Manganese (Mn) is an essential transition metal crucial for steel production, acting as a deoxidizer and strengthening agent. Its ores are vital for various industries, including metallurgy, chemical industries, and increasingly, battery technology. India possesses significant manganese ore reserves, primarily found in association with ancient sedimentary and metamorphic rocks. Understanding the geology of these ores, their classification, and distribution is critical for resource management and sustainable exploitation. This note will detail the different types of Mn-ores, their formation, and occurrences, with a focus on the Indian context. Classification of Manganese Ores Manganese ores are classified based on their chemical composition and geological origin. The primary classifications include: Oxide Ores: These are the most common and economically important. Pyrolusite (MnO 2 ): Black to dark grey, often dendritic or botryoidal. It’s the richest manganese ore. Psilomelane (BaMnMn 8 O 16 (OH) 4 ): A complex hydrated manganese oxide, often associated with pyrolusite. Romanèchite (Mn 5 O 10 (OH) 2 ): Another hydrated manganese oxide, typically found in weathered zones. Carbonate Ores: Rhodochrosite (MnCO 3 ): Pink to red, often found in hydrothermal veins. Silicate Ores: Manganiferous Jasper: A variety of chert containing manganese oxides. Geological Occurrence and Formation Manganese ores are formed through various geological processes: Sedimentary Processes: The most significant source of manganese ores globally. These form through the precipitation of manganese from seawater, often in association with iron formations. The Gunflint Formation in Canada is a classic example. Hydrothermal Activity: Manganese can be transported and deposited by hydrothermal fluids, forming veins and replacement deposits. Weathering and Supergene Enrichment: Weathering of manganese-bearing rocks can lead to the concentration of manganese oxides in residual deposits. Metamorphic Processes: Metamorphism can remobilize and concentrate manganese in certain rock types. Manganese Ore Deposits in India India is a significant producer of manganese ore, with approximately 29% of the world’s reserves (as of 2015, based on knowledge cutoff). The major producing states are: Madhya Pradesh: Accounts for the largest share of India’s manganese ore production. Balaghat and Chhindwara districts are key areas. The ores are typically found in Gondwana formations. Maharashtra: Significant deposits are found in Nagpur and Bhandara districts, also within Gondwana formations. Karnataka: Sandur-Hospet range is a major manganese-producing area. Odisha: Koraput and Sundargarh districts host substantial manganese deposits. Andhra Pradesh: Srikakulam district has notable occurrences. Table: Major Manganese Producing States in India (Approximate Production Share - 2022-23) State Production Share (%) Madhya Pradesh 34 Maharashtra 28 Odisha 22 Karnataka 10 Andhra Pradesh 6 Economic Significance and Uses Manganese ores are crucial for: Steel Production: Approximately 70-80% of manganese ore is used in steelmaking. Alloys: Used in the production of ferromanganese, silicomanganese, and other alloys. Chemical Industry: Used in the manufacture of potassium permanganate, manganese dioxide (for batteries), and other chemicals. Battery Technology: Increasing demand for manganese in lithium-ion batteries, particularly in cathode materials. Manganese ores are vital resources with diverse applications, particularly in the steel industry and emerging battery technologies. India’s substantial reserves necessitate efficient and sustainable mining practices. Understanding the geological context of these ores, their classification, and regional distribution is crucial for effective resource management and ensuring long-term supply for domestic and global demands. Further exploration and technological advancements in ore processing will be key to maximizing the economic potential of India’s manganese resources.

Question 27 | UPSC Mains GEOLOGY-PAPER-II 2012

Mn-ores

How to Approach

This question requires a detailed understanding of manganese ores – their types, occurrences in India, economic significance, and methods of extraction. The answer should be structured to cover geological aspects, economic geology, and relevant occurrences within the Indian context. Focus on classification, associated minerals, and key producing regions. A concise and informative approach is crucial, given the limited marks.

