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Britannia Mine, ARD, and the Millennium Plug Project Centre for Environmental Research in Minerals, Metals, and Materials Brennan Lang, John Meech, and.

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Presentation on theme: "Britannia Mine, ARD, and the Millennium Plug Project Centre for Environmental Research in Minerals, Metals, and Materials Brennan Lang, John Meech, and."— Presentation transcript:

1 Britannia Mine, ARD, and the Millennium Plug Project Centre for Environmental Research in Minerals, Metals, and Materials Brennan Lang, John Meech, and Rimas Pakalnis

2 The Millennium Plug Project 40 km from Vancouver Britannia Mine

3 The Millennium Plug Project Beautiful Howe Sound

4 The Millennium Plug Project Sea to Sky Highway

5 The Millennium Plug Project Britannia Beach Harbour

6 The Millennium Plug Project Britannia Beach - from the mill building

7 The Millennium Plug Project Britannia Valley

8 The Millennium Plug Project 300 Tonne Truck at the Museum

9 The Millennium Plug Project Inside the mine at Britannia

10 The Millennium Plug Project Mine History Britannia Mine operated between by the Britannia Mining and Smelting Co. and between by the Anaconda Mining Company - 47 million tonnes of ore mined km of underground development - 5 open pits (glory holes) Britannia Concentrator

11 The Millennium Plug Project Britannia Flood and Landslide - October 1921

12 The Millennium Plug Project Old Time Miners – circa 1950s

13 The Millennium Plug Project Customs Shed at Britannia – 1940s

14 The Millennium Plug Project 1992 Flash Flood Debris

15 The Millennium Plug Project Cementation Launders – 4100 Level

16 The Millennium Plug Project Mill Building in 2002

17 The Millennium Plug Project Mill Building in 2010

18 The Millennium Plug Project View inside the Mill Building

19 The Millennium Plug Project Beaty Lundin Centre – Britannia Mining Museum

20 The Millennium Plug Project A New Museum is Born

21 The Millennium Plug Project Site Ownership (2001) Britannia Mines and Reclamation Ltd.Britannia Mines and Reclamation Ltd. – owned mine and mineral claims, as well as residential – owned mine and mineral claims, as well as residential area north of Britannia Creek and “North Fan Area” area north of Britannia Creek and “North Fan Area” Britannia Beach Historical SocietyBritannia Beach Historical Society – owned most of “South Fan Area” – owned most of “South Fan Area” Province of B.C.Province of B.C. – owned foreshore area between highway & Howe Sound – owned foreshore area between highway & Howe Sound

22 The Millennium Plug Project Map of the Fan Area Howe Sound Britannia Mines and Reclamation Corporation British Columbia Assets and Land - a Crown Corporation Britannia Beach Historical Society - BC Museum of Mining Britannia Mines and Reclamation Corporation Housing Development

23 The Millennium Plug ProjectResponsibility BMARC was the only organization to declare itself a Responsible Person under the Waste Management Act BMARC was the only organization to declare itself a Responsible Person under the Waste Management Act Other Potentially Responsible Persons named as part of the Contaminated Sites process in 1999 were: Other Potentially Responsible Persons named as part of the Contaminated Sites process in 1999 were: Private PRPs:Alcoa, Canzinco, Alumax Inc., Anaconda/Arco, Howmet Holdings Corporation, Arrowhead/Ivaco, Intalco Aluminum Corporation Private PRPs:Alcoa, Canzinco, Alumax Inc., Anaconda/Arco, Howmet Holdings Corporation, Arrowhead/Ivaco, Intalco Aluminum Corporation Province of British Columbia Province of British Columbia Government of Canada Government of Canada Government indemnified companies in exchange for $30M Government indemnified companies in exchange for $30M

24 The Millennium Plug Project Site Ownership (2003) Macdonald Development Corporation bought the mortgage and foreclosed on BMARCMacdonald Development Corporation bought the mortgage and foreclosed on BMARC – Macdonald retained ownership of the residential area – Macdonald retained ownership of the residential area north of Britannia Creek and “North Fan Area” north of Britannia Creek and “North Fan Area” – Macdonald sold remaining ~9,500 acres to the – Macdonald sold remaining ~9,500 acres to the Provincial Government Provincial Government

