GLOSSARY - MINERALOGY - Multotec · The AK1 deposit at Argyle Diamond Mine is a well -known lamproite orebody.The surface weathered ore has a Bond Work index of 10 kWh/t and an Abrasion

GLOSSARY - MINERALOGY

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Beneficiation

Treatment of a crude ore in order to improve it’s quality.

Example: beneficiating raw coal to a steam coal for power generation or to a coking coal for furnaces.


Liberation

Freeing of valuable minerals / metals in an ore or mineral by crushing and grinding.

Well Liberated Minerals

Poorly Liberated Minerals


Run-of-Mine Ore

Uncrushed ore in its natural state just as it is when blasted.

Ore, as accepted for treatment from the Mine.


Gangue

Waste rock that surrounds an ore deposit.

The waste material in an ore.

The valueless tailings/waste fraction of an ore rejected by a

separating process.


Recovery

Indicates the proportion of valuable material acquired from the processing of an ore. Generally stated as a percentage of the values recovered compared to the total values present.


Tailings

The neutralised waste discarded after the economically recoverable metals have been extracted from the ore.


Units • 1 tonne / ton = 1 000 kg = 2 204.6 lb

• 1short ton = 2000 lb = 0.90718 tonne

• 1 tonne = 32151 Troy ounces

• 1 Troy ounce = 31.1035 gram

• 1 oz / short ton = 34.2859 gram / tonne

• 1 gram / short ton = 0.03215 oz / short ton

• M or m = million, bn or billion = 1 000 m

All tons in this presentation are metric


ORES AND MINERALS


Rocks and Minerals

Rocks are aggregates of minerals.

Minerals are either elemental compounds

(e.g. feldspars, pyroxenes, amphiboles and micas are rock-forming silicate minerals) or free, uncombined native elements (e.g. gold, silver, copper).

With a few exceptions (e.g. water, mercury, opal) minerals are solid inorganic elements or elemental compounds with definite atomic structures and chemical compositions (within fixed limits).

The various types of coals are rocks.


• from molten magma (intrusive) or lava (surface), crystalline structure, random or aligned crystals, no fossils.

Igneous rock

Metamorphic rock • igneous, metamorphic or sedimentary

rock changed by heat and pressure, rare fossils, usually crystalline, two types: foliated, wavy or more random structure,e.g. gneisses.

Sedimentary rock • form in layers or strata, loosely

grained, quartz often dominant, calcite in limestones, contain fossils


Igneous Rocks (note: large masses of molten magma are called plutons)

granite, pegmatite, granodiorite, syenite,

anorthosite, agglomerate, gabbro, pyroxenite, kimberlite, peridotite

quartz porphyry, microgranite, lamprophyre, dolerite, norite

rhyolite, andesite, pumice, tuff,

obsidian, basalt, pitchstone,

volcanic bomb, ropy lava


Metamorphic Rocks

• Foliated: gneisses, amphibolite, eclogite

• Unfoliated: marbles, granulite, skarn

• Foliated: schists, phyllite

• Unfoliated: hornfels, marbles

• Foliated: slates, phyllite

• Unfoliated: marbles, skarn, mylonite

Gneiss Schist Slate


Sedimentary Rocks

• mainly rock: conglomerate, breccia

• mainly calcium carbonate: limestones

• mainly rock: greywacke

• mainly quartz: sandstones, arkose

• mainly calcium carbonate: limestones, travertine, tufa

• others: potash, rock salt, dolomite, ironstone

• mainly quartz: loess, shale, clay, mudstone

• mainly calc carbonate: chalk, marl, limestones

• others: peat, anthracite, lignite, amber, jet, chert, flint

Shale Sandstone Conglomerate


GEOLOGICAL AND HUMAN TIME SEQUENCE OF THE EARTH

ERAS / AGES DIVISIONS (15 PERIODS/SYSTEMS) MILLIONS OF YEARS FOSSIL TYPESBEFORE PRESENT TIME OTHER IDENTIFICATIONS

IRON AGE 1200 - 500 BC iron artefacts

BRONZE AGE 3000 - 2000 BC bronze artefacts, first cities

Present Neolithic 9000 - 4000 BC Modern Man agriculture, towns Homo Sapiens

Mesolithic 10 000 BC bow & arrow

STONE AGE Upper Palaeolithic 30 000 BC stone & bone tools, artQUATERNARY

Palaeolithic Middle Palaeolithic 100 000 yrs Neanderthal Man specialised tools

Lower Palaeolithic 1.0 million Homo Erectus fire, tools

Pleistocene (nearly present) 1.6 includes ice-formed depositsat least 15 ice ages/retreats

PlioceneNeogene

Miocene (less than present) 26TERTIARY

Oligocene

Palaeogene Eocene (dawn of the present)

Paleocene 65

Cretaceous 140 chalk, limestone, dinosaurs"Age of Reptiles"

