Hutti Gold Mines Limited

Hutti Gold Mines Limited (HGML) is a company located in the state of Karnataka, India and engaged in the mining and production of gold. It is the only company in India which produces gold by mining and processing the gold ore.cite web|url=http://pib.nic.in/release/release.asp?relid=21478|work=Online webpage of the Press Information Bureau|title=Gold Production during April-September, 2006|publisher=Government of India|accessdate=2007-08-01] cite web|url=http://mines.nic.in/imsene.html|work=Online webpage of the Department of Mines|publisher=Government of India|title=Ministry of Mines|accessdate=2007-08-01] Owned by the Government of Karnataka, HGML has two plants located in Hutti and Chitradurga. HGML mines gold from its main gold mine located in Hutti and other satellite mines.cite web|url=http://www.hinduonnet.com/thehindu/2002/01/17/stories/2002011703030300.htm|work=Online Edition of The Hindu, dated 2002-01-17|title= Hutti Gold Mines becomes member of World Gold Council|publisher=The Hindu|accessdate=2007-08-01] It is the first Indian member of the World Gold Council.

Mining

The mines used by HGML are mainly located in the Hutti-Muski precambrian greenstone geological belt which contains both readily extractable native gold and gold-bearing sulphides.cite web|url=http://www.hinduonnet.com/thehindu/seta/2002/02/21/stories/2002022100060300.htm|work=Online Edition of the Hindu, dated 2002-02-21|publisher=2002, The Hindu|title=Biotechnology in gold extraction|accessdate=2007-08-02] HGML consists of two gold unitscite web|title=HGML Gold Mines|url=http://pib.nic.in/archieve/lreleng/lyr2003/rjul2003/30072003/r3007200313.html|work=Online webpage of the Press Information Bureau|publisher=Government of India|accessdate=2007-08-02] :
* Hutti Gold Unit: This consists of HGML's main mine located at Hutti and the satellite mines, Uti and Hirabuddini, all of which are located in the Raichur district. Hutti is an underground mine, Uti is an open-cast mine while Hirabuddini is an exploratory mine.
* Chitradurga Gold Unit: This consists of an open-cast mine located in Ajjanahalli in Tumkur district and an exploratory underground mine at G. R. Halli in Chitradurga district.

These mines in total produce about 3 tonnes of gold a year. With the closure of the Bharat Gold Mines Limited which had operations at Kolar Gold Fields in Karnataka and at Chittoor district in Andhra Pradesh, HGML is the only company in India that produces gold by mining. It has gold ore reserves of about 31.02 million tonnes which could last for about 60 years and yield about 150.4 tonnes of gold.

Extraction of gold

The process of cyanide leaching is used by HGML to extract native gold which is present in a quartzite matrix. However, this method cannot be used to extract gold which is present in sulphides. HGML has made use of advanced technologies like biotechnology to come up with a cheaper and efficient method to extract gold from sulphides. With the help of the Indian Institute of Science, Bangalore, an extraction method was devised in which the sulphides were subjected to oxidation using the bacteria, "Thiobacillus ferrooxidans" under optimal conditions. The bacteria dissolved the sulphides like pyrite and arsenopyrite and thus revealed the native gold. The native gold was then subjected to cyanide leaching to produce pure gold. This method also produces other precious metals like silver which could be present in the sulphides. After repeated experimentations to come up with the optimal procedure, HGML constructed the first bioreactor in the middle of 2001.

Business

HGML had an accumulated loss of Rs. 30 crore ($7.5 million) for the period 1995-2000 but made up this loss a bit by generating profits of Rs 19 crore ($4.75 million) in the first nine months of 2001.cite web|url=http://blonnet.com/2002/01/18/stories/2002011800140900.htm|work=Online Edition of the Hindu, dated 2002-01-18|publisher=2002, The Hindu|title=Hutti Gold Mines to upgrade milling plant|accessdate=2007-08-02] It went back into red in the year 2002-2003 and was on the verge of closure before it bounced back in the year 2004-2005 to post a profit of Rs. 48 crores ($12 million).

Notes