Lec01 OreDepGeol Terminology

Applied Geology

GEOL3010/5017 Ore Deposits

Unit Introduction

Dr Kirsten RempelDepartment of Applied Geology

Western Australian School of Mines

Unit Information

Unit Coordinator: Dr Kirsten Rempel Office: 312.209

Phone: 9266 4376email: [email protected]

Bentley office hours: Mondays, 3 - 4 PM and Thursdays, 12 - 1 PM

Blackboard is another place to look for information

Online Resources

A.K.A. the Blackboard site Unit Outline - Please read carefully

Materials: lecture notes, practicals, iLectures, supplementary resources

Announcements: important information about the unit (exam formats, assignment tips, deadlines...)

Quizzes - instant feedback on your understanding

Links to online textbooks and other readings

BB is updated regularly – check in often!

Reference Materials

Recommended texts: online resource or bookshop Evans, A.M., 1993. Ore Geology and Industrial Minerals:

An Introduction. Blackwell Scientific, 390 p. (3rd edition) Robb, L., 2004. Introduction to Ore-forming Processes.

Blackwell Scientific, 373 p.

Practical work: Collins, P.L.F., 1997. Ore Petrology Reference Manual.

(on blackboard) Equipment for examining/describing ore samples

(e.g., hand lens, hardness scribe, magnet, etc)

TuitionLectures - both of these:

Monday 11:00 - 12:00 201-332Thursday 10:00 - 11:00 401-001

* iLectures should be available, but not guaranteed!

Practicals (Bentley) - one of these:Monday 12:00 - 13:00 312-202Tuesday 08:00 - 10:00Tuesday 12:00 - 14:00Tuesday 14:00 - 16:00

* You can normally attend any practical session, but priority goes to those registered. The practical exam must be written during your registered session.Attendance in practicals is expected & necessary

Assessment

Practical componentPractical exercises & test = 40% Ore petrology exercises * (20%) Ore petrology practical test (20%)

Theory componentLiterature review assignment = 20%Theory (written) examination = 40%

- only 3 selected exercises will be marked -Lab exercises: Submitted to 3rd-year assignment box

Lit review: Submitted on Blackboard

Unit Requirements

Unit completion requirements Achieve at least 50% for the unit At least 40% in both theory & practical components

Complete all practicals and assignments, even if late

Submission of assigned work Due dates are on your unit outline & will be announced

Late submission penalised by -10% per day Extensions for medical & serious personal situations only

Tuition Plan (weeks 1-9)Week Start Date Lecture/Lab and Topic

L = Lecture; P = PracticalAssessments

1. 2 MarchL1: Introduction; Ore deposit morphology & architecture, terminologyP1 Bentley: Introduction to ore petrology & microscopy (not assessed)L2: Ore deposit models, ore-forming processes (genesis) & classification

Lit review assignment

issued

2. 9 March

L3: Magmatic deposits I. Orthomagmatic Cr, disseminated PGE & Fe-Ti-V P2 Bentley: Magmatic deposits I - Chromite & PGE (Cumulates)L4: Magmatic deposits II. Ni sulphide deposits; liquid immiscibilityP1-P2 Kalgoorlie: Introduction to ore petrology, Magmatic deposits I

3. 16 MarchL5: Magmatic deposits III. Diamonds & carbonatites (REE deposits) P3 Bentley: Magmatic deposits II - Massive Ni-Cu sulphide oresL6: Hydrothermal ore-forming processes, systems & environments

P2 due (Bentley)

4. 23 March

L7: Rare metal pegmatites (magmatic-hydrothermal transition)P4 Bentley: Magmatic deposits II - Massive Ni-Cu sulphide ores, cont’d.L8: Intro to hydrothermal alterationP3-P4 Kalgoorlie: Magmatic deposits II - Massive Ni-Cu sulphide ores

P2 due (Kal)

5. 30 MarchL9: Orogenic greenstone-hosted gold deposits P5 Bentley: Hydrothermal deposits I - Epithermal gold L10: Research methods I. Stable isotopes (S, C, O, H; applications)

P3-P4 due (Bentley)

6. 6 April TUITION-FREE WEEK7. 13 April TUITION-FREE WEEK

8. 20 April

L11: Research methods II. Fluid inclusions and applications to ore depositsP6 Bentley: Hydrothermal deposits II - Orogenic gold depositsL12: Methods III. Resource & reserve estimation, JORC codeP5-P6 Kalgoorlie: Hydrothermal deposits II - Orogenic gold deposits

