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ORE, WASTE and MINERALOGY
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What is an ore?
What is waste?
What is the role of mineralogy in MMPE?
How do these questions change for
different commodities?
Downstream Processing
• Mine/mill complex
– produces ore or concentrate or unrefined
metal/product
– product transported by airplane, rail, truck or ship to
smelter or refinery
– if leaching is used at mine/mill, unrefined metal or
final product is produced
• Smelting
– pyrometallurgical processing (multi-stage)
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roasting to partially remove/control sulfur content
melting to separate oxides from sulfides (flux and slag)
oxidation to remove sulfur and iron
need SO2 control and slag disposal system
Downstream Processing
• Leaching
– hydrometallurgical processing
– vat leach, agitation leach, heap leach, in-situ leach
– Pressure Oxidation or Biological Leaching
– solid/liquid separation or ion adsorption process
– solution purification (solvent extraction/ion exchange)
– need residue disposal method (dewatering/storage)
• Refining
– electrometallurgical processing
• electrowinning to recover metals from solution
• electrorefining to purify unrefined metal
• treatment of slime deposits for PMs recovery
What is an Ore?
Definition:
An ore is a mass of mineralization within
the Earth's surface which can be mined
- at a particular place;
- at a particular time;
- at a profit.
What is Waste?
Definition:
Waste is mineralized rock that is removed from a
mine to provide access to an underlying or nearby
orebody containing at least one mineral of value.
Types of Waste:
- footwall material (typically barren material)
- hangingwall material (typically contains sulfides)
- gangue material contained within the ore
What is Waste?
Waste rock can become ore at some later time.
- metal/commodity prices can change
- other values are discovered within the waste
- new technology is developed
- environmental protection costs become too high
- ore has been exhausted; too costly to close mine
Mineralogy in Mineral Processing
Types of minerals in the ore have major impact on
operation and control of the processing plant.
- relative abundance of ore minerals
- feed grade and concentrate grade
- types of gangue minerals
- slime content (clays, etc.)
- pH effects (alkali rock)
- pyrite and pyrrhotite (iron sulfides)
- association of ore and gangue minerals
- liberation characteristics
- disseminated vs. massive
Process Mineralogy
- establish regular mineralogical analysis of mill
feed and other process streams
- perform a size-by-size analysis of rock and ore
mineral contents and associations
- relative abundance
- free/locked ratios of grinding circuit streams
- perform metallurgical testwork on ore samples
containing different mineralogy
Virtual Atlas of Opaque and Ore Minerals in their Associations
< http://www.smenet.org/opaque-ore/ >
Process Mineralogy
- establish metallurgical performance of each
process stage for each ore mineral type
- determine size ranges where losses occur and
examine minerals responsible for these losses
- establish impact of impurities on product quality
- use all the above information to decide on
process changes to improve plant performance
with respect to recovery and product quality
Copper Ores
Minerals:
Sulfides
Oxides
chalcopyrite - CuFeS2
bornite - Cu4FeS5
covellite - CuS
chalcocite (Cu2S)
cubanite (CuFe2S3)
cuprite - Cu2O
malachite - Cu2CO3(OH)2
pseudomalachite - Cu5(PO4)2(OH)4
azurite - Cu3(CO3)2(OH)2
chrysocolla - CuSiO3·nH2O
- (Cu,Al)2H2Si2O5(OH)4·nH2O
Gangue Minerals:
pyrite
arsenopyrite
quartz
Mn-wad
feldspars
calcite
silicates
dolomite
clays
Copper Ores
Ore Types:
Porphyry: igneous rock of large crystal size (phenocrysts)
embedded in a ground mass. Typical mineralization is
disseminated chalcopyrite with molybdenite (MoS).
Massive:
pyrite/pyrrhotite host with chalcopyrite, pentlandite,
sphalerite, arsenopyrite, galena.
Vein-type: quartz host with veins of chalcopyrite, chalcocite and
pyrite
Copper Ores
Problems:
Liberation: fine grinding may be required.
Recovery: oxide/sulfide ratio changes,
presence of slime particles,
poor recovery of coarse copper minerals.
Product: poor liberation, presence of As, Bi, Pb
Quality
high %H2O, variable Cu grade
Separation: poor distribution of Co, Zn, Pb, etc.
