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R. H. SAWKAR JOURNAL GEOLOGICAL SOCIETY OF INDIA Vol.76, September 2010, pp.208-214

Gold Mining: A Development Authority in Karnataka R.H. SAWKAR Geological Society of India, No.63, 12th Basappa Layout, Gavipuram, Bangalore - 560 019 Email: [email protected]

INTRODUCTION

Table 1. India's position in world gold industry

Gold has been an important commodity in society since times immemorial. Apart from its use as ornaments, it plays a very important role in commercial transactions. Today it is an investment commodity, playing a determinative role in guiding world economy. Fundamental physical aspects of demand and supply monetary markets and geopolitical conditions around the world have great influence on the price of gold. In the coming years there will be a move towards greater backing of currencies with gold. Already the Europe and USA have considerable gold holdings backing their currencies. Japan, China and India would require 22,000 tonnes of gold to provide 15% support to their currencies. This demand will have an impact on the price of gold in a big way considering the fact that the annual world gold production from mines is just around 2,600 tonnes per annum. India’s position in World gold industry is given in Table 1. For investors gold is a traditional hedge in uncertain times, whenever inflation due to crude oil position or geopolitical tensions loom large, gold price has skyrocketed 800

Total stocks Central Bank holding Annual production Annual recycling Annual demand Annual imports Annual exports

India (tonnes)

World (tonnes)

13,000 400 2 100-300 800 600 60

145,000 28,000 2,600 1,100-1,200 3,700 -

Percentage share 9 1.4 0.08 13 22 -

amid the current market turmoil. Graphs showing the movements of gold as against oil, when jitters give gold a push is given in (Fig.1). In recent times although the prices of crude oil has come down gold prices has moved up as shown in Fig.2. CRUSTAL ABUNDANCE AND EXTENT OF RESERVES

Average crustal abundance of gold is said to be 0.004 ppm. If the average crustal thickness is taken as 60

GOLD

OIL

$ per troy ounce

$ per barrel

600

45

400

30

200

15

0

0 1946 - 2006

1946 - 2006 source: US DOE/www.economaaic.com, www.ioaa.com

Fig.1. Comparison of gold and crude oil price. 0016-7622/2010-76-3-208/$ 1.00 © GEOL. SOC. INDIA JOUR.GEOL.SOC.INDIA, VOL.76, SEPT. 2010

GOLD MINING: A DEVELOPMENT AUTHORITY IN KARNATAKA

209

Fig.2. Gold price, US$ per ounce (London pm fix).

20 km, the total available gold in the crust would be of the order of 11 x 1011 metric tonnes. Over 99% of this material is distributed in such minor quantities, that its extraction would prove highly uneconomical. The total quantity of gold ever mined is taken at 1,25,000 tonnes and the estimated reserve available for exploitation is put at 62,000 tonnes. These together form only 0.0002% of what is available in the crust (Craig and Reinstidt, 1998). Therefore, there is ample scope for locating new deposits of gold. Gold available in the crust is concentrated in special environments as to constitute resources. Reserves represent a very small quantity of the resource potential, which can be extracted with profit under present conditions. All our efforts should be directed, therefore, towards identifying resources, but, more importantly, converting the resources into reserves category. Estimation of resource potential is as important as reserve estimation and forms the first step in any exploration programme. OFFICIAL ESTIMATE OF INDIA’S GOLD RESERVES

An estimate of India’s reserves of gold as presented by the Indian Bureau of Mines (IBM) for the year 2007 is given in Table 2. The figures furnished by IBM fail to give the

real picture of the immense potential there is in the country for gold. PICTURE OF HUTTI AND GADAG

Table 3 relate to reserves and resources of Hutti and Sangli and Table 4 to Gadag Gold Field excluding Sangli. The picture presented on verifiable facts is more reasonable. Karnataka has extensive tracts of greenstone belts and if all of them are explored thoroughly the gold potential in Karnataka can be as high as in the rest of the continents having similar geological set up. GOLD MINING IN KARNATAKA Ancient Industry

Gold mining in Karnataka was a major industry in prehistoric times. Both placer and vein gold were exploited. Numerous ancient workings for gold can be identified in almost all districts of the State and a considerable quantity (an estimate places it at 990 tonnes) have been produced over a period of time extending to thousands of years. The ancient miners had reached depths of up to 200 m and their prospecting operations were so thorough that not a single gold-bearing quartz vein remained untouched. Why this

