Grenvil Marquis Dunn

Principal Engineer

Updated: 11 February 2019

Qualifications

1970 BSc Honours degree in Chemical

Engineering from

University of Cape Town

Professional Affiliations

Pr Eng (RSA)

C Eng (UK)

Fellow of Institution of Chemical Engineers

MSAIMM

Member TMS (AIME)

MSAIChE

Key Skills

Consultancy and plant design
Flowsheet development
Pilot plant testwork campaigns
Provide basic engineering process packages including: process flow diagrams and process instrumentation diagrams, design basis, mass balance, equipment lists, motor lists, operating and capital cost, control, philosophy materials selection

Summary of experience

28 years in operations role in Hydrometallurgy
17 years as Director and consultant for own company Hydromet (Pty) Ltd [South Africa] and 2 years for Hydromet WA (Pty) Ltd [Australia]. Working in Nickel, Cobalt, Copper, Uranium, Gold, Lithium and PGMs
8 years in Project Engineering and Management and Consultancy for two companies: Hatch and SRK
2008 to current - Principal Hydrometallurgist for Orway Mineral Consultants (OMC), concurrent with Hydromet (Pty) Ltd.
1998 to current - Project Engineering, Project Management and Consulting roles for various organizations
1971 to 1992 - Pressure Hydrometallurgical operations in various positions at Impala Platinum Base Metal/Precious Metals Refinery in South Africa. From Shift operator, Plant manager, Project manager and General manager

Key Commodities

Nickel – pressure and atmospheric leaching of concentrates, mattes, and laterite to intermediates and metal
Cobalt and Copper – pressure and atmospheric leaching of concentrates, sulphides, oxides etc to intermediates and metal
Uranium – alkali and acid processes
PGM - recovery and refining
Lithium recovery from Salar brines, and refining

Experience

PGMs

Recovery of high grade PGM from sulfide matte, alloys and phosphides
Pressure Chlorine leaching
Solvent Extraction and Ion exchange of platinum and palladium
Ion exchange of rhodium and ruthenium
Distillation of ruthenium and osmium
Salting processes and salt to metal conversion
Integrated testwork

Nickel

Pressure and atmospheric leaching of concentrates, mattes, ores and sulfides
Impurity removal e.g. arsenic, iron, aluminum, copper, zinc, chromium
Solvent extraction and ion exchange
Hydrogen reduction
Electrowinning
Semi products – hydroxides, sulfides and carbonates
Pilot plant campaigns establishing processes

Cobalt

Pressure and atmospheric leaching of concentrates, mattes, sulfides, oxides (heterogenite, etc.)
Solvent extraction and ion exchange
Hydrogen reduction
Electrowinning
Semi products – hydroxides, sulfides and carbonates
Pilot campaigns

Copper

Pressure and atmospheric leaching of concentrates, mattes, oxides and sulfides
Impurity removal e.g. selenium and tellurium
Solvent extraction electrowinning
Direct electrowinning
Pilot and demonstration plant campaigns

Uranium

Alkali and acid processes
Bench and pilot campaigns, continuous ion exchange, SX and U3O8/UO4 production
Reviews

