Calling for judicious use of sand

Depletion

Calling for judicious  use of sand

P U Antony states the hazards of river sand mining and suggests the use of manufactured sand as the best alternative. 

The Karnataka Lorry Owners’ Association has been on an indefinite strike for some time now, protesting against the new sand policy of the government. On September 16, 2013, Karnataka government issued an order to the Public Works Department (PWD), mandating the civil body to use only manufactured sand (M-sand) instead of river sand for all its building activities. A move widely seen as a good initiative aimed to plug the demand-supply deficit in order to ease pressure on sand mining.

It is estimated that the demand for sand is about 3.3 million tonnes a month in the state while the supply is just 8,00,000 to 9,00,000 tonnes. In November 2013, the Karnataka state cabinet, under the chairmanship of Chief Minister Siddaramaiah, decided to constitute sand-monitoring committees at district and taluk levels to monitor illegal sand mining, which is rampant in parts of Karnataka. The business has powerful protectors due to skyrocketing prices of the mineral. Depending on the supply-demand and distance factors, the price of sand currently varies from Rs 30,000 to Rs 60,000 a truck load.

The recent controversy surrounding the suspension of IAS officer Durga Shakti Nagpal, Sub Divisional Magistrate in Greater Noida of Gautam Buddh Nagar in Uttar Pradesh, who had taken on the sand mafia attracted much public attention. In the light of this incident, the National Green Tribunal (NGT) issued a restraint order against all sand-mining activity being carried out across the country without environmental clearance.

Perils of sand mining

Excessive sand and gravel mining causes the degradation of rivers by lowering the stream bottom, resulting in bank erosion. Depletion of sand in stream beds and along coastal areas causes the deepening of rivers and estuaries and the enlargement of river mouths and coastal inlets. It may also lead to saline-water intrusion from the nearby sea. Bed degradation and sedimentation lead to substantial negative effects on aquatic life. Sand mining also affects the adjoining groundwater system and the uses that local people make of the river. 

Construction boom and mammoth infrastructure growth have complicated the whole demand-supply situation of sand. Construction industry estimates demonstrate that to build a 100 sq m structure, around 22 cubic metre of sand is required. Over-exploitation of local rivers for sand mining and the active intervention of the Karnataka High Court forced the state to regulate and monitor sand mining since 2009 through a sand mining policy. The policy was revised in 2011 following further directives of the High Court on illegal sand mining. Shortage of river sand in the state has prompted construction industry to have multiple alternatives even before M-sand. ‘Filtered’ sand was one of the most popular alternatives. It is soil washed in a sieve that rids it of impurities and clean sediment, or silica is used for construction. It came under the scanner of state Lokayukta in May 2008 for its lack of binding force and the resultant collapse of buildings in Bangalore.

M-sand was proven to produce stronger concrete compared to river sand. All the four southern states have recognised M-sand as a substitute for river sand and have been promoting its use over the years. Karnataka has been the most pro-active of the lot. In fact, the 2011 sand policy encourages establishment of M-sand units by giving it top priority while allotting quarries.

The government hopes that the shift to M-sand is bound to ease sand prices in the market and also curb illegal sand mining. Point to be noted here is that M-sand is nothing but crushed rock, that too mostly granite. Though it yields higher quality concrete, rocks are also minerals that need to be conserved. The government mandate for M-sand would result in over-exploitation of another minor mineral and damage to the environment.

Stone quarrying and crushing is associated with high environmental damage and air pollution concerns. In fact, court directives regarding environmental concerns related to stone crushers of the state predates sand mining concerns. The Karnataka High Court’s 1998 order to relocate all stone crushers to a designated ‘safer’ zone in order to keep a check on pollution hasn’t been completely implemented yet. The Karnataka State Pollution Control Board (KSPCB) has been slapping closure notices on stone-crusher units to control the menace. Following a Supreme Court directive, 3,700-odd crusher units across Karnataka were shut last year.

M-sand should not be confused as a by-product or waste of stone quarry. To meet 2.4-2.5 million tonne per month shortage of sand in the state, at least 2.4-2.5 million tonnes extra virgin granite have to be mined in the state, assuming an impossible 100 percent efficiency in M-sand manufacturing system. If one goes by the trend, for every state-of-art M-sand manufacturing unit, 100 or so informal small-scale and highly inefficient units will crop up. 

Alternatives

The dilemma for the construction sector is acute, but solutions are not far to look for. The idea of producing artificial sand from the slag left after manufacturing steel as the best alternative to sand is gaining acceptance. Approximately 500 tonnes of slag is produced from the manufacture of every 1,000 tonnes of steel. The sand made from such slag costs about Rs 100 per tonne on site, considerably less than the river sand. But converting industrial waste like slag into a substitute for river sand has its own complications.Thus, the easier way out is to promote M-sand and filtered sand which are made of natural material, even if not environmentally sound. But if the worries of construction industry have to be soundly addressed, then we need to rise above these quick fixes. 

The Bureau of Indian Standards should devise guidelines for safe induction of recycled sand into the construction industry. Alongside, the burgeoning construction industry too should be regulated through strict legislation. 

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