Iron oxide copper gold ore deposits
Encyclopedia
Iron oxide copper gold ore deposits (IOCG) are important and highly valuable concentrations of copper
, gold
and uranium
ore
s hosted within iron oxide dominant gangue
assemblages which share a common genetic
origin.
These ore bodies range from around 10 million tonnes of contained ore, to 4,000 million tonnes or more, and have a grade of between 0.2% to 5% copper, with gold contents ranging from 0.1 to 3+ grams per tonne (parts per million). These ore bodies tend to express as cone-like, blanket-like breccia sheets within granitic margins, ore as long ribbon-like breccia or massive iron oxide deposits within faults or shears.
The tremendous size, relatively simple metallurgy and relatively high grade of IOCG deposits can produce extremely profitable mines.
Iron oxide copper-gold deposits are also often associated with other valuable trace elements such as uranium, bismuth
and rare earth
metals, although these accessories are typically subordinate to copper and gold in economic terms.
Some examples include the Olympic Dam, South Australia
and La Candelaria, Chile deposits.
expressions of large crustal-scale alteration events driven by intrusive activity. The deposit type was first recognised, though not named as IOCG, by discovery and study of the supergiant Olympic Dam copper-gold-uranium deposit, and South America
n examples.
IOCG deposits are classified as separate to other large intrusive related copper deposits such as porphyry copper deposits and other porphyry metal deposits primarily by their substantial accumulations of iron oxide minerals, association with felsic-intermediate type intrusives (Na-Ca rich granitoids), and lack of the complex zonation in alteration mineral assemblies commonly associated with porphyry deposits.
The relatively simple copper-gold +/- uranium ore assemblage is also distinct from the wide spectrum of Cu-Au-Ag-Mo-W-Bi porphyry deposits, and there is often no metal zonation within recognised examples of IOCG deposits. IOCG deposits tend to also accumulate within faults as epigenetic mineralisation distal to the source intrusion, whereas porphyries are internal to their intrusive hosts.
-like affinities (e.g.; Wilcherry Hill, Cairn Hill), although they are not strictly skarns in that they are not metasomatites in the strictest sense.
IOCG deposits can express a wide variety of deposit morphologies and alteration types dependent on their host stratigraphy, the tectonic processes operating at the time (e.g., some provinces show a preference for development within shears and structural zones), and so on.
IOCG deposits have been recognised within epithermal regimes (caldera
and maar
styles) through to brittle-ductile regimes deeper within the crust (e.g.; Prominent Hill, some Mount Isa
examples, Brazilian examples). What is common in IOCGs is their genesis within magmatic-driven crustal-scale hydrothermal systems.
IOCG deposits typically occur at the margins of large igneous bodies which intrude into sedimentary strata. As such, IOCG deposits form pipe-like, mantle-like or extensive breccia-vein sheets within the host stratigraphy. Morphology is often not an important criterion of the ore body itself, and is determined by the host statigraphy and structures.
IOCG deposits are usually associated with distal zones of particular large-scale igneous events, for instance a particular Suite or Supersuite of granites, intermediate mafic intrusives of a particular age. Often the mineralising intrusive event becomes a diagnostic association for expressions of IOCG mineralisation within a given province.
IOCG mineralisation may accumulate within metasomatised wall rocks, within brecciated maar
or caldera structures, faults or shears, or the aureole of an intrusive event (possibly as a skarn
) and is typically accompanied by a substantial enrichment in iron oxide minerals (hematite
, magnetite
). IOCG deposits tend to accumulate within iron-rich rocks such as banded iron formation
s, iron schists, etcetera, although iron enrichment of siliciclastic rocks by metasomatism is also recognised within some areas.
Although not exclusively Proterozoic
, within Australia and South America a majority of IOCG deposits are recognised to be within Neoproterozoic to Mesoproterozoic basement. Worldwide, ages of recognised IOCG deposits range from 1.8Ga to 15 Ma, however the majority are within the 1.6Ga to 850Ma range.
Ore minerals in IOCG deposits are typically copper-iron sulfide chalcopyrite
and gangue
pyrite
, forming 10-15% of the rock mass.
