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Water and Wastewater: Challenges & Opportunities in the Mining Industry


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By 2014, mine operators around the world will be investing more than US$13-billion in water-related infrastructure, according to Global Water Intelligence. AECOM’s Till Freihammer examines what this means for the industry in terms of emerging opportunities and challenges. The presentation was first delivered at the 2nd Annual Water Management for Mining Summit in Toronto, Canada, on May 10, 2013.

Published in: Technology, Business

Water and Wastewater: Challenges & Opportunities in the Mining Industry

  1. 1. Till Freihammer
  2. 2. AECOM overview– A global leader• Professional Technical and Management Support Services• Key end markets: Energy; Environment; Facilities; Government; andTransportation– Broad range of services, including:• Architectural Planning/Consulting and Engineering Design• Asset/Facilities Management• Design-Construct/Public-Private Partnerships• Environmental Health and Safety• Government Support• Management Support• Program, Cost and Construction Management• Specialist Consultancy• Transportation Planning– Approximately 45,000 employees operating in more than 140 countries– US$8.2 billion of revenue during the 12 months ended March 31, 2013– Currently No. 322 on the Fortune 500 list– Ranked by Ethisphere as one of the world’s 110 most ethical companies– Recognized by the U.S. Chamber of Commerce’s Business Civic LeadershipCenter as honoree for Best Corporate Stewardship
  3. 3. Presentation OutlineTreating Mine Wastewater– Global perspective• Water infrastructure as a global business• Water management– Mine water and wastewater• Minerals reserves and production• Water use and water risks• Water treatment regulations for the mine industry• Treatment technologies– Case studies• Examples of mine wastewater projects
  4. 4. Mine Wastewater — Global Perspective– Water is essential for mining operations• Mining — dust suppression, cleaning equipment, etc.• Processing — wet grinding, washing, flotation, leaching, etc.• Transportation — pumping tailings and products• Utilities — cooling water, pollution control, etc.– Water is impacted by mining operations• Acid rock drainage from mine waste• Residual chemicals in mine waste• Tailings management• Diversion of streams• Significant water use
  5. 5. Mine Wastewater — Global PerspectiveIncreasing importance of water infrastructure for themining industry– New mines being developed in arid regions– Lower grade ores mean increased waterdemand for processing– Higher standards for mining wastewatereffluent– Increased environmental liability in mineclosures– Recognition that water is a scarce resource– Corporate Social Responsibility
  6. 6. Mine Wastewater — Global PerspectiveWater Balance in a Typical MineWaterChemicals andReagentsRaw Mineral Ores Refined MineralProductWaste MineralProductEffluent WaterWater Losses:EvaporationDrainagePrecipitationTheMiningProcessGlobal Water Intelligence . (2011) Water for mining: opportunities in scarcityand environmental regulation.
  7. 7. Mine Wastewater — Global Perspective– Water infrastructure for the mining industry is amajor global business– Key mining locations: Australia, Canada, Peru,Chile, Brazil, U.S.A., South Africa, Russia,China and others– Global mining-related water infrastructureexpenditure in 2011 estimated at US$7.74billionGlobal Water Intelligence . (2011) Water for mining: opportunities in scarcityand environmental regulation.
  8. 8. Mining SectorKey Locations in North America
  9. 9. Mine Wastewater — Global Perspective– Generally, mining industry is cyclical, depending on commodity prices– Currently, mining industry is growing rapidly but …
  10. 10. Mine Wastewater — Global PerspectiveWater Management Challenges & Opportunities– Alternative Water Supplies — Increasing potential due to decreasing waterresources. Desalination technology has strong potential– Water Reuse — Increasing potential due to water scarcity and tougherregulatory climate; mill internal recycling of process water– Metal Recovery from Mine Waste — Increasing potential due to highcommodity prices and lower ore grades– Effluent Treatment — Higher environmental standards mean greaterinvestment in effluent treatment and remediation projects– Brine Management (RO plants) — Salt disposal is becoming a concern interms of stricter regulations and disposal cost– Acid Mine Drainage — treatment
  11. 11. Selected Metals — Reserves and ProductionMetallicMineral/MetalTop 3 Reserves – in Mt Top 3 Producers – in MtIron Ore Brazil: 16000 (Fe-content)Australia: 15000 (Fe content)Russia: 14000 (Fe content)China: 900Australia: 420Brazil : 370Zinc Australia: 53China:42Peru: 23China:3.5Peru: 1.52Australia: 1.45Copper Chili:150Peru: 90Australia: 80Chili:5.52Peru: 1.285China: 1.15Nickel Australia: 24Botswana:8.7New Caledonia: 7.1Russia: 0.265Indonesia:0.232Philippines: 0.156Gold Australia: 7300 tonsSouth Africa :6000 tonsRussia: 5000 tonsChina:345 tonsAustralia: 255 tonsUnited States: 230 tonsGlobal Water Intelligence . (2011) Water for mining: opportunities in scarcityand environmental regulation.
