Hatti is situated in Raichur District, Karnataka State and is 80 km due west of Raichur, which is also the nearest railway station. Hatti was a small village in 1939, with hardly 60 or 70 huts and kutcha houses. Now there is a town Panchayat, and the population of the village is about 20,000. The population of the labour colony constructed by the Company is about 20,000.
History
This mine is probably one of the most ancient metal mines in the world, dating to the Pre-Ashokan period, the ancient miners having worked down to a depth of over 2300 feet. It is probable they had broken the rock by "fire-setting" i.e. heating it by means of fires and suddenly cooling it by pouring water onto the heated rock causing pieces to break off. As per carbon dating done by Dr. Rafter from Australia in the year 1955, the age of the two samples of timber found in old workings was estimated to be about 1980 years old. For crushing the ore to extract the gold they used a grinding stone similar to those used now for making masalas and a few of which can even now be found in the area. The actual gold was recovered by passing the crushed ore, mixed with water, over goats' skins, the fur trapping the heavy particles of gold while allowing the lighter minerals to be washed off. In addition to the ancient mining in mentioned above, there was further mining in the area between 1890 and 1920 when the price of gold was about Rs. 18 for 10 grams. The biggest of these ventures was at Hutti where, from 1902 to 1919, nearly 7,400 kg of gold were obtained from very rich ore, at an average yield of 19 g/metric tonne. Most of this ore came from the main mine, which reached a depth of about 1,100 m below surface. The industry closed down in 1920 due to technical difficulties and lack of funds. In 1937, the Nizam's Government decided to prospect the area again with a view to possible re-opening of the mines so as to provide employment. The area was a backward district, which was considered at that time to be a more or less perpetual famine area. In 1940, after some satisfactory exploratory work, it was decided to install a plant to treat 100 metric tons of mine ore per day, but before the plant could be obtained, operations were suspended, and from 1942 to 1946, due to World War II, the mine was shut down except for pumping. After the end of the war, the scheme was resumed and production started in September 1948, at the rate of 130 tonnes of ore per day. By 1972 this rate had progressively increased to 600 tonnes of ore per day.
The Hatti Gold Mines Co., Ltd., Hatti, Raichur District
The Company was originally formed in 1947 as the Hyderabad Gold mines Company Ltd., with the Hyderabad State Government holding a majority of the shares. With the re-organisation of the States in 1956, the Company was transferred to Mysore State and became Hatti Gold Mines Limited.
Process of Gold Recovery and Disposal
Ore containing gold is broken in the underground workings by drilling and blasting. The broken ore is hoisted up to surface and sent to the Mill where it is crushed and ground to fine powder. This powder is mixed with water and is passed over tables covered with blankets which trap the free gold. This concentrate of gold is further purified by melting with fluxes to remove impurities and then cast into bars, weighing about 25000 g. Each, in which form it is known as "bullion". The gold which is not trapped by the blankets is either very fine or is associated with other minerals, such as iron sulphide. The powdered ore containing this gold is agitated in a weak solution of sodium cyanide which dissolves the major portion of gold. The cyanide solution containing the dissolved gold is then passed over zinc, which causes the gold to be precipitated. The cyanide polluted effluent water is contaminating the local ground water. This gold precipitate is acid treated and roasted to remove impurities and then cast into bullion bars. Method of working and production: There are six separate reefs which are being actively worked in the mine at present. The mine is developed mainly through two vertical shafts up to 22nd level at present. Cross-cuts in the country rock from these shafts are put to intersect and develop all the reefs at the vertical interval of 30 to 40 litres. Development rise are taken driven in the mineralized zone. Along the entire strike length of the reef connection the level above and below by series of rises by winzef at the interval of 60 to 70 meters forming different stoping blocks. The blocks that are formed are black stripe and black concreted with 0.6 meters reinforced concrete, two meters above the level. The blocks are made ready for stoping. Stoping will then mainly be done at 15 level by overhand flat black shrinkage method by breasting along the strike in slices of two to three meters. Stoping by overhand step and filling by hydraulic stand storing is adopted for level below 15th level. This is done by breasting along the strike in two meter slices. The main mine which was extensively worked in previous years is water-logged and is still to be re-opened after dewatering and revlaction. As this is a major operation requiring considerable money and time, this will be undertaken time in the future between September, 1984 and 31 March 1983 the mine produced about 38,56,300 metric tonnes of ore to yield about 26,550 kg at an average recovery of 6.88 g per metric tonne. In addition about 48,800 metric tonnes of gold tailings lifted about 112 kg of gold production for the year 1982 – 83 was about 62.83 kg gold per month at an average recovery grade of 5.24 per g per metric tonne.
Demographics
Indiacensus, Hutti Gold Mines had a population of 14,716. Males constitute 51% of the population and females 49%. Hutti Gold Mines has an average literacy rate of 74%, higher than the national average of 59.5%: male literacy is 82%, and female literacy is 66%. In Hatti Gold Mines, 9% of the population is under six years of age.
