When limestone contains over 45 per cent of magnesium (MgCO) it is called dolomite. Economic uses of dolomite are mainly metallurgical, as refractoriness (in iron, lead and copper smelting furnaces), as blast-furnace flux, as a source of CO2 gas and magnesium salt, as lime-mortars and other minor uses.
Dolomite occurrences are widespread in almost all parts of the country. The total recoverable reserves of all grades of dolomite are 4,387 million tones. The reserve of BF and SMS grade are large, but those of refractory grade at 118 million tons (only 2.7% of the all-India reserves). About 92 per cent of the reserves of dolomite are distributed in 7 states of Madhya Pradesh-Chhattisgarh, Orissa, Gujarat, Karnataka, West Bengal, Uttaranchal and Maharashtra.
Production
About 90 per cent of the country’s production of dolomite comes from five states of Orissa,- Chhattisgarh, Andhra Pradesh, Jharkhand and Rajasthan. Of these Orissa and Chhattisgarh together account for over 57 per cent of the total production of dolomite in India. The production of dolomite has witnessed 238 times increase between 1951 and 548
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2002-03. the production was only 14,000 tons in 1951 which increased to 33.291akh tones in 2002- 03. The value of production has recorded still faster increase of 12,247 times during this period.
Regional Distribution
Orissa-Orissa is the largest producer of dolomite contributing 28.81 per cent of the national production. Here important deposits of dolomite occur in Sudargarh, Sambalpur and Koraput districts. Birmitrapur (reserves 256 m. tonnes), Hathibari, Khatepur, Bildih (in Sundargarh district) and Sulai (Sambalpur district; reserves 5 m. tonnes) are the important producers. The production from Birmitrapur area is sent to the steel plants at Rourkela, Jamshedpur and Burnpur.
Chhattisgarh-Madhya Pradesh-Chhattisgarh (including Madhya Pradesh) is the second largest producer of dolomite supplying 30.85 percent of the national output. Here bulk of the supply comes from Kodwa-Mohbatta (Durg district), Chatane, Hirri, Dhurarbatta, Atta and Baraduar (Bilaspur district. The mineral is supplied to the Bhilai steel plant.
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Jharkhand-Bihar-In Jharkhand dolomite occurs in Singhbhum (north of Chaibasa). Shahabad (near Banjari), Palamau and Daltonganj districts. Jharkhand contributes 7.75 per cent of the total dolomite production of the country.
Others-other important areas of dolomite production in the country include Vadodara and Bhavnagar districts in Gujarat; Jalpaiguri district in West Bengal; Salem and Tirunelveli districts in Tamil Nadu; and the Krol hill area of Himacha Pradesh.
Most of the dolomite produced in the country is utilised in steel plants. The production from Gujarat is pulverised into chips, while from Uttaranchal (Dehra Dun) is consumed in Naya Nangal fertilizer plant.