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Recovery of Cyanide From Tailings Using Resins

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This presentation by METS Consulting Metallurgist will look at cyanide recovery, the environmental impacts and treatment processes that have been successfully used worldwide for cyanide removal. It will also look at assessing the hazards of using cyanide and successful implementation of the processes.

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Recovery of Cyanide From Tailings Using Resins

  1. 1. > M i n e r a l P r o c e s s i n g > E n g i n e e r i n g D e s i g n > T r a i n i n g > S p e c i a l i s t S e r v i c e s Mineral Engineering Technical Services PO Box 5778 St Georges Tce WA 6831 P: (+61 8) 9421 9000 F: (+61 8) 9325 8311 ABN 66 009 357 171 W: www.metsengineering.com E: info@metsengineering.com A division of Midas Engineering Group Cyanide Destruction & Recovery From Tailings Including Possible Resin Technology Insights Session Presented by: Peter Steckis, Metallurgical Manager
  2. 2. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE • DISCLAIMER With respect to all the information contained herein, neither Mineral Engineering Technical Services, nor any officer, servant, employee, agent or consultant thereof make any representations or give any warranties, expressed or implied, as to the accuracy, reliability or completeness of the information contained herein, including but not limited to opinions, information or advice which may be provided to users of the document. No responsibility is accepted to users of this document for any consequence of relying on the contents hereof. • COPYRIGHT © Passing of this document to a third party, duplication or re-use of this document, in whole or part, electronically or otherwise, is not permitted without the expressed written consent of Mineral Engineering Technical Services. • ACKNOWLEDGEMENTS This document is a dynamic record of the knowledge and experience of personnel at Mineral Engineering Technical Services. As such it has been built upon over the years and is a collaborative effort by all those involved. We are thankful for the material supplied by and referenced from various equipment manufacturers, vendors, industry research and project partners.
  3. 3. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE The Group
  4. 4. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Midas Office Locations Noosa- Brisbane- Newcastle- Sydney- Melbourne- Perth-
  5. 5. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Key Attributes • Working globally since 1988 • Dynamic and innovative niche consultancy • Dedicated team providing customised service • Specialist in Mineral Processing & Engineering Projects • Unique solution finder Pragmatic, efficient, complete engineering through quality, personalised & exceptional service delivery
  6. 6. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Introduction • More projects required by law to destroy cyanide in tailings • Minimise exposure to wild life • Cyanide forbidden in some states in the USA • OH&S issues • Environmental issues • Cyanide DETOX • Cyanide recovery • Case studies
  7. 7. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Introduction • Remediation Methods ― Destruction (oxidation) ― Separation (physical, adsorption and complexation) > Non-destructive: use to concentrate and recover cyanide for recycling purpose > Toxicity of cyanide remained  disposal problem • Recovery Methods Complexation Method Physical Methods Acidification/volatilisation, metal addition, flotation and solvent extraction Dilution, membranes, electrowinning and hydrolysis/distillation Oxidation Methods Adsorption Methods Biological, catalytic, electrolytic, chemical and photolytic methods Minerals, activated carbons and resins adsorb cyanide from the solution. Various contact vessels can be used, ie: elutriation columns, agitated cells, packed-bed, columns and loops, etc… Afterwards it is screened by flotation or gravity separation
  8. 8. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Toxicity of Cyanide Table 1: The toxicity of poisons derived from plants and animals compared with sodium cyanide (adapted from Mann, 1992) Poison Lethal dose (µg/kg bodyweight for the mouse) Botulinus toxin 0.03 Tetanus 0.07 Cobra neurotoxin 0.30 Strychnine 500 Sodium cyanide 10 000 Table 2: The toxicity of industrial poisonous gases compared with hydrogen cyanide (adapted from Richardson, 1992) Poisonous Gas Threshold Limit Value (ppm) Short-term Limit (ppm) Carbon monoxide 25 300 Chlorine 0.5 1 Hydrogen cyanide 5 10 Hydrogen sulphide 10 10 Nitrogen dioxide 3 5 Sulphur dioxide 2 5