25 The Millennium Plug Project Acid mine drainage from tunnels (620 m 3 /hr)Acid mine drainage from tunnels (620 m 3 /hr) About 800 kg of Cu & Zn discharged per dayAbout 800 kg of Cu & Zn discharged per day Over 13,000 tonnes of metal since closureOver 13,000 tonnes of metal since closure Groundwater contamination on the FanGroundwater contamination on the Fan Potential impacts on aquatic lifePotential impacts on aquatic life Waste dumps and stockpilesWaste dumps and stockpiles Tailings at bottom of Howe SoundTailings at bottom of Howe Sound Sealing abandoned adits, demolition of derelict buildings (public safety issues)Sealing abandoned adits, demolition of derelict buildings (public safety issues) Reclamation Issues in 2001

26 The Millennium Plug Project Acid mine drainage from tunnels (620 m 3 /hr)Acid mine drainage from tunnels (620 m 3 /hr) About 800 kg of Cu & Zn discharged per dayAbout 800 kg of Cu & Zn discharged per day Over 13,000 tonnes of metal since closureOver 13,000 tonnes of metal since closure Groundwater contamination on the FanGroundwater contamination on the Fan Potential impacts on aquatic lifePotential impacts on aquatic life Waste dumps and stockpilesWaste dumps and stockpiles Tailings at bottom of Howe SoundTailings at bottom of Howe Sound Sealing abandoned adits, demolition of derelict buildings (public safety issues)Sealing abandoned adits, demolition of derelict buildings (public safety issues) Reclamation Issues in 2001 ________________________________________________________ Concentration Annual Metalppm Tonnestonnes Aluminum ,000 Zinc ,525 Copper ,725 Iron ,350 Manganese Cadmium Cobalt Total = ,194

27 The Millennium Plug Project 2200 Level effluent 20-50% of the flow 45-70% of the copper 25-40% of the zinc 4100 Level effluent 50-80% of the flow 30-55% of the copper 60-75% of the zinc Groundwater discharge < 5% of the flow 2-3% of the copper 3-4% of the zinc Plug the 2200 Adit Build a Treatment Plant Reclaim pits and waste dumps

28 The Millennium Plug Project Glory holes/pits at Britannia Mine

29 The Millennium Plug Project Open Pits and Glory Holes

30 The Millennium Plug Project Cutaway View of the Mine Workings

31 The Millennium Plug Project Water Quality in 1995

32 The Millennium Plug Project Water Quality Change in 2001 Discharge Level (m 3 /hr) Level (m 3 /hr) Cu in 2200 Level (ppm) 59 - Cu in 4100 Level (ppm) 18 (26) 20 Zn in 2200 Level (ppm) 29 - Zn in 4100 Level (ppm) 21 (23) 20 Copper Reduction (%) - 30 Zinc Reduction (%) - 15

33 The Millennium Plug Project Discharge from 2200 Level prior to 2001

34 The Millennium Plug Project At the adit

35 The Millennium Plug Project A Synergistic Research Plan UBC had need for a research facility to conduct test work into the design of bulkheads to seal tunnelsUBC had need for a research facility to conduct test work into the design of bulkheads to seal tunnels By placing this Lab at the 2200 level portal, two synergistic events occurred:By placing this Lab at the 2200 level portal, two synergistic events occurred: UBC installed its research lab at a full-scale siteUBC installed its research lab at a full-scale site Britannia Mines and Reclamation Corp. was able to comply with part of its Remediation OrderBritannia Mines and Reclamation Corp. was able to comply with part of its Remediation Order The most harmful ARD from Britannia could be mitigatedThe most harmful ARD from Britannia could be mitigated Britannia Mine closure plan would move closer to fulfillmentBritannia Mine closure plan would move closer to fulfillment

36 The Millennium Plug Project Jane Creek showing a “Yellow-Boy”

37 The Millennium Plug Project Sampling and Monitoring

38 The Millennium Plug Project In the 2200 Level Adit

39 The Millennium Plug Project Installing Grout Tubes

40 The Millennium Plug Project The Millennium Plug Built in much the same way as an earth dam Built in much the same way as an earth dam Impervious clay core Impervious clay core Layers of sand, gravel, cobble, rip rap Layers of sand, gravel, cobble, rip rap Resistant to acidic conditions Resistant to acidic conditions Cheaper to build Cheaper to build Uses locally available materials Uses locally available materials Generates a “walk-away” solution Generates a “walk-away” solution