Table 2. Estimate of India's gold reserves (source: IBM Year book, 2007) Reserves

Resources Pre Feasibility

Measured

Indicated

Inferred

Recoverale

Total

Grand Total

19,251

STD 222 1.724

STD331 27.062

STD 333 83.529

STD 333 118.635

STD 334 140.083

371.035

390.289

85.12

6.74

62.08

118.4

52.74

165.73

405.69

490.81

2.552

23.569

-

26.121

26.121

2.29

3.57

5.86

5.86

All India

Proved

Probable

Total

Primary ore in million tonnes

15.55

STD 121 STD 112 1.075 2.623

Metal in tonnes

66.92

3.8

14.4

Ore placer in million tonnes

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210

R. H. SAWKAR Table 3. Extent of reserves and resources of Hutti and Sangli mines Hutti Mines

Type of resource

Reserves in million tonnes

Grade g/t

Sangli Mines Metal reserves in tonnes

Reserves in million tonnes

Type of resource

Grade g/t

Metal reserves in tonnes

Proved reserves at 2 g/t cut-off

6.87

6.42

44.10

Open pit drill proved from 730 up to 650 RL

2.34

2.27

5.311

RL 730/650 CB ration 1:7; 80 m

@ 1.5 g/t cut-off (to 721 m depth) present operation depth (resources)

17.89

3.14

56.18

Possible drill indicated open pit From 650/550 R.L.

1.78 from 650/550 RL

2.15

3.827

RL 650/550 OB ratio 1:15 100 m

Between 721-1000 m depth resources

15.96

4.52

72.52

Underground inferred resources up to a depth of 1000 m

6.51

+3.00

19.53

RL 550/150

Between 1100-3000 m depth

79.80

4.52

360.69

Not estimated

Total reserves and resources

120.52

4.42

533.13

10.63

2.68

28.668

Source: Radhakrishna and Curtis, 1999, p.103

Source: Based on Exploration of British mining companies, GSI, MECL and RMMPL

Table 4. Summary of reserves and resources in mine developed blocks of Gadag gold field excluding Sangli Mine Sl. No. 1.

Mine Strike length (in km)

Mysore (16 km)

Shafts (m)

Inclines (m)

On lode development (m)

% of payable lodes

76 (E)

623 (E)

1664 (E)

47%

170

Adit 35 m

Block No.23 (1.7 km)

2.

3.

Proved (tonnes)

Indicated (tonnes) grade (g/t)

Inferred (tonnes)

Total (MT) ore (g/t) metal (kg)

117,304 (T) 5.61 g/t 658 kg

692,156 (T) 5.00 g/t 3,461 kg

346,078 (T) 5.00 g/t 1,730 kg

1.16 (MT) 5.06 g/t 5,849 kg

-

-

-

1,029,849 (T) 3.70 g/t 3,810 kg

1.03 (MT) 3.70 g/t 3,810 kg

S.K. Katti, Attikatti Main Lode (2.3 km)

96

79

572

-

6,000 (T) 3.00 g/t 18.kg

519,305 (T) 4.09 g/t 2,124 kg

441,275 (T) 3.70 g/t 1,633 kg

0.97 (MT) 3.91 g/t 3,774 kg

South K Katti, Attikatti f/w Lode (1.8 km)

88

91

116

-

-

547,143 (T) 6.25 g/t 3,420 kg

-

0.55 (MT) 6.25 g/t 3,420 kg

Kabuliayakatti Main Lode (1.6 km)

93 -

235 203 171

5015

20%

240,853 (T) 6.05 g/t 1,457 kg

694,945 (T) 4.00 g/t 2,780 kg

4,000,000 (T) 3.00 g/t 1,200 kg

1.34 (MT) 4.07 g/t 5,437 kg

North Hosur Mine (1.7 km) Hosur Mine (1.7 km)

55 204

71 412

1360 4063

16.28% 29%

233,959 (T) 3.74 g/t 875 kg

Champion Reef East and West (1.7 km)

152

505

2133

27%

196,336 (T) 3.83 g/t 752 kg

4,000,000 (T) 3.5 g/t 14,000 kg

2,000,000 (T) 3.25 g/t 6,500 kg

6.43 (MT) 3.44 g/t 22,127 kg

6,453,549 (T) 4.0 g/t 25,784 kg

4,217,202 (T) 3.53 g/t 14,874 kg

11.47 (MT) 3.87 g/t 44,418 kg

4.