MESOZOIC Jurassic 210 dinosaurs"middle life"continental drift begins

Triassic 245

Permian 290

Carboniferous 365 coal age"Age of Amphibians"

Devonian 410PALAEOZOIC "Age of fishes""old life"

Silurian 440

Ordovician 500

Cambrian 570 trilobites

Proterozoic 2400 fossils now knownPRE-CAMBRIAN

Archaean 4500 no fossils

* Periods are divided into Upper Periods can be divided intoand Lower and sometimes, Middle Zones according to dominant

fossils, and may span 500 m yrseach or much less


Ore Deposit Types

VALUES HOST DEPOSIT EXAMPLE CHARACTERISTICS

Cu, Zn, Sn granite-hosted tin South Crofty UK deposits in granitic plutons. similar to porphyry coppers. low grade.

Au, Cu, Ag sediment-hosted Muruntau Uzbekistan metals concentrate in hydrothermal fluids.

Cu, Ag kupferschiefer Lublin Poland stratiform sulphide deposits; marine or deltaic environments. proterozoic-tertiary sediments.

Au, Ag epithermal gold Carlin USA, McLaughlin USA, Lepanto Philippines

shallow deposits at convergent plates. vein and disseminated sulphide types.

Cu, Ni mafic sulphide- hosted Mt Keith WA, Voisey Bay Canada

primary sulphides in igneous rocks in archaean greenstones. up to high tonnages.

Diamonds kimberlite alluvial & marine

Premier RSA Kleinsee RSA

ultramafic rocks in volcanic pipes, sills. proterozoic and later. weathering of kimberlites formed gem quality placer deposits.

Pt, Pd, Rh, Ir, Ru, Os layered mafic intrusions Bushveld UG2 RSA

orthomagmatic sulphides in large layered igneous complexes. high temp magma formation & crystallization. proterozoic.

Pt, Pd, Rh, Ir, Ru, Os, Cu, Ni layered mafic intrusions Bushveld Merensky Reef RSA,

Stillwater as above. differences in geochemical evolution of magma concentrated Ni and Cu in layers.


Ore Deposit Types (continued)

VALUES HOST DEPOSIT EXAMPLE CHARACTERISTICS

Pt, Pd, Rh, Au alluvial Goodnews Bay USA sediment-hosted placer deposits from weathering of mafic igneous complexes, concentration of PGEs and Au by fluvial processes.

Pt, Pd, Rh, Ir, Ru, Au, Cu, Ni layered mafic intrusions Merensky Reef,

Norilsk, Sudbury same geological setting and genesis as before with Ni, Cu and Au concentrated in certain layers.

Coal open pit Witbank RSA, Griffin WA

shallow stratiform seams. overburden usually mid-to-late phanerozoic sediments.

Chromium chromitite

Dwarsrivier RSA

chromitite in two deposit types. stratiform: ultrabasic layered igneous complexes. podiform: different structural form, tectonised ultrabasic sequences of ophiolote complexes.

Tantalum tantalite Greenbushes WA in sheared archaean granite-greenstone terranes. low volume, high value.

Other Minerals

laterite nickel bauxite (Al) stratabound iron stratabound manganese

Murrin Murrin WA Huntly WA Thabazimbi RSA, Hammersley WA Sishen RSA

extensive surface deposits. secondary mineralisation after weathering of crystalline parent rocks. high volume, low value.


Ore Deposit Types VALUES HOST DEPOSIT EXAMPLE CHARACTERISTICS

Au

shear-hosted paleo- conglomerates

Finniston, Sunrise Dam WA, Ashanti Ghana, Witwatersrand Alluvial (Magaden Russia)

archaean mesothermal lode deposits in shear zones. gold-bearing conglomerates from weathering of archaean greenstone belts. 7g/t.

Cu carbonatite Palabora proterozoic to recent intrusive magmatic carbonates and associated alkaline igneous rocks

Ag epithermal ex hydrothermal fluids of extrusive /shallow intrusive igneous rocks.

Pb, Zn, Ag carbonate - hosted

Galmoy Ireland, Reocin Spain, Pine Point Canada

phanerozoic deposits in thick sequences of dolomite/limestone rocks. Formed in warm sea. 3-10%

Cu, Mo porphyry Escondida Chile low grade (0.5-2%) large deposits (1000 Mt). Molybdenum may occur.

Cu, Au skarn porphyry

Nickel Plate Canada, La Luz Nicaragua Grasberg Indonesia, Bingham USA

phanerozoic deposits formed at high temps by igneous intrusions at convergent plate margins. see Cu, Mo porphyrys

Cu, Zn volcanogene Neves Corvo Portugal, Black Mountain RSA

stratiform massive sulphide deposits between volcanic units


Placer Deposit

An alluvial deposit of ore, usually a mineral-bearing gravel or sand. Any concentration of the heavier and more durable minerals that have deposited from the actions of erosional forces.


