Course Number GHT 206
Principles of Economic Geology
Course Teacher : Professor Dr. Sanzida Murshed
Economic geology
✓ The branch of geology that focuses on the
distribution of economic mineral deposits, the
assessment of their reserves, and the economic
factors influencing their extraction.
✓ The primary goal of this study is to understand
the formation and localization of ore deposits
within Earth's crust and to identify new deposits
for extraction.
Important terminologies
➢ Mineral Deposit: A naturally occurring accumulation of minerals,
which may or may not be economically viable for extraction.
➢ Ore: A type of rock that contains minerals rich in valuable
elements, including metals. Ores are extracted through mining
and then processed to refine and obtain the desired elements.
➢ Ore Deposit: An ore deposit is a concentrated accumulation of
ore. If a mineral deposit contains a high enough concentration of
valuable minerals to be mined profitably, it is classified as an ore
deposit.
➢ Tenor of Ore : This term refers to the grade or richness of a
mineral deposit, specifically the concentration of the valuable
mineral or metal it contains. It is typically expressed as a
percentage of the metal present.
Important terminologies…
➢ Cut-off Grade: The minimum ore grade required for a
deposit to be economically mined.
➢ Gangue: Gangue is the commercially worthless material
that surrounds, or is closely mixed with, a wanted mineral in
an ore deposit.
➢ Lode deposit: In geology, a lode is a deposit of
metalliferous ore that fills or is embedded within
fissures, cracks, or veins in a rock formation. It may also
occur as a mineralized vein between rock layers.
➢ Placer Deposit: A surface accumulation of valuable minerals
formed by weathering and sedimentation processes (e.g., gold,
tin).
Ore Genesis
✓ Ore bodies are formed by a variety of geological processes.
The process of ore formation is called ore genesis.
✓ Ore genesis theories generally involve the following
components:
❑ Source is required because metal must come from
somewhere, and be liberated by some process.
❑ Transport is required first to move the metal bearing fluids or
solid minerals into the right position, and refers to the act of
physically moving the metal, as well as chemical or physical
phenomenon which encourage movement.
❑ Trapping is required to concentrate the metal via some
physical, chemicalor geological mechanism into a concentration
which forms mineable ore
➢ Mineral Resource: The total amount of a mineral deposit or
fossil fuel present including both known reserves and undiscovered
deposits.
➢ Mineral Reserve: The portion of a mineral deposit or fossil fuel
reserve that can be exploited with existing technology and under
current economic conditions.
➢ Mineral exploration: Mineral exploration is an intensive, organized and
professional form of finding commercially viable concentrations of
minerals to mine. This entails geochemical prospecting, drilling and
resource estimation via geo-statistics to quantify economic ore bodies.
➢ Mineral economics: aspects of natural resource extraction and use
and therefore involves studying topics in economic and financial analysis
that are developed to meet the special needs of the natural resource
industries.
➢ Mining: The process of extracting minerals, from the Earth's
surface or subsurface for economic gain.
Classification of Mineral Resources
❑ Metallic Minerals: Iron, copper, gold, lead, zinc,
aluminum, etc.
❑ Non-metallic Minerals: Limestone, gypsum,
phosphate, graphite, etc.
❑ Energy Resources: Coal, petroleum, uranium,
natural gas
❑ Critical Minerals: Rare Earth Elements (REEs),
lithium, cobalt (for high-tech and energy
industries)
Methods of Mineral Exploration
❑ Geological Surveys: Mapping rock types and
structures.
❑ Geophysical Methods: Using magnetism, gravity,
and electrical conductivity.
❑ Geochemical Sampling: Analyzing soil, water, and
rock chemistry.
❑ Remote Sensing & GIS: Satellite imagery for mineral
detection.
❑ Drilling & Sampling: Direct testing of subsurface
deposits.
Processes of mineral formation
1. Magmatic Concentration
2. Sublimation
3. Metasomatism
4. Hydrothermal Processes
5. Sedimentation
6. Submarine exhalative and volcanic process
7. Evaporation
8. Residual and Mechanical Concentration
9. Biological process
10. Oxidation and Supergene enrichment
11. Metamorphism
