Owned by the Government of Karnataka, HGML has two plants located in Hutti and Chitradurga.
[citation needed] The mines managed by HGML are mainly located in the Hutti-Muski precambrian greenstone belt which contains both readily extractable native gold and gold-bearing sulphides.
The process of cyanide leaching is used by HGML to extract native gold which is present in a quartzite matrix.
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.