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
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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 Deposit Nomenclature
Ore Deposit Nomenclature
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)
Morphology Terminology
Example: Concordant deposits
Concordant & stratabound Concordant & stratiform
Source: GSC/National Resources Canada
Source: Evans (1987)
Stratiform Pb-Zn mineralisation at Silvermines, Ireland
Morphology Terminology
Example: Discordant depositsDiscordant & tabular
Source: Evans (1987) Source: Evans (1987)
Llallagua tin vein system (cassiterite), Bolivia
Vein Swarm, Filon Maestro, Spain(Ormonde Mining)
Morphology Terminology
Example: Discordant depositsDiscordant & tubular
Vulcan tin pipe, Herberton, Queensland
Source: USGS (2004)
Solution-collapse breccia pipe, Colorado Plateau
Source: Evans (1987)
Morphology Terminology
Discordant & irregular
Stockwork vein network & alteration Golden Cross deposit, NZPhoto: D. Arne
Example: Discordant deposits
Morphology Terminology
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)
Morphology Terminology
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
Morphology Terminology
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)
Textural Terminology
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
Textural Terminology
Bedded ore
Bedded, folded and offset sulphide ore,Howards Pass deposit, CanadaPhoto: GSC, NRC
Bedded and offset sulphide ore,Tom deposit, CanadaPhoto: GSC, NRC
Textural Terminology
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