Copper Ores
Anhedral chalcopyrite (yellow, top right) is inter-grown
with quartz (light grey, right centre). Pounded to euhedral
rutile (grey-white, centre left) is disseminated throughout
the host rock. The poorly polished dark grey gangue is
phyllosilicate. - El Salvador, Chile
Copper Ores – Concentrating
Simplest Copper Flotation Circuit
Copper/Gold Ores – Concentrating
Copper/Gold Flotation Circuit
Copper/Moly Ores – Concentrating
Copper/Moly Flotation Circuit
Copper Ores – Concentrating
Multiple Sulfide Differential Flotation Circuit
Copper Ores – Concentrating
Mixed Oxide/Sulfide Copper Flotation Circuit
Copper Ores – Direct Leaching
Copper Oxide Processing to final metal
Copper Ores – Concentrating
Copper Oxide Processing - LPF
Copper Ores – Concentrating
T.O.R.C.O. Processing of Cu Ores (Segregation Process)
- Requires at least 4%Cu
Copper – Downstream Processing
Kidd-Creek Smelter flowsheet
Copper Anode Casting Wheel
Nickel Ores
Minerals:
pentlandite (NiFeS)
chalcopyrite (CuFeS2)
Gangue Minerals:
pyrrhotite (FexSy where x:y = 0.9-1.1)
quartz
feldspars
silicates
clays
Mn-wad
calcite
Nickel Ores
Ore Types:
Massive: pentlandite and chalcopyrite in relatively equal
quantities in massive pyrrhotite (FexSy).
Massive: low copper content in pyrrhotite host.
Massive: presence of clay slimes, talc
chalcopyrite/pentlandite with pyrrhotite
Nickel Ores
Problems:
Ni-associations: 3 types
- as pentlandite
- solid-solution in pyrrhotite
- "flame" pentlandite in pyrrhotite
Liberation:
fine grinding may be required
for "flame" pentlandite.
Recovery: solid-solution losses.
magnetic vs. flotable pyrrhotite
Product: clay contamination
Quality
high %H2O, variable Cu/Ni grade
Nickel Ores
Problems:
Cu-Ni separation: - at milling stage
- at the smelting stage
- at the matte separation stage
Pyrrhotite
Recovery:
- magnetic (low intensity) for
monoclinic FeS (x:y > 1.0)
- flotation for hexagonal FeS (x:y < 1.0)
Synthetic Minerals:
heazlewoodite (Ni3S2)
chalcocite (Cu2S)
Fe-Ni alloy (PMs)
Nickel Ores
Chalcopyrite, pyrrhotite, pentlandite,
and cubanite - Stillwater, Montana, USA
Notice flame pentlandite in chalcopyrite
Nickel Ores
125µm
Pyrrhotite (brown) has pentlandite (light brown, higher
reflectance, centre) exsolution bodies as flames, aligned
along (0001). Minor amounts of chalcopyrite (yellow, centre
right) are associated with cleavage and fractures within
pyrrhotite. Silicates are black.
Nickel Ore
Rhomb-shaped areas of
deeply etched hexagonal
pyrrhotite are surrounded
by more lightly etched
monoclinic pyrrhotite,
which is the main phase.
Very lightly etched
monoclinic pyrrhotite
(pale brown, bottom right) has a rim of granular pentlandite
(light brown, higher reflectance). Pyrrhotite is intergrown with
chalcopyrite (yellow, centre) and encloses magnetite (grey,
top left).
Cu/Ni Downstream Processing
• Nickel
– Typical Mine/Mill Treatment
Downstream Processing
• Nickel
– Matte Separation processing
Lead/Zinc Ores
Minerals: galena (PbS)
sphalerite (ZnxFeyS) where x:y = 0.0-0.1)
marmatite (high-Fe sphalerite)
anglesite (PbSO4)
cerrusite (PbCO3)
smithsonite (ZnCO3)
hydrozincite (Zn5(CO3)2(OH)6)
hemimorphite (Zn4Si2O7(OH)2·H2O)
Gangue Minerals:
pyrite/marcasite (FeS2)
quartz
pyrrhotite (FexSy)
feldspars
silicates
clays
Mn-wad
calcite/dolomite/limestone
Lead/Zinc Ores
Ore Types:
Massive:
galena and sphalerite in a variety of relative
quantities in massive pyrite/marcasite (FeS2).
Massive:
carbonate-hosted ore - Mississippi Valley.
