Manganese and chromite

Detail

1. Manganese: what it is and what it is used for

• Manganese is a hard, brittle, silvery-grey metal. Ferrous minerals are minerals that contain iron or are used mainly to make iron and steel, and manganese is one of them. In nature it is always found mixed with iron, laterite and other minerals [2].
• Main use is steel.
• It is used to smelt iron ore. Smelting means heating ore in a furnace until the metal melts out.
• It is used to make ferro-manganese, an alloy of iron and manganese that is added to molten steel.
• About 10 kg of manganese is needed to make one tonne of steel.

• Across the world, 90–95% of the manganese ore mined goes into iron and steel [2].

• What it does inside steel: it makes steel stronger, tougher, harder and easier to work. It also acts as a deoxidiser (it removes oxygen) and a desulphuriser (it removes sulphur), and it stops air holes ("blowholes") from forming in steel blocks [2].

• Other uses: bleaching powder, insecticides, paints and dry-cell batteries. Battery-grade ore must be rich in manganese dioxide: at least 70% MnO₂ and at most 6% iron [2].
• Main ores [2]:

Ore	Approx. Mn content
Pyrolusite (MnO₂)	~63.2%
Psilomelane (manganese oxide with water and impurities)	45–60%
Manganite	~62.4%
Braunite	~62% (with ~10% silica)

2. Geology: which rocks hold manganese

• Manganese occurs in almost all rock formations, but mainly in the Dharwar system. The Dharwar system is a group of very old metamorphic rocks (rocks changed by heat and pressure), first studied around Dharwar in Karnataka. These rocks are rich in metallic minerals.
• Most Indian deposits are metamorphosed bedded sedimentary deposits. This means layers of sediment were laid down long ago and later changed by heat and pressure. They belong to two Archaean (the oldest rock age) series [2]:
• Gondite Series: Madhya Pradesh (Balaghat, Chhindwara, Jhabua), Maharashtra (Bhandara, Nagpur), Gujarat (Panchmahal) and Odisha (Sundargarh).

• Kodurite Series: Odisha (Ganjam, Koraput) and Andhra Pradesh (Srikakulam, Visakhapatnam).

• The deposits are shallow and lateritoid (laterite-like) in Odisha, Karnataka and Goa. They are deep and regular in Madhya Pradesh, Maharashtra and Andhra Pradesh [2].

3. Reserves and production

• Total reserves/resources (as on 1.4.2020): 503.62 million tonnes. Of this, 75.04 Mt are "Reserves" (proven and ready to mine) and 428.58 Mt are "Remaining Resources" [2].
• Grade problem: only 8% of the resources are ferromanganese grade, and just 0.16 Mt are battery/chemical grade [2].
• Production 2021-22: 2,696 thousand tonnes, almost the same as in the year before. It came from 127 reporting mines. 32 public-sector mines gave 46% of the output [2].
• 69% of the ore produced in 2021-22 was low grade (below 35% Mn). Only 8% was high grade (above 46% Mn) [2].
• The state that holds the most ore is not the state that mines the most (Odisha leads in reserves, Madhya Pradesh in output):

State	Share of reserves/resources (1.4.2020) [2]	Share of production (2021-22) [2]
Odisha	34% (1st)	19% (3rd)
Karnataka	24% (2nd)	—
Madhya Pradesh	12%	31.5% (1st)
Maharashtra	12%	27% (2nd)
Goa	7%	—
Andhra Pradesh	6%	—
Jharkhand	3%	—

• (NCERT: Madhya Pradesh and Odisha are the leading producers.) Current IBM data puts Madhya Pradesh 1st and Maharashtra 2nd in production, while Odisha leads in reserves [2].

4. Producing belts by state

State	Producing districts / belt	Note
Madhya Pradesh	Balaghat–Chhindwara–Nimar–Mandla–Jhabua belt	Gondite deposits. Far from steel plants
Odisha	Bonai, Kendujhar, Sundergarh, Gangpur, Koraput, Kalahandi, Bolangir	Lies in the central part of the iron ore belt, so it is close to steel plants
Karnataka	Dharwar, Ballari, Belagavi, North Canara, Chikkamagaluru, Shivamogga, Chitradurga, Tumakuru	2nd in reserves
Maharashtra	Nagpur, Bhandara, Ratnagiri	Far from steel plants
Minor producers	Telangana, Goa, Jharkhand	—

• Location drawback (NCERT Class 12): the mines of Madhya Pradesh and Maharashtra are far from the steel plants of the Chhota Nagpur–Odisha belt. This raises the cost of moving the ore.
• New exploration: Madhya Pradesh and its State Mining Corporation are exploring for manganese in Jabalpur, Balaghat, Chhindwara and Jhabua [2].