Supergene
profiles can be developed above weathered examples of IOCG deposits, as exemplified by the Sossego deposit, Para State, Brazil
, where typical oxidised copper minerals are present, e.g.; malachite
, cuprite
, native copper
and minor amounts of digenite
and chalcocite
.
Alteration is a mixture of sodic-calcic (albite
-epidote
) to potassic (K-feldspar
) in style, and may vary from province to province based on host rocks and mineralising processes. Typically for large-scale hydrothermal systems, fluid types within IOCG systems show a mixed providence of magmatic, metamorphic and often meteoric waters. Deposits may be vertically zoned from deeper albite-magnetite assemblages trending toward silica-K-feldspar-sericite
in the upper portions of the deposits.
Gangue minerals are typically some form of iron oxide mineral, classically hematite
, but also magnetite
within some other examples such as Ernest Henry and some Argentinian examples. This is typically associated with gangue sulfides of pyrite, with subordinate pyrrhotite
and other base metal sulfides.
Silicate gangue minerals include actinolite
, pyroxene
, tourmaline
, epidote
and chlorite
, with apatite
, allanite
and other phosphate minerals common in some IOCG provinces (e.g.; North American examples), with carbonate-barite
assemblages also reported. Where present, rare earth metals tend to associate with phosphate minerals.
When iron oxide species trend towards magnetite or crystalline massive hematite, IOCG deposits may be economic based on their iron oxide contents alone. Several examples of IOCG deposits (Wilcherry Hill, Cairn Hill, Kiruna) are iron ore deposits.
, exploration for Olympic Dam style IOCG deposits has relied on four main criteria for targeting exploratory drill holes;
This exploration model is applicable to the most basic of exploration criteria for identifying prospective areas likely to form IOCG deposits. In better exposed terranes, prospecting for alteration assemblages and skarns, in concert with geochemical exploration is also likely to yield success.
Punta del Cobre IOCG province, Chile
Cloncurry district, Queensland, Australia:
Para State IOCG province, Brazil
Marcona
IOCG district in Southern Peru
Some authors (e.g., Skirrow et al. 2004) consider the iron ore deposits of Kiruna, Sweden as being IOCG deposits. Similar styles of fault-hosted magnetite-hematite breccias with minor copper-gold mineralisation and skarns are recognised within the Gawler Craton, South Australia, which would be recognised as IOCG deposits.
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
, gold
Gold
Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...
and uranium
Uranium
Uranium is a silvery-white metallic chemical element in the actinide series of the periodic table, with atomic number 92. It is assigned the chemical symbol U. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons...
ore
Ore
An ore is a type of rock that contains minerals with important elements including metals. The ores are extracted through mining; these are then refined to extract the valuable element....
s hosted within iron oxide dominant gangue
Gangue
In mining, gangue is the commercially worthless material that surrounds, or is closely mixed with, a wanted mineral in an ore deposit. The separation of mineral from gangue is known as mineral processing, mineral dressing or ore dressing and it is a necessary and often significant aspect of mining...
assemblages which share a common genetic
Ore genesis
The various theories of ore genesis explain how the various types of mineral deposits form within the Earth's crust. Ore genesis theories are very dependent on the mineral or commodity....
origin.
These ore bodies range from around 10 million tonnes of contained ore, to 4,000 million tonnes or more, and have a grade of between 0.2% to 5% copper, with gold contents ranging from 0.1 to 3+ grams per tonne (parts per million). These ore bodies tend to express as cone-like, blanket-like breccia sheets within granitic margins, ore as long ribbon-like breccia or massive iron oxide deposits within faults or shears.
The tremendous size, relatively simple metallurgy and relatively high grade of IOCG deposits can produce extremely profitable mines.
Iron oxide copper-gold deposits are also often associated with other valuable trace elements such as uranium, bismuth
Bismuth
Bismuth is a chemical element with symbol Bi and atomic number 83. Bismuth, a trivalent poor metal, chemically resembles arsenic and antimony. Elemental bismuth may occur naturally uncombined, although its sulfide and oxide form important commercial ores. The free element is 86% as dense as lead...
and rare earth
Rare earth element
As defined by IUPAC, rare earth elements or rare earth metals are a set of seventeen chemical elements in the periodic table, specifically the fifteen lanthanides plus scandium and yttrium...
metals, although these accessories are typically subordinate to copper and gold in economic terms.