41 The Millennium Plug Project The Millennium Plug Research Station Longitudinal Section Contact Grouting Throttled Pipeline Pressurized Pipeline Concrete Plug Pressurized Chamber Bentonite/Sand Seal Quartzite Rock/Sand Sand/Gravel Filters Cobble/Rip Rap ARD effluent is diverted back into the mine workings. Pressurized chamber allows the Millennium Plug to be studied under pressure/seismic conditions up to 300 m of water head Service pressure = 9 m, but concrete plug designed for 300 m The Millennium Plug was to be left in place to "back-up" the concrete plug that will fail in years from attack by acidic water (pH = ) (pH = ) Into the mine Coffer Dam Not to scale 4 m 25 m

42 The Millennium Plug Project

43 The Concrete Plug was poured on December 17 th in a blinding snow storm over an 18 hour period. A total of 16 cement trucks had to be pulled up to the 2200 Level using front-end loaders and a bulldozer. The effluent was turned off at 3:30 pm on December 31 st, 2001.

44 The Millennium Plug Project Results at Britannia Creek Bridge Copper and Zinc down by 2 orders of magnitudeCopper and Zinc down by 2 orders of magnitude pH up by 2 units to virtually neutralpH up by 2 units to virtually neutral

45 The Millennium Plug Project Some people like to drink the Britannia Creek water and it is now safe to do so, although like all natural water streams in the wild, it is not recommended without prior chemical treatment.

46 The Millennium Plug Project EPCOR Water Treatment Plant HDS = High-Density Sludge Started up December 2005 Capital Cost= ~ $12.0M Capital Cost= ~ $12.0M Operating Costs= ~ $ 1.5M Operating Costs= ~ $ 1.5M

47 The Millennium Plug Project HDS Plant – Process Flow Diagram Sludge/Lime Mix Tank Lime Reactor Clarifier Effluent Overflow Sludge disposal Sludge Recycle Lime Tank Flocculants Tanks Recycle Water Flocculants Lime Paste Acidic Feed Water Air

48 The Millennium Plug Project Element Required Typical mg/L mg/L Dissolved Cu ≤ Dissolved Zn ≤ Dissolved Cd ≤ Dissolved Fe ≤ Dissolved Al ≤ Dissolved Mn ≤ Total Suspended Solids ≤ pH 6.5 to HR LC50 fish bioassay 100% (non-acutely toxic) Permit Requirements

49 The Millennium Plug Project Sludge Disposal Sludge Disposal involves filtrationSludge Disposal involves filtration Pressure plate filtersPressure plate filters Final water content = 60%solids (like toothpaste)Final water content = 60%solids (like toothpaste) Material consists of colloidal particles (sub-micron)Material consists of colloidal particles (sub-micron) All metals are present as hydroxides or hydrated sulfatesAll metals are present as hydroxides or hydrated sulfates Cu and Zn contents are about 4-5% eachCu and Zn contents are about 4-5% each Crystalline Ettringite, Ca 6 Al 2 (SO 4 ) 3 (OH) 12 ·26 H 2 O~ 35%Crystalline Ettringite, Ca 6 Al 2 (SO 4 ) 3 (OH) 12 ·26 H 2 O~ 35% Calcite, CaCO 3 (minor quantities of aragonite) ~ 15%Calcite, CaCO 3 (minor quantities of aragonite) ~ 15% Gypsum, CaSO 4 ·2H 2 O ~ 5%Gypsum, CaSO 4 ·2H 2 O ~ 5% Quartz, SiO 2 ~ 5%Quartz, SiO 2 ~ 5% Amorphous Phases ~ 40%Amorphous Phases ~ 40%

50 The Millennium Plug Project Sludge Disposal Sludge Disposal involves filtrationSludge Disposal involves filtration Pressure plate filtersPressure plate filters Final water content = 60%solids (like toothpaste)Final water content = 60%solids (like toothpaste) Material consists of colloidal particles (sub-micron)Material consists of colloidal particles (sub-micron) All metals are present as hydroxides or hydrated sulfatesAll metals are present as hydroxides or hydrated sulfates Cu and Zn contents are about 4-5% eachCu and Zn contents are about 4-5% each Crystalline Ettringite, Ca 6 Al 2 (SO 4 ) 3 (OH) 12 ·26 H 2 O~ 35%Crystalline Ettringite, Ca 6 Al 2 (SO 4 ) 3 (OH) 12 ·26 H 2 O~ 35% Calcite, CaCO 3 (minor quantities of aragonite) ~ 15%Calcite, CaCO 3 (minor quantities of aragonite) ~ 15% Gypsum, CaSO 4.2H 2 O ~ 5%Gypsum, CaSO 4.2H 2 O ~ 5% Quartz, SiO 2 ~ 5%Quartz, SiO 2 ~ 5% Amorphous Phases ~ 40%Amorphous Phases ~ 40% Ettringite Calcium sulfoaluminate is found in all Portland cement concretes and is commonly referenced in petrographic reports. Calcium sulfate sources i.e., gypsum, are added to Portland cement to prevent rapid setting and improve strength development. Sulfate is also present in supplementary cementitious materials and admixtures. All sulfate compounds react with calcium aluminate to form Ettringite within the first few hours after mixing with water. All sulfur is consumed to form Ettringite within 24 hours.