  9. 9. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Historical Spill Incident Since 1995 Aug 95 Guyana 3.2 billion litres of tailings into a river system Dec 00 Guyana Further spill into same river Jan 00 Romania 130,000m3 of tailings into river systems Jun 01 PNG Cyanide spill into ocean Oct 01 Ghana 2 spills, 1 mine wastewater, 1 cyanide Nov 01 China Liquid NaCN spill into a river May/Jun 02 USA 24,000/40,000 gallon spills of cyanide solution Jan 03 Western Honduras Massive spill into river Jan 03 Nicaragua Cyanide solution spill into river Mar 04 Romania Contaminated water spill into river ~10 tonnes Jun 04 China 7 lethal releases of chemicals Oct 04 Australia Report of mine tailings leaking into groundwater at Kalgoorlie Jun 05 Laos Cyanide spill into river Oct 05 Philippines 2 spills of process treatment water Jun 06 Ghana Spill into river Dec 06 Alaska Cyanide found leaking into ground from tailings
  10. 10. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Cyanide Form Free cyanide Simple cyanide Complex cyanide WAD cyanide SAD cyanide Includes the cyanide ion and hydrogen cyanide A salt which dissociated to form a cyanide ion Dissociates to form another cyanide compound Weak acid dissociable, cyanide that is readily released from cyanide containing compounds when the pH is lowered Strong acid dissociable, cyanide that is released from cyanide containing compounds under highly acidic conditions CN- + HCN NaCN Au(CN)2 Cd(CN)2 Co(CN)6 4-
  11. 11. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Process Selection Criteria • Recovery is favoured over destruction with high cyanide consuming ores • Each project is unique with respect to species in the tailings • Environmental regulations vary with respect to allowable concentration limits in the treated tailings • There is a large choice of different cyanide destruction methods • The cost and efficiency of each method varies • Legislation varies from country to country
  12. 12. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Cost Effectiveness • The cost of destroying cyanide can be a significant percentage of total operating costs, and unlike other costs it generates no income. It is therefore important, for both regulatory and economic reasons, to select the correct process ― The cost for cyanide destruction, particularly for sodium metabisulfsulfite. E.g. in the INCO process, it can be a large cost, as high as $A0.50 to $2.00/tonne of tailings treated plus the new cyanide cost of approximately $1.50/tonne ― On the other hand the cost of recovering cyanide can be as low as $0.50/tonne of tailings when copper credits are added back • The CAPEX cost is a serious consideration when cyanide recovery is involved compared to cyanide destruction. The AVR or SART processes treat solution tailings rather than pulp and therefore the CAPEX cost of solid liquid separation has to be added • Recycled cyanide is much cheaper than new cyanide and also has the advantage of less environmental risk. Less new cyanide is required so there are less transport, storage and handling issues
  13. 13. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE DETOX Alternatives • Natural attenuation/degradation • Alkaline chlorination • INCO/SO2 and air • Hydrogen peroxide • Ferrous sulphate • Caros acid • Ozonation • Electrolytic oxidation • Bio degradation
  14. 14. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Natural Attenduation/Degradation • Mainly related to the volatilisation of HCN from TSFs • No reagents required, the final product is usually HCN Table showing the efficiency of cyanide removal in tailing impoundments by natural degradation Mine CN entering the tailings system (mg.L-1) CN discharging from the tailings system (mg.L-1) Lupin, NWT, Canada 184 0.17 Holt McDermott, Ontario, Canada 74.8 0.02 Cannon, Washington, USA 284 <0.05 Ridgeway, Couth Carolina, USA 480 0.09 Golden Cross, New Zealand 6.8 (WAD CN) 0.33 (WAD CN) Kurara 120 0.5 Gabanintha 250 120
  15. 15. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Advantages and Disadvantages of Alkaline Chlorination • Advantages ― Well established process ― Produce low residual effluent of free cyanide and WAD cyanide ― Process can be adapted to continuous or batch operation ― Process can be employed for treating pulp ― Cyanate and ammonia can be removed through breakpoint chlorination • Disadvantages ― Not suitable for treating high levels of cyanide • Increase in reagent costs ― Close control of pH to avoid release of cyanogen chloride gas (CNCl) (harmful if inhaled) ― Inefficient for removal of iron complexed cyanides in particular under ambient conditions ― Requires further treatment for removal of free chlorine and chloramines prior to discharge ― May produce high concentration of cyanate that can potentially increase the ammonia concentration