KIMBERLITES AND DIAMONDS


• Crumbly, grey-green, often soft, igneous, ultrabasic, coarse grained dark rock often with porphyritic texture and brecciated appearance. In peridotite rock mantle pocketed with eclogite (50% garnet).

• Usually found in archaean cratons of basement rock 2.5 billion years old. Youngest known diamond-bearing pipe is 45 miilion years old.

• Usually in pipes (hypabyssal occurrence in plutons) of up to 1km diameter (largest 361 acres).

• Primary mineral is serpentized olivine and associated minerals are phlogopite, pyroxenes, carbonate, chromite, pyrope garnet, rutile and perovskite.

Kimberlite


• Origin - kimberlite pipes

• Gem - octahedra, cubes, dodecahedra, tetrahedra crystals.

• Boart – rounded with radiating structure.

• Carbonado – microcrystalline mass.

• SG 3.52, hardness 10, carbon

Diamond


• Indicator minerals diamonds in kimberlites are chrome diopsides (green), garnets (pink, purple, orange, yellow, green), microdiamonds.

• Pyrope garnets (shown): some purple (or deep red) garnets have same high chrome low silica chemical profile as diamonds (Harzburgitic signature). If these G10 garnets are not present there will be no diamonds.

• Eclogite rock can be very diamond-rich and contains orange garnets, not G10s.

Indicator Minerals For Diamond-bearing Kimberlites

Kimberlite pipes often occur in clusters and different ilmenites in the pipes assist in defining them.


Lamproite

A second primary source of diamonds of potassium-rich hypabyssal lamprophyric rocks formed from magmatic intrusions (Miocene). Olivine lamproite and leucite lamproite are known to be diamond-bearing. Indicators minerals are chromites, andradite and zircon – garnets are rare. The AK1 deposit at Argyle Diamond Mine is a well-known lamproite orebody.The surface weathered ore has a Bond Work index of 10 kWh/t and an Abrasion Index of 0.22. The deeper more competent unweathered ore has a BWI of 18 and an AI of 0.60.


Hypabyssal

Intrusive igneous rocks In smaller host bodies at intermediate depths, examples: dykes and sills Medium to fine-grained “Plutonic” if formed in very large masses at greatest depths, coarse-grained, visible minerals, e.g. batholiths


Carbonatites Calcium carbonate (calcite)-rich rock Magmatic ! Can contain magnetite, apatite, micas, sulphide minerals.


Basalts

Formed from “basic” lavas Most common of all volcanic rocks Dark compact rocks (mafic), very fine-grained Acid lavas form light low density rocks (felsic)


Laterites Of peculiar composition, found in moist-tropical regions. Crusty, reddish-brown deposits, hardened by precipitation of iron. Laterite can develop through deep weathering and are rich in hydroxides of aluminium and iron, concentrated by the upward leaching by ground water due to the rapid surface evaporation of moisture. Murrin Murrin in a laterite-hosted orebody typically 20 m in depth and 10 m overburden and has a nickel-cobalt mineralisation. Bauxite, Al2O3.2H2O is a lateritic mineral.


MINERALS


Mineral Solid substance having a regular and definite chemical composition


Mineral Content

Industrial minerals can have a high concentration of values such as 94% iron oxide in iron ore. Base metals contents are often in the low percentages, e.g. copper 3%. Precious metals ores usually have a tiny content of values, e.g. gold and platinum contents are typically 0.0005% or 5 gram/ton or 5 parts / million.


RESOURCES


RESOURCES AND RESERVES

IN SITU RESOURCES reported as mineralization in place INFERRED INDICATED MEASURED

EXTRACTABLE RESERVES reported as mineable production estimates PROBABLE PROVEN

consideration of mining, metallurgical, economic, marketing, legal, environmental, social and governmental factors

the modifying factors

increasing level of geological knowledge and confidence


Reserves

That part of a mineral deposit which can be economically and legally extracted at the time of the reserve determination. There are two categories of reserves: Probable and Proven


Probable Ore Tonnage & grade are computed partly from specific measurements (samples/production data) and partly from projections (geological evidence over a reasonable distance). Refers to sites available for inspection, measurement and sampling but which are inappropriately spaced for outlining the ore completely or fully establishing it’s grade.


Proven Ore

Tonnage is computed from dimensions revealed in outcrops, trenches, drill holes, underground workings and grade from the results of adequate sampling. The sites for inspection, sampling and measurement are so well spaced and the geological character so well defined that size, shape and mineral content are accurately established.

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GLOSSARY - MINERALOGY - Multotec · The AK1 deposit at Argyle Diamond Mine is a well -known lamproite orebody.The surface weathered ore has a Bond Work index of 10 kWh/t and an Abrasion