Limestone (CaC03) is associated with rocks composed of either calcium carbonate, carbonate of calcium and magnesium, or mixtures of the two. If magnesium is present up to 20 per cent it is called magnesium limestone and if it is above 20 per cent it is known as dolomite limestone. Limestone deposits are of sedimentary origin and occur in almost all geological formations of the country except Gondwanas.
Limestone is mainly consumed in cement industry (76%), iron and steel industry (16%), chemicals (4%), sugar, paper, fertilizer, and ferro-manganese industries (4%).
The total recoverable reserves of limestone of all categories and grades are placed at 75,679 million tones. The total conditional reserves have been estimated at 701 million tones.
The production of limestone increased to 145.55 million tons in 2002-03 from 2.96 million tons in 1951 exhibiting a forty-nine times growth during the last 52 years. The value of production has increased more than 1488 times during 1951 and2002- 03 (from 10.25 million Rs. to 15,249.4 million Rs.).
More than two-third of India's production of limestone comes from five states of Madhya Pradesh, Rajasthan, Andhra Pradesh, Gujarat and Chhattisgarh each of which contribute more than 9 per cent of the country's output of the mineral. Karnataka, Tamil Nadu, Maharashtra and Himachal Pradesh (each producing over 5 per cent of the country's limestone) account for another 28 per cent of the country's production of limestone.
Madhya Pradesh-Chhattisgarh-M P. and
Chhattisgarh with estimated reserves at 2,126 million tones contribute 26 per cent of the total limestone production of the country. Here extensive deposits of limestone occur at Katna and Jukehi Keymore (Jabalpur district), Alaktara (Bilaspurdis- trict), Tikaria and Narsinghgarh (Damoh district) and between Baijnath and Madhupur.(Rewa district) and near Maihar and Satna areas (Satna district). Deposits of limestone also occur in Rajgarh, Raipur, Durg, Bastar. Dhar, Betul and Sagar districts.
Andhra Pradesh-Andhra Pradesh, accounting for 15.99 per cent of the total limestone production in the country, is the third largest producer of limestone in India. Here important deposits are con- lined to Narji stage of Kurnool system. Main producers are Vishakhapatnam, Krishna, Guntur, Karimnagar, Kurnool, Nalgonda, Adilabad, Warangal and Mahbubnagar districts.
Rajasthan-Rajasthan occupies second place (16.23%) amongst the limestone producing states of the country. Here cement grade limestone is obtained from Ajmer, Banswara, Bikaner, Dungarpur, Jodhpur, Kota, Sirohi, Tonk, Bundi, Alwar, Sawai Madhopur, Chittaurgarh, Nagaur, Pali, Jhunjhunu and Udaipur districts.
Gujarat-In Gujarat good quality of limestone is found near Pasuval, Diwania and Khunia in Palanpur taluka of Banaskantha district; near Dari, Veraval, Savni, Patan/Grokhundi, Sutrapara and Warodra in Junagarh district; near Posina in Sabarkantha district; near Balasinar in Kheda district; and near Lanawada in Panchmahals district.
Karnataka-Karnataka accounts for 10 per cent of the reserves and 8.37% of the total production of limestone in the country. Here limestone deposits are scattered in Bijapur, Belgaum, Shimoga and Gulbarga districts.
Tamil Nadu-In Tamil Nadu large reserves of limestone's are found in Ramnathapuram,Tirunelveli, Tiruchchirappalli, Salem, Coimbatore, Madurai and Thanjavur districts. Except from Salem district much of the deposit is of cement grade limestone.
Others-Other important producers are : Maharashtra-Yavatmal, Chandrapur, Nanded, Ahmadnagardistricts; Himachal Pradesh-Bilaspur Kangra and Chamba districts; Orissa-Sundargarh (Birmitrapur, Hathibari, Purnapani, Katopuryheria, Pagposh and Amghat),Sambalpur (near Malkanagiri), and Kalahandi (near Rostamar, Bomok, Kinerbela and Parkela) districts; Bihar-Shahabad (Baujari- Rohtas, Baulia-Chunhata-Dhananti and Birki-Chapla areas)district; Jharkhand-Palamau, Hazaribag, Ranchi and Singhbhum districts; Uttar Pradesh-Mirzapur, Sonebhadra, Lucknow and Unnao districts; Uttaranchal; Assam-Nagaon and Sibsagar districts; Meghalaya-Garo, Khasi and Jaintia hills districts; Haryana-Mahenderagarh and Ambala districts; Jammu and Kashmir-Anantanag and Jammu districts; West Bengal-Darjeeling and Jalpaiguri districts; and Punjab-Hoshiarpur district.