River sand mining Vis a Vis manufactured sand for sustainability

Abstract

Sand and gravels are basic construction raw material globally. With increased economic activity, rate of extraction of sand and gravels has gone up three folds during last two decades reaching 40 billion tonnes per year. Critical hot spots for sand extraction are China and India. Uncontrolled illegal sand mining is common – reduction in ground water level and water transparency, increased water turbidity, adverse impact on birdlife. It is estimated that every year 10 million cubic meters of sand is extracted in Morocco by sand mafias converting large sand beaches into rocky landscape. Singapore has extended its area by 20% by importing 517 million tonnes of sand over last 20 years from neighbouring countries. Some of the countries like India and Malaysia have developed river sand mining guidelines to ensure equilibrium of river, avoid aggradation of hydraulic structures, protection of rivers against erosion, and avoid water pollution. Principal of sustainability is based on equilibrium of meeting business objectives, environmental compliance and social compliance of various stake holders. Tipple bottom line pillars for sustainability include financial stability, environmental stewardship and social equity. For minimizing environmental effect due river sand mining, many countries have adopted technology of manufacturing sand through series of crushers – primary jaw crusher, secondary cone crusher and tertiary vertical shaft impact (VSI) crusher. Japan has developed V7 dry sand manufacturing technology. Manufacturing Sand (M-Sand) has comparable gradation with river sand. Various technical specifications of aggregates and M-Sand adopted by India and US are provided in this paper. There is need of creating R&D facilities in every region for sustainability to develop specifications of M-Sand based on available resources and meet local sand requirement.