  16. 16. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Oxidation Method – INCO/SO2 Process • Involves the mixing of sulphur dioxide and air with free cyanide, metal- complexed cyanide, thiocyanate to produce cyanate (can also use SMBS) • Reaction can be catalysed with cupric or nickel cations (Copper Sulphate) • Ineffective for reactive sulphide ores • Can potentially lead to the production of by-products such as sludge and gypsum • Been incorporated in mining operations in Canada and U.S. since 1983
  17. 17. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Advantages and Disadvantages of INCO Process • Advantages ― Yields low effluent cyanide and metal concentration ― Effective in treating slurries and solutions ― Suitable for batch or continuous operations ― Capital and operating costs are comparable to other chemical treatments • Disadvantages ― Not suitable for treating high levels of cyanide • increase in reagent costs and high power consumption due to air requirements ― May generate high levels of sulfate in the treated solution ― Additional treatment may be required to remove iron cyanide, thiocyanate, cyanate, ammonia, nitrate and/or metal before discharged to the environment
  18. 18. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Detoxification of cyanide by hydrogen peroxide in gold mines Hydrogen Peroxide (H2O2) Process Before treatment (mg/L) After treatment (mg/L) Total cyanide WAD cyanide Cu Fe Total cyanide WAD cyanide Cu Fe Case study #1 Pond Overflow (1) 19 19 20 <0.1 0.7 0.7 0.4 <0.1 Case study #2 Barren Bleed (2) 1,350 850 478 178 <5 <1 <5 <2 Case study #3 Heap Leach Solution (3) 353 322 102 11 0.36 0.36 0.4 (4) <0.1 (Source: Griffiths, 1989) Notes: 1) Preliminary plant results from pre-operational test runs 2) Typical results during first six months of operation 3) Average of 25 measurements made over ten days of plant operation 4) Value dropped from 1.0 to 0.4 over four days due to coagulation and settling
  19. 19. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Advantages and Disadvantages of Hydrogen Peroxide Process • Advantages ― Process is simple in design and operation ― By combining oxidation and precipitation, it is efficient for removal of all forms of cyanide ― Adaptable to batch or continuous operations ― Does not require close pH control ― Produces low quantities of waste sludge ― Effective during bench, pilot and full-scale operation • Disadvantages ― High reagents costs ― May produce high concentration of cyanate that can potentially increase the ammonia concentration ― Does not remove ammonia or thiocyanate ― Not suitable for treating tailings slurries ― May require addition treatment processes
  20. 20. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Metal Sulphates • Common metals used  iron, zinc, aluminium, copper • Commercial application  Prussian blue precipitation (precipitation of Fe4[Fe(CN)6]3 on the addition of FeSO4) – unstable in alkaline solutions • Applicable to SAD cyanide complexes, thiocyanate has a limited response • Not a stand-alone process Prussian blue precipitate (Source: Technische Universitat Kaiserslautern website, 2013)
  21. 21. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Caro’s Acid • Peroxymonosulfuric acid (H2SO5), also known as Caro’s acid, is a reagent used in a recently developed cyanide treatment process that has found application at some sites H2SO5 + CN- → OCN- + SO4 2- + 2H+ • Caro’s acid used in the process must be produced on-site using sulfuric acid and hydrogen peroxide - Caro’s acid decomposes very quickly • Caro’s acid is used in slurry treatment applications - • The addition of a copper catalyst is not required • Typically used in situations where the sulfur dioxide and air process is not suited. • The retro fitting of cyanide destruction into older operations where tankage is not in place • In solution applications, other destruction processes, such as the hydrogen peroxide process are preferred