Some examples include the Olympic Dam, South Australia
Olympic Dam, South Australia
Olympic Dam is a mining centre in South Australia located some 550 km NNW of Adelaide, the capital city of South Australia. It is the site of an extremely large iron oxide copper gold deposit producing copper, uranium, gold and silver. The site hosts an underground mine as well as an...
and La Candelaria, Chile deposits.
Classification
Iron oxide copper gold (IOCG) deposits are considered to be metasomaticMetasomatism
Metasomatism is the chemical alteration of a rock by hydrothermal and other fluids.Metasomatism can occur via the action of hydrothermal fluids from an igneous or metamorphic source. In the igneous environment, metasomatism creates skarns, greisen, and may affect hornfels in the contact...
expressions of large crustal-scale alteration events driven by intrusive activity. The deposit type was first recognised, though not named as IOCG, by discovery and study of the supergiant Olympic Dam copper-gold-uranium deposit, and South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
n examples.
IOCG deposits are classified as separate to other large intrusive related copper deposits such as porphyry copper deposits and other porphyry metal deposits primarily by their substantial accumulations of iron oxide minerals, association with felsic-intermediate type intrusives (Na-Ca rich granitoids), and lack of the complex zonation in alteration mineral assemblies commonly associated with porphyry deposits.
The relatively simple copper-gold +/- uranium ore assemblage is also distinct from the wide spectrum of Cu-Au-Ag-Mo-W-Bi porphyry deposits, and there is often no metal zonation within recognised examples of IOCG deposits. IOCG deposits tend to also accumulate within faults as epigenetic mineralisation distal to the source intrusion, whereas porphyries are internal to their intrusive hosts.
Similar deposit styles
IOCG deposits are still relatively loosely defined and as such, some large and small deposits of various types may or may not fit within this deposit classification. IOCG deposits may have skarnSkarn
Skarn is an old Swedish mining term originally used to describe a type of silicate gangue, or waste rock, associated with iron-ore bearing sulfide deposits apparently replacing Archean age limestones in Sweden's Persberg mining district. In modern usage the term "skarn" has been expanded to refer...
-like affinities (e.g.; Wilcherry Hill, Cairn Hill), although they are not strictly skarns in that they are not metasomatites in the strictest sense.
IOCG deposits can express a wide variety of deposit morphologies and alteration types dependent on their host stratigraphy, the tectonic processes operating at the time (e.g., some provinces show a preference for development within shears and structural zones), and so on.
IOCG deposits have been recognised within epithermal regimes (caldera
Caldera
A caldera is a cauldron-like volcanic feature usually formed by the collapse of land following a volcanic eruption, such as the one at Yellowstone National Park in the US. They are sometimes confused with volcanic craters...
and maar
Maar
A maar is a broad, low-relief volcanic crater that is caused by a phreatomagmatic eruption, an explosion caused by groundwater coming into contact with hot lava or magma. A maar characteristically fills with water to form a relatively shallow crater lake. The name comes from the local Moselle...
styles) through to brittle-ductile regimes deeper within the crust (e.g.; Prominent Hill, some Mount Isa
Mount Isa Mines
The Mount Isa copper, lead, zinc and silver mines near Mount Isa, Queensland, Australia are part of the Xstrata mining company.-History:In 1923 the orebody containing lead, zinc and silver was discovered by the miner John Campbell Miles. The company Mount Isa Mines was founded 1924 but full scale...
examples, Brazilian examples). What is common in IOCGs is their genesis within magmatic-driven crustal-scale hydrothermal systems.
