The Hutti gold deposit occurs within the 65 K.M. long Hutti-Maski greenstone belt consisting of Archaean metavolcanic rocks. In common with all known gold occurrences in India, the Hutti deposit was extensively and intensively explored and mined by ancients during centuries proceeding and immediately following the start of this Christian era (A.D). The Hutti mine is probably one of the most ancient metal mines in the world, dating to the Pre-Ashokan period. The ancient miners worked down to depths between 35m and 190m. The later which was intersected in 640 ft. level workings of the main mine in the 1890s, being the deepest known ancient working in the world. Evidences from the bottom of the ancient workings indicate that mine excavations by ancients was achieved by means of fire-setting. The carbon dating test of the old timber recovered from the bottom of ancient mine workings indicated that the ancient mining activity was about 1,900 years old. Indications are that only simple metallurgy viz., crushing, grinding and gravity separation for recovering gold was adopted by the ancients. The industry subsequently declined and eventually disappeared between 500 and 600 A.D perhaps due to the break-up of slavery as a social institution. Re-discovery of the various gold fields in the Hutti belt by the Hyderabad (Deccan) Company took place in the closing years of last century after 1980 and a mine of considerable size was established at Hutti (then in Hyderabad State) between 1887 and 1920 when the Main Mine was developed by the Hutti (Nizams's) Gold Mines Co., an offshoot of the Hyderabad (Deccan) Company and mined upto 1056m. depths recovering 7.40 tonnes of gold from about 0.38 million tonnes of ore at an average grade of 19.48 g/t. A little development work was also done during this period on Oakley's & Village Reefs simultaneously. The mines were closed during 1920 as permit development and areas had been worked out and insufficient funds did not permit development and discovery of new reefs or extension of reefs then being worked, apart from difficulties faced from World War I during this period.
1887 - Gold Mining was undertaken by Hyderabad (Deccan) Company for the Nizam of Hyderabad.
1880 - 1920 Modern mining took place by M/s. John Taylor's and Sons. During the period between 1902 to 1918 only the Main Reef alone produced 3.8 lakhs tonnes of ore and yielded 7.41 tonnes of gold @ an average grade of 19.45 g/t. and was mined upto 1052 m. depth.
1920 - Mine closed down due to paucity of materials, funds, and also attributable to World War I.
1938 - Detailed exploration by geological & geophysical surveys, diamond drilling and dewatering of the Village Reef mine were conducted, which resulted in rediscovery of Zone - I and Oakley's Reefs.
1947 - On 8th July 1947 'Hyderabad Gold Mines Company Limited' was incorporated and the mining operations were entrusted to John Taylor & Sons by the Nizam of Hyderabad.
1956 - It was renamed as 'The Hutti Gold Mines Company Limited' (HGML) with the formation of Mysore State (now Karnataka) when the states were reorganized.
1966 - Indian Gold Control Act 1966 imposed severe restrictions on Gold trade and industry.
1971 - In its Silver Jubilee year, the capacity was tripled from 310 Tonnes per day (TPD) to 910 TPD.
1985 - The two loss making Copper Units 'Chitradurga Copper Company' and 'Karnataka Copper Consortium Limited' at Kalyadi were amalgamated with HGML. Thus the company's operations were extended to Copper mining and production of Copper Concentrate.
1992 - The Gold Control Act was repealed allowing free import of gold resulting in almost stabilization of Indian gold prices.
1996 - Introduction of Carbon-in-Pulp (CIP) technology in the Mill
1997 - In its 'Golden Jubilee Year', HGML undertaken a comprehensive Modernization & Expansion programme to double it's production by increasing capacity at Hutti and conversion of Copper unit to Gold unit at Chitradurga.
1998-99 & 2002 - Phasewise Ball Mill addition
2002-04 - Introduction of large Agitators (11 m dia x 11.5 m height)
2005 - Improvement in the Sand stowing system, Detoxification plant, new high rate thickener and Carbon column
2005 - 10RP area exploration, Uti Gold Project and Hira-buddinni Gold Project development & expansion, Wind Mill expansion at CGU.
2010-12 SAG & Ball Mill of 100 TPH, IInd phase Mining.
2012 - MOU with Karnataka State Bio fuel Development Board for establishing Bio-Fuel Park.
2013 - The Mega Circular Shaft (6 m Dia, upto 940 m depth) sinking is started on 25.01.2013.
2014-15 - 50TPD two Ball mill. Decline Mining in Hutti North block