Overview
This lecture covers the definition, classification, importance, and modes of occurrence of mineral resources, including their types and practical examples.
Definition of Mineral Resources
- Mineral resources are naturally occurring inorganic substances found in Earth's crust.
- A mineral is a pure inorganic substance composed of the same type of particles and occurs naturally.
- Minerals are generally free of carbon (exceptions exist, like diamond).
- Earth's crust (except small organic parts) is made up mostly of minerals.
- Some minerals consist of a single element (e.g., gold, silver, diamond, sulfur).
Composition and Elements
- Over 2,000 minerals have been identified, mostly containing inorganic compounds.
- Most minerals are formed by combinations of eight elements: oxygen, silicon, aluminium, iron (ferrus), calcium, sodium, potassium, and magnesium.
- These eight elements make up 98.5% of Earth's crust.
Characteristics and Types of Mineral Resources
- Mineral deposits refer to naturally occurring materials in Earth's crust that can be profitably extracted and converted.
- Mineral resources are non-renewable, taking millions of years to form.
- They include metals (iron, copper, aluminium) and non-metals (salt, gypsum, sand, phosphate).
Classification of Minerals
- Minerals are classified as metallic, non-metallic, and energy minerals.
- Metallic minerals: Provide metals; subdivided into:
- Ferrous (contain iron, e.g., iron ore, nickel, cobalt, manganese)
- Non-ferrous (no iron, e.g., copper, lead, tin, bauxite)
- Precious (high economic value, e.g., gold, silver, diamond, platinum)
- Non-metallic minerals: Do not contain metals (e.g., mica, salt, potash, sulfur, granite, limestone, marble, sandstone)
- Energy minerals: Provide energy or power (e.g., coal, petroleum, natural gas)
Importance of Minerals
- Almost everything we use is made from minerals.
- Export of minerals earns foreign exchange for countries.
- Mining and extraction of minerals provide employment.
- Major minerals like coal and petroleum are crucial energy sources.
Modes of Occurrence of Minerals
- In igneous/metamorphic rocks: Found in crevices/joints as small veins or larger lodes (e.g., tin, copper, zinc, lead).
- In decomposed rocks: Formed by weathering and removal of soluble parts, leaving residual minerals (e.g., bauxite).
- In alluvial deposits: Found in sands of valley floors/bases of hills as placer deposits, typically not corroded by water (e.g., gold, silver, tin).
- In sedimentary rocks: Occur in beds/layers formed by deposition and concentration in horizontal strata (e.g., coal, some iron ore, salt, gypsum, potash, sodium salts).
- Minerals can also be found in ocean water.
Key Terms & Definitions
- Mineral — Pure inorganic substance occurring naturally in Earth's crust.
- Ferrous minerals — Minerals containing iron.
- Non-ferrous minerals — Metallic minerals without iron content.
- Precious minerals — Minerals with high economic value like gold or diamond.
- Non-metallic minerals — Minerals without metal content.
- Energy minerals — Minerals used as sources of energy.
- Veins and lodes — Small and large mineral deposits in rocks.
- Placer deposits — Mineral deposits found in alluvial sediments.
Action Items / Next Steps
- Review and memorize the classification chart of minerals (metallic, non-metallic, energy).
- Read the provided practice questions and prepare answers.
- Start reading editorials for exam preparation to improve comprehension and analytical skills.
- Begin preparing for chosen optional subjects if not already started.