51 The Millennium Plug Project In Portland Cement: Plates of calcium hydroxide and Needles of etteringite (CaO) 6 (Al 2 O 3 )(SO 3 ) 3 ·32H 2 O Crystalline etteringite Ca 6 Al 2 (SO 4 ) 3 (OH) 12 ·26 H 2 O (Ca(OH) 2 ) 6 (Al 2 O 3 )(SO 3 ) 3 ·26 H 2 O

52 The Millennium Plug Project BC SWEP Test Link BC SWEP Test BRITISH COLUMBIA SPECIAL WASTE EXTRACTION PROCEDURE BC Waste Management Act LEACHATE EXTRACTION PROCEDURE USING ACETIC ACID (pH 5.0) Effluent toxicity testing - 100% survival of Rainbow Trout in 100% conc. effluent.

53 The Millennium Plug Project Sludge Disposal Sludge disposed in Jane Basin – cost = ~$40/tonneSludge disposed in Jane Basin – cost = ~$40/tonne Temporary holding site at 4100 LevelTemporary holding site at 4100 Level Campaign trucking to Jane Basin in summer monthsCampaign trucking to Jane Basin in summer months Future optionsFuture options Manufacture building cladding using sludge and pumiceManufacture building cladding using sludge and pumice Pumice is mined at Mt. Meager and crushed at SquamishPumice is mined at Mt. Meager and crushed at Squamish Can use low-temperature process with organic resinsCan use low-temperature process with organic resins Can use high-temperature process to harden into a ceramicCan use high-temperature process to harden into a ceramic Examine opportunities to recover Cu and ZnExamine opportunities to recover Cu and Zn From the effluent prior to HDSFrom the effluent prior to HDS From the sludge by leachingFrom the sludge by leaching

54 The Millennium Plug Project Pumice rock – extremely light

55 The Millennium Plug Project Brick Veneer Cladding - examples NRC Process Evaluation - Canyon Stone -

56 The Millennium Plug Project What is ARD and how do we deal with it? Impact first reported in 1556 by Agricola in De Re MetallicaImpact first reported in 1556 by Agricola in De Re Metallica Yet the term Acid Rock Drainage wasn’t coined until 1970Yet the term Acid Rock Drainage wasn’t coined until 1970 Significant work by NRCan (MEND Program) and Canadian companies developed innovative techniques to handle this ubiquitous problemSignificant work by NRCan (MEND Program) and Canadian companies developed innovative techniques to handle this ubiquitous problem ARD requires sulphides, water, and air (and bacteria)ARD requires sulphides, water, and air (and bacteria) Minerals are the source of sulphur and ironMinerals are the source of sulphur and iron Air is the source of oxygenAir is the source of oxygen Water is the transfer medium for oxygen from air to rockWater is the transfer medium for oxygen from air to rock Bacteria catalyze the reaction of Fe +2 to Fe +3Bacteria catalyze the reaction of Fe +2 to Fe +3

57 The Millennium Plug Project How long does ARD last? ROCK

58 The Millennium Plug Project How long does ARD last? Rio Tinto in Spain – 2 millennium after mining Corta Atalaya, Rio Tinto, Spain - abandoned pyritic open pit - Forever!