P5 due (Bentley)

P3-P4 due (Kal)

9. 27 AprilNo Monday lecture or Bentley practical (ANZAC Day)L13: Epithermal Au-Ag vein deposits (subvolcanic-volcanic environments)

Tuition Plan (weeks 10-17)

10. 4 May

L14: Porphyry Cu-Mo and Cu-Au deposits (granitic-subvolcanicenvironments)P7 Bentley: Hydrothermal deposits II - Orogenic gold deposits, cont’d.L15: Granophile Sn-W deposits (veins, greisens, skarns)P7-P8 Kalgoorlie: Hydrothermal deposits III - VMS and SEDEX deposits

P5-P6 due (Kal)

11. 11 MayL16: Volcanic-hosted massive sulphide (VMS) Zn-Cu-Pb-Ag-Au depositsP8 Bentley: Hydrothermal deposits III - VMS and SEDEX deposits

L17: Sedimentary exhalative (SEDEX) shale-hosted Pb-Zn-Ag deposits

P6-P7 due (Bentley)

12. 18 May

L18: Sediment-hosted base metal deposits: Mississippi-Valley Type (MVT) Pb-ZnP9 Bentley: Hydrothermal deposits III - VMS and SEDEX deposits, cont’dL19: Stratiform Cu deposits (SCD), uranium depositsP9-P10 Kalgoorlie: Hydrothermal deposits I, BIFs & iron ore

Lit review assignment due(Bentley & Kal)

P7-P8 due (Kal)

13. 25 May

L20: Iron ore deposits: Banded iron formations (BIFs)P10 Bentley: BIFs & iron ore L21: Secondary and supergene enrichment processes: Al, Au, Ni laterites, placer gold deposits

P8-P9 due (Bentley)

14. 1 June

L22: Metallogeny & plate tectonics: Metallogenic provinces and epochs; plate tectonics and ore processes P11 Bentley: Practical test (during scheduled prac sessions)L23: Review sessionP11 Kalgoorlie: Review and practical test (during scheduled prac sessions)

P10 due (Bentley)

P9-P10 due (Kal)

Practical Test (Bentley & Kal)

15. 8 June Study Week16. 15 June Exam Week 1

Theory Exam 17. 22 June Exam Week 2

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ACKNOWLEDGEMENT

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ORE DEPOSIT GEOLOGYMorphology & Terminology

GEOL3010/5017 Ore Deposits

Dr Kirsten RempelDepartment of Applied Geology Western Australian School of Mines

Additional Reading

Robb, L., 2005 Introduction: terminology, classification (p. 1-15)

Evans, A.M., 1993 Ch. 2: deposit morphology (p. 26-38)

What is economic geology?

Mineral resources

Mineral/ore deposit nomenclature

Descriptive terminology

Ore genesis

LECTURE OUTLINE

Study of geologic bodies and materials that can be used profitably

e.g., fossil fuels, metals, non-metallic minerals, water

Application of geologic knowledge and theory to...

Understanding the origin of mineral (ore) deposits

Search for mineral (ore) deposits

Use of the Earth’s resources

ECONOMIC GEOLOGY

Economic Geology

ECONOMICGEOLOGY

Scientific AspectsGeological studiesOre deposit modelsExploration models

Applied AspectsMineral exploration

MiningMineral economicsOre beneficiation

Metallurgy

Geological mappingStructural geologyPetrology (igneous/meta)SedimentologyMineralogyGeochemistryHydrologyRegolithExploration geophysicsExploration geochemistry

Integration of numerous aspects of geosciences

Fuel (energy) Resources

Earth Resources

Non-crystalline substances

(e.g., coal, petroleum)

MINERAL RESOURCES

Mineral Resources

Crystalline substances

(e.g., minerals)

Economic quantity concentrated in specific geological settings

Fuel (energy) Resources

Earth Resources

MetallicMineral

Resources

IndustrialMineral

Resources

Mineral Resources

Mineral Resources

Mineral Resources

Metallic mineral resources Source of metals within minerals

Ore deposits are mined for the metals that they contain and that can be extracted by industrial processes

Examples:

Chalcopyrite (CuFeS2) is mined for its copperSphalerite (Zn,Fe)S is mined for its zincCassiterite (SnO2) is mined for its tinRutile (TiO2) & ilmenite (FeTiO3) for titanium