  22. 22. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Ozonation • Treatment of cyanide bearing wastewater has been carried out using ozone • Advantages of ozone oxidation include: ― Extremely effective against all free and complexed cyanides ― Used alone or in combination with UV light ― Does not form any undesirable by-products such a chlorinated organics or ammonia ― Does not require the purchase, storage or handling of dangerous chemicals on site ― Ozone is produced on site from air using an ozone generator The reaction with ozone does not require high temperatures or pressures
  23. 23. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Electrowinning • Applicable to SAD and WAD cyanides but not thiocyanate • Low efficiency, however progress is continuing to make it economically viable • Has been applied at CELEC regeneration system or high surface area (HAS) reactor IonnetTM heavy metal separating system - electrowinning (Source: Allied Plating Supplies website, 2013) (Source: Precious Metals Processing Consultants website, 2013)
  24. 24. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Oxidation Method – Bio-Oxidation • Converting cyanide into cyanate (a less toxic species) by means of bacteria, fungi, algae, yeasts and plants, enzymes and amino acid followed by hydrolysis to ammonium and bicarbonate ion • Final products depends on biomass used, cyanide species, initial cyanide concentration, pH and temperature Rotating biological contactor plant for the removal of cyanide and thiocyanate at the Homestake Mine
  25. 25. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Cyanide Recovery Alternatives • Water recovery • AVR • SART • Resin technology
  26. 26. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Water Recovery • Cyanide can effectively be recovered and re-used by recycling cyanide-containing solutions within a metallurgical circuit • This is commonly conducted using tailings thickeners or tailings filters to separate solution from tailings solids, with the solution being recycled in the grinding and leaching circuits • Can be determined by a simple mass balance calculation including the improved economics. • In the dry Australian climate water recovery is favoured because water is often scarce
  27. 27. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Acidification/Volatilisation/Recovery • Reaction is favoured at low pH, typically the process is operated at pH between 1.5 and 2 • Also known as Mills-Crowe process • New development  CyanisorbTM process • Disadvantage  consumes high amounts of acid and alkaline • Advantage  low energy consumption and increased volatilisation rate compared to hydrolysis/distillation process • Effective for WADs and to a lesser extent for thiocyanate and SADs CyanisorbTM process (Source: Around of Mining and Metallurgy Blog, 2008)
  28. 28. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE CYANISORB® • The CYANISORB® process consists of four operations: ― Converting cyanide and metal-cyanide complexes to HCN ― Stripping HCN from tailings in a packed tower ― Recovering HCN gas into an alkaline solution ― Adjusting the pH of the detoxified tailings
  29. 29. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE CYANISORB® Plant Design The Golden Cross plant is currently operating with an average recovery of tailings WAD cyanide of 80–90% Tailings Slurry Acidification Stage Stripping Stage Recycle Scrubbed air Absorption Stage 10% H2SO4 Tailings Re-neutralisation Stage Lime Disposal Circulating NaOH Fresh NaOH NaOH/NaCN Air/HCN pH Control
  30. 30. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Benefits • Metallurgical Benefits ― Reduced sodium cyanide costs ― Less cyanide purchases required and lower transport and handling costs ― Possibility of higher NaCN addition rates when required without NaCN loss with the tailings • Tailings Treatment - Economic Benefits ― Reduced exposure to NaCN price increases ― Tailings detoxification costs are reduced ― Cyanide recycling provides an approximately zero nett tailings detoxification cost
  31. 31. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE SART (Sulfidisation, Acidification, Recycle and Thickening) Process • Alternative recovery route for high grade cyanide soluble copper slurries ― Cu and CN are recoverable ― Comparatively low OPEX and CAPEX costs ― Bench scale testwork, pilot plant trials and feasibility study for the Telfer Gold Mine (WA, Australia) ― Site personnel verify the route is effective and economical • Sulfidisation, Acidification 2Na3Cu(CN)4 + 3.5H2SO4 + NaHS  Cu2S + 3.5Na2SO4 + 8HCN • Recycle - Fine Cu2S is recycled as seed to previous step • Thickening 2HCN + Ca(OH)2  Ca(CN)2 + 2H2O
