MINERAL SECTOR

Minerals in Manipur are mainly confined to certain types of rocks such as ophiolite suite, Oceanic Pelagic Sediment (OPS) and melanges in the Ophiolite Belt. Amongst these, chromite, limestone and serpentinites (as dimensional stone) are important for immediate exploitation. Other minerals are PGE/PGM, idocrase, rock salt, etc.

Chromite Deposits

 The chromite deposits of Manipur fall in the third category of Indian chromite associated with the Tertiary Ophiolite Formation. The GSI and the State Geology & Mining Division have recorded a number of chromite occurrences of metallurgical and refractory grades from the ophiolite belt of Manipur in Ukhrul and Chandel districts bordering Myanmar.

 Chromites occur as floats on the surface and in-situ pods of varying dimensions. These chromites are found as massive boulders, blocks, tabular bodies as well as nodular masses within the altered ultramafics. Some are also found as disseminated type. These belong to the Alpine Type Podiform Chromite. There is possibility of occurrences of deep-seated chromite in this belt. Intensive searching and exploration using geophysical and drilling inputs are necessary. Preparation for intensive search is going on and will be completed soon.

Some of the important chromite deposits in Manipur are as under:

Limestone Deposits

Cement and SMS grades of limestone are found in the lensoidal bodies of melanges in the west and in the oceanic pelagic sediment (OPS) in the east of Ophiolite belt of Manipur in Ukhrul and Chandel districts. Limestones are mainly massive with a few fissile at the periphery. They occur as bouldery outcrops and bedded lensoids of varying dimensions. These limestones can also be used in lime burning industries. The important limestone deposits are mainly reported from three linear melange bands in the west of Ophiolite belt in Disang sediments. There are more than 85 small limestone deposits in the ophiolite belt of Manipur.

Some of the important limestone deposits in Manipur are as under:

Serpentinites

Serpentinites occur extensively in Chandel and Ukhrul districts within the Ophiolite Belt of Manipur extending over an area of 1100 sq.km.( about 110 km. long and 5-15 km. wide). The belt trends NE-SW from south of Moreh in Chandel District to north-east of Tushom in Ukhrul District up to Nagaland border and technonically overlies the Disang sediments on its west and is interlayered with Oceanic Pelagic Sediments.

Serpentinites are also commercially known as “Green Marble”. It, like granite and marble, can be processed into monuments, tiles, slabs and other building blocks. It is considered that Serpentinite of Manipur has a huge market potential, both as finished products and raw forms, both within India and outside. So far manipur is concerned, it could become the most important mineral industry generating large scale employment and appreciable export earning.

PGE/PGM & Its Associated Sulphides  

The Arakan-Chin belt extending between the Andaman Islands and the North-East India corresponds to a trench-arc up-thrust of the Middle Cenozoic. Small ultramafic bodies are associated with these elongated fold belt. The belt transects the eastern part of Manipur where it covers an area of about 100 km by 15 km. Occurrences of chromite, nickel, PGM and Copper Sulphides have been found along this ophiolite belt in Myanmar, and it is highly probable that the same mineralisations can be found in the Manipur section of the belt (BRGM-France). The GSI has also reported presence of some PGE/PGM in some chromite and serpentinite samples from Kwatha ,Chandel district (20 and 90 ppb) and Phangrai (Ukhrul district). The GSI has further viewed that trace metals like Ni, Co, V, Cu, Cr, Sr, As, Mo, Sn, Mn, Ba, Ti, Zr; precious metals like Au, Ag, PGE (by replacing Cr, V, Ti, Al); and REE like Ce, Ga, La could be enriched in selected locales/horizons in the pelagic sediments. High concentration of Nickel (up to 74,000 ppm ) in the soil above the ultramafite was indicated by the GSI in the areas of Gamnom to Ningthi, Ukhrul District, Manipur. The geochemical prospecting also indicated the increase in nickel concentration near the soil-rock contact. Two sulphide mineralisations were also located at Nampisha and Yentem ophiolite suites by the DGM. The State DGM has initiated actions to take up the exploration at some selected blocks in technical collaboration with the G.S.I.

Hydrocarbon

The western margin of Manipur constitutes a portion of basinal (geosynclinal) part of the Assam-Arakan Oil Basin. This has been categorized by the Ministry of Petroleum & Natural Gas, Govt. of India as belonging to Category – I Basin (proven petroliferous basin). Sediments of over 10 km thick and ranging in age from Upper Cretaceous to Recent is present in the fold and thrust belt (Naga Schuppen Belt). Eocene-Pliocene sequence contain potential source, reservoir and cap rock. More than 40 oil and gas fields have been discovered from the nearby basin.