5.01 Metals in the Earth's Crust

• Composition of the Earth's Crust

  • The crust is the outer layer of the Earth, composed of various compounds and elements.

  • Major components:

    • Oxygen: 45%

    • Silicon: 27%

    • Aluminum: 8%

    • Iron: 6%

    • Calcium: 5%

    • Magnesium: 3%

    • Sodium: 2.5%

    • Rest metals and non metals 2%

    • Potassium: 1.5%

  • Nearly three-quarters of the crust consists of oxygen and silicon, often found in compounds like silicon dioxide (sand).

• Scarcity of Metals

  • Only six metals are abundant; others are scarce, making up less than 2% of the crust.

  • Scarce metals include:

    • Copper

    • Zinc

    • Lead

    • Tin

    • Mercury

    • Silver

    • Gold

    • Platinum

  • Scarce metals are expensive and are being depleted quickly.

• Definition of Ores

  • Ores are rocks containing a high concentration of a single metal or metal compound worth extracting.

• Economic Considerations for Mining

  • Mining companies assess:

    1. Quantity of ore available

    2. How much metal from it

    3. Extraction challenges

    4. Mining and extraction costs, worker costs, excavator etc costs

    5. Market price for the metal

    6. Profitability of mining

  • Local community concerns include environmental impact and job creation.