  12. 12. Key Water Supply Risks– Security of water supply and management is an increasingly importantinvestment factor for the mining industry– Estimated global water withdrawal for mining is 7 to 9 km3/a (GWI 2011)• Compare to annual national freshwater withdrawal in Canada of 42 km3/aor Germany of 47 km3/aRisk ConsiderationsWater scarcity Mine requirements compete with other water usersManagement of excess water Flooding and subsequent damagePoor management of water quality Tailings, environmental degradationInefficient water use Increased withdrawal rates, cost impacts
  13. 13. Mine WastewaterRegulations and Guidelines– Regulations regarding the withdrawal and use of water– Regulations regarding the discharge of wastewater and monitoring of waterquality– Regional and National regulations– International Frameworks• International Mine Water Association — 1979 (• International Network for Acid Prevention (• International Council on Mining and Metals — 2001 (• Global Water Initiative — (
  14. 14. Mine WastewaterTreatment TechnologiesCategory Examples ApplicationNeutralization lime or limestone addition acid rock drainagePassive treatment wetland systems polishingMetals removal sulfide precipitation, biological filters, fluidizedbed reactormetal recovery - saleableproductMetals removal hydroxide precipitation (HDS process),coagulation-flocculation, clarificationmetal removal; arsenic removalMembranes microfiltration, ion exchange, reverse osmosis water reuse; metals removalBiological treatment Fixed film or suspended Nitrogen removal, seleniumremoval, bioleachingEvaporators andconcentratorsbrine concentrators, crystallizers zero liquid dischargeDewatering clarifiers, dissolved air flotation volume reduction of tailingsFiltration andthickeningpressure filters, paste thickeners volume reduction of tailingsCyanide treatment alkaline chlorination,hydrogen peroxide processgold mine effluent
  15. 15. Treating Mine WastewaterCase 1: Mine Dewatering SystemBackground– Copper — nickel mineoperated from late 1960s toearly 1980s– Mine shut down due tomarket conditions– Mine pits and mine shaftflooded to surface– Plan to re-open mine —currently in the advancedexploration phase
  16. 16. Treating Mine WastewaterCase 1: Mine Dewatering SystemScope of Work– Assess existing surface and groundwaterquality– Develop a mine dewatering and treatmentstrategy, including• Design dewatering system — 30,000m3/day• Design water treatment system to removeelevated metal concentrations to meetdischarge limits of receiving waterenvironment• Develop preliminary cost estimates andschedule– Develop implementation plan
  17. 17. Wastewater Treatment StrategyHigh rate clarificationCoagulationFlocculationSedimentationpolymerMetals precipitationRaw water fromdewateringsystemFerricSulfateLimeTreating Mine WastewaterCase 1: Mine Dewatering SystempH adjustmentSulfuricacidresidualsdisposalSludgerecirculation
  18. 18. Treating Mine WastewaterCase 1: Mine Dewatering SystemChallenges– Site works — there is little existing infrastructure at the site (electrical,structural, etc.)– Temporary design — all equipment and infrastructure designed to be easilyremovable when they are no longer needed– Unknown water quality — water quality at lower depths of mine pits and shaftis unknown– Flexible process concept required due to varying flows during dewatering andfuture mine operations– Remote location — limited availability of resources (chemicals, equipmentparts, etc.) and limited availability of trained operators
  19. 19. Treating Mine WastewaterCase 2: Giant Mine Remediation — Yellowknife, NWTBackground– Gold mine started operating in late 1940s, closed in2004.– In 2005, Government of NWT and Canada agreedto remediate and maintain the mine– Arsenic trioxide dust (mine by-product) is storedunderground. Permafrost was supposed to keepstorage areas dry. Permafrost is receding, resultingin groundwater movement and seepage fromstorage areas– Current wastewater treatment system operatesseasonally to treat contaminated water. Effluentcurrently meets MMER
  20. 20. Treating Mine WastewaterCase 2: Giant Mine Remediation — Yellowknife, NWT– Characterize the treated waterquantity and quality– Analyze three treatment options andrecommend a concept for preliminarydesign– Develop/undertake a bench scaletesting program to optimize therecommended treatment system– Complete the preliminary design andcost estimate for the selectedtreatment systemScope of Work — Water Treatment
  21. 21. Treating Mine WastewaterCase 2: Giant Mine Remediation — Yellowknife, NWTWastewater Treatment Plant Design CriteriaParameterAkaitcho Water Quality2009-10 data (mg/L)General Northwest Pond2009-10 data (mg/L)Effluent Limits*(monthly mean)Arsenic 1.99 - 123 17.0 – 40.6 0.50Copper 0.005 – 0.103 0.006 – 0.04 0.30Cyanide <0.005 – 0.028 N/A 1.00Lead <0.0001 – 0.150 0.004 – 0.017 0.20Nickel 0.0006 – 0.198 0.064 – 0.106 0.50Zinc 0.046 – 0.559 0.034 – 0.205 0.50TSS <1.0 – 20.2 <1.0 – 39.2 15.0Ammonia 0.02 – 5.3 0.06 – 0.49 12pH 6.5 – 8.2 6.5 – 8.4 6.0 – 9.5Oil & Grease <1.0 - 10 N/A 5* Note: Effluent Limits are from water license N1L2-0043