5. MOIL: the main public-sector producer

• MOIL Ltd has its headquarters at Nagpur and is India's largest manganese ore producer [2].
• It runs underground and opencast mines in Nagpur and Bhandara (Maharashtra) and Balaghat (Madhya Pradesh). All of these mines are about a century old [2].
• Balaghat mine is MOIL's largest. It has reached a depth of about 435 m, and a shaft is being sunk to 750 m [2].
• Dongri Buzurg mine (Bhandara) is an opencast mine. It produces manganese dioxide ore for the dry-battery industry [2].
• At Balaghat, ore is carried to the railheads by aerial ropeways [2].
• MOIL runs a 12,000 tonnes-per-year ferromanganese plant at Balaghat. Its target is 3.5 Mt of ore by 2030 [2].

6. India in the world: why India still imports

• World reserves: about 1,700 Mt of metal content. Shares: South Africa 38%, China, Australia and Brazil 16% each, Ukraine 8%, Gabon 3%, India 2% [2].
• World production 2021: about 56 Mt. Shares: South Africa 34%, Gabon 16%, China 12%, Australia 11%, Ghana 6%, India 4% [2].
• Imports 2021-22: 6.50 Mt, up 60% from 4.05 Mt the year before. That is more than double India's own output of 2.7 Mt [2].
• Main sources: South Africa 44%, Gabon 21%, UAE 10%, Australia 8% [2].

• Reason: Indian ore is mostly low grade, and steel output keeps growing.

• Future source: deep-sea polymetallic nodules (small lumps on the ocean floor rich in manganese) may become a resource in the coming decades [2].

• Health risk: long exposure to manganese dust can cause manganism, a nerve disorder with symptoms like Parkinson's disease [2].

7. Chromite: what it is and what it is used for

• Chromite (iron chromium oxide, FeCr₂O₄) is a ferrous mineral. It is the only commercially viable ore of chromium [3]. NCERT Class 12 lists it only as a ferrous mineral.
• Why chromium matters: it resists corrosion (rusting and chemical attack), oxidation and wear, and it makes steel harder. As an alloying metal for steel, it is perhaps second only to manganese [3].
• Main uses:
• Ferrochrome and charge chrome. These are iron–chromium alloys added to make stainless steel and special steels. Ferroalloy/charge-chrome plants are the largest consumers of chromite [3].
• Refractories. These are heat-resistant bricks and linings for furnaces. Chromite suits them because it has a high melting point, stays stable at high heat and is cheap [3].
• Chemicals. Chromite is used to make sodium and potassium bichromates, which are used in tanning, pigments and plating [3].

8. Distribution: an Odisha monopoly

• Total resources (as on 1.4.2015): 344 Mt. Of this, 102 Mt (30%) are Reserves and 242 Mt (70%) are Remaining Resources [3].
• More than 96% of the resources are in Odisha, mostly in Jajpur, Kendujhar and Dhenkanal districts [3].
• Two main ore belts in Odisha [3]:
• Sukinda ultramafic belt (Sukinda valley, Jajpur district). This is India's main chromite area. Ultramafic rocks are very dark igneous rocks rich in magnesium and iron, and chromite forms inside them.

• Baula–Nuasahi belt (Kendujhar district).

• Minor deposits: Manipur, Nagaland, Karnataka (Hassan district has some mining), Jharkhand, Maharashtra, Tamil Nadu, Telangana and Andhra Pradesh [3].

• Production 2018-19: 3,971 thousand tonnes, up 14% from the year before. Odisha produced all of it. The public sector gave 31% [3].
• Main mines [3]:
• South Kaliapani of Odisha Mining Corporation and Sukinda of Tata Steel are opencast mines.
• Kathpal (FACOR), Nuasahi (IMFA), Bangur (OMC) and Baula (FACOR) are underground mines.

• In the Sukinda belt the ore is mostly friable and powdery. In Kathpal and the Baula–Nuasahi belt it is hard and massive.

• World position: Kazakhstan (40%) and South Africa (35%) together hold about 75% of world chromite reserves. India holds about 18% (USGS data, cited by IBM 2020) [3].

