Controls of Ore Localization | Geology Optional Notes for UPSC PDF Download

Factors Controlling Availability of Ore Deposit

• Geological Factors:
  • Geological processes play a crucial role in concentrating minerals in the Earth's crust.
  • Rich mineral deposits may remain unexploited until geological conditions are favorable.
  • Example: The formation of gold deposits in quartz veins due to hydrothermal processes.
• Engineering Factors:
  • Engineering considerations are essential for the practical extraction of mineral deposits.
  • Technological advancements influence the feasibility of mining operations.
  • Example: The use of advanced drilling techniques to access deep-seated ore bodies.
• Environmental Factors:
  • Environmental concerns impact the development and exploitation of mineral resources.
  • Sustainable mining practices are increasingly important in today's context.
  • Example: Implementing reclamation plans to restore mined areas back to their natural state.
• Economic Factors:
  • Economic viability is a significant determinant of whether a mineral deposit will be exploited.
  • Market demand, commodity prices, and production costs influence economic feasibility.
  • Example: A decrease in the price of copper leading to the closure of some copper mines.

Geological Factors and Ore Deposits

• Crustal Abundance of Metals

  • Crustal rocks contain small amounts of metals, measured using Clarke values.
  • Clarke values compare the concentration of an element in a rock to the average amount in the Earth's crust.
  • Geological processes like magmatism, sedimentation, and metamorphism concentrate these metals in specific settings to form ore deposits.

• Formation of Ore Deposits

  • Ore deposits form when a valuable metal is concentrated in a reachable part of the Earth's crust for profitable extraction.
  • Processes like weathering and erosion can concentrate metals like gold to create economically exploitable placer deposits.
  • Factors influencing ore deposit formation include concentration ranges and specific geological conditions.

• Concentration of Metals

  • Metals like Fe, Al, Mg, Ti, and Mn are widely distributed in the Earth's crust.
  • These metals only need a small enrichment to form workable deposits.
  • Precious metals require much higher enrichment factors, often in the thousands, to form viable deposits.

Engineering and Environmental Factors in Mineral Exploitation

Engineering Factors:

• Engineering constraints are crucial in the exploitation of mineral deposits.
• An economically feasible ore deposit may not be viable without meeting specific engineering parameters.
• For instance, certain countries have restrictions on mining depths; e.g., advanced nations typically limit working depths to around 4 km.
• The deepest oil wells reach depths of about 8 km, making resources beyond these limits inaccessible for exploitation.
• Illustration: The closure of the Kolar gold mine (Champion Reef) due to economic infeasibility at depths of 3.4 km, leading to high expenses for mine air conditioning.

Environmental Factors:

• Environmental considerations are equally significant in exploiting known ore deposits.
• Despite the presence of a significant uranium deposit in the Srisailam area of Andhra Pradesh, the Ministry of Environment and Forests has not granted mining clearance.
• The location within the Rajiv Gandhi Tiger Reserve has led to environmental clearance denial.
• Even with abundant mineral resources, mining approval can be withheld if the potential environmental impact is deemed excessive.
• Example: The denial of mining clearance for the uranium deposit in Srisailam due to its location within a protected wildlife reserve.

Economic Factors in Mineral Economics

Role of Economic Factors

• Mineral economics are pivotal in the exploitation of resources, where profitability is a key consideration.
• Exceptionally, strategic minerals may be mined during emergencies, such as in times of war, without strict adherence to economic viability.
• The price of a commodity significantly influences the cost associated with mineral production.
• Even if a deposit boasts high quality and quantity, the expenses related to extraction, processing, and environmental protection can render it unviable for mining. In such cases, importing the metal may be more cost-effective for a country.
• The interplay between demand and supply also plays a crucial role in dictating the cost dynamics of mineral production.

Example to Illustrate

An example of economic factors influencing mineral economics can be seen in the case of a country with a significant iron ore deposit. Despite the high quality of the ore and ample reserves, if the costs associated with extraction, beneficiation, and environmental safeguards surpass the market price of iron ore, mining might not be feasible. In such a scenario, the country might opt to import iron ore instead of mining its own reserves.