59 The Millennium Plug Project Is it only Mining that causes ARD? Blood Falls at Taylor Glacier, Antarctica

60 The Millennium Plug Project Acid Rock Drainage – Metal Leaching ARDARD – Formed by atmospheric oxidation (i.e., by water, oxygen, and carbon dioxide) of common iron-sulphur minerals pyrite and pyrrhotite in presence of bacteria Thiobacillus ferrooxidans, T. acidophilus, and T. thiooxidans MLML – Acid (H 2 SO 4 ) leads to dissolution of metals and subsequent pollution of aquatic environments

61 The Millennium Plug Project Basic Chemistry of ARD (from FeS 2 ) Basic Chemistry of ARD (from FeS 2 ) Basic Issues behind the Chemistry: -Equilibrium of Ferrous-Ferric Ions -Presence of Bacteria (Thiobacillus ferrooxidans) -Must have an initial source of oxygen (i.e., air) -Must have a way to transfer electrons (i.e., water)

62 The Millennium Plug Project ARD Reactions Ferrous Sulphate formed by Abiotic Oxidation: 2FeS 2 + 2H 2 O + 7O 2 = 2FeSO 4 + 2H 2 SO 4 Bacterial Oxidation of Ferrous Sulphate (T. ferrooxidans): 4FeSO 4 + O 2 + 2H 2 SO 4 = 2Fe 2 (SO 4 ) 3 + 2H 2 O Ferric Sulphate is Reduced and Pyrite Oxidized by these Reactions: Fe 2 (SO 4 ) 3 + FeS 2 = 3FeSO 4 + 2S 2S + 6Fe 2 (SO 4 ) 3 + 8H 2 O = 12FeSO 4 + 8H 2 SO 4 Elemental Sulphur Oxidation (T. thiooxidans): 2S + 3O 2 + 2H 2 O = 2H 2 SO 4 Acid dissolves metals into solution meaning ARD is virtually always accompanied by high metal levels discharged into the environment.

63 The Millennium Plug Project Bacteria are essential Thiobacilli from bacterial generator (no flagella)- left (x 5,000) - centre (x 20,000) Thiobacilli grown on ferrous iron (flagella) - right (x 5,000) Formation of Bio-films can lead to long delay in onset of ARD (7-10 years) from Le Roux, N.W., et al., Bacterial Oxidation of Pyrite, Proc. 10th International Mineral Processing Congress, Institution of Mining and Metallurgy, London, )

64 The Millennium Plug Project Metal Leaching – Influence of ORP (Eh or REDOX) Garrels, R.M. and Christ, C.L. (1965), Solutions, Minerals and Equilibria, Harper & Row, New York, Malouf, E.E. and Prater, J.D. (1961), Role of Bacteria in the Alteration of Sulphide, J. Metals, NY, 13, p

65 The Millennium Plug Project Control of ARD Removal of essential component (sulfide, air, or water): 1. Waste Segregation and Blending – Blend-in neutralizing potential (NP) rock to yield pH Base additives – Add limestone to buffer acid reactions 3. Covers and caps – Water covers are the most effective 4. Soil, clay, and synthetic covers (geomembranes) – minimize water and air infiltration

66 The Millennium Plug Project Control of ARD Removal of essential component (sulfide, air, or water): 5. Bactericides – Chemicals that reduce bacteria (T. ferrooxidans) – Effective in the short term, but costly 6.Collection and treatment of contaminants Active or Passive treatmentActive or Passive treatment – Active treatment - high-density lime sludge – Passive treatment in constructed wetlands 7.Bioremediation (micro-organisms) – Remove metals directly – Introduce viruses against the bacteria

67 The Millennium Plug Project Factors affecting Soil Cover Performance International Network for Acid Prevention, Evaluation of Long-term Performance of Dry Cover Systems, Final Report. O’Kane Consultants Inc., (Eds.), Report No

68 The Millennium Plug Project Geomembranes Geomembranes 1.Plastics (polyethylene (PE) 2.High density poly. (HDPE) 3.Chlorinated poly. (CPE) 4.Chloro-sulphonated poly. (DuPont HYPALON) 5.polyvinyl chloride (PVC) 6.Low-density poly. (LLDPE) 7.Geosynthetic clay liners (GCL) 8.Geomembranes impregnated with bitumen After Meer, S.R. and C.H. Benson, Hydraulic conductivity of geosynthetic clay liners exhumed from landfill final covers. J. Geotech. and Geoenviron. Eng., 133(5):

