Minerals, Oil, Gas and Coal of Assam
Assam is one of India's most important mineral and energy resource states. Its foothills and hill districts contain petroleum, natural gas, coal, limestone and a variety of other minerals, while its oilfields and refineries have shaped the industrial history of the entire nation. Assam is not only the birthplace of the oil industry in Asia but also hosts some of the oldest refineries in India. This chapter covers petroleum and natural gas, the refineries, the coalfields and other minerals, along with the key institutions and facts that are repeatedly asked in ADRE, APSC and other competitive examinations.
Petroleum and natural gas
The oil history of Assam begins at Digboi, often called the Oil City, where the first oil well in Asia was drilled in 1889 and commercial production started in 1901. Digboi is therefore regarded as the birthplace of the oil industry in Asia. The early operations were carried out by the Assam Oil Company, and today the Digboi refinery and oilfields are part of the Assam Oil Division of Indian Oil Corporation Limited (IOCL). After independence, major discoveries were made in Upper Assam, especially the Naharkatiya oilfield, followed by the Moran-Hugrijan, Rudrasagar, Lakwa and Dikom fields. The state's main oil and gas bearing districts are Tinsukia, Dibrugarh and Sivasagar in Upper Assam. Oil India Limited (OIL), a major public sector company, has its headquarters at Duliajan in Dibrugarh district and operates many of these fields. Natural gas found along with crude oil is used for power generation, for the Namrup fertilizer plant and for various industries.
Refineries of Assam
Assam has four major refineries. The Digboi Refinery, set up in 1901, is the oldest refinery in India and one of the oldest in the world. The Guwahati Refinery, commissioned in 1962, was the first public sector refinery of India and is operated by IOCL. The Bongaigaon Refinery, established in 1972, is also an IOCL unit. The Numaligarh Refinery Limited (NRL) at Numaligarh in Golaghat district was commissioned in 1999 and is closely linked with the implementation of the Assam Accord; it is a major industrial landmark of the state. These refineries together make Assam a leading refining hub of North East India.
Coal and coalfields
Assam's coal is found mainly in the Makum coalfield near Margherita in Tinsukia district, which is the largest and most important coalfield of the state. Other coalfields include Dilli-Jeypore, Nazira and Singrimari. The coal is of the Tertiary age, generally high in sulphur but low in ash, and it is used by railways and thermal power stations. Large-scale coal mining in the region was started by the Assam Railways and Trading Company, and today the North Eastern Coalfields, a subsidiary of Coal India Limited, operates mines in the Margherita area. Important mining centres include Ledo, Margherita and Tipong.
Other minerals
Besides petroleum and coal, Assam produces several other minerals, mostly from the hill districts of Karbi Anglong and Dima Hasao. Limestone is mined at Umrangso in Dima Hasao and is used by the cement plant at Bokajan in Karbi Anglong, run by the Cement Corporation of India (CCI). Other minerals include dolomite, china clay or kaolinite, refractory clay, sillimanite, quartz, feldspar, graphite and gypsum. These minerals support the state's cement, ceramics and refractory industries and add to its industrial base.
Key institutions
Oil India Limited (OIL) has its headquarters at Duliajan and is the principal oil and gas producing company of the region. The Assam Oil Division of IOCL manages the Digboi refinery and oilfields. The Brahmaputra Valley Fertilizer Corporation Limited (BVFCL) runs the Namrup fertilizer plant, which uses natural gas as feedstock. The North Eastern Coalfields of Coal India looks after coal mining in Assam. Together these institutions make the mineral and energy sector a pillar of Assam's economy.
Key facts at a glance
- Digboi: first oil well in Asia (1889), commercial production 1901; birthplace of Asia's oil industry.
- Oldest refinery in India: Digboi (1901).
- First public sector refinery of India: Guwahati (1962), IOCL.
- Bongaigaon Refinery (1972) - IOCL; Numaligarh Refinery (NRL, 1999) - Golaghat.
- Oil India Limited (OIL) HQ: Duliajan, Dibrugarh.
- Major oilfields: Naharkatia, Moran-Hugrijan, Rudrasagar, Lakwa, Dikom.
- Largest coalfield: Makum, near Margherita (Tinsukia); coal is Tertiary, high-sulphur.
- North Eastern Coalfields (Coal India) HQ: Margherita.
- Limestone: Umrangso (Dima Hasao); cement plant: Bokajan (CCI, Karbi Anglong).
- Namrup fertilizer plant: BVFCL, uses natural gas.
Quick revision points
- Digboi = Oil City; Asia's first oil well and India's oldest refinery.
- Guwahati Refinery = first public sector refinery of India.
- OIL is based at Duliajan; its fields include Naharkatia and Rudrasagar.
- Makum is the leading coalfield; coal is Tertiary and high in sulphur.
- Umrangso provides limestone for the Bokajan cement plant.
How to prepare this topic
- Memorise the four refineries with their years and operators.
- Link oilfields with their districts - Naharkatia, Moran, Rudrasagar, Lakwa.
- Note the "firsts": first oil well, first refinery, first public sector refinery.
- Learn the coal facts: Makum, Ledo, Margherita, high-sulphur Tertiary coal.
- Remember the other minerals and their locations, especially limestone and cement.
Common exam traps
- Digboi is the oldest refinery, while Guwahati is the first public sector refinery - do not interchange.
- OIL's headquarters is Duliajan, not Digboi or Guwahati.
- Makum, near Margherita, is the largest coalfield; Ledo and Tipong are mining centres.
- Numaligarh Refinery belongs to NRL, not directly to IOCL like Digboi, Guwahati and Bongaigaon.
- Umrangso is in Dima Hasao, whereas the cement plant at Bokajan is in Karbi Anglong.
Frequently Asked Questions
Where is the birthplace of the oil industry in Asia?
Digboi in Assam, often called the Oil City, is regarded as the birthplace of the oil industry in Asia. The first oil well in Asia was drilled there in 1889, and commercial production began in 1901. The Digboi Refinery, set up in 1901, is the oldest refinery in India.
Which is the first public sector refinery of India?
The Guwahati Refinery, commissioned in 1962 and operated by Indian Oil Corporation Limited, was the first public sector refinery of India. The Digboi Refinery is older but belonged to the private Assam Oil Company before becoming part of IOCL's Assam Oil Division.
Where is Oil India Limited headquartered and which are its main fields?
Oil India Limited (OIL) has its headquarters at Duliajan in Dibrugarh district. Its main oil and gas fields include Naharkatia, Moran-Hugrijan, Rudrasagar, Lakwa and Dikom, located in the Upper Assam districts of Tinsukia, Dibrugarh and Sivasagar.
Which is the largest coalfield of Assam and what type of coal is found there?
The Makum coalfield near Margherita in Tinsukia district is the largest and most important coalfield of Assam. The coal is of the Tertiary age, generally high in sulphur but low in ash, and is mined by the North Eastern Coalfields, a subsidiary of Coal India Limited.
Which minerals besides oil and coal are found in Assam?
Assam produces limestone, dolomite, china clay or kaolinite, refractory clay, sillimanite, quartz, feldspar, graphite and gypsum, mainly from Karbi Anglong and Dima Hasao. Limestone is mined at Umrangso in Dima Hasao for the cement plant at Bokajan in Karbi Anglong, run by the Cement Corporation of India.