9. Sukinda: the environmental cost of chromite mining

• Cause → process → result:
• Cause: large opencast mines dig out powdery ore and leave big dumps of waste rock and overburden (soil and rock removed to reach the ore).
• Process: rain and mine water wash over this waste. Chromium in it changes into hexavalent chromium (Cr⁶⁺ or Cr-VI), a form of chromium that dissolves easily in water and causes cancer [3].

• Result: Cr-VI gets into rivers, ponds and wells. Contaminated water bodies are a major problem in the Sukinda belt [3]. The valley has been listed among the world's most polluted places.

• Health: breathing chromium compounds is linked to lung cancer in chromite workers. The risk can be up to 30 times higher than normal. Cancers of the nose, throat and gut have also been reported [3].

• Air pollution: waste dumps release dust, especially in the dry season. Ferrochrome plants, steel plants and coal power plants also release chromium into the air [3].
• Remedies [3]:
• Chemical treatment: mine water is treated with ferrous sulphate before it is let out. This turns Cr-VI into trivalent chromium (Cr-III), which does not cause cancer.
• Bio-remediation: using microbes or plants to clean up pollution. IBM's Mining Research Cell studied this method for Sukinda with Utkal University in 2008-09.

10. Policy status: critical minerals list (2023)

• In 2023 the Ministry of Mines released a list of 30 critical minerals [4]. Critical minerals are minerals that are essential for the economy and national security but whose supply is at risk.
• The list includes lithium, cobalt, nickel, graphite, REE, vanadium, titanium, tungsten and others. Neither manganese nor chromium is on it [4].
• 24 of the 30 minerals are placed in Part D of the First Schedule of the MMDR Act (Mines and Minerals (Development and Regulation) Act) as critical and strategic minerals [4].

Prelims Hooks

• Madhya Pradesh leads manganese production (31.5%, 2021-22). Odisha leads manganese reserves (34%, as on 1.4.2020). This is a common trap.
• The order of manganese producers in 2021-22 is Madhya Pradesh > Maharashtra > Odisha.
• Gondite Series goes with Balaghat, Chhindwara and Bhandara. Kodurite Series goes with Ganjam, Koraput and Srikakulam. Both are Archaean.
• Pyrolusite (MnO₂) is the main manganese ore. Dongri Buzurg (Bhandara) supplies MnO₂ ore for dry batteries.
• MOIL has its headquarters in Nagpur. Its largest mine is Balaghat (Madhya Pradesh).
• Manganese use in steel is about 10 kg per tonne of steel. About 90–95% of world manganese ore goes into iron and steel.
• South Africa leads the world in both manganese reserves and production. Kazakhstan leads in chromite reserves, followed by South Africa.
• Chromite is the only commercial ore of chromium. More than 96% of India's resources are in Odisha, in the Sukinda (Jajpur) and Baula–Nuasahi (Kendujhar) belts. In Karnataka, Hassan has minor chromite mining.
• Hexavalent chromium (Cr-VI) causes cancer. Ferrous sulphate turns it into the safer trivalent chromium (Cr-III).
• Trap: manganese and chromium are not among India's 30 critical minerals (2023), even though they are key steel alloy minerals.

Mains Points

• Location mismatch raises costs (GS-I distribution):
• Odisha's manganese lies inside the iron ore belt, close to steel plants.
• The century-old Gondite mines of Madhya Pradesh and Maharashtra are far from them, so moving ore by rail and ropeway costs more.

• So the largest reserves (Odisha) and the largest output (Madhya Pradesh) are in different places.

• Import dependence despite reserves (GS-III resources):

• About 69% of Indian manganese ore is low grade, and only 8% of resources are ferromanganese grade.
• So India imported 6.5 Mt in 2021-22, more than double its own output. About 44% came from South Africa.

• Possible answers: beneficiation (processing low-grade ore to raise its metal content), deeper mechanised mining (MOIL's 3.5 Mt target for 2030) and deep-sea nodules.

• Sukinda as a case study of mining's environmental cost (GS-III environment):

• Opencast mining of friable chromite creates waste dumps, and water washing over them carries hexavalent chromium into rivers and wells.
• This has caused cancer risk among workers and nearby people, and the valley has been called one of the world's most polluted places.

• Remedies: ferrous-sulphate treatment of mine water, bio-remediation, dump management and strict pollution control enforcement.

• One state dominates chromite: Odisha has more than 96% of resources and gave all output in 2018-19. This makes the stainless-steel and ferrochrome supply chain depend on one region, and that region carries the whole ecological cost. It is an argument for sustainable mining and for directing mining revenue back to the affected areas.