  22. 22. Treating Mine WastewaterCase 2: Giant Mine Remediation — Yellowknife, NWTWastewater Treatment Strategy Flow range 17 – 34 l/shigh rate clarificationRemoval of arseniccoagulationflocculationsedimentationpolymersludge disposalsludgesludgethickenerKMnO4Fe2(SO4)3high rate clarificationRemoval of metalscoagulationflocculationsedimentationpolymerCa(OH)2Fe2(SO4)3belt filterpressto sumpto CO2 contacttanks, filters,effluent tanks
  23. 23. Diffusers – treatedwater dischargeWatertreatment plantSurface waterinfiltrationGround water inputYellowknife BayMineTreating Mine WastewaterCase 2: Giant Mine Remediation — Yellowknife, NWTChallenges– Northern climate– Influent water toxicity• Quality fluctuations– Groundwatermanagement– Mine water levelmanagementMine Water – collection – treatment - discharge
  24. 24. Treating Mine WastewaterCase 3: Low-level Radioactive Waste Management FacilityPort Granby, ONBackground– 0.45 million m3 of low level radioactive waste andsoil will be excavated, transported to an approvedlocation, covered with an engineered cap.Contaminated surface water and groundwater willbe treated at a new WWTP– Waste material comprises residues from radiumand uranium refining , contaminated equipmentand other materials– Waste contains radium-226, uranium and arsenic– Legal agreement reached in 2001 betweenmunicipalities and Federal Government for thecleanup and long-term management of this waste
  25. 25. Treating Mine WastewaterCase 3: Low-level Radioactive Waste Management FacilityPort Granby, ONAtomic Energy of Canada Limited.(2011). Presentation on the PortGranby Waste Management ProjectPresentation
  26. 26. Treating Mine WastewaterCase 3: Low-level Radioactive Waste Management FacilityPort Granby, ONWastewater Treatment System Design– Pilot scale testing for water treatment in 2010 to confirm theperformance of treatment systems and determine the designrequirements. Pilot scale tests included:• Membrane bio-reactor (MBR)• Reverse osmosis (RO) treatment– Overall removal rates for arsenic, uranium, radium-226 andnitrate were 98-99%
  27. 27. Treating Mine WastewaterCase 3: Low-level Radioactive Waste Management FacilityPort Granby, ONWastewater Treatment System Design Criteria– Average flow 10,000 to 14,000 m3/month (14 to 19 m3/hr)– Peak flow 25,000 to 35,000 m3/month (35 to 48 m3/hr)– Estimated maximum concentrations of primary contaminants:Water SourceArsenic(mg/L)Uranium(mg/L)Radium-226(Bq/L)Existing WMF 10 9 22Long Term WMF 10 20 75Atomic Energy of Canada Limited. (2011) . Licensing Package4502-508760-LP-001, Rev.1.
  28. 28. Wastewater Treatment and Residuals Management Strategyremoval of metals & radionuclidesnitrification/de-nitrificationcontaminatedwater from allsourcesTreating Mine WastewaterCase 3: Low-level Radioactive Waste Management FacilityPort Granby, ONpH adjustmentremoval of metals & radionuclidesremoval of nitrateequalizationaerationtankmembranetank treatedeffluentcontaminatedsolids to longterm WMFclarifierbrinereactiontankbrine evaporatorbiological treatment (MBR)reverseosmosisdryerthickening/dewatering
  29. 29. Treating Mine WastewaterCase 3: Low-level Radioactive Waste Management FacilityPort Granby, ONChallenges– Challenging residuals management process– Varying inputs — concentrations and flows will vary significantly over thelife of the WWTP due to weather, construction– Relatively unknown water matrix– Flexible process concept required due to varying flows during constructionphase and post-constructionSource: Atomic Energy of Canada Ltd. Presentation on the Port Granby Waste Management ProjectOne Day Public Hearing. Sept. 2011
  30. 30. Treating Mine WastewaterProject Requirements of Mine Industry — Examples:– Accelerated timelines — fast track schedules• Standardized process equipment packages• Pre-fabricated buildings– Bench scale testing programs and pilot testing programs– Design/build– Increased water use efficiency– Minimize foot print– Environmental baseline assessments– Public and native populations consultations
  31. 31. Top Ten Issues for Mining Companies in 2013– Rising energy and equipment costs– Continuing commodity market volatility– Capital project deceleration– Upturn in mergers and acquisitions– Expanding resource nationalism– Raising business standards to combat corruption– Increasing government and community requirements– Addressing Labor issues– Improving safety outcomes– Increasing investments in technologyDeloitte. (2013) Tracking the trends 2013 : The top ten issues mining companiesmay face in the coming year.
  32. 32. Till FreihammerTill Freihammer is a senior process engineer with 15 years of experience in thewater and wastewater sector. He has worked in France, Germany, UnitedKingdom and Canada from operations, process commissioning andtroubleshooting to design, tendering and project delivery. His responsibilitiesinclude selection and validation of process design strategies, cost estimating,and the coordination of multidisciplinary teams. His experience covers a widearea of industrial and municipal water and wastewater processes includingmembrane technology for water and wastewater
  33. 33.