മിനറല് റിസോഴ്സസ്സ്
Kerala State is endowed with a number of occurrences/deposits of minerals such as Heavy Mineral Sands ( Ilmenite, Rutile, Zircon, Monazite, Sillimanite) ,Gold, Iron ore, Bauxite, Graphite, China Clay, Fire Clay, Tile and Brick Clay, Silica Sand, Lignite, Limestone, Limeshell, Dimension Stone (Granite), Gemstones, Magnesite, Steatite etc. However, mining activities on large scale are confined mainly to a few minerals - Heavy Mineral Sands, China Clay and to a lesser extent Limestone/Limeshell, Silica Sand and Granite. In fact, Heavy mineral sand and China Clay contribute more than 90% of the total value of mineral production in the State.
MINERAL BASED INDUSTRIES IN THE STATE
The State owns mineral deposits like placers, china clay (kaolin), limestone, limeshell, silica sand, bauxite, graphite, iron ore, granite etc. The major mineral based industries like Indian Rare Earths Ltd., Chavara, Kerala Minerals and Metals Ltd., Chavara, Malabar Cements, Walayar, Travancore cements Ltd., Kottayam, Kundara Ceramics, Kollam, English Indian Clays Ltd. (EICL), Thiruvananthapuram, Excel Glass Industry, Alappuzha, Kerala Clays and Ceramic Products Ltd., Palayangadi, Kannur are some of the mineral based industries working in the State since several years. The resources of beautiful ornamental granites in the state are being exported to different countries.
DETAILS OF INDIVIDUAL MINERAL DEPOSITS
MINERAL SAND
The Heavy Mineral Sand deposits in Kerala contain an assemblage of Ilmenite, Rutile, Leucoxene, Monazite, Zircon and Sillimanite. The State possesses one of the world class deposits of mineral sands in the coastal tracts between Neendakara and Kayamkulam. This, commonly known as the Chavara deposit, after the main locality, covers a total length of 22 km and a width of about 8 km in the northern side and 6 km in the southern side. The Chavara barrier beach portion contains concentration of heavy minerals above 60%. The Chavara deposit is estimated to contain 127 million tonnes of heavy minerals with ilmenite content of 80 million tonnes from the total reserve of raw sand of the order of 1400 million tonnes. In the northern portion beyond Kayamkulam Pozhi extending up to Thottappally in Alappuzha district, the total reserve of heavy minerals estimated to the order of 17 million tonnes with ilmenite content of 9 million tonnes from the raw sand of 242 million tonnes.
Chavara barrier beach with a width of 225 m is divided into 8 blocks numbered I to VIII for separating ilmenite for the manufacture of TiO2. The blocks are apportioned between Kerala Minerals and Metals Ltd. (KMML),a State Government undertaking and Indian Rare Earths Ltd. (IRE), a Government of India enterprise under the Department of Atomic Energy.
Apart from the Chavara heavy mineral deposits a number of heavy mineral placers have been delineated in different parts of the State.
* Kayamkulam-Arattupuzha-Thrikkunnapuzha-Thottapally
^ Kannimalssery-Neendakara-Maleppuram-Odetti, Anjengo-Vettoor, Veli-Kazhakuttom, Vizhinjam-Kovalam-Pachallur
$ Valapattanam-Azhikode, Ponnani-Chavakkadu
GOLD
Gold occurs in Kerala both as primary and placer deposits. The known occurrences are mainly in Wayanad-Nilambur regions. Discovery of gold in Attapady valley of Palakkad district is new and promising.
IRON OREMining activity in the Wayanad Gold Field was abandoned in the early part of the 20th century. The main reason for this appears to be the discovery of the very rich gold deposits in Kolar Gold Field in Karnataka around that time.
Investigaiton/exploration initiated by the Geological Survey of India (GSI) during the 1950's and 1960's concluded that the Wayanad Gold Field deserves more detailed studies and that exploratory mining in selected projects could prove to be economically workable. Following this, the United Nations assisted Kerala Mineral Exploration & Development Project of the State (now merged with Department of Mining and Geology) studied the gold placers in Chaliyar and Punnapuzha rivers draining Nilambur valley. Exploration for primary gold was also taken up which resulted in delineating the Maruda prospect. Two other prospects of interest have also been identified close to Maruda viz. Mannucheeni and Thannikkadavu.