Selenium and Tellurium

Recovery from sulfide concentrates

Lithium

Recovery from brines

Nickel, Cobalt, Copper, Gold: Project experience – Studies/Reviews/Design

Year	Country	Company	Description
2018	South Africa	Tharisa / Karo	Desk top study options for processing PGM mattes/concentrates/malloys
2018	South Africa	Senet	Design of a sulfurous acid plant for the Kamoto Copper Project in DRC
2018	Australia	RCFM	Due diligence assistance for resource capital funds management. Technical review of Nkamouna project in Cameroon
2018	South Africa	Anglo	Process and mechanical design of Anglo Platinum electrochemically controlled pressure leach for the recovery of copper from a PGM containing matte
2018	Australia	Jolimont	Review of the Glyleach process
2017/2018	Australia	OZM	Ongoing testwork support for removal of radionuclides from copper concentrate employing an electrochemically controlled pressure oxidation leach developed by Hydromet in 2012
2017/2018	Undisclosed	SFA	Review of the Kell Process for SFA
2017/2018	Idaho	Midas	Gold pressure oxidation autoclave design with in-situ arsenic attenuation based on batch and pilot plant testwork managed by Hydromet for Midas Stibnite Gold Project.
2017/2018	Namibia	Celsius	Targeted electrochemically controlled cobalt leach from intergrown cobalt and iron sulfide minerals for Opuwa Cobalt Project
2017	Papua New Guinea	Goldpu	Desktop study (Capex and Opex) and testwork employing Hydromet electrochemically controlled developed Single Stage Leach on Copper concentrate upgrading copper for Wafi Goldpu Project
2015/2016	Turkey	META	Consulting and commissioning of the nickel pressure acid leach plant
2013-2016	Australia	Oz Minerals	Managed a 700 hour pilot and 5 month demonstration plant confirming the process to remove uranium and its daughter radionuclides from a copper-iron-sulfide concentrate. provided basic engineering data to facilitate two levels of study plus FEED 1 for copper concentrate upgrade project
2015	South Africa	Angloplats Rustenburg	Consulting on the installation of a flash thickener recycle facility for exothermic autoclaves
2015	Turkey	MEAB/ META	Study for the recovery of scandium from the HPAL products for nickel cobalt project
2014	Argentina	Peregrine Metals	Managed batch testwork to confirm the hydrometallurgical process to remove arsenic from copper concentrates so that they can be admitted penalty-free to smelters. Conducted trade off study comparing total oxidation+SX+EW with this upgrade process
2014-2016	Mexico	Cuprosa	Managing testwork and conducting the engineering for an electrochemical process to recover copper and arsenic from a Lead-Copper matte
2014/2015	Zimbabwe	Zimplats	Consulting on the design of the nickel-copper-PGM matte refinery at the BMR
2014/2015	Mexico	Chesapeake Gold Corp	Pre feasibility study: Gold/zinc pressure oxidation plant with Zn SX and Zn EW for Metates gold project
2012	Brazil	Anglo American / SNC Minerconsult	Pre feasibility study: HPAL Nickel Laterite (Ore to metal). Lead process engineer on their Jacare project
2011/2012	Tanzania	African Eagle	Study: process consultant, testwork and piloting and basic engineering for their Dutwa Nickel Project
2011-2012	USA	Twin Metals Minnesota/ Antofagasta	Study: recovery of PGM, Ni, Cu and Co from the Duluth sulphide deposits using Platsol and other relevant processes
2011-2012	USA	Essential Metals/ Formation Capital	Implementation: copper cobalt pressure leach with CuSX–EW and cobalt precipitation of MHP with releach to cobalt rounds using CoEW recovery in divided cells. Consultant to client and engineer during detailed engineering and construction phase for their Cobalt Plant Project
2011-2012	USA	Stillwater Mining	Study: base metals and downstream processing of PGM rich concentrates for Nickel Copper Plant
2011	Cameroon	Lycopodium/ OMC	Study: feasibility study for a cobalt and nickel refinery to its intermediate mixed sulphide precipitate for Nkamouna their project
2011	Western Australia	Equinox	Study: scoping study – pressure leach option for treatment of Lumwana copper concentrate employing flash thicken recycle process
2009	Brazil	Vale	Study: process options laterite study for recovery of MHP from laterites and sulphides for Onca Puma Project
2009	Australia	HNC Resources	Study: Alternate nickel and cobalt recovery circuit on their Browns Oxide Project
2008	Australia	Metallica Metals	Study: Consultant to the heap leachate-to-MHP base case. Provided Basic Process Engineering Package to Study Engineer for their Nornico Nickel Laterite Project
2007/2008	DRC	Glencore	Mutanda Mine – Mumi copper/cobalt project. study: Provided basic process engineering package for the feasibility study
2007/2008	Kazakhstan Russia	Oriel Resources	Schevchenko Nickel Laterite Project study: provided Basic Engineering Package for DFS for demonstration plant – consultant to client
