PANJIM: Goa’s low grade rejects have been found with gold concentration ranging from 7.71 parts per million (ppm) – 13ppm indicating auriferous nature of State’s iron ore, reveals a study conducted by Goa University.
The Department of Botany, in their study conducted through samples collected from low grade banded iron formation (BIF) ore rejects in North Goa and Banded Hematite Quartzite (BHQ) mining sites at Shirgao and Velgeum-Surla in North and Sacorda in South, has established that the BHQ contains 12-13 ppm and Banded Magnetite Quartzite (BMQ) has 8.4 ppm, whereas the iron ore reject dumps contain 7.71ppm of gold.
“The gold concentration ranges from 7.71-13 ppm indicates auriferous nature of Goa’s iron ore,” the study said.
The researchers — Sujata Dabolkar and Nandkumar Kamat, however, have also left scope for further confirmation of gold by Geological Survey of India (GSI), IIT’s and other research institutes of India. “There needs to be further research on neglected auriferous iron ore of Goa,” they recommended.
As per rough estimate, Goa has around 750 million tonnes of iron ore reject, lying at various mining sites.
According to the researchers, Goa is situated in the northwestern part of the Western Dharwar Craton (WDC) which is Asia’s major metallogenic province. The Dharwar Craton is divided into Eastern and Western Cratons wherein Goa is situated in the northwestern part of the WDC.
They also said that there is also report of occurrence of 0.1 ppm gold in laterite and iron ores in Sindhudurg District. The GSI has also reported the presence of gold in the Schist belt of Chitradurga District and Shimoga.
“These formations show the characteristics similar to the iron ores occurring within the Goa which include Vageri, Bicholim and Sanvordem formations,” the research paper, which was accepted in October stated.
The researchers said that lacking in knowledge of systematic geochemical evaluation, Goa’s iron ore centered mining and export strategy had completely overlooked gold mineralisation of economic importance.