ORE DEPOSIT NOMENCLATURE

Definitions and terms Mineral deposit Ore deposit (ore body) Ore Ore minerals Gangue Descriptive terminology Ore evaluation

Host structures Ore morphology Ore textures Genetic processes

Ore Deposit Nomenclature

Mineral deposit Mass of naturally occurring mineral material (metal ores

or non-metallic minerals) potentially of economic value Abnormal abundance of metallic or non-metallic

minerals in the crust Geological entity

Ore deposit (ore body) Continuous well-defined mass of material of sufficient

mineral content to make extraction economically feasible

Highly anomalous concentration of (metallic) minerals

Classification as an ore deposit depends on:

Geological factors (e.g., deposit morphology) Mining parameters (e.g., mining method) Metallurgical factors & processing techniques Economic factors (e.g., market value of commodity) Social & environmental factors Governmental & legal factors Political factors (royalties & political stability)



Ore Mass of rock containing an ore mineral, or aggregate

of ore minerals, that can be mined and extracted economically (i.e., at a profit)

Ore mineral Mineral(s) in the ore that is(are) economically desirable

for the contained metale.g., hematite (Fe), pentlandite (Ni), gold

Gangue (pronounced “gang”) Those minerals that occur with the ore minerals but

which have no value (for a particular deposit)e.g., quartz, calcite, pyrite... Hematite, pentlandite, gold?

Ore Deposit NomenclatureOre minerals *I Native elements gold, silver, bismuth, platinoids,

diamondsII Sulphides (sulphosalts) galena, sphalerite, chalcopyrite

pyrite, pyrrhotite, molybdeniteIII Oxides (hydroxides) magnetite, hematite, cassiterite,

tantalite, rutile, ilmenite, goethite, chromite

IV Halides halite, sylvite

V Carbonates, Nitrates, Borates azurite, malachite

VI Sulphates, Molybdates, Tungstates (WO4)

scheelite, wolframite

VII Phosphates monazite (Ca,La,Th)PO4

VIII Silicates spodumene, Li-mica (lepidolite)

* Refer to lists of ore minerals in Robb (2005), introduction

EVALUATION TERMINOLOGY

Terms used in evaluation of ore deposits:

Mineralisation/ore Host rock (country rock, wall rock) Waste (waste rock) Grade

Concentration of a metal or mineral in the ore Cut-off grade

Lowest grade of ore that can mined & treated economically Mineral Resources & Ore Reserves

Quantity of ore available to be mined at a specific grade Strict criteria apply to the use of these terms

Evaluation Terminology

Ore =ore minerals+ gangue + waste rock

Waste =additional rock removed during mining of the ore

Waste(rock removed from stope during mining)

Oreore minerals+ gangue

+ waste

Host rock

Host rock

Stope outline(mining cavity)

Drive

Open pit

Example: Gold in quartz-pyrite vein

Evaluation TerminologyDevelopment drive in ore

Bendigo gold mine, VictoriaPhoto: Bendigo Mining NL

Host rock

Host rock

Waste(waste rock

removed with ore)

MORPHOLOGY TERMINOLOGY

Morphology terms Describe overall shape (morphology) of a mineral/ore

deposit, in relation to its host rocks

Fundamental ore deposit shapes:

1. Concordant parallel with primary structures

in the enclosing rocks2. Discordant cut across primary structures in

the enclosing rocks

Morphology Terminology

Fundamental shapes: Concordant

Stratabound = entirely within a single stratigraphic unit (irregular in shape)

Stratiform = parallel to lithological layering

Discordant Tabular = veins, fissures, shear zones

Tubular = shoot, pipe, chimney, manto

Irregular = disseminated, stockwork

Replacement (regular – irregular)


Example: Concordant deposits

Concordant & stratabound Concordant & stratiform

Source: GSC/National Resources Canada

Source: Evans (1987)

Stratiform Pb-Zn mineralisation at Silvermines, Ireland


Example: Discordant depositsDiscordant & tabular

Source: Evans (1987) Source: Evans (1987)

Llallagua tin vein system (cassiterite), Bolivia

Vein Swarm, Filon Maestro, Spain(Ormonde Mining)


Example: Discordant depositsDiscordant & tubular

Vulcan tin pipe, Herberton, Queensland

Source: USGS (2004)