Total in Mine developed area

794,452 (T) 4.73 g/t 3,760 kg

5.

Further possible depth extension in developed mines and unexplored blocks of Venkatpura, Nabhapura, Nagavi and Gap areas between developed mines

9,500,000 (T) 3.00 g/t 28,500 kg

9.500 (MT) 3.00 g/t 28,500 kg

6.

BIF blocks of Asundi, Gaulgerimath, Mallkarapura, Suganahalli, Tarikoppa, Tongod Balehosur Magala - Open cast resources of gold associated with sulphidic belts of Gadag schist belt and shallow depth of 100 m

4,120,000 (T) 2.21 g/t 9,105 kg

4.120 (MT) 2.21 g/t 9,105 kg

17,837,202 MT 2.94 g/t 52,479 kg

25.09 (MT) 3.27 g/t 82,025 kg

Grand Total 794,452 (T) Resources 4.73 g/t 3,760 kg

6,453,549 (T) 4.0 g/t 25,784 kg

m = meters; km = kilometer; T = Tonnes; g/t = grams/tonne; kg = kilogram; MT = Million tonnes. JOUR.GEOL.SOC.INDIA, VOL.76, SEPT. 2010

GOLD MINING: A DEVELOPMENT AUTHORITY IN KARNATAKA

industry came to an abrupt end by 500/600 AD is not known, until the advent of British rule in India. Recent Industry

The gold mining industry was revived during the period 1880-1910, mainly by British enterprise. A number of ancient workings were reopened during this period, but active mining was confined largely to Kolar which earned enormous profits and dividends of 150% and 165% being paid to the shareholders in England. Consequently there was a big ‘boom’ in gold mining and a plethora of companies came into existence. In these early years only the highest grades of ore (> 20 g/t) available in the Champion reef at Kolar and the Main reef at Hutti were worked. The Kolar gold mines ore averaged over 40 g/t in the first twenty years. Except for these two mines, work at all other places ceased by 1910. The Hutti mines continued to operate until 1920. Many identified resources delineated by Geological Survey of India could not be developed due to lack of basic infrastructure or metallurgical difficulties and financial allocations for exploration. Currently all over the world the open pit and underground mining follows modern extraction technology. This has led to exploitation of lower grade ores economically. The declining grade trend (see Fig.3) suggests that future production will depend upon

Grade (g/t Au) 100

Average grade of gold mined in Average grade of gold mined in USA+Canada+Australia+South USA + Canada + Australia + South Africa Africa

Average grade of gold mined in the Average grade of gold world

10

mined in the World

1

Average grade of discoveries in the World

Average grade of gold discoveries in the world (3-Year rolling average for discoveries > 1 Moz (3-year rolling average for discoveries > 1 Moz) 0.1 1950

1960

1970

1980

1990

2000

2010

Fig.3. Declining gold grade trend (source: SEG Newsletter, No.81, April 2010, p.22).

the development of lower grade deposits as to meet the demands. OCCURRENCES OF GOLD IN KARNATAKA AND GROUPING FOR P ROSPECTING

Gold mining is by no means a new industry in the State. It has numerous old workings, some of them date back to more than 2000 years, testifying to widespread nature of the industry. There is hardly a single greenstone belt, which is free from ancient workings (Fig.4 and Table 5). JOUR.GEOL.SOC.INDIA, VOL.76, SEPT. 2010

211

GOLD DEVELOPMENT AUTHORITY OF KARNATAKA

Throughout the history, gold has been the most sought of metals. Man has insurmountable fascination for the metal for more than 5,000 years. Gold has caused some of the greatest human migration and it has been the object in the excavation of the deepest holes in the Witwatersrand in South Africa and at Kolar and Hutti in India. Gold mining industry has changed little since the promulgation of an ordinance on 25th January, 1994, to amend the Mines and Mineral Regulation & Development Act, 1957, to allow private companies and individuals to explore and mine gold, copper, chromium, lead, zinc and precious stones, which were till then exclusively in the domain of Government owned public sector mining companies. The tardy progress in achieving exploration success to date is directly attributable to legislative and administrative delays of both Central and State Governments in taking effective steps to implement the new policies. Karnataka, which was once the premier producer of gold, producing +30 tonnes of gold per annum, should now attempt to visualize the extent of its endowment of gold, its potential, past, present and possible future exploration, the causes for the present stagnation in the gold mining industry and the action required for the industry to become an ‘engine of change’ in many rural areas where gold deposits are located. Policies, decisions and actions of the Central and State Governments in respect of the gold mining industry, therefore, need to be planned towards achieving these goals. Old Mysore State was known for its progressive steps in the exploration of mineral deposits and was the first to introduce diamond drilling in India in early 1900. It may be mentioned here that the Mysore Geological Department spared the services of drillers to GSI, Geophysicists to ONGC and Geologists to Atomic Mineral Division and has the distinction of having introduced innovative ideas in mineral industry. Based on the opinion of Radhakrishna (JGSI, v.39(5), 1992, p.364; Mineral Resources of Karnataka, 1996, p.245) it is suggested that a Gold Authority of Karnataka be created, with special Financial and Administrative powers, solely for the exploitation of gold occurring in different parts of Karnataka. With the creation of such an Authority, it would be possible to produce up to10 tonnes of gold per annum in some of the above mentioned groups within a short period of 5 years. Karnataka has undoubted extent of gold resources and also has talent in, exploration, mine development, metallurgy, environment and experience in opencast and underground mining is readily available. However, requisite infrastructure and

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R. H. SAWKAR

Index to locations, greenstone belts wise Dharwar-Shimoga Belt 1. Karajgi 2. Chinmulgund 3. Kudrekonda 4. Palavanahalli 5. Chorana Edehalli 6. Honnuhatti-HosurTambadhihalli 7. Jalagaragundi 8. Shiddarhalli 9. Nandi 10. Hanni-Bukkambudi 11. Honnayakanahalli 77. Karthikere-Kalasapura 78. Devrukal Nuggihalli Belt 12. Yelavari-Gollarhalli 13. Jalagaranhalli 14. Aladahalli-Honnenahalli 15. Tagadur 16. Kempinkote Holenarsipur Belt 17. Anekere-Kallenahalli K.R. Pet Belt 18. Pura-Bellibetta-Katargatti Chitradurga Belt (A) Gadag region 24. Hosur-Shirunj 25. Yelisirur-Venkatapura 26. Nagavi-Beldadi-Nabhapur 27. Kabuliyatkatti-Attikatti 28. Mysore and Sangli Mines

44. Ajjanahalli 45. Bellara 46. Honnebagi (D) Nagamangala Tract 47. Kalinganahalli 48. Nagamangala 49. HunjanakereTittanamangala Sandur Belt 51. Lingadahalli 52. South of Vibhutigudda Kushtagi Belt 53. Naranhalli 54. Kilarhatti Mangalur Belt 55. Mangalur Gold Mine Hutti Belt 56. Hutti Gold Mine 57. Virapur-Yathkal 58. Tuppadhur 59. Buddini 60. Maski 61. Sanbal 62. Ramaldinni 63. Udbal 64. Kadoni 65. Uti 66. Wandalli 67. Chinchergi 68. Hira Buddini 69. Bullapur

(B)Chitradurga Sulphide Zone

Deodurga Belt 70. Chikhonnakuni

29. Konganhosur 30. Honnemaradi 31. Chikkannanahalli 32. G.R. Halli 33. Gonur-Kotemardi 34. Madakeripura 35. Kunchiganhal 36. Ingaldhal 37. Kallehadlu 38. Halekallu

Kolar Belt 71. Manighatta 72. Patna-Tambahalli 73. BetrayanbettaKamandahalli 74. K.G.F. Western Lode 75. K.G.F. Champion Reef 76. Mallappakonda

(C) Ajjanahalli-Bellara Tract 39. Bodimardi/Iplara 40. Dindivara 41. Anesdri 42. Javanhalli 43. Ramenhalli

Southern High Grade Migmatite Terrain 19. Nadapanhalli 20. Karimadanahalli 21. Sonhalli (Honhalli) 22. Woolagiri (Volagere) 23. Amble

Fig.4. Locations of the groups of prospecting areas in Karnataka (source: Radhakrishna and Curtis, 1999).

Table 5. Grouping of prospecting areas Group Area

Centre

Approx no. Gold of prospets tonnes/yr

1

Hutti Maski schist belt

Hutti

14

15

2

Chitradurga schist belt (Ajjananhalli-Bellava tract)

Ajannahalli

8

10

3

Kolar schist belt

KGF

6

10

4

Gadag schist belt

Kabulayatkatti

6

10

5

Dharwar-Shimoga belt

Kudrekonda

13

04

6

Nuggihalli belt

Kempankote

5

02

7

Southern migmatite terrain

Volagere

6

03

58

54

Total

JOUR.GEOL.SOC.INDIA, VOL.76, SEPT. 2010

GOLD MINING: A DEVELOPMENT AUTHORITY IN KARNATAKA

213

Table 6. Position of RP, PL and ML areas for the year 2008 to 2010 Application

2008

2009

2010

RP

PL

ML

Plant

RP

PL

ML

Plant

RP

PL

ML

Plant

No. of Applications

24

5

-

-

15

3

1

-

100

35

3

Pending with DMG

4

1

-

-

6

-

-

-

40

35

3

-

Pending with State Govt.

5

-

-

-

7

-

-

-

60

-

-

-

Pending with Central Govt.

15

4

-

-

2

3

1

-

-

-

-

-

1000 TPD under construction

Karnataka State Government has made a policy not to insist for NOC's from Revenue and Forest Authority for grant of prospecting license (RP = Reconnaissance Permit; PL = Prospecting License; ML = Mining Lease)

funds are lacking. The problems can easily be resolved through private investment and disinvestment in public sector undertakings of HGML and MML as envisaged in the revised mineral policy of 1992. With creation of such an Authority it would be possible to get appropriate clearances under Central, MMRD, Forest & Environment Acts and State Governments can provide required land, power and water. Most of the gold prospects are located in rural areas. At the July 2010 price of Rs 1,800/ gram, with the possible production of 70 tonnes of gold per annum and 20% of the value of gold produced as salary and wages, it would be possible to generate 1,38,082 employment with an average annual salary of Rs.+160,000/ per annum or Rs. 500 per day per person. It may be recalled that the standard of life and environment in the former gold producing KGF and current HGML areas were of very high standard compared to other mining industries. There has been inordinate delay in granting the appropriate sanctions. Table 6 gives an idea about the delay in each stage. With the creation of a Gold Authority of Karnataka, it is possible to reduce delays and clearances under various Acts. By doing so, Karnataka will regain her age-long lustre in the art of gold mining and, at the same time, will contribute in increasing measure to the prosperity and advancement of Karnataka. Gold mining does not require large quantities of water, power, land, and is less polluting compared to steel and cement, but will produce permanent wealth, which can be used for development of villages, where most of the ancient gold deposits are located. Karnataka Government should give similar importance to gold mining industry as has been given to Steel and Cement in its Global Investors meet held on 3rd and 4th June 2010 at Bangalore where 353 MOU’S worth of Rs. 4 lakh crores was reported as signed (D.V. Pichamuthu, 2010). Karnataka State Government has made a policy not to JOUR.GEOL.SOC.INDIA, VOL.76, SEPT. 2010

insist for NOC’s from Revenue and Forest Authority for grant of Prospecting License. CONCLUSIONS AND RECOMMENDATIONS

Karnataka has been known as the land of gold since ancient times. Numerous old workings for gold exist in almost every district. There is no doubt that it was once a flourishing industry providing employment to a large number of people. However, various reasons this activity suddenly ceased and most of the mines had been abandoned, these have to be rediscovered but the industry failed to recover the earlier status or grandeur. Monetary gains, were given priority over employment, mining activity became concentrated at one or two places like Kolar and Hutti. Even at Hutti mining was started as a famine relief operation. The history of gold mining at Hutti indicates how a small prospecting venture can be made a profitable through careful management. The numerous other known occurrences of gold can also be brought to the stage of Hutti but lack of interest on the part of the Government and industrial establishment has allowed, an industry with enormous growth potential and employment, to remain stagnant. Exploration seems to go on forever without taking progressive measures of development into productive ventures. Valuable time is lost in formalities, in framing rules. Numerous restrictions are imposed and the there has been inordinate delay in granting mineral concession, maps, exploration details and offer of incentives to entrepreneurs who are prepared to risk their money. A more liberal policy is called for employment generation and improving the standard of living of the people who have been sadly neglected. The example of China (with few large-scale mines, but many small ones) should be an eye opener. China, which was way down in the list of