Department of Mining and Geology through a detailed investigation has established a reserve of 0.55 million tonnes of grade of 4 g/tonne of gold in Marudp, Nilambur, Malappuram District Further exploration is required for planning a commercial venture for mining and extraction of gold.
Exploration through test pits carried out in placer deposits of Nilambur valley along the rivers Punnapuzha and Chaliyar puzha have indicated reserves of the order of 2.5 Million m3 of placers with 0.1 gm/m3 of gold. Possible reserves of the order of 30 Million m3 of placers were also projected for the area. In view of the gap in technology for mining of gold placers in the country, a program for exploration and pilot scale mining was taken up during 1994-'96 through French Assistance (BRGM). The studies confirmed the incidence of gold on the present day river channel with an average grade of 0.1 g/m3. The geochemical survey covering 570 km2 to locate alluvial gold placers in Nilambur valley has indicated 15 anomaly areas for further studies.
Investigations by Geological Survey of India (GSI) during 1991-92 have revealed the occurrence of primary gold in Attapady Valley, Palakkad district Systematic stream sediment sampling had helped in delineating these parallel prospective zones extending 10-22 km with a width over 2 km in the western termination of the Bhavani Shear Zone, Within these zones 12 prospects have been identified for detailed prospecting. In Kottathara prospect, 0.08 million tonnes of gold have been established over a lode length of 250 m and a true width of 2.39 m with an average grade of 12.98 g/t. Work is being continued in the adjoining Naiku Padi and in the extension zones. Puttumala had retrieved 0.0067 million tonnes of an average grade of 14.99 g/t. In view of this a conglomeration of a number of small prospects could be a viable prospecting and exploration strategy for the Attappady gold deposits.
Iron Ore
Five iron ore deposits of banded magnetite quartzite type have been identified in
Kozhikode District and one in Malappuram District. Geological Survey of India/Department of Mining and Geology,National Mineral Development Corporation (NMDC) and United Nations assisted Kerala Mineral Exploration & Development Project have explored the deposits of iron ores in these areas.
These deposits are estimated to contain 84 million tonnes of reserve (geological reserves) with iron content varying from 32 to 41 %. The reserves and the percent of Fe content are as follows:
BAUXITE
Bauxite occurs in close association with laterite all along the west coast of the State. Traces of bauxite are seen in almost all laterite cappings. But bauxite deposits of economic significance in south Kerala are a few and are located at Sooranad, Vadakkumuri, Chittavattom, and Adichanallur in Kollam district and Mangalapuram, Chilambil, Sasthavattom and Attipra areas of Thiruvananthapuram district. Geological Survey of India (GSI) and Mineral Exploration Corporation Ltd. (MECL) have conducted extensive studies of bauxite occurrence of Kasargod and Kannur districts in North Kerala during the period between 1968-'74 including geological mapping, pitting, drilling and sampling.
Based on various investigations, the total bauxite reserves in the State are estimated at 12.5 million tonnes. The largest bauxite deposits are in Nileswaram with a reserve of 5.32 million tonnes of grade around 45% AI2O3 and SiO2 less than 5%.
CHINA CLAY
China clay (kaolin) consisting dominantly of kaolinite is one of the most sophisticated industrial minerals with a host of applications, viz., in ceramics, refractories, paper coating, filler for rubber, insecticides, cement, paint, textiles, fertilizers and others including abrasives, asbestos products, fibreglass, chemicals, cosmetics, pharmaceuticals, electrical ware, foundry and glass.
The Department of Mining and Geology through their past investigation campaigns in parts of Kerala, identified two major china clay zones viz., the southern china clay zone between Thiruvananthapuram and Kundara (Thiruvananthapuram and Kollam districts) and the northern china clay zone between Kannapuram Madayi -Cheruthazham in Kannur district to Nileswarm - Manjeshwaram in Kasargod district. An estimated reserve of 172 million tonnes (probable reserve of 80 million tonnes and possible reserve of 92 million tonnes) of china clay of sedimentary and residual origin has been arrived at.
Kerala china clay is one of the finest quality clay and is world class. In fact, Kaolin marketed by English Indian Clays Ltd. (EICL), Thiruvananthapuram claims to have similar or even better properties compared to imported clays.