Massive:
presence of clay slimes, talc
galena/sphalerite with pyrrhotite
Lead/Zinc Ores
Ore Types:
Pb/Zn:
galena, sphalerite and pyrite
Cu/Pb:
chalcopyrite, galena and pyrite
Cu/Zn:
chalcopyrite, sphalerite and pyrite
Cu/Pb/Zn: chalcopyrite, galena, sphalerite and pyrite
Lead/Zinc Ores
Problems:
Pb-Zn separation: - two-stage flotation
- differential (Pb first/Zn second)
Cu-Pb-Zn ores: - combined bulk/selective and
differential flotation
- Cu/Pb bulk followed by Zn float
Pb-Zn oxide flotation: use of sulfidizing agents
Lead/Zinc Ores
Problems:
Zn depression: ZnS is readily activated by Cu ions
Cu/Pb separation: essential to avoid smelter penalties
Liberation: difficult to assess without mineralogy
Product: Zn conc > 55-58%Zn
Quality
Pb conc > 60-65%Pb
Cu conc > 25%Cu
Copper/Lead/Zinc Ores
Euhedral arsenopyrite (white,
high reflectance, left) is intergrown with galena (light bluewhite with triangular cleavage
pits, centre), chalcopyrite
(yellow, centre) and sphalerite
(light grey, centre right), with
fine chalcopyrite inclusions
(top left) or submicroscopic
chalcopyrite (grey to brown-grey, centre right).
A lath of poorly polished molybdenite (light grey, centre) is enclosed
within chalcopyrite and galena and has partially rimmed arsenopyrite
(bottom right). Minor amounts of rutile (light grey) form acicular
crystals within the gangue (right centre). Black areas are polishing
pits.
Copper/Lead/Zinc Ores
Reniform (kidney-shaped)
sphalerite (light grey, centre) is
interbanded with galena (white,
centre bottom) and chalcopyrite (yellow) in successive
growth rings. Chalcopyrite in
the centre of the right sphalerite
Has replaced poorly crystalline pyrite (white, top right).
Chalcopyrite can be seen to have higher relief than galena
(bottom left). The gangue (dark grey) is sulfate. Black
areas are polishing pits.
Lead/Zinc Downstream Processing
Simplified Lead Extraction and Refining
Lead/Zinc Downstream Processing
Simplified Zinc Extraction and Refining
Iron Ores
Minerals:
hematite (Fe2O3)
magnetite (Fe3O4)
martite (Fe2O3:Fe3O4)
goethite/limonite (Fe2O3·nH2O)
siderite (FeCO3)
ilmenite (FeTiO3)
Gangue Minerals:
quartz
silicates
MnO2
feldspars
clays
calcite
Iron Ores
Ore Types:
high grade hematite:
Carajas, Brazil (pure mineral)
low grade hematite:
Shefferville ores, N. Quebec
(yellow/red/blue ores)
hematite/magnetite:
Iron Ore Company of Canada
disseminated magnetite: Taconite ores in Minnesota
hydrated/weathered ores: Itabirite and Limonitic ores
carbonate ores:
Siderite ores (Sault St. Marie)
Iron Ores
Problems:
magnetite recovery: associations with hematite
gravity separation: fine size liberation
flotation: reverse flotation of gangue
Product: SiO2 content < 2%
Quality
product size
(lump, sinter feed, pellet feed)
magnetite content
Samarco Iron Ore Flowsheet
Samarco Iron Ore
Concentrator
Samarco Iron Ore Pipeline
Labrador Iron Mining - Shefferville
Iron Ore Processing
Iron Ore Pellet Plant
Iron Ore Pellets
Malmberget, Norway
Iron Ore – Pig Iron
Fe2O3 + 3CO → 2Fe + 3CO2
2 C(s) + O2(g) → 2 CO(g)
3 Fe2O3(s) + CO(g) → 2 Fe3O4(s) + CO2(g)
Fe3O4(s) + CO(g) → 3 FeO(s) + CO2(g)
CaCO3(s) → CaO(s) + CO2(g)
FeO(s) + CO(g) → Fe(s) + CO2(g)
C(s) + CO2(g) → 2 CO(g)
Final Products
CaO + SiO2 → CaSiO3 Fayalite Slag
Pig Iron (95 %Fe; 5%C)
Iron Ore – Blast Furnace
Blast Furnace
Iron Ore – Steel-Making
Uranium Ores
Producers
• Canada
• Australia
• Kazakhstan
Users
• US / Canada
• Japan / Korea / China
• France
Downstream Processing
• Uranium Ore processing
Uranium Mines - Australia
Uranium Resources
Uranium Reserves
•Total World Reserves = 5,404,000 tonnes Uranium
Uranium Reserves (x1,000 t) (2009)
Uranium Production - annual
• Total World (2010) = 53,663 tonnes U
132,463 tonnes U3O6
Kazakhstan,
Monthly Spot Price of Uranium
Copper-Uranium Ore
Olympic Dam Mine, Australia
Olympic Dam Refinery, Australia
Olympic Dam Refinery, Australia
Olympic Dam Refinery, Australia
Coal Processing
Two Products
• Thermal Coal
• Metallurgical Coal
Coal Processing
Downstream Processing
• Coal processing
Coal Processing
Coal Processing
Coal Processing
Gold Ores
Minerals: native gold
electrum
tellurides
associated with pyrite and/or other sulfides
Gangue:
quartz
pyrite
arsenopyrite
feldspars
calcite/dolomite
limestone
other rock-type minerals
Gold Processing
• Gold processing options
Gold Flakes
Gold Panning
Gold Flakes
Grinding and Cyanide Leaching
Musslewhite Mine, Ontario
Dissolution of Gold in Cyanide
Elsner's Equation
Precipitation of Au from Solution
Smelting Gold
Campbell Mine, Ontario
Pouring Slag
Musslewhite Mine, Ontario
Pouring Gold Bullion Bars
What its all about!
