Extraction of Sand from Waste dumps of Mining: A New Approach to Address the Environmental Issue of Goa
Keywords:Clays, Environment, Goa, Iron Ore, Mining, Sand, Sustainability
Goa is India's smallest state by area (3700 sq.km) but rich of mineral deposits such as -iron ore, manganese ore, bauxite and many minor minerals like basalt, laterite stones, rubbles, river sand etc., Exploration and exploitation for iron ore has started at the beginning of the 20th century. Iron ore mining in Goa is completely in the private sector. The mining belts extend over a length of 65km from SE to NW of the State covering around 700 sq.km. The iron ore deposits are distributed over the Northern, southern, and central blocks of Goa. It is the only state with large area under mining. Mineral production in Goa started in the late 1940s. Initially with Manganese ore but later shifted to iron ore with phenomenal growth in production. Every year around 60million tonnes of iron ore was being handled till 2015. Subsequently capping has been imposed by Hon’ble Supreme Court to mine 20 million tonnes from 100 mines by open cast method to control the pollution levels. The mining is carried out by mechanized methods and generated large number of employments, around 5 lakh people by both direct and indirect means. The state is having 400 million tonnes of iron ore resources. The highest production of iron ore from Goa was 40 million tonnes per annum in the past, but for extraction of everyone tonne of ore approximately 4 tonnes of waste rock has to be removed as the mining has gone deep and extent of each lease area is small. The waste rock comprises manganiferous and phyletic clays which are soft and easily erodible. Further, Goa witnesses heavy rainfall up to 3500mm during SW monsoon every year, thus the surface waters are getting polluted. As said above the lease areas are being small and the generation of waste rock is high. So, the disposal of waste rock and its prevention poses a problem. The analysis of waste rock indicates the waste rock is rich of sand grains which can be extractable by simple crushing and screening method. So, a detailed conceptual plan is necessary to sustain the mining and to tackle the environmental issues which are suggested in this paper.
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