Production
The paper coating grade china clay is produced by English Indian Clays Ltd., Thiruvananthapuram and Kerala Ceramics Ltd., Kundara. Ceramic grade high quality china clay is produced by Kerala Clays and Ceramic Products Ltd. (KCCP) from their mines at Kannapuram and Pazhayangadi, Kannur District and Pudukai, Kasargod District.
Among the 25 working china clay mines in Kerala, 17 are in Thiruvananthapuram, 4 in Kollam, and 2 each in Kannur and in Kasargod districts, and these jointly produced 4,47,000 tonnes in 2000-'01 fiscal. Kerala has a prominent place in the refined clay map of the country, contributing about 58% of the national annual out put.
Being the largest producer of high grade processed china clay, the enormous export potential and relatively good infrastructure like ports, road and rail links, Kerala is yet to make a mark in the export of china clay. In spite of a four fold jump in the production of R.O.M. or raw clay in the past two decades, the corresponding rise in the output of processed clay was only three fold.
Potential for China Clay Industries
The very large reserves of china clay, identified and proved by the Department, calls for new mining ventures and clay based industries. The Data Repository of the Department and Kerala Clay Data Book of Regional Research Laboratory, Thiruvananthapuram have adequate data and information on china clay in Kerala. Jointly these database provide most useful baseline data, like color, plasticity, tensile strength and particle size, to diverse users and industries.
BALL CLAY
Ball clay (inferred reserve of 5.67 million tonnes) is found to occur in certain areas in Kollam, Alappuzha, Ernakulam, Thrissur and Kannur districts. Though it does not conform to specification of ball clays, yet it is considered to be a good substitute. At present, there is no commercial production.
FIRE CLAY
The fire clay occurrences are in association with Tertiary sediments in the coastal land and the inferred reserve stands at 11.50 million tonnes. However, this resource is waiting to be exploited.
TILE AND BRICK CLAYS
The tile and brick clays are usually of low grade and red burning. The main requisites are that they should mould easily and burn hard at low temperature. There are about 400 tile factories and about 5000 brick kilns spread over the entire state to manufacture tile and bricks. The vast resources of alluvial clays in the paddy land and valley fill areas are used by this industry in the State. Clays available for the manufacture of tiles are mostly found in the districts of Thrissur, Kozhikode, Ernakulam, Kollam, Thiruvananthapuram, Kannur and Palakkad Districts.
There are two main types of tile and brick clays in the State, lacustrine and floodplain. The former are confined to Kannur district. Clays are generally fine plastic to dull white to variegated colours and occur in the depressions in the laterite near Pattuvam, Alakode, Thaliparamambu etc. The flood plain deposits, which occur in the neighbourhood of rivers are found in a number of districts.
Tile manufacturing units are concentrated in certain areas in the State mainly Feroke area of Kozhikode district, Amballur, Ollur of Thrissur district, Aluva of Ernakulam district, Chathannur of Kollam district and Amaravila of Thiruvananthapuram district.
GRAPHITE
Graphite occurs in nature in the form of vein, dissemination (flaky) and amorphous variety. The first two types of occurrences are found in Kerala. The vein - type graphite mined earlier around Veli, Vellanad and Changa is confined only to the Thiruvananthapuram district. The flake type of graphite is extensive in occurrence in Thiruvananthapuram, Kollam, Kottayam, Idukki and Ernakulam districts which have been studied by Geological Survey of India and are quite akin to the celebrated flaky graphite mined in the Malagasy Republic. The graphite occurs as thin flakes distributed more or less evenly in the rock constituting on an average about 5% -10% of the bulk of the rock, although rich pockets are not uncommon. The studies in various laboratories in the country and abroad in respect of the bulk samples collected from the flaky graphite deposits of Vadakode, Nagapuzha (Muvattupuzha taluk, Ernakulam district) and Chirakkadavu (Kanjirappally taluk, Kottayam district) point to good beneficiation characteristics, a high recovery of fixed carbon (about 85%) and preservation of suitable flake size facilitating their use in key value added industrial application like crucible manufacture etc. The reserve position in respect of the flaky graphite deposits of Ernakulam and Kottayam districts are given below:
SILICA SAND
The coastal tract between Alappuzha and Aroor in Alappuzha District contain extensive deposits of silica sand. The best deposits are confined to the narrow strip of land sandwiched on either side by Vembanad lake and stretching from Cherthala to Arookutti over a distance of about 35 km. Besides there are also smaller deposits in other districts of Kerala.