Gold Bullion
MINE LIFE CYCLE, DOWNSTREAM
PROCESSING, AND SUSTAINABILITY
STAGE 1 - Exploration and Assessment
STAGE 2 - Construction
STAGE 3 - Operation
STAGE 4 - Closure
MINE LIFE CYCLE, DOWNSTREAM
PROCESSING, AND SUSTAINABILITY
STAGE 1 - Exploration and Assessment (1-10 years)
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Exploration - Geophysics
Exploration - Drilling (1/10)
Geology - Analytical and Mineralogical Assessment
Economic Feasibility Assessment (1/10)
Orebody Modeling (1/10)
Mine Planning and Metallurgical Testwork
Mine Life Cycle (continued)
STAGE 2 – Construction (0.5-2 years )
• Mine
– Shaft-sinking & tunnel/stope development (U/G)
– Adit & tunnel/stope development (mountain-top)
– Top soil removal, key-cut, haul road (Open-Pit)
• Plant
– Site Preparation, Foundations, Construction of buildings
– Procurement and Installation of Equipment
• Waste and Tailing Disposal
– Site Selection and Preparation
– Construction of Initial Coffer Dam for tailing disposal
Mine Life Cycle (continued)
STAGE 3 - Operations ( 3 - 100+ years )
• Mine
– Blast, Load, Haul, Dump
– Transport (hoist, convey, truck, rail), Stockpile
– Safely Store Waste (on site or in-mine)
• Mill
– Crush, Grind (comminution)
– Physical Separation (maybe chemical)
(beneficiation)
– Thicken and Filter (dewater)
– Safely Store Tailing
Mine Life Cycle (continued)
STAGE 3 - Operations ( 3 - 100+ years )
• Waste Disposal
– Dump
– Contour, Spread top soil
– Hydro-seed and plan for final drainage
• Tailing Disposal
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Plan for Lifts as Tailing Dam builds
Control water levels
Recover water for recycle
Revegetate dam walls
Mine Life Cycle (continued)
STAGE 4 - Closure( 1 – 20+?? years )
• Mine
– Flood Pit
– Seal Underground workings
– Long-term Acid Rock Drainage plan for waste dumps
• Mill
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Salvage Equipment
Raze Buildings
Contour and reseed site
Long-term ARD plan for tailing dam
Sustainability
• Important Factors
– Technical
– Economic
– Social/Political
– Environmental
• Past mining activities focused on only the first two
• Last two are now equally, if not more important
Sustainability
• A Mine must plan for closure before it starts up
• A mining company must always consider local
communities in all parts of the world
• As an industry, we must find ways to enhance our
image and influence government decision-making
• Future methods must reduce the mining 'footprint'
– no more open pits (????)
– waste returned to the mine
– processing at the face
– robotics and remote-mining systems
Sustainability
• BC Mining Industry must encourage its members
to institute vertical integration policies
• We need to invest in much more value-added
processing (i.e. smelting and refining in BC)
• Downstream manufacturing industries must be
encouraged to develop in BC
• Provide necessary systems to begin significant
recycling of metals and other materials in Pacific
North-West
Sustainability
• Social/Political Issues
– Land Use
– Government policies
– The Influence of Activism
– Environmental concerns
– Aboriginal peoples and treaties
– Need for jobs and a diversified economy
• In BC, the Tatsenshini/Windy Craggy decision
has had important long-term impact on Mining
• Similarly, Delgamuk decision and Nishka Treaty
are important to the future of BC's mining industry