2006-2008	DRC	FQM	Kolwezi Musonoi Tailings (KMT) project study: atmospheric leach - copper SX and EW, cobalt to MHP and recovery to metal. Provided PFS Basic Engineering Package for hydrometallurgical plant – tailings to cobalt/copper metal. Process design for leach, sulphur dioxide contacting, reflux, iron removal and cobalt semi product. Detailed design for cobalt refinery
2007	RSA	RSA	Braemore Resources ConRoast Project study: responsible for the development of the BMR recovery process. Directed the base metal and PGM recovery testwork. Provided PFS Basic Engineering Package for the nickel, copper, cobalt recovery circuit treating an alloy to produce a high grade (+65% PGM) concentrate copper by EW and (Ni and Co) to MHP
2006-2007	Zambia	FQM	Kansanshi Copper Project Study: Provided Basic Engineering Package for the copper circuit concentrate POX employing the Flash Thicken Recycle concept to increase the existing autoclave capacity
2007	Australia	Lionore	Avalon Phase 1 Project study: For processing of Honeymoon Well concentrates at the reconfigured Bulong Nickel Plant Kalgoorlie for nickel concentrate pressure leaching in saline waters to produce nickel cathode
2007	DRC	Camec PLC	Luita Copper and Cobalt EW Project study: Provided a process design package for the copper and cobalt electrowinning
2006	USA	Stillwater Mining	Implementation: Detailed Mechanical Design and assist in construction of new alloy autoclave vessel for nickel/copper pressure leach for SMC’s Autoclave Design Project
2006	USA	Augusta Resources	Copper Molybdenum Project study: Provided PFS Basic Engineering Package for copper pressure leach, solvent extraction and electrowinning
2002/2004	Zambia	Avmin	Chambishi Cobalt Recovery Plant Project implementation: Design cobalt recovery plant including iron removal, zinc solvent extraction, cobalt MHP and resolution
2002/2004	Zambia	Avmin	Chambishi Pressure Leach autoclave upgrade project study into explosions with pressure leach autoclave andandand provided a basic engineering package for the autoclave upgrade for safe operations
2002/2003		Murrin Murrin	Anaconda Nickel Project Litigation - mixed sulfides and refinery circuits for nickel and cobalt recovery
2002/2005	Australia	Western Mining Company	Study: Engineering Feasibility Study for MKO pressure leach and concentrate leach of Ni Sulfides. Design cobalt recovery plant including iron removal, zinc solvent extraction, cobalt MHP and resolution
2000/2002	USA	Hatch Consulting Company	For Stillwater Mining Company implementation: Upgrade of the Stillwater Platinum Base Metal Refinery in Montana USA - recovery of nickel and copper from matte and production of high grade PGM concentrate. Commissioned copper pressure leach autoclave
1994/1995	Zimbabwe	SRK	Hartley Base Metal Refinery Implementation: Responsible for the process design producing high grade PGM concentrate, nickel and copper by-products involving atmospheric leaching, pressure oxidation of sulfides with front flash cooling, nickel and copper PLS purification and Electrowinning
1992-2004	RSA	SRK	Lonmin Projects 1992 – 1994 Implementation of: Upgrading and Increasing the capacity of the Base Metal Refinery Autoclaves employing the Front Flash Cooling technique which I pioneered in the mid 80s Increased recovery of nickel in atmospheric leach from 60% to over 85% Modified pressure leach process to reduce PGM dissolution and in a single step to upgrade PGM from ± 0.7% to 65% Improved selenium and tellurium removal step to produce ‘on-spec’ copper. Chlorine Pressure Leach Plant – for Platinum Refinery Ruthenium and recovery circuit with acidic thermosyphon evaporation PGM Solvent Extraction Plant Design and engineering of the doubling of capacity of the BMR POX autoclaves to produce high grade PGM concentrate from smelter matte 2001 - Implementation: Pressure leach plant to recover/remove metalloids (As, Si and Te) from concentrate 2003/2004 - Implementation: 50% capacity upgrade for Lonmin Base Metal Refinery
1989-1992	RSA	Impala Platinum	Overall responsibility for Impala’s Refining Operations i.e. Nickel, Copper and PGM
1986-1988	RSA	Impala Platinum	Impala Refinery Operations Responsible for 5th electric furnace at the Smelter Responsible for all refinery expansion in the Nickel/ Copper Refinery Upgrade of platinum refinery for recovery of base metal and metalloid without co-extraction of PGMs. Design and commissioned the conversion of POX autoclaves from air to oxygen pressure leach Implemented the autoclave flash-cooling technology
1983-1985	RSA	Impala Platinum	Responsible for the nickel and copper refinery operations
1982-1983	RSA	Impala Platinum	Responsible for the design and installation of the cobalt refinery at the nickel copper operation. Recovery of cobalt as a metal powder from the nickel refinery barren liquors
1978-1921	RSA	Impala Platinum	Responsible for day to day operations of metal production and precious metal concentrate upgrade in the nickel copper Refinery
1975-1977	RSA	Impala Platinum	Responsible for commissioning smelter sulfuric acid plant
1973-1975	RSA	Impala Platinum	Nickel Copper Refinery – metallurgical support
1973-1975	RSA	Impala Platinum	Shift operator in the nickel copper refinery