The sand deposit comprises of flat to gently dipping sandy stretches, generally about 5m above Mean Sea Level.
Reserves of Deposit Based on the recent appraisal carried out by the Department of Mining and Geology over the open area likely to be available for mining, the inferred reserve of silica sand in the villages are estimated as below:
Quality of Sand
Investigation carried out at Regional Research Laboratory (RRL), Thiruvananthapuram have revealed that the silica sand of Pallippuram is superior compared to the sands of certain other countries (Mdina and Baraboo of USA and Germany) as raw material for silica refractory. Chemical analysis indicates that the sand are of high quality suitable for glass manufacturing. The brown sands occurring below the white sand in Varanad area have also shown that they are superior in quality to the white sand in the same area and are suitable for manufacture of glass. Varanad sand could be used for making high grade colourless glass such as crystal glass, table ware etc. The scope for beneficiation of the sand established its usefulness in optical and ophthalmic glass industry. The products suit to the specification of sheet rolled and polished glass manufacture as per US Bureau of Standards.
LIGNITE
Lignite, the only fuel mineral discovered recently in the State assumes special significance. Since no coal deposits have been identified and the landed cost of coal remains high, the possibility of substitution of coal and fire wood by lignite in the user industries would be worth pursuing. As per the recommendations of the task force on lignite constituted for Kerala, the erstwhile Kerala Mineral Exploration & Development Project had carried out detailed investigation for lignite in Madai area, Kannur district.
Detailed exploration including drilling taken up revealed that lignite occurs in multiple seams having an average cumulative thickness of 4.65 m. Calorific values ranges from 1583 to 4556 K cal/kg and the average is 2830 K cal/kg. A reserve of 5.40 MT have been estimated from this area of 1.19 km2. Small as well as pilot scale tests on the lignite samples established fluidised bed combustion and a high combustion efficiency (more than 96%) of lignite.
Detailed exploration carried out by the department in NileswaramAnkakalari-Palayi-Chathamath area in Kasargod district has identified lignite seams at a depth of 18 m. The average cumulative thickness is about 4 m, and the average calorific value is about 2250 K Gal/kg. The reserves estimated tentatively are of the order of 250 million tonnes. The exploration also indicated 2 million tonnes of China clay and 3 million tonnes of plastic clay in the area.
Drilling at Kadankottumala, near Cheruvathur has indicated that lignite seams of average cumulative thickness of 2.85 m occur in the sedimentaries in the depth range from 16.70 m and 33.40 m. A reserve of 1 million tonnes of lignite has been estimated tentatively. In Kayyur-Klayicode area east of Nileswaram a reserve of 0.55 million tonnes of lignite with clay has also been estimated.
LIMESTONE
Crystalline Limestone
Kerala State is deficient in crystalline limestone and only a few bands of crystalline limestone in Palakkad and Idukki districts have been located in addition to the limestone deposit proved at Pandarathu, Walayar, Palakkad district. The Pandarathu limestone deposit (24 million tonnes) is now the captive mine producing limestone for M/s. Malabar Cements Ltd., the Portland cement plant in Kerala.
A number of small bands have also been identified in other localities in Nattuvanki, Athurasram, Vannamadai, Thavalam in Palakkad district and in a few localities in Idukki district.
Kankar Limestone
Limestone of Kankar variety has been reported from Chittoor- Kozhinjampara area in Palakkad district. The economic significance of low-grade limestone has not been indicated by the studies conducted so far. The 16 km2 area between Thavalam and near Anaiketty shows that kankar caps the amphibolite over 0.3 km2.
Fossiliferous Limestone
Fossiliferous Limestone is known to occur in various parts of Kollam district such as Kallurkadavu, Mughathala, Kannanallur, Kottiyam, Mayyanad, Nedumgandam and Edava in Thiruvananthapuram district. The occurrence of shell limestone is in the form of discontinuous lenses intercalated with black carbonaceous clay in the Tertiary formations.
Lime Shell
The State is deficient in high-grade limestone. Consequently the requirement of lime for chemical industry is depended on the limeshell resources occurring in the backwaters/estuaries, river mouths and lagoons along the coastal tract.