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R. H. SAWKAR

countries producing gold, today tops the list overtaking giants like USA, Russia and South Africa. It would be worthwhile to form a special group for studying the ways and means by which that country was able to take a giant leap and achieve spectacular results. The identification of obstacles which are hampering the growth of the industry and steps to be taken for revival of the industry should form the main task of the Department of Mines and Geology. Properly conceived and executed most the known ancient workings, British developed mines and GSI explored areas can mature into valuable mines. In this connection a start has already been made on a combined open cast and underground operations in the Gadag Gold Field. Unlike foreign companies whose main aim is to generate quick profits, our aim should not be centred on profit making, but on generating employment and developing suitable infrastructure by converting a resource lying idle in the ground into a marketable commodity in great domestic demand. “Gold is still the back-bone of international finance and the one commodity whose value has appreciated steadily, often steeply through decades” ... India cannot afford to let the precious endowment remain buried in the ground. Every effort should be made to utilise the resource and add to our prosperity. Importance of Geochronological and Isotope Data

Available evidences world wide indicate that gold mineralisation has occurred mainly around 2.6±0.1 b.y. ago and greenstone belts of that age are the best targets for gold exploration. In view of this, in any exploration program, the precise determination of the age of the greenstone belt becomes important. A major crustal event that resulted in massive influx of carbon dioxide from the mantle, led to the development of granulite facies rock and vis a vis stabilization of the craton at 2.5 to 2.6 b.y. Gold mineralization seems to be closely associated with this event. Study of fluid inclusions and the isotope character of the fluids may throw light on the source character of Archaean gold. Need for a Modern Assay Laboratory

Data relating to the age of rocks hosting gold

mineralization is virtually scanty at present. This information is vital for the identification of gold-bearing belts. The State, too, has no laboratory where large number of samples can be analysed for their gold content at ppm and ppb levels. Unless these two requirements are fulfilled, there is no possibility of making much headway in gold exploration. It is premature to condemn large extent of greenstone belts in the State as unfavourable for significant gold mineralization on the basis of drilling a few random shallow drill holes spaced at wide intervals. More intensive interdisciplinary studies, involving all the latest technologies, is necessary. Exploration of gold in the greenstone belts is a challenging task and should be undertaken in all seriousness and the blot which has disfigured India’s reputation and made it occupy the lowest position in the list of gold producers of the world should be removed. Creation of Gold Authority

Every country in the world is taking active steps to improve production of gold metal. Between 1980 and 1990, Australia has increased production by 782%; North America by 460%. The extent of granite-greenstone belts in these countries is more or less the same as in India and the geological conditions are also similar. There is apparently no reason why India should lag behind. The deplorable position in which it finds itself, producing just 1.5 tonnes a year is to be ascribed to total lack of interest and the absence of a will to forge ahead. Official agencies with political control and limited budget allocation have not been able to provide the necessary leadership. Even the liberalisation policy has not changed the climate. Indecision and inordinate delays in taking to decisions still prevail and have not permitted any marked improvement. Government which has taken a bold step in liberalisation ought to follow it up by another equally important step of constituting an independent ‘Karnataka Gold Authority’, in much the same way as the Bangalore Development Authority’, fully empowered to take decisions with a view to stepping up production of gold. Unless such an authority is created and sufficient administrative freedom and financial resources provided, gold production is not likely to register any significant increase.

References CRAIG, Z.R. and REINSTIDT, T.D. (1998). Gold production history of the United States. Ore Geol. Review, v.13, pp.407-464. IBM Year Book 2007. PICHAMUTHU, D.V. (2010) Global Investors Meet-Bangalore. Geol. Soc. India, vol. 76, No.2, p. 202. RADHAKRISHNA, B.P. and CURTIS, L.C. (1999) Gold in India. Geol.

Soc. India, Min. Resources of India Series. 307p. RADHAKRISHNA, B.P. (1992) Wrong Priorities. Jour. Geol. Soc. India, v.39(5), pp.363-365. RADHAKRISHNA, B.P. (1996) Mineral Resources of Karnataka. Geol. Soc. India, Bangalore 471p. SEG Newsletter, No.81, April 2010, p.22. JOUR.GEOL.SOC.INDIA, VOL.76, SEPT. 2010