Uranium, Lithium, Scandium, Selenium, Tellurium: Project experience – Studies / Reviews / Design

Year	Country	Company	Description
2018	AOG Greece	MEAB	Eurare Scandium Demonstration Plant Project. Design of a plant for recovery of Scandium from bauxite residue
2015-2018	Jordan	Jordanian Uranium Mining Company (Jumco)	Project Management and design, build, installation and commission a demonstration pilot plant in the Central Jordanian Desert of a uranium ore-to-oxide
2016	Turkey	META	Scandium Project. Design of a demonstration plant for recovery of scandium from nickel laterite leach residues
2013-2017	?	Client – Unspecified	Removal of uranium and other radionuclides from a copper concentrate to satisfy international regulations governing the transport, trade and processing by smelting (TTP) of copper concentrates. The ''clean'' concentrate from this process is upgraded in copper content to the extent that TTP costs are reduced significantly. Managed all testwork programs in 2013, 2014 (Pilot Plant 700 hours) and 2015 (Demonstration Plant 3000 hours). Currently providing front end engineering design.
2013-2015	Jordan	Jumco	Retained as Process Consultant to guide testwork direction in the development of a technically and economically feasible process for recovering uranium in the Central Desert. Design and overseeing build of Demonstration Plant.
2010-2016	Botswana	A-cap Resources	Flowsheet development, Pre-Feasibility Study, Planning Pilot Plant Scope of Work for commencement of DFS. A-Cap Lethlekane Project in Botswana (2010 to current)
2011	Namibia	Marenica Energy Ltd	Technical Steering Committee for technology development
2013	Jordan	IAEA	Consulting for the processing of uranium from the Central Jordan Region
2011-2012	Mauritania/ Guinea	Forte Energy	Uranium Project. Hard primary rock and superficial secondary uranium project development phase providing direction to geometallurgy and hydrometallurgy
2012	Algeria	IAEA	Mission to Algeria. Consulting to Centre de Recherche Nucleaire de Draria (CRND) on uranium recovery and processing from and secondary ores in Tahaggart
2011	USA	Aurora Energy Ltd	Review of client testwork from Hazen Research
2011-2012	Australia	Energy Metals Ltd	Flowsheet development, prefeasibility study and testwork management. Option studies with PLS evaporation for Bigryli Project in NT Australia
2010 to current	Egypt	IAEA	Mission to Egypt. Consulting to Nuclear Materials Authority (NMA) on uranium recovery and processing from primary and secondary ores in Eastern Desert and Sinai Peninsula.
2010	Western Australia	BHP Billiton	Yeelirrie Uranium Project. Review of scoping study
2010/2011	Spain	Berkeley Minera Espana	Salamanca Uranium Project. Process and Metallurgy, Client Support.
2010- 2011	Namibia	Rossing Uranium	Process consultant for Extract Resources. Process development, pilot plant management and basic engineering data provision to the engineer
2009	South Africa	Niger Uranium Studies	Henkries Project. Process consultant – studies, preparations of scope of work for client on African project.
2009	South Africa	Gold Fields	Gold Fields Tailings Project Study: uranium, gold and sulphur recovery from tailings. laboratory work scope, basic process engineering support
2008	Zambia	Equinox	Uranium Project Review. Consultant for Equinox. Provided Basic Engineering Package (PFS) for Ammonia Lime Boil Recovery Circuit.
2008	Central Africa	USA Denison Mines	Mutanga Uranium Project. Study: Ore, Upgrade Leach, CIX to final Uranium oxide product. (+800 hours).
2006-2008	Namibia	Langer Heinrich Uranium	Consultant for Langer Heinrich Uranium. LHU Process audit. Review of vanadium and its deportment in the LHU flowsheet.
2007	Namibia	Metago Environmental Eng	Review current Rossing tails disposal circuit PFS study and report on high density approach (alternate disposal methods)
2001-2003	Namibia	Rossing	Study: Rossing Uranium to install belt filters for the leach solid liquid separations plant upgrade CCD incorporating thickeners and rotoscoops and U3O8 solvent extraction plant