Genesis
Iron oxide copper gold deposits typically form within 'provinces' where several deposits of similar style, timing and similar genesis form within similar geologic settings. The genesis and provenance of IOCG deposits, their alteration assemblages and gangue mineralogy may vary between provinces, but all are related to;- Major regional thermal event broadly coeval with IOCG formation, represented by low to medium grade metamorphism, and/or mafic intrusions, and/or I- or A-type granitoids
- Host stratigraphy is relatively Fe-enriched (BIF, ironstones), but have relatively little reduced carbon (e.g.; coal, etc.).
- Regional-scale alteration systems, operating over tens or hundreds of kilometres, involving admixture of at least two fluids
- Large-scale crustal structures which allow extensive hydrothermal circulation of mineralising fluids
IOCG deposits typically occur at the margins of large igneous bodies which intrude into sedimentary strata. As such, IOCG deposits form pipe-like, mantle-like or extensive breccia-vein sheets within the host stratigraphy. Morphology is often not an important criterion of the ore body itself, and is determined by the host statigraphy and structures.
IOCG deposits are usually associated with distal zones of particular large-scale igneous events, for instance a particular Suite or Supersuite of granites, intermediate mafic intrusives of a particular age. Often the mineralising intrusive event becomes a diagnostic association for expressions of IOCG mineralisation within a given province.
IOCG mineralisation may accumulate within metasomatised wall rocks, within brecciated maar
Maar
A maar is a broad, low-relief volcanic crater that is caused by a phreatomagmatic eruption, an explosion caused by groundwater coming into contact with hot lava or magma. A maar characteristically fills with water to form a relatively shallow crater lake. The name comes from the local Moselle...
or caldera structures, faults or shears, or the aureole of an intrusive event (possibly as a skarn
Skarn
Skarn is an old Swedish mining term originally used to describe a type of silicate gangue, or waste rock, associated with iron-ore bearing sulfide deposits apparently replacing Archean age limestones in Sweden's Persberg mining district. In modern usage the term "skarn" has been expanded to refer...
) and is typically accompanied by a substantial enrichment in iron oxide minerals (hematite
Hematite
Hematite, also spelled as haematite, is the mineral form of iron oxide , one of several iron oxides. Hematite crystallizes in the rhombohedral system, and it has the same crystal structure as ilmenite and corundum...
, magnetite
Magnetite
Magnetite is a ferrimagnetic mineral with chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. The chemical IUPAC name is iron oxide and the common chemical name is ferrous-ferric oxide. The formula for magnetite may also be written as FeO·Fe2O3, which is one part...
). IOCG deposits tend to accumulate within iron-rich rocks such as banded iron formation
Banded iron formation
Banded iron formations are distinctive units of sedimentary rock that are almost always of Precambrian age. A typical BIF consists of repeated, thin layers of iron oxides, either magnetite or hematite , alternating with bands of iron-poor shale and chert...
s, iron schists, etcetera, although iron enrichment of siliciclastic rocks by metasomatism is also recognised within some areas.
Although not exclusively Proterozoic
Proterozoic
The Proterozoic is a geological eon representing a period before the first abundant complex life on Earth. The name Proterozoic comes from the Greek "earlier life"...
, within Australia and South America a majority of IOCG deposits are recognised to be within Neoproterozoic to Mesoproterozoic basement. Worldwide, ages of recognised IOCG deposits range from 1.8Ga to 15 Ma, however the majority are within the 1.6Ga to 850Ma range.
Mineralogy and alteration
Chalcopyrite
Chalcopyrite is a copper iron sulfide mineral that crystallizes in the tetragonal system. It has the chemical composition CuFeS2. It has a brassy to golden yellow color and a hardness of 3.5 to 4 on the Mohs scale. Its streak is diagnostic as green tinged black.On exposure to air, chalcopyrite...
and gangue
Gangue
In mining, gangue is the commercially worthless material that surrounds, or is closely mixed with, a wanted mineral in an ore deposit. The separation of mineral from gangue is known as mineral processing, mineral dressing or ore dressing and it is a necessary and often significant aspect of mining...
pyrite
Pyrite
The mineral pyrite, or iron pyrite, is an iron sulfide with the formula FeS2. This mineral's metallic luster and pale-to-normal, brass-yellow hue have earned it the nickname fool's gold because of its resemblance to gold...
, forming 10-15% of the rock mass.
Supergene
Supergene (geology)
In ore deposit geology, supergene processes or enrichment occur relatively near the surface. Supergene processes include the predominance of meteoric water circulation with concomitant oxidation and chemical weathering. The descending meteoric waters oxidize the primary sulfide ore minerals and...
profiles can be developed above weathered examples of IOCG deposits, as exemplified by the Sossego deposit, Para State, Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
, where typical oxidised copper minerals are present, e.g.; malachite
Malachite
Malachite is a copper carbonate mineral, with the formula Cu2CO32. This green-colored mineral crystallizes in the monoclinic crystal system, and most often forms botryoidal, fibrous, or stalagmitic masses. Individual crystals are rare but do occur as slender to acicular prisms...
, cuprite
Cuprite
Cuprite is an oxide mineral composed of copper oxide Cu2O, and is a minor ore of copper.Its dark crystals with red internal reflections are in the isometric system hexoctahedral class, appearing as cubic, octahedral, or dodecahedral forms, or in combinations. Penetration twins frequently occur...
, native copper
Native copper
Copper, as native copper, is one of the few metallic elements to occur in uncombined form as a natural mineral, although most commonly occurs in oxidized states and mixed with other elements...
and minor amounts of digenite
Digenite
Digenite is a copper sulfide mineral with formula: Cu9S5. Digenite is a black to dark blue opaque mineral that crystallizes with a trigonal - hexagonal scalenohedral structure. In habit it is usually massive, but does often show pseudo-cubic forms. It has poor to indistinct cleavage and a brittle...
and chalcocite
Chalcocite
Chalcocite, copper sulfide , is an important copper ore mineral. It is opaque, being colored dark-gray to black with a metallic luster. It has a hardness of 2½ - 3. It is a sulfide with an orthorhombic crystal system....
.
Alteration is a mixture of sodic-calcic (albite
Albite
Albite is a plagioclase feldspar mineral. It is the sodium endmember of the plagioclase solid solution series. As such it represents a plagioclase with less than 10% anorthite content. The pure albite endmember has the formula NaAlSi3O8. It is a tectosilicate. Its color is usually pure white, hence...
-epidote
Epidote
Epidote is a calcium aluminium iron sorosilicate mineral, Ca2Al2O, crystallizing in the monoclinic system. Well-developed crystals are of frequent occurrence: they are commonly prismatic in habit, the direction of elongation being perpendicular to the single plane of symmetry. The faces are often...
) to potassic (K-feldspar
Feldspar
Feldspars are a group of rock-forming tectosilicate minerals which make up as much as 60% of the Earth's crust....
) in style, and may vary from province to province based on host rocks and mineralising processes. Typically for large-scale hydrothermal systems, fluid types within IOCG systems show a mixed providence of magmatic, metamorphic and often meteoric waters. Deposits may be vertically zoned from deeper albite-magnetite assemblages trending toward silica-K-feldspar-sericite
Sericite
Sericite is a fine grained mica, similar to muscovite, illite, or paragonite. Sericite is a common alteration mineral of orthoclase or plagioclase feldspars in areas that have been subjected to hydrothermal alteration typically associated with copper, tin, or other hydrothermal ore deposits...
in the upper portions of the deposits.
Gangue minerals are typically some form of iron oxide mineral, classically hematite
Hematite
Hematite, also spelled as haematite, is the mineral form of iron oxide , one of several iron oxides. Hematite crystallizes in the rhombohedral system, and it has the same crystal structure as ilmenite and corundum...
, but also magnetite
Magnetite
Magnetite is a ferrimagnetic mineral with chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. The chemical IUPAC name is iron oxide and the common chemical name is ferrous-ferric oxide. The formula for magnetite may also be written as FeO·Fe2O3, which is one part...
within some other examples such as Ernest Henry and some Argentinian examples. This is typically associated with gangue sulfides of pyrite, with subordinate pyrrhotite
Pyrrhotite
Pyrrhotite is an unusual iron sulfide mineral with a variable iron content: FeS . The FeS endmember is known as troilite. Pyrrhotite is also called magnetic pyrite because the color is similar to pyrite and it is weakly magnetic...
and other base metal sulfides.
Silicate gangue minerals include actinolite
Actinolite
Actinolite is an amphibole silicate mineral with the chemical formula .-Etymology:The name actinolite is derived from the Greek word aktis , meaning "beam" or "ray", because of the mineral's fibrous nature...
, pyroxene
Pyroxene
The pyroxenes are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. They share a common structure consisting of single chains of silica tetrahedra and they crystallize in the monoclinic and orthorhombic systems...
, tourmaline
Tourmaline
Tourmaline is a crystal boron silicate mineral compounded with elements such as aluminium, iron, magnesium, sodium, lithium, or potassium. Tourmaline is classified as a semi-precious stone and the gem comes in a wide variety of colors...
, epidote
Epidote
Epidote is a calcium aluminium iron sorosilicate mineral, Ca2Al2O, crystallizing in the monoclinic system. Well-developed crystals are of frequent occurrence: they are commonly prismatic in habit, the direction of elongation being perpendicular to the single plane of symmetry. The faces are often...
and chlorite
Chlorite group
The chlorites are a group of phyllosilicate minerals. Chlorites can be described by the following four endmembers based on their chemistry via substitution of the following four elements in the silicate lattice; Mg, Fe, Ni, and Mn....
, with apatite
Apatite
Apatite is a group of phosphate minerals, usually referring to hydroxylapatite, fluorapatite, chlorapatite and bromapatite, named for high concentrations of OH−, F−, Cl− or Br− ions, respectively, in the crystal...
, allanite
Allanite
Allanite is a sorosilicate group of minerals within the broader epidote group that contain a significant amount of rare earth elements. The mineral occurs mainly in metamorphosed clay rich sediments and felsic igneous rocks...
and other phosphate minerals common in some IOCG provinces (e.g.; North American examples), with carbonate-barite
Barite
Baryte, or barite, is a mineral consisting of barium sulfate. The baryte group consists of baryte, celestine, anglesite and anhydrite. Baryte itself is generally white or colorless, and is the main source of barium...
assemblages also reported. Where present, rare earth metals tend to associate with phosphate minerals.
When iron oxide species trend towards magnetite or crystalline massive hematite, IOCG deposits may be economic based on their iron oxide contents alone. Several examples of IOCG deposits (Wilcherry Hill, Cairn Hill, Kiruna) are iron ore deposits.
Exploration
Within the Olympic Domain of the Gawler CratonGawler craton
The Gawler Craton covers approximately 440,000 square kilometres of central South Australia. Its Precambrian crystalline basement crustal block was cratonised ca. 1550-1450 Ma...
, exploration for Olympic Dam style IOCG deposits has relied on four main criteria for targeting exploratory drill holes;
- A substantial gravity anomaly, taken to be representative of accumulation of iron oxide minerals within the crust, which is seen as being associated with classic Olympic Dam style IOCG mineralisation. Gravity data is often interpreted via a 3D inversion to resolve the density contrast and sub-surface position of a dense body of rock. More qualitatively, the 'edges' of a gravity body are considered more prospective as this theoretically represents the mineralised margins of an intrusive body.
- High magnetism within the crust, again taken to be representative of accumulation of substantial iron oxide minerals within proximity to the targeted IOCG mineralising events
- Proximity to apparent crustal-scale linear features in geophysical data, which are taken to represent the fundamental crustal architectural faults up which mineralising intrusions and fluids would by preference travel
- Presence of the prospective Hiltaba Granite Suite, which is dated to 1570Ma coeval with Olympic Dam and the other known IOCG examples within the province
This exploration model is applicable to the most basic of exploration criteria for identifying prospective areas likely to form IOCG deposits. In better exposed terranes, prospecting for alteration assemblages and skarns, in concert with geochemical exploration is also likely to yield success.
Examples
Gawler Craton IOCG province, South Australia- Olympic Dam, South AustraliaOlympic Dam, South AustraliaOlympic Dam is a mining centre in South Australia located some 550 km NNW of Adelaide, the capital city of South Australia. It is the site of an extremely large iron oxide copper gold deposit producing copper, uranium, gold and silver. The site hosts an underground mine as well as an...
: 8,330 million tonnes of ore at 0.8 % Cu, 280 ppm U3O8, 0.76g/t Au and 3.95 g/t Ag + 151 Mt at 1.0 g/t Au - Prominent Hill Mine, South Australia: 152.8 Mt at 1.18 % Cu, 0.48 g/t Au, 2.92 g/t Ag + 38.3 Mt at 1.17 g/t Au
- Hillside, South Australia : 170Mt @ 0.7 % Cu and 0.2 g/t Au (upgraded resource estimate Dec2010)
- Wilcherry Hill, South Australia: +60Mt @ 31% Fe, associated Cu and Au
- Cairn Hill : Resources 14Mt @ 50% Fe, 0.2% Cu, 0.1 g/t Au. Reserves of 6.9Mt @ 51.% Fe, 0.2% Cu and 0.1 g/t Au
- Carapateena, South Australia: 203Mt @ 1.31% Cu, 0.56g/t Au, only partially explored. Best drilling results include 905 m at 2.1 % Cu and 1.0 g/t
Punta del Cobre IOCG province, Chile
- La Candelaria, Chile Cu-Au-Ag Deposit: Resources of 600 Mt @ 0.95% Cu, 0.2 g/t Au, 3 g/t Ag. Reserve comprises 470 Mt @ 0.95% Cu, 0.22 g/t Au, 3.1 g/t Ag
- Mantoverde Cu-Au Deposit: Cu oxide resources 180 Mt @ 0.5% Cu overlying a sulfide resource of >400 Mt @ 0.52% Cu.
- Mantos Blancos Deposit: Resources of >500 Mt @ 1.0% Cu.
Cloncurry district, Queensland, Australia:
- Ernest Henry : 122 Mt at 1.18 % Cu, 0.55 g/t Au
- Mt. Elliot : 475 Mt at 0.5 % Cu, 0.3 g/t Au
Para State IOCG province, Brazil
- Cristalino Cu-Au Deposit: 500 Mt @ 1.0% Cu, 0.2-0.3 g/t Au. Reserves amount to 261 Mt @ 0.73% Cu
- Sossego Cu-Au Deposit: 355 Mt @ 1.1% Cu, 0.28 g/t Au. Reserves of 245 Mt @ 1.1% Cu, 0.28 g/t Au
- Igarapé Bahia Cu-Au-(REE)-(U): >30Mt @ 2g/t Au.
- Alemão Cu-Au-(REE)-(U): Resources of 170 Mt @ 1.5% Cu, 0.8 g/t Au (depleted).
- Salobo Cu-Au: Reserves of 986 Mt @ 0.82% Cu, 0.49 g/t Au at a 0.5% Cu cutoff (2004).
Marcona
Marcona District
Marcona District is one of five districts of the province Nazca in Peru. The district capital is San Juan de Marcona a port on the Pacific coast.-Marcona Mine:The major industry in the Marcona District is the Marcona Mine, an open-pit iron mine...
IOCG district in Southern Peru
- Marcona Mine 1,400 million tonnes iron ore
- Pampa de Pongo 1,000 million tonnes 75% magnetite
- Mina Justa copper-gold deposit
Some authors (e.g., Skirrow et al. 2004) consider the iron ore deposits of Kiruna, Sweden as being IOCG deposits. Similar styles of fault-hosted magnetite-hematite breccias with minor copper-gold mineralisation and skarns are recognised within the Gawler Craton, South Australia, which would be recognised as IOCG deposits.
External links and further reading
- "Footprints of Fe-oxide(-Cu-Au) systems"
- Porter, T.M. editor, Hydrothermal iron oxide copper-gold and related deposits : a global perspective, PGC Publishing a division of Porter GeoConsultancy (2002), 349 pages, ISBN 0958057400
- Porter, T.M. editor, Hydrothermal iron oxide copper-gold and related deposits : a global perspective, Volume 2, PGC Publishing a division of Porter GeoConsultancy (2002) 377 pages, ISBN 0958057419