Mineral Deposit Geology and Models

Question 1

_____ which occurs at the surface can be worked by cheap open pit methods.

Answer 1

Large, low-grade deposits

Question 2

_____ will necessitate more expensive underground methods of extraction

Answer 2

Thin tabular vein deposits

Question 3

_____, aided by the savings from bulk handling of large daily tonnages, has led to a trend towards the large scale mining of low grade orebodies

Answer 3

Open pitting

Question 4

Ore bodies of _____ can be mined more cheaply than those of _____, particularly when they include barren zones

Answer 4

regular shape, irregular shape

Question 5

For an open pit mine, the shape and attitude of an orebody will also determine ____

Answer 5

how much waste has to be removed during mining

Question 6

if an orebody viewed in plan is longer in one direction than the other, we can designate this long dimension as its _____.

Answer 6

strike

Question 7

The inclination of the orebody perpendicular to the strike.

Answer 7

dip

Question 8

The longest dimension of the orebody.

Answer 8

axis

Question 9

The _____ of the axis is measured in the vertical
plane ABC

Answer 9

plunge

Question 10

Can be measured in any other plane, the usual choice being the plane containing the strike,

Answer 10

pitch or rake

Question 11

if the orebody is fault-controlled then the _____ may be measured in the fault plane.

Answer 11

pitch

Question 12

These bodies are extensive in two dimensions but have restricted development in their third dimension.

Answer 12

Tabular orebodies

Question 13

Frequently pinch and swell out as they are followed up or down a stratigraphical sequence

Answer 13

Vein

Question 14

Sometimes called fissure-veins

Answer 14

Veins

Question 15

Can create difficulties during both exploration and mining often because only the swells are workable.

Answer 15

pitch-and-swell structure

Question 16

Tabular orebodies that are vertical or sub-vertical

Answer 16

pipes or chimneys

Question 17

Horizontal or subhorizontal tabular orebodies

Answer 17

mantos

Question 18

Ore minerals are peppered throughout the body of the host rock in the same way as accessory minerals are disseminated through igneous rock; in fact, they often are accessory minerals.

Answer 18

Disseminated orebodies

Question 19

Closed-spaced veinlets cutting the host rock forming an interlacing network

Answer 19

stockwork

Question 20

Mineralization of this type generally fades _____ into sub-economic mineralization and the boundaries of the orebody are assay limits.

Answer 20

gradually outwards

Question 21

(Skarn or contact metamorphic or pyrometasomatic or replacement deposit) Mineralogy

Answer 21

calc-silicate minerals
- diopside
- wollastonite
- andradite garnet
- actinolite

Question 22

(Skarn or contact metamorphic or pyrometasomatic or replacement deposit) Ore Mineralogy

Answer 22

• iron
• copper
• tungsten
• graphite
• zinc
• lead
• molybdenum
• tin
• uranium
• talc

Question 23

these orebodies show a considerable development in two dimensions, parallel to the bedding and perpendicular to it, referred to as stratiform.

Answer 23

Sedimentary host rocks

Question 24

Any type or types of orebody, concordant or discordant, which are restricted to a particular part of the stratigraphical column

Answer 24

Strata-bound

Question 25

Parallel to the bedding and perpendicular to it,

Answer 25

Stratiform

Question 26

Sedimentary host rocks e.g

Answer 26

- Limestone hosted - Argillaceous hosted - Arenaceous hosted - Rudaceous hosted (Placer Deposit)

Question 27

Sedimentary iron and manganese formations and evaporites occur scattered through the stratigraphical column where they form very extensive beds conformable with the stratigraphy.

Answer 27

Chemical sediments

Question 28

Volcanic hosts

Answer 28

Volcanogenic Massive sulfides

Question 29

VMS are generally stratiform bodies, _____ or _____, developed at the interfaces between volcanic units or at sedimentary interfaces.

Answer 29

lenticular, sheet-like

Question 30

Plutonic hosts

Answer 30

Layered Mafic Intrusions (LMI)

Question 30

Plutonic hosts (Magmatic Segregation Deposits)

Answer 30

- Layered Mafic Intrusions (LMI) - Layered Cr-Pt MAfic-Ultramafic Complexes -Cu-Ni-Pt Segregation - Anorthosite - Titanium - Ultramafic volcanic rock associations - Cu - Ni

Question 31

Known also as “Mesothermal Au”, “Slate belt-type Au”, “Archean Au”, “deposits related to solution- remobilization”

Answer 31

Orogenic Gold

Question 32

Restricted to the ultramafic rocks of the various ophiolite belts where climatic conditions and physiographic favor laterization processes.

Answer 32

Laterite

Question 33

high iron content, low nickel, cobalt, magnesia, and silica.

Answer 33

Limonite

Question 34

high nickel, cobalt, and magnesia, but low iron content.

Answer 34

Garnierite/Saprolite

Question 35

is an aluminium ore. It is the world's main source of aluminium. It consists mostly of the minerals gibbsite Al(OH)3, boehmite γ-AlO(OH) and diaspore α-AlO(OH), mixed with the two iron oxides goethite and hematite, the clay mineral kaolinite and small amounts of anatase TiO2.

Answer 35

Bauxite

Question 36

Bauxite source rocks

Answer 36

Nepheline Syenite Clay Clayey limestone Clay shales Crystalline gneisses Basalt Alluvium