    Figure 3. Porewater concentration profiles for (a) cr (b) sol- and (c) col- as sampled by in situ dialysis (1 cm vertical resolution). The horizontal broken line indicates the tailings -

    overlying water interface. Each curve is from an individual peeper inserted into the tailings

    in the experimental cell, n = 3 (1996 and 1997) and n = 4 (1998) ......................................•.. 39

    Figure 4. Porewater H2S concentrations profiles sampled by in situ dialysis (1 cm vertical

    resolution, detection limit = 0.004 1lM). The horizontal broken line indicates the tailings - overlying water interface. Each curve is from an individual peeper inserted into the tailings

    in the experimental cell, n = 3 (1996 and 1997) and n = 4 (1998) ........................................ .42

    Figure 5. Porewater dissolved iron (a) and dissolved manganese (b) concentrations profiles

    sampled by in situ dialysis (1 cm vertical resolution, detection limits = 0.21lM and 0.05 IlM

    for Fe and Mn respectively). The horizontal broken line indicates the tailings - overlying

    water interface. Each curve is from an individual peeper inserted into the tailings in the

    experimental cell, n = 3 (1996 and 1997) and n = 4 (1998). In 1998, one aberrant data point for both Fe and Mn, presumably resulting from contamination, was not inc1uded in their

    respective profiles ................................................................................................................... 43

    Figure 6. Porewater dissolved copper (a) dissolved cadmium (b) and dissolved zinc (c)

    concentrations profiles sampled by in situ dialysis (1 cm vertical resolution, detection limits

    = 3 nM, 0.1 nM and 0.08 !lM for Cu, Cd and Zn respectively). The horizontal broken line

    indicates the tailings - overlying water interface. Each curve is from an individual peeper

    inserted into the tailings in the experimental cell, n = 3 (1996 and 1997) and n = 4 (1998).45

    Figure 7. Total metal concentrations (Cd, Cu, Ni, Pb, Zn, Fe) in surface layer oftailings in Cells

    1 and 2. Ca) October 1996 sampling; (b) June 1997 sampling. Note heterogeneity for Cd, Cu,

    Pb and Zn in Celll ................................................................................................................. 48

  • v

    Summary

    The objective of this study was to assess the effectiveness of an engineered shallow water

    coyer in reducing the oxidation of sulfidic mine tailings and thus preventing the development of

    acid rock drainage. Fresh tailings from the Louvicourt Mine (Louvicourt, Abitibi, QC) VIere

    submerged under a O.3-m water coyer in experimental field ceUs. From 1996 to 1998" we

    followed the chemistry of the interstitiaI water near the tailings-overlying water interlàce using in

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