Sand Mining and its impacts

In recent development, the state government of Bihar issued an order banning sand mining around bridges in rivers and those under construction across the state. The move has been taken to check illegal sand mining that threatens bridges in the rivers.

• Sand mining is apan-India problem.
  • It is prevalent in the Garo Hills in Meghalaya, the Sutlej in Punjab, Yamuna in Delhi, the Ganga in Haridwar, Urmil and Betwa in Bundelkhand, Kosi in Bihar, the Chambal and Narmada in Madhya Pradesh, Ojat in Gujarat, the Subarnarekha in Odisha, Musi in Telangana, Netravati and Phalguni rivers in Karnataka, Godavari and Krishna in Andhra Pradesh, and Cauvery in Tamil Nadu. 
• A United Nations study calculates that humankind’s total consumption of sand—more than 40 billion tons a year—is now double the amount of sediments being replenished naturally on the Earth by the sum of the world’s rivers.
• UNEP in its report ‘Sand and Sustainability’ highlighted that the demand for sand has increased three-fold over the last decades, driven by shifting consumption patterns, growing populations, increasing urbanisation and rapid infrastructure development.

Overview and geology of sand

• Sand is a granular material composed of finely divided rock and mineral
• Composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal settings is silica (silicon dioxide, or SiO2), usually in the form of quartz.
• Sand is classified as a “minor mineral”, as per The Mines and Minerals (Development and Regulations) Act, 1957 (MMDR Act).
• Sand mining is the extraction of sand, mainly through an open pit (or sand pit) but sometimes mined from beaches and inland dunes or dredged from ocean and river beds.

• Sand is the most-consumed natural resource on the planet besides water. Today’s modern civilization is built on sand, where some of its uses include:
  • Brick, Concrete and Mortar - Thus, sand becomes an important component for the Construction Industry.
  • Glass - Sand rich in silica is the principal component in common glasses.
  • Paint
  • Paved Roads
  • Petroleum Fracking
• River sand is always preferred as Desert sand is largely useless to us. Grains of desert sand are often too rounded to serve as industrial binding agents, and marine sand is corrosive.
• The quantity of natural generation of sand is static. Moreover, production of sand is not uniform across seasons with a shortage faced in many jurisdictions.
• Due to uncertainties and inadequateness in supply, the selling rate of the material varies significantly leading to black marketing and illegal mining of the mineral.

Impact of Sand Mining from rivers

On Environment

• Alteration of Rivers: