Ores, Minerals & Mining – Comprehensive Study Notes

Ores and Minerals

  • Minerals are essential resources required to be sustained for both present and future generations.
  • Two guiding questions for the entire discussion:
    • What processes are involved in extracting mineral resources?
    • How do these processes affect the environment?

Definition of an Ore

  • Ore (General Idea): Naturally-occurring material that can be mined profitably.
    • May be a mineral or a rock; may be metallic or non-metallic.
  • Criteria that determine whether a rock/mineral qualifies as an ore:
    • Overall chemical composition.
    • Percentage of extractable resource relative to total volume.
    • Current and forecast market value of the resource.
  • Key maxim: “All ores are minerals but not all minerals are ores.”
  • Profitability‐dependent value:
    • Cost of extraction varies with location, depth, concentration, spatial extent, required technology, and overall market conditions.

Processes & Settings for Locating Ores

Hydrothermal Fluid Circulation

  • Most common form of ore mineral deposition.
  • Origin: groundwater or seawater heated by magma OR hot solutions expelled from cooling plutons.
  • Produces metal-rich veins (gold, silver, copper, etc.).

Metamorphic Processes

  • Alteration & recrystallization of pre-existing minerals under P–T changes.
  • Generates/locates materials like graphite, marble, asbestos.

Magmatic Process

  • Early-formed minerals crystallize & segregate from magma, concentrating valuable elements.

Kimberlite Magma

  • Originates >150\text{ km} depth; source of diamonds.
  • Rapid ascent → forms vertical kimberlite pipes; prime diamond ore bodies.

Chemical Sedimentary Process

  • Evaporite deposits produced by precipitation from seawater/lake water.
  • Yields halite, gypsum, limestone, anhydrite, etc.

Action of Ocean Waves / Currents (Placer Formation)

  • Moving water selectively removes lighter sediments, leaving heavy minerals.
  • Results in placer deposits rich in gold, platinum, zircon, diamonds.

Chemical Weathering

  • Tropical climates accelerate chemical alteration → residual ore deposits.
  • Generates laterite ores (iron, nickel, aluminum).

Mining: Concept & Public Perception

  • Mining: Set of processes through which useful resources are withdrawn from non-renewable stocks.
    • Essential to industrial societies; many materials cannot be “grown.”
  • Controversial due to historical neglectful or irresponsible practices → negative public image.

General Mining Workflow

  1. Prospecting / Exploration
    • Locate ore body capable of yielding large amounts of the target mineral.
  2. Drilling
    • Extract core samples; evaluate grade, quality, quantity.
  3. Modeling
    • Define ore body’s size, shape, grade distribution.
    • Guides blasting, digging, safety, efficiency, processing.
  4. Impact Assessment
    • Analyze social & environmental consequences; propose mitigation & rehabilitation strategies.
  5. Mine Design & Construction
    • Engineers + scientists cooperate; project proceeds only after permits & community approvals.
  6. Ore Extraction
    • Separate high-grade ore from surrounding rock.
  7. Milling / Concentration
    • Crush ore; separate & concentrate valuable fraction; generate tailings (waste).
  8. Site Decommissioning
    • After depletion, close, clean, reclaim, or repurpose the mine area.

Extraction Method Categories

  • Choice depends on mineral nature, depth, geometry, surrounding rock, economics, and environmental constraints.

1. Sand & Gravel Extraction

  • Minimal waste; feasible only when deposits have high grade and accessibility.

2. Extraction from Buried Ore Bodies

  • Requires removal of large volumes of waste rock to access comparatively small ore volumes.

3. (Implied) Surface or Underground Mining Variants

  • Not explicitly listed but inferred from previous categories and workflow.

Ore Processing

  • Sequence: crushing → separating → purifying to yield marketable ore minerals.

Philippine Ore Resources & Statistics

  • Country lies within highly dynamic tectonic setting (volcanism + plate convergence) → abundant metallic & non-metallic minerals.
  • Land‐based potential:
    • 9\text{ million ha} (~30\% of the total 30\text{ million ha} land area) contain metallic deposits.
    • 5\text{ million ha} identified as prospective non-metallic sites.
  • Offshore domain (~2.2\text{ million km}^2): placer gold, magnetite, chromite sands, aggregates, decorative stones, polymetallic sulfides.
  • Overall estimated reserves:
    • Metallic: 14.5\text{ billion t}
    • Non-metallic: 67.66\text{ billion t}
  • Prime producing districts:
    • Copper & Gold: Baguio & Mankayan (Benguet), plus Surigao–Davao.
    • Nickel: Palawan & Surigao.

Natural Resource Management (NRM)

  • Integral to minimizing mining impacts.
  • Definition: Strategic management of land, water, soil, plants, animals with explicit regard for impacts on both present and future generations.
  • Emphasizes sustainability, rehabilitation, and inter-generational equity.

KWL Chart Template (for Student Reflection)

  • K – What I KNOW about ores, minerals, mining, environmental issues.
  • W – What I WANT to know (process details, socio-economic effects, policy frameworks, etc.).
  • L – What I LEARNED after studying the module.