Introduction covering the following topics:
Course identity and main aims of its study.
The importance of course for economic geologists.
Subdivisions of the course.
A refreshing account on the main aspects of optical mineralogy.
The components of ore microscope; the mechanism of working of ore
microscope
The main differences between the optical properties of minerals in both
transmitted and reflected lights.
The main objective of the course is supplying students with the different aspects
of the light behavior on polished surfaces.
The students are supposed to be informed with a collective idea about the
intimate relationship between ore microscopy and the branch of ore dressing
since the interlocking index of ore and gangue minerals strongly determines the
proper method of ore beneficiation.
The course also demonstrates the main groups of ore minerals under the ore
microscope.
As an output, the course is intended to give students expertise in handling the
problems connected to ore genesis and beneficiation. Accordingly, the students
would be able to use the materials of the course in their future career, especially
for those who will work in the mining companies and authorities, as well as the
concentration plants.
Mid-Terms Exams (3 or 4 Exams)
40%
Students Activities (including subjects in mineralogy and mineral paragenesis of
some ore deposits)
10%
Final Practical Exam
Final Theoretical sheet
30%
20%
Preparation of different kinds of polished surfaces (sections and
slabs).
This account will demonstrate the precautions to be considered during
the preparation of the polished surfaces.
The account also covers the aspect of how to overcome the
imperfections to in order to ensure good quality surfaces.
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Optical properties of ore minerals in ordinary light (without using the
polarizer and analyzer).
These properties include form, habit, fractures, hardness and zoning.
Optical properties of ore minerals in polarized light (using the polarizer only,
and analyzer out).
They include color, reflection pleochroism and reflectivity
Optical properties of ore minerals between crossed-nicols (using both
the polarizer and analyzer). They include anisotropism, internal
reflection and twinning.
The group of native elements.
The group of sulphide minerals.
The group of oxide minerals.
Ore Textures: Descriptive and genetic classifications of ore textures.
1. Descriptive ore textures:
Single Grains
1. 1. 1. Internal
 Zoning
 Twining
1. 1. 2. External
 Morphology
Xenomorphic (= Allotromorphic Textur)
Hypidiomorphic Texture
Idiomorphic (= Panidiomorphic ) Texture.
 Grain-size
 Grain and crystal relationship
Simple banding
Complex banding
Space filling
Crustified banding
Comb or cockad texture
 Nucleation
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 Intergrowths
Emulsion intergrowth
Myrmeckitic texture
Oriented intergrowth
Penetration intergrowth
Aggregates
1.2.1.Arrangement aggregates
 Breccia aggregates
 Oriented, lineated or fibrous aggregates
 Rundum aggregates
 Rhythmic textures
1.2.2. Contact and intergranular rims and films
1.2.3. Inclusions
Genetic classification of ore textures:
Primary ore textures
Primary growth Texture
Colloform Textures:
botryoidal texture
Concentrically banded texture
Reticulate texture
Spherical Texture
Granular textures:
Salt and Pepper structure
Graphic and subgraphic textures
Zonal texture
Primary Depositional Textures
Oolitic texture
Theories of formation of oolitic textures
Spheroidal textures
Primary growth ore textures: Growth zoning and colloform textures.
Primary depositional Textures: Banding and laminations, vertical
grain size variations and oolitic textures.
Secondary textures:
Secondary replacement textures: rim, zonal, atoll, carrier, selective
and irregular types.
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Secondary deformational textures.
Paragenesis of ore minerals: tools used in determining
the paragenetic sequence. i. e. crystal shape, concavity
and convexity of crystals, colloform textures,
replacement textures, cross-cutting relations, etc…...
The application of ore microscopy in ore dressing,
upgrading and beneficiation.
Ore microscopy of representative examples of some
mineral deposits from Saudi Arabia.
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