Batch and Pilot Plant Management Experience

Year	Country	Company	Description
2018	Namibia	Celsius Resources	Designed and managed the electrochemically controlled cobalt leach
2017/18	South Africa	Anglo Platinum	Testwork management for a copper-over PGM selective electrochemically controlled leach
2017/2018	USA	Midas Gold	Extensive batch and pilot campaign on a gold pressure oxidative leach employ in-situ arsenic attenuation process
2018	Argentina and Australia	LSC Lithium	Batch testwork in Argentina and batch continuous testing in Australia to confirm an evaporative process to recover lithium from brines and produce a battery grade lithium product (99.98%)
2015	Australia	Confidential Client	Preparing to manage a 6 month demonstration plant campaign for upgrading copper concentrate by removing radionuclides to render the material acceptable for trade, transport and smelting
2015	Canada	OZ Minerals	Designed and managed a 7 month batch and demonstration scale plant employing an electrochemically controlled copper concentrate upgrade process
2014	Australia	Confidential Client	Managed 700 hour pilot plant campaign upgrading a copper concentrate by removing radionuclides to render the material acceptable for trade, transport and smelting
2010- 2011	Namibia	Extract Resources	Rossing South Project. Managed two pilot plant campaigns of 1200 hours duration
2010/ 2011	Australia	SGS	Pilot plant uranium – ore to oxide pilot plant at SGS (800 + 400 hours)
2009	Australia	SGS	Mutanga pilot plant at SGS for uranium (800 hours)
2008	Zambia	Denison Mines	Mutanga Uranium Project ore, upgrade leach, CIX to final uranium oxide product (+800 hours)
2008	Uganda	Glencore	Mutanda Mine Mumi atmospheric leach copper SX/EW to cobalt plant feed (+400 hours)
2008		Various	Iron removal Atmospheric high density iron-aluminium sludge High density iron removal process from nickel and cobalt sulfates High density iron removal process from nickel laterite leachates (3 of 120 hours).
2008	Australia	Glencore	Copper SX/EW to cobalt plant feed (400 hours) for Mumi atmospheric leach – Mutanda Mine
2008	Australia	BHP Billiton	Ansto pilot plant. Two stage heap leachate to MHP (360 hours)
2008	Russia Kazakhstan	Oriel Resources / Mechel	Schevchenko Nickel Project. Atmospheric tank leach of laterite ores to MHP (+800 hours)
2007	USA	Formation Capital	Essential Metals Cobalt Project. Production of cobalt metal from copper recovery plant bleeds (+500 hours)
2006	DRC	First Quantum Minerals	Kolwezi Musonoi Tailings (KMT) cobalt production of cobalt metal from copper recovery circuit bleed (+500 hours)
2006/ 2007	USA	Formation Capital	Essential Metals Project. Nitrogen species catalyzation leaching for copper/cobalt
2004/ 2005	Australia	Western Mining Company	WMC Nickel. Pressure leach of mount keith high magnesium nickel concentrates (+700 hours)
2002	South Africa	Angloplats	Angloplats Nickel Copper. Production of high grade PGM concentrate and removal of nickel and copper from Angloplats converter matte
1998/ 1999	USA	Stillwater Mining Company	SMC Nickel Matte Leach. Recovery of nickel and copper from Stillwater matte and production of high grade PGM concentrate (1400 hours)
1998	South Africa	Avmin	Avmin Cobalt Project. Recovery of cobalt from atomised alloy to metal (1400 hours)
1980-1981	South Africa	Impala Platinum Refineries	Impala Cobalt Project. Recovery of cobalt as metal powder from nickel refinery barren liquors. (1985) Autoclave flash cooling – piloted this invention

Commissioning Experience

Year	Company	Description
2003-2004	Lonmin	Pressure copper leach autoclave employing flash cooling
2003	Angloplats	Thermosyphon effluent evaporation plant for chloride liquors
2002	Avmin Chambishi	Zinc impurity removal by solvent extraction
2001	Lonmin	Commissioned As, Se, Te removal pressure leach autoclaves
2000	SMC	Commissioned copper pressure leach autoclave (ramp up in 30 days)
1996	Implats	Venturi scrubber – fine nickel particulates
1994-1995	Lonmin	Ruthenium distillation and recovery circuit complete with acidic chloride thermosyphon evaporation
1988-1992	Implats	Chlorine pressure leach of PGM concentrate, Pt-Pd SX, Rh-Ir IX, ruthenium distillation in chloride media
1986-1989	Implats	Copper nickel matte autoclaves employing flash recycle cooling
1986	Implats	Nickel hydrogen reduction autoclave, powder washing briquetting and sintering plant
1985	Implats	Ammonium sulphate evaporation/crystallisation plant
1985	Implats	Ammonium chloride vent off-gas filter
1985	Implats	Pressure iron removal autoclaves
1985	Implats	Selenium/tellurium removal and direct electrowinning circuit
1982	Implats	Cobalt metal recovery plant
1977	Implats	Smelter off gas sulphuric acid plant
1974	Implats	Ammonium sulphate crystallization plant
1974	Implats	Steam methane gas reforming plant – hydrogen and carbon dioxide plant

PGMs

Nickel

Cobalt

Copper

Uranium

Selenium and Tellurium

Lithium