By far the largest reserves of lime shell are known to occur in Vembanad lake and adjoining portions comprising parts of Alappuzha, Ernakulam and Kottayam Districts. The Department of Mining and Geology by its detailed investigation in certain parts of Vembanad lake and adjoining areas have established a reserve of 3.29 million tonnes as shown below:
The lime shell resources next in importance to Vembanad lake are those in Kannur and Kasargod districts in North Kerala.
The department had also investigated on the occurrence of limeshell in Thrissur, Malappuram and Kannur districts and the reserves indicated are as follows:
MAGNESITE
A total possible reserve of 0.037 million tonnes has been estimated in Mulli-Salayur areas, Attappadi in Palakkad District by the Department of Mining and Geology. In Salayur area, magnesite veins varying in thickness from 10 to 30 m were observed in pits. The average recovery of magnesite was assessed as 100 kg/m3 of magnesite - bearing rocks and samples on analysis were found to contain 43.05 to 46.73% MgO, 1.51 to 6.59% of Si02 and 0.29 to 0.59% of CaO.
STEATITE / TALC
It is consumed in many manufacturing industries of paper, insecticide, textile, fertilizers, ceramics, rubber products, cement, asbestos etc.
Several steatite occurences have been identified in Thalassery Taluk of Kannur district. The total reserves estimated are of the order of 7.94 million tonnes.
GRANITE (DIMENSION STONE)
An important aspect of recent trend in architecture and construction is the increasing use of a host of crystalline rocks as dimension stones after being cut and polished for enhancing aesthetics and decor of buildings and monuments. In this regard a number of rock types broadly grouped as"Granite" that exist in various parts of Kerala are utilised for this purpose.
The major granite belt of Kerala can be classified by its geologic setting into three categories:
Charnockite-Khondalite belt of Thiruvananthapuram, Kollam, Pathanamthitta and Kottayam districts (colour ranges from pale green with mottled red, bluish green with cordierite, deep dark green, greyish white).
True intrusive or anatectic granites and associated migmatites of Proterozoic age from Idukki, Palakkad, Kannur, Kasargod and Wayanad districts (colour: Pink, light pink, Gray, yellowish white and bluish pink with wavy .patterns).
Dolerite-Gabbro dykes, Proterozoic intrusive hypabasal dyke swarms from Kottayam, Palakkad, Malappuram and Kozhikode districts (colour: dark greenish blue, black and dark gray with black spots).
In Kerala, the importance of exploration of granites has been recognised rather late although investigations have been initiated right from 1976. There has been a spurt in quarrying leases for granite dimension stone in the early nineties that resulted in creatiol"1 of international market for green and white coloured granites of Kerala. Though Kerala has large resources of dimension stone granite in most of the districts amenable for being cut and polished, there are only 19 quarries producing 3589 cbm annually (2001-'02) which is low compared to the production of other southern States of Tamilnadu, Karnataka and Andhra Pradesh.
In Kerala, the importance of exploration of granites has been recognised rather late although investigations have been initiated right from 1976. There has been a spurt in quarrying leases for granite dimension stone in the early nineties that resulted in creatiol"1 of international market for green and white coloured granites of Kerala.
Though Kerala has large resources of dimension stone granite in most of the districts amenable for being cut and polished, there are only 19 quarries producing 3589 cbm annually (2001-'02) which is low compared to the production of other southern States of Tamilnadu, Karnataka and Andhra Pradesh.
There are three different geological setting in which gemstones occurs in Kerala viz.
- the pegmatites traversing the crystalline rocks
- in association with gravels in the river channels of the present day
- in the older gravels which are often consolidated and lateritised
These settings have fairly extensive geographical distribution in Thiruvananthapuram district, the localities of importance are Andoorkonam, Aruvikkara, Balaramapuram, Bonaccord Estate, Braemore Estate, Changa, Chullimanur, Madathara, Manickkal, Pirappancode, Venjaramoodu, Venganoor, Vembayam, Thonnakkal, Uzhamalakkal, Manvila, Mudakkal, Nedumangad, Vellanad, Nettani, Ooroottambalam, Pothencode and in Kollam, the main gem bearing localities are Adukkalamula, Podiattuvila, Kulathupuzha, and Talachira. Besides these localities several stretches of rivers like Kallar- Vamanapuram Ar, Karamana Ar, Neyyar in Thiruvanathapuram District and Kulathupuzha, Kallada rivers in Kollam district are also subjected to sporadic mining activities, though there is no legalized gem mining in the State.