  32. 32. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Adsorption Method • Common adsorbents: – Mineral: > Cyanide is adsorbed via ion exchange or precipitation – Activated carbon: > Packed bed system > Effective for dilute cyanide - in particular for WADs and SADs > Non-selective • Needs to be coupled with screening, gravity separation or flotation • Cyanide is desorbed into a low volume solution
  33. 33. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Adsorption Method • Common adsorbents: – Resins: > Can be selective and capacity depends on the chelating or ion-exchange properties > Predominantly used in packed bed system > More cost effective compared to activated carbon due to high resistant to fouling and fast desorption kinetics > Not effective for thiocyanate
  34. 34. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Advantages and Disadvantages of Resins • Advantages ― Not poisoned by organics – no thermal regeneration ― Unaffected by clay ores ― Do not absorb calcium – reduced acid washing requirements ― Improve recovery in the presence of preg-robbing ores ― High selectivity resins offer advantages with Cu/Au ores ― High loading capacity (100,000 g/t) and faster loading kinetics ― Enhanced abrasion resistance over activated carbon ― Reduced capital costs for small to medium operations • Disadvantages ― Resin particle size – 0.8-1.2 mm – screening more difficult ― Strong base resins less selective for gold over base metals compared to activated carbon ― Resin is approximately ten times more expensive than carbon ($30,000/t) ― Database of experience is limited
  35. 35. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Resins – Case Study • Operations in Environmentally sensitive area − Tailings final product from CCD thickeners − Filtration of tailings using belt filters − Inefficient operation of belt filters when clay levels high • Cyanide increasing as well as some metal losses − Investigated use of Resin in Pulp for metal scavenging and cyanide reduction − Testwork carried out in laboratory in Perth 0 50 100 150 200 250 300 350 400 450 0 4 8 Cyanideconcentration(ppm) Time (h) Cyanide Solution Concentration
  36. 36. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Resins – Case Study • Testwork (IXR) − Tailings final product from recovery testwork − Testwork procedure was developed – Multi contact − Resin in Pulp scenario − A100/2412 (Metals) and A500/2788 (Gold silver and cyanide) resins tested − Bottle roll tests - sequential contact with resin − 12.5 g/L target concentration of resin – Slightly higher for A500/2788 − Cyanide levels in pulp monitored − Assumes that cyanide is loaded onto the resin • Resin stripping − Acidic conditions and HCN generated − Requirement to recover HCN gas in caustic solution • Significant development required − Resin type and selectivity − Stripping of the resin − Recovery of cyanide
  37. 37. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Environmental Issues - Birds & Wildlife Contaminated ducks Bird fatalities Species in danger
  38. 38. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Attempts at Minimizing Bird Fatalities due to Cyanide in Tailings Hazing techniques: − Propane gas gun − Bird whalers − Streamers − Loud music − Netting − Flying kites − Flagging tape − Wine casks − Fishing lines (Source: Magnum Photos website, 2005)
  39. 39. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Minimizing Bird Fatalities Due To Cyanide In Tailings (Source: Bird B Gone Blog, 2012) (Source: Zon Scare Cannons website, 2013)
  40. 40. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE International Cyanide Management Code The Motivation ? • No set regulation for management of cyanide • Numerous spills and other incident involving cyanide solutions International Cyanide Management Code - Use of Cyanide logo Aug 1995 : Omai, Guyana - dam failure May 1998 : Kyrgyz Republic – truck Jan 2000 : Baia Mare, Romania Mar 2000 : Papua New Guinea – helicopter 2002 : Nevada, USA - pipe failures (Source: International Cyanide Management Code website, 2013)
  41. 41. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE International Cyanide Management Code • Established based on the collective efforts from 40 participants: ― Global mining industry ― Cyanide producers ― Non-Governmental Organisations ― Governments ― United Nations Environmental Programme (UNEP) ― International Council on Mining and Metals (ICMM) ― Gold Institute ― World Wildlife Fund for Nature (WWF) ― International Finance Corporation (IFC) ― European Commission (Source: United Nations Environment Programme website, 2013) (Source: World Wildlife Fund for Nature website, 2013)
  42. 42. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Case Studies • Mt Muro • Rapu Rapu • Mina Sertao • Andorinhas