Classification of Manganese Ores

Manganese ores are classified based on their chemical composition and geological origin. The primary classifications include:

Oxide Ores: These are the most common and economically important.
- Pyrolusite (MnO₂): Black to dark grey, often dendritic or botryoidal. It’s the richest manganese ore.
- Psilomelane (BaMnMn₈O₁₆(OH)₄): A complex hydrated manganese oxide, often associated with pyrolusite.
- Romanèchite (Mn₅O₁₀(OH)₂): Another hydrated manganese oxide, typically found in weathered zones.
Carbonate Ores:
- Rhodochrosite (MnCO₃): Pink to red, often found in hydrothermal veins.
Silicate Ores:
- Manganiferous Jasper: A variety of chert containing manganese oxides.

Geological Occurrence and Formation

Manganese ores are formed through various geological processes:

Sedimentary Processes: The most significant source of manganese ores globally. These form through the precipitation of manganese from seawater, often in association with iron formations. The Gunflint Formation in Canada is a classic example.
Hydrothermal Activity: Manganese can be transported and deposited by hydrothermal fluids, forming veins and replacement deposits.
Weathering and Supergene Enrichment: Weathering of manganese-bearing rocks can lead to the concentration of manganese oxides in residual deposits.
Metamorphic Processes: Metamorphism can remobilize and concentrate manganese in certain rock types.

Manganese Ore Deposits in India

India is a significant producer of manganese ore, with approximately 29% of the world’s reserves (as of 2015, based on knowledge cutoff). The major producing states are:

Madhya Pradesh: Accounts for the largest share of India’s manganese ore production. Balaghat and Chhindwara districts are key areas. The ores are typically found in Gondwana formations.
Maharashtra: Significant deposits are found in Nagpur and Bhandara districts, also within Gondwana formations.
Karnataka: Sandur-Hospet range is a major manganese-producing area.
Odisha: Koraput and Sundargarh districts host substantial manganese deposits.
Andhra Pradesh: Srikakulam district has notable occurrences.

Table: Major Manganese Producing States in India (Approximate Production Share - 2022-23)

State	Production Share (%)
Madhya Pradesh	34
Maharashtra	28
Odisha	22
Karnataka	10
Andhra Pradesh	6

Economic Significance and Uses

Manganese ores are crucial for:

Steel Production: Approximately 70-80% of manganese ore is used in steelmaking.
Alloys: Used in the production of ferromanganese, silicomanganese, and other alloys.
Chemical Industry: Used in the manufacture of potassium permanganate, manganese dioxide (for batteries), and other chemicals.
Battery Technology: Increasing demand for manganese in lithium-ion batteries, particularly in cathode materials.

Additional Resources

Key Definitions

Gondwana Formation

A supergroup of sedimentary rocks formed during the Gondwana period (approximately 360 to 150 million years ago) in India. These formations are known for their coal deposits and also host significant manganese ore occurrences.

Ferromanganese

An alloy of iron and manganese, containing approximately 75-80% manganese. It is primarily used as a deoxidizer and alloying agent in steel production, improving the strength, toughness, and wear resistance of steel.

Key Statistics

India holds approximately 29% of the world’s manganese ore reserves, estimated at 380 million tonnes of metallic manganese content (as of 2015).

Source: Ministry of Mines, Annual Report 2015-16

Global manganese ore production was approximately 17.4 million tonnes in 2022, with South Africa being the largest producer.

Source: US Geological Survey, Mineral Commodity Summaries 2023

Examples

Balaghat Manganese Mine, Madhya Pradesh

The Balaghat region in Madhya Pradesh is a prime example of a sedimentary manganese ore deposit. The ores are found within the Tirodi Formation of the Gondwana Group, formed through the accumulation of manganese-rich sediments in a shallow marine environment.

Frequently Asked Questions

▶What is the difference between pyrolusite and psilomelane?

Pyrolusite is a pure manganese dioxide (MnO<sub>2</sub>) mineral, while psilomelane is a complex hydrated manganese oxide with a variable composition. Pyrolusite is generally richer in manganese content and considered a higher-grade ore.