M4 Earth Science

Lesson 1 – Importance of Minerals to Society

  • Mineral resources are natural Earth materials with a variety of uses; they must be extracted from the ground to be processed into products we use daily.

  • In physical vs health sciences:

    • Physical/geology: minerals are naturally occurring crystalline solids making up rocks and soils.

    • Health sciences: mineral = chemical elements essential to growth and healthy bodies.

  • Minerals are needed to manufacture almost everything we cannot obtain from living organisms; they provide shelter, tools, and raw materials for most products.

  • Everything not made of wood or plant materials often comes from minerals; mining is necessary to obtain these resources.

Key Terms and Definitions

  • Mineral Occurrence: concentration of a mineral of scientific/technical interest.

  • Mineral Deposit: mineral occurrence of sufficient size and grade to enable extraction.

  • Ore Deposit: mineral deposit tested and known to be economically profitable to mine.

  • Aggregate: rock/mineral material used as filler in cement, asphalt, plaster, etc. (nonmetallic deposits).

  • Ore: naturally occurring material from which a mineral or minerals of economic value can be extracted.

Mineral Formation and Types of Deposits

  • Deposits arise from geologic processes that concentrate minerals in specific environments.

  • Hydrothermal Ore Deposits:

    • Vein deposits: well-defined, inclined, discordant; often in fault or fissure openings.

    • Disseminated deposits: minerals distributed as minute masses; common in porphyry copper.

    • Massive sulfide deposits: metals precipitated as sulfides near mid-ocean ridges.

    • Stratabound ore deposits: minerals precipitated in sediment pore spaces (lake/ocean bottoms).

  • Magmatic Ore Deposits:

    • Crystal fractionation and crystal settling concentrate heavier minerals (e.g., chromite, magnetite, platinum).

  • Metamorphic Ore Deposits:

    • Alteration and recrystallization; pegmatites enriched in lithium, gold, rare elements.

    • Kimberlite magmas source diamonds; form kimberlite pipes.

  • Sedimentary Ore Deposits:

    • Evaporites: precipitated in closed marine environments (halite, gypsum, borax, sylvite).

    • Iron formations: iron-rich, often evaporite-like deposits.

  • Placer Ore Deposits:

    • Heavy minerals concentrated by moving water (gold, platinum, diamond, tin).

  • Residual Ore Deposits:

    • Result from chemical weathering; bauxite (aluminum ore), nickeliferous laterites; secondary enrichment.

  • Profitability depends on grade, depth, location, and processing technology; ore bodies are unevenly distributed.

Mineral Resources in Modern Society (Uses)

  • Copper: electrical conductors, motors, appliances, piping, alloys.

  • Gold: electronics, jewelry, medical/dental equipment, reflective/heat-shield applications.

  • Zinc: protective coatings, alloys.

  • Nickel: stainless steel manufacture.

  • Silver: electrical conductors, photography, medical uses.

  • Aluminum: electrical conductors, aircraft/ships, doors/windows, packaging.

  • Iron: steel manufacturing, magnets, paints, carbon-containing products.

  • Borax: fiberglass, high-temperature glass, cleaners, ceramics, fertilizers.

  • Talc: cosmetics, absorbent powders.

  • Clay: cement and concrete (construction).

  • Coal: steelmaking, electricity fuel, additives from slag.

  • Phosphate: phosphoric acid for fertilizers and chemicals.

  • Potash: fertilizers and chemical industry.

  • Lithium and rare earth elements: batteries and high-tech applications.

  • Common household items largely come from metallic and nonmetallic minerals; many items are alloys (e.g., brass = Cu + Zn; steel = Fe + C + others).

Home Use, Recycling, and Resource Management

  • Most common household materials are mineral-derived; many are non-renewable.

  • 3Rs: Reduce, Reuse, Recycle to conserve minerals and extend resource life.

  • Recycling and reuse help mitigate environmental impacts and sustain supplies for the long term.

Locating Ores and the Mining Lifecycle

  • Ore deposits are profitable only if extraction costs are outweighed by value; deposits are unevenly distributed globally.

  • Locating ores involves recognizing environments where geologic processes concentrate minerals (hydrothermal, magmatic, metamorphic, sedimentary).

  • Phases of mineral exploration:

    • Project design and feasibility

    • Field exploration: regional reconnaissance, detailed exploration, prospect evaluation

    • Pre-production feasibility study: ore size, shape, grade distribution, and mine design

    • Environmental and social impact assessment and mitigation planning

    • Mine design and construction with permits

Mining Methods and Milling Process

  • Mining methods depend on deposit type, rock strength, ore grade, costs, and current prices:

    • Underground mining: for high-grade metallic ores deep below surface; costly due to drilling/blasting; typical depths > 103 ft10^3\text{ ft} (≈ 3×102 m3 \times 10^2\text{ m}).

    • Surface mining: open pits, quarrying, placer mining, strip mining; lower cost for near-surface, lower-grade ores.

    • Placer mining: concentrates heavy minerals from sediment in rivers/beaches; example: titanium from beach sands.

  • Milling (ore processing) steps:

    • Crushing and grinding to reduce size

    • Separation techniques:

    • Heavy media separation: sinks heavier minerals from lighter waste

    • Magnetic separation: uses magnets for magnetic minerals

    • Flotation: creates froth to separate minerals based on surface properties

    • Cyanide heap leaching: low-grade gold ore where cyanide solution dissolves gold from crushed rock

  • Environmental management and rehabilitation:

    • Environmental Impact Assessment (EIA), environmental management plans, mine closure planning

    • Rehabilitation includes topsoil replacement, reintroduction of flora/fauna, neutralizing acidic waters, backfilling and stabilizing slopes

Philippine Context and Regulation

  • Republic Act No. 7942 (Philippine Mining Act of 1995): governs exploration, development, utilization, and processing of mineral resources; aims to safeguard the environment.

  • DENR oversees implementation via Mines and Geosciences Bureau (MGB) for conservation/management and Environmental Management Bureau (EMB) for environmental standards and pollution control.

  • The Philippines is highly mineralized: among the world’s top in mineral resources; major metallic minerals include gold, copper, iron, chromite, nickel, cobalt, and platinum; nonmetallic include sand/gravel, limestone, marble, clay, etc.

  • Notable districts: Benguet (gold/copper), Surigao and Davao (gold and nickel); Palawan and Surigao (nickel).

  • The nation’s mining framework emphasizes environment protection, community considerations, and sustainable resource management.

Conservation and Resource Management (Summary)

  • Minerals are non-renewable; conserve through responsible use, extended product life, sharing and repurposing items.

  • Apply the 3Rs to mineral-derived products; rehabilitation and ecosystem restoration are essential after mining.

  • Environmental stewardship and adherence to laws help minimize long-term impacts and enable sustainable use of resources.

Quick Numerical References (for memory cues)

  • Gold concentration in Earth’s crust: 0.005 ppm0.005\text{ ppm}

  • Lifetime mineral requirement (example): about 3.5×106 pounds3.5\times 10^6\text{ pounds}, ≈ 1.5876×106 kg1.5876\times 10^6\text{ kg}

  • Depth reference for underground mining: greater than 103 ft10^3\text{ ft} ≈ 3×102 m3\times 10^2\text{ m}

  • Some key processes: hydrothermal veins, magmatic settling, metamorphic alteration, evaporite precipitation, placer concentration, residual weathering

Note: The Philippine-specific legal and regulatory context emphasizes that mining must be conducted with environmental safeguards, community engagement, and post-closure rehabilitation to minimize long-term impacts.