  43. 43. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Na2S2O5 POND SOLUTION STREAM RAW WATER M M M AIR AIR TREATED SOLUTION SPLITTER HOIST MIX TANK SODIUM METABISULPHITE STORAGE TANK METERING PUMPS CYANIDE DESTRUCTION REACTOR TANK 1 CYANIDE DESTRUCTION REACTOR TANK 2 1600 Nm3/h (1000scfm) 1600 Nm3/h (1000scfm) 3200 Nm3/h (2000scfm) AIR BLOWERAIR FILTER SILENCE LIME FEED LIME STORAGE TANK DESIGN OPERATING CONDITIONS Mt Muro INCO Process (Source: METS Image Library 2014)
  44. 44. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Rapu Rapu • Strong anti mining sentiment in the Philippines. NGO’s and church vocal • Super typhoon (one in hundred year event) resulted in tailings dam overflow • Overflow direct to ocean • Fish kill immediate and obvious to local fishermen • Company reacts. Government shuts facility • Project re opened after mitigation steps put in place to ensure cannot happen again (Source: METS Image Library 2014) Mitigation Steps: • Overflow from tailings dam to ponds • Ponds have cyanide destruction facilities • Reed beds after ponds • Cannot flow direct to ocean
  45. 45. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Mina Sertao & Andorhinas (BRAZIL) (Source: METS Image Library 2014)
  46. 46. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE Conclusions • The historical spill incidents such as Baia Mare and Guyana have created an environment where regulators are wary of gold cyanide projects • Either DETOX or cyanide recovery is seen as being responsible and minimising the potential environmental risk • As indicated in the previous discussion, there are over nine cyanide treatment processes that have been successfully used worldwide for cyanide removal at mining operations • The key to successful implementation of these processes is by considering site water and cyanide balances under both average and extreme climatic conditions and the range of cyanide treatment processes available and their ability to be used individually or in combination to achieve treatment objectives • Proper testing, design, construction, maintenance and monitoring of both water management and cyanide management facilities are required • Process selection is not straight forward and each project is unique in finding the best solution. With regards to cost effectiveness the economics have moved to cyanide recovery in preference to destruction • Assessing the hazards of using cyanide should be based on the Australian Risk Assessment Standard. It is in the interests of all gold mining companies adopting the International Cyanide Management Code
  47. 47. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE What did you get out of this presentation? Please share your thoughts in an informal discussion Questions ? Attendee Outcomes
  48. 48. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE References • METS Image Library 2014 • Allied Plating Supplies. 2013. Electrowinning Metal Recovery System . [ONLINE] Available at: http://www.alliedplating.com/store.asp?pid=18509. • A.M King. 2013. INVENTORY# 7J-SL02. [ONLINE] Available at: http://www.amking.com/mining-equipment/milling- equipment/miscellaneous/7j-sl02. • Around of Mining and Metallurgy Blog. 2008. Green from Gold "The Rehabilitation of Golden Cross" . [ONLINE] Available at: http://andiky.blogspot.com.au/2008/11/green-from-gold.html. • Bird B Gone. 2012. Heavy Duty Pond Netting Protects Migrating Birds from Collection Ponds . [ONLINE] Available at: http://birdcontrolblog.com/tag/pond-netting/. • International Cyanide Management Code. 2013. Use of Cyanide Code Logo . [ONLINE] Available at: http://www.cyanidecode.org/become- signatory/use-cyanide-code-logo. • Magnum Photos. 2005. Scarecrow in Tailings Pond . [ONLINE] Available at: https://www.magnumphotos.com/C.aspx?VP3=CMS3&VF=SearchDetailPopupPage&VBID=2K1HZOTQHSHSH&PN=1&IID=2K7O3R10EMS L. • Precious Metals Processing Consultants. 2013. Ionnet™ . [ONLINE] Available at: http://www.preciousmetals-pmpc.com/precious-metal- recovery/. • Technische Universitat Kaiserslautern. 2013. The Micro-Lab Kaiserslautern. [ONLINE] Available at: http://www.chemie.uni- kl.de/fachrichtungen/ac/sitzmann/ML-eng.htm. • Zon Scare Cannons. 2013. ZON LP GAS SCARE CANNONS and ACCESSORIES . [ONLINE] Available at: http://scarecannon.com/. • World Wildlife Fund for Nature. 2013. Australia . [ONLINE] Available at: http://www.wwf.org.au/.
  49. 49. j ENVIRONMENTAL PROCESSING DESIGN & VERIFICATION PRODUCT INNOVATION PROJECT MANAGEMENT OPERATIONS TRAINING SKILLSHIRE THANK YOU www.metsengineering.com

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