Solution-collapse breccia pipe, Colorado Plateau

Source: Evans (1987)


Discordant & irregular

Stockwork vein network & alteration Golden Cross deposit, NZPhoto: D. Arne

Example: Discordant deposits


Controls on Ore Deposit Morphology: Commonly some physical factor (bedding, layering

faults, fractures) Deposits in...

sedimentary rocks controlled by bedding

volcanic rocks controlled by bedding/layering

igneous rocks irregular in shape, orcontrolled by internal layering or intrusion margin

metamorphic rocks controlled by deformational structures (folds, faults, shear zones) or metamorphic structures (foliations)


Controls on Ore Deposit Morphology, cont’d Mineral deposits usually connected with some form

of natural trap, which can control the shape

Primary control (syn-mineralisation) Ore body forms during accumulation of the host rock

(sedimentary, volcanic, igneous)

Example: topography trapping heavy minerals in a stream bed

Lithological control (pre-mineralisation) Ore body confined to specific strata

Example: skarn deposit in carbonate rocks


Controls on Ore Deposit Morphology, cont’dStructural control (syn or pre-mineralisation)(may be referred to as 'ground preparation')

Ore body shape may be controlled by pre-existing features/structures features that develop during a mineralising event large & small scale structures (can also control the

distribution of minerals)

Faults, joints (open fractures) and folds may control the overall shape of an ore body

Example: stockwork deposit (irregular system of fissures filled with minerals)

STRUCTURAL TERMINOLOGYDescribe the structural setting and relationships of an ore deposit to the host rock (on a deposit-scale)

• Footwall

• Hanging wall

• Lode

• Shoot

• Stringer

• Pinch and swell

Lodegold in quartz-pyrite vein

Host rock

Host rock

Drive

Open pit

Structural Terminology

Pinch & swell and ore shoots:

Pinch & swell develops when fractures cut across rocks of different competencies

Ore shoots are zones with an ore-bearing structure that are much

thicker or higher grade than the remainder of the structure

TEXTURAL TERMINOLOGY

Describe internal texture of components making up an ore deposit (macroscale)

• Breccia• Vein – single, sheeted, ladder, saddle• Stockwork – intersecting sets of veins • Disseminated• Massive• Bedded• Banded• Crustiform banding• Comb texture• Cockscomb texture• Vuggy

Textural Terminology

Breccia ores

Fault-controlled breccia ore, Pillara Zn-Pb mine, WA Brecciated ore, Kapok, WA

Photo: D. Arne

Fault

Orebody

Textural TerminologyVein deposits

Sheeted vein swarm Bendigo Gold mine, Vic

Photo: Bendigo Mining

Sheeted veinsCadia Hill NSW (Corbett 2002)


Vein Stockwork: network of pyrrhotite-pyrite-chalcopyrite veins in basalt. Windy Craggy, Canada. Images: GSC, NRC

Stacked saddle reefs: Dufferin deposit, Nova Scotia Image: GSC/NRC

Vein deposits

Textural TerminologyMassive ore

Massive Ni-sulphide ore, Kambalda

Disseminated ore

Disseminated Ni-sulphide ore,

Mt. Keithphoto: CSIRO


Bedded ore

Bedded, folded and offset sulphide ore,Howards Pass deposit, CanadaPhoto: GSC, NRC

Bedded and offset sulphide ore,Tom deposit, CanadaPhoto: GSC, NRC


Open space fill texturesCrustiform quartz,Empire Vein, NZ

Crustiform quartz, NZ

Galena

Dolostone

Internal sediment

Calcite

Textural TerminologyOpen space fill textures

Banded replacement ore, Cadjebut mine

Colloformsphalerite

ORE GENESIS

Ore genesis: Origin or mechanism of formation of an ore (mineral)

deposit

Fundamental genetic types of ore deposit:based on timing relationship between deposit & host rocks

Syngenetic Ore deposits that form at the same time as the host rock

Epigenetic Ore deposits that form some time after the host rock

In this lecture...

Economic geology uses a lot of new terminology, applied to a variety of features:

1) Ore evaluation- resource and reserve, ore vs. waste

2) Ore morphology- concordant vs. discordant - stratabound vs. strataform

3) Host structures - hangingwall vs. footwall, pinch & swell

4) Ore textures- massive vs disseminated, open space filling

5) Genetic processes- syngenetic vs. epigenetic

Lec01 OreDepGeol Terminology

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