Brief summary of the available minerals and reserve is highlighted below:
Many limestone deposits have been located in the ophiolite mélange and oceanic pelagic sediments in Ukhrul and Chandel District. Limestones are located at Lambui, Kasom, Paorei, Phungcham, Kazing Malung, Shokpau, Yongphu, Shingda, Marao, Singkap, Shangshak, Koshu, Nungou, Mawai, Shongphel, Sirarukhong, Cretland, Chingsou, Humine, Makan, of Ukhrul District and Toupokpi, Chakpikarong, Pallel, Nungphura, Nungpal, Sajiktampak , Haikot of Chandel District. The limestones are cement to SMS grades with a Proved Reserve of 9.845 million tones, Probable Reserve Reserve of 3.441 million tones and Possible Reserve of 18.412 million tones.
More than 25 occurrences of chromite have so far been located in Manipur. These are located at Lunghar, Phangrai, Sirohi, Gamnom, Pushing, Khangkhui, Yentem, Nungbi, Hangkau, Apong, Chingai, Poi, Pinghang, Nampisha, Kangpat, and Chattrick Khunou of Ukhrul District and Kwatha, Sibong, Khudengthabi and Minou-Mangkang of Chandel District. A probable reserve of 0.38 million tones has been assessed. Chromites are of metallurgical and refractory grades.
GSI had reported incidence of Nickel in the soil up to a maximum o 74,000 ppm between Gamnom and Ningthi of Ukhrul District. GSI also noted the nickel content of 12,000ppm in the bed rock near Gamnom. Besides, GSI undertook geochemical activities near Khudengthabi and Moreh of Chandel District. Nickel content in some of the trench samples reaching up to 0.7 %.
State DGM reported the nickel content upto 2.03% in weathered harzburgite near Pushing village. Out of the results of chemical analysis of 81 samples from Yentem to Hangkau 9 samples indicated high Nickel content. It most falls in the area of Hangkau and Apong.
4.Copper Mineral :
GSI had earlier reported occurrences of copper in the ophiolite of Kwatha of Chandel District and Nampisha of Ukhrul District of Manipur. Some old pits of sulphides within foliated Serpentinites at Sadangching (hill), 6 km in the northeast of Kwatha village were studied. Occurrences of Malachite, Azurite and Magnetite were recorded along the weak planes. The copper stained boulders indicated copper values ranging 2.5 – 6.75 % and Nickel values 0.2- 0.30%.
State Geology & Mining Division had also studied the copper deposits of Nampisha. There are 3 abandoned pits and dumps of copper in the area. State DGM also located sulphide deposits at Yentem,. The chemical analytical data indicates 1.64% of Cu.
Platinum Group Element (PGE)/ Platinum Group Metal (PGM):
GSI initiated preliminary investigation of PGE/PGM in the course of preliminary investigation of chromite in the State and reported Ir value in chromite up to 90 ppb in Kwatha of Chandel District and Phangrai of Ukhrul district. GSI studied serpentinites and chromitites in particular from Luntching ( Copper Hill ), Nampisha of Ukhrul District highly reflective native metal, nickel and iron sulphide grains under Scanning Electron Microscope attached with Analytical X-ray unit as well as High Resolution Acanning Electron Microscope at Regional Sophisticated Instrumentation Centre, North east Hill University, Shillong and Indian Institute of Science, Bangalore. The studies have indicated presence of Pt, Pd, Au, and high proportion of Rh in association of Cr, Ni, Fe, sulphide and native copper ( G. Pratap Reddy & K.S. Gupta , GSI, 1992).
In the Comprehensive Action Plan for Exploration for PGE in India, January, 2000 Manipur-Nagaland ophiolite is included as 21st PGE Exploration Target in which sampling and analysis of chromite, sulphide zones and stream sediment, heavy conc. Study was suggested.
The Geology & Mining Division of the Directorate, during 2003-04 Field Season, undertook preliminary sampling for PGE/PGM studies from various part of the Ukhrul ophiolite. The analytical data is summarises as:
Soil sample : Ir - 2 to 16 ppb, Pd - 30 to 110 ppb, Pt - Nil, Rh - Nil, Ru -18 to 19 ppb
Stream sediments sample : Ir - 2 to 34 ppb, Pd - 7 to 210 ppb, Pt - 5 to 77ppb, Rh - Nil, Ru - 6 to 37 ppb.
Chromite sample : Ir - 8 to 81 ppb, Pd - 30 to 160 ppb, Pt - 5 to 60 ppb, Rh - less than 2 ppb, Ru - 6 to 90 ppb
Sulphide sample : Ir - Nil, Pd - 110 ppb, Pt - Nil, Rh - Nil, Ru - Nil,
Serpentinised Harzburgite sample : Ir - 7to 30 ppb, Pd - 32 to 130 ppb, Pt -18 to 45 ppb, Rh - 67 ppb, Ru - 2 to 19 ppb
During 2007-08 Field season samples for PGE/PGM studies were collected between Gamnom and Pushing in Ukhrul District. Some of the sapless have been sent to GSI at Kolkata for testing. The result is awaited.
Copper Mineral :
GSI had earlier reported occurrences of copper in the ophiolite of Kwatha of Chandel District and Nampisha of Ukhrul District of Manipur. Some old pits of sulphides within foliated Serpentinites at Sadangching (hill), 6 km in the northeast of Kwatha village were studied. Occurrences of Malachite, Azurite and Magnetite were recorded along the weak planes. The copper stained boulders indicated copper values ranging 2.5 – 6.75 % and Nickel values 0.2- 0.30% (Dr. R. Shukla , V.K. Shukla & U.K. Mishra 1988 and K.S. Gupta & D. Purushothaman, GSI 1992).
In Nampisha area ( Luntching Hill ) there are 4 abandoned pits/adits of copper. The rock in hand specimen contain good amount of cuprite, native copper and other sulphide. Stringers and specks of copper are seen in the wall of adits in the weathered serpentinites. There are dumps of copper near the adits.
During 2007-08 Field season the sulphide of Yentem village of Ukhrul District was collected and analysed. The result indicates 1.64% of Cu.
There are possibilities for locating mineralisation of copper in the ophiolite of Manipur. The proper planning is indeed necessary to invest the copper ore in this ophiolite.
Serpentinites as Building stone:
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 Distrit up to Nagaland border and tectonically overlies the Disang sedimentary belt 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 attractive tiles, slabs and other building blocks. It is considered that the Serpentinites of Manipur have a huge market potential, both as finished products and in raw forms, both within India and outside. So far Manipur is concerned, it could become a most important mineral industry generating large scale employment and appreciable export earning.
Considering the economic and employment potentials as above, it is considered that investigations for Serpentinites in the State could be taken up on high priority. The materials have been tested for the cutting and polishing effects and have given good results.
Idocrase / Rhodonite:
They occur as small lensoid bodies within ultramafics in the ophiolite suites of rocks in Ukhrul and Chandel districts. A notable deposit is located in the noerh east of Kwatha of Chandel District. Numerous small bouldery outcrops are also found in the Kwatha and Khudengthabi villages. Other known occurrences are located at Gamnom,, Pushing, Nampisha, etc. They can be used as semi-precious stone and carving stone in handicraft.