69 The Millennium Plug Project Passive Treatment Technologies NameDescriptionFunctionSelected References Aerobic wetlands Shallow wetlands Emergent vegetation Fe and Mn oxidation, Co-precipitation of metals Sorption on Biomass Eger and Wagner, 2003 USDA and EPA, 2000 Open limestone channels Acidic water flows over limestone, or other alkali Alkalinity addition Al, Fe, Mn oxide precipitation Ziemkewicz et al., 1997 Anoxic limestone drains Water flows through limestone channel under anoxic conditions Alkali addition; Fe Precipitation; Limestone Armouring Prevention Watzlaf et al., 2000 Anaerobic wetlands Subsurface wetland, isolated from air by water or material Alkali addition; Sulphate Reduction Precipitation of metal sulfides; Sorption on Vegetation Brenner, 2001 USDA and EPA, 2000 Successive Alkalinity Producing Systems Vertical flow systems drain through limestone layers & anaerobic organic matter Alkalinity addition; Sulphate Reduction Metal Precipitation Kepler and McCleary,1994 Zipper and Jage, 2001 Sulfate-Reducing Bioreactors Collected water in anoxic chamber containing organic matter and SRBs Alkalinity addition; Sulphate Reduction Metal Precipitation Gusek, 2002 Permeable Reactive Barriers Intercepted groundwater flows through permeable barrier containing reactive material Alkalinity addition; Sulphate reduction Metal Precipitation and Sorption Benner et al., 1997 US DOE, 1998 Amendments Materials added to ARD sources or holding areas Alkalinity addition; Sulfate Reduction and Metal Precipitation; Sorption; Chelation; Revegetation Chaney et al., 2000

70 The Millennium Plug Project S o Reduction Process Schematic BioteQ After R.W. Lawrence, BioteQ H2SH2S Nutrients BIOREACTOR (S o Reduction) Sulphur Electron donor Cu Precip Zn Precip CuSZnS Treated Water Contaminated Drainage Metals, SO 4 Soda Ash or Lime

71 The Millennium Plug Project SRB Plant – Major Equipment BioteQ After R.W. Lawrence, BioteQ Copper ProductZinc Product ARD Bioreactor S o e - donor Lamellar Clarifier Filter Press Gas-Liquid Contactor To Lime Plant or Discharge

72 The Millennium Plug Project SRB Plant Layout: ~360m 2 BioteQ After R.W. Lawrence, BioteQ GAS-LIQUID CONTACTOR BIOREACTOR 1.8 m LAMELLA CLARIFIER (projected settling area 150 m 2 ) 5.9 m 3.1 m LAMELLA CLARIFIER (projected settling area 150 m 2 ) GAS-LIQUID CONTACTOR 2.4 m FILTER-PRESSES 0.8 m x 3 m W x L REAGENT PREP AREA Cu -CONC STORAGE 8 m MCC REAGENT STORAGE TRUCK DOOR Zn -CONC STORAGE 7 m BLOWERS SCRUBBER

73 The Millennium Plug Project Production Summary Flow Cu Concentrate Zn Concentrate Feed Water Discharge Water [mg/L] 18.0 Cu, 20.0 Zn, 0.1 Cd [mg/L] 0.05 Cu, 0.01 Zn, Cd tonnes per year contained copper tonnes per year contained zinc 51.1% Cu, 2.1% Zn, 0.24% Fe, 33.1% S 52.4% Zn, 1.5% Cu, 0.3% Cd, 0.8% Fe, 27.1% S 14,880 m 3 /d – average over 12 months Sludge Reduction tonnes per year (15-20%) Lime Savings $64,000 per year (32%) Additional Benefits

74 The Millennium Plug Project Commercial Scale Plants

75 The Millennium Plug Project Basic Reaction Chemistry of SRB Processing of ARD for Metal Recovery Sulphate reduced by organic compounds: SO 4 = + CH 3 COOH + 2 H + = HS HCO H + 1. SO 4 = + CH 3 COOH + 2 H + = HS HCO H + 1. Sulphide ions precipitate metal sulphides: HS - + M 2+ = MS↓ + H + 2. HS - + M 2+ = MS↓ + H + 2. S = + M 2+ → MS↓3. S = + M 2+ → MS↓3. Equilibrium of H 2 S H 2 S (g) = H 2 S (s) = HS - + H + = S = + 2H + 4. H 2 S (g) = H 2 S (s) = HS - + H + = S = + 2H

76 The Millennium Plug Project Some Links on Acid Rock Drainage Natural ARD Natural ARD Introduction to ARD – Chris Mills Introduction to ARD – Chris Mills Global ARD Guidelines – INAP Global ARD Guidelines – INAP Mine Effluent Neutral Drainage Program - NRCan Mine Effluent Neutral Drainage Program - NRCan

77 The Millennium Plug Project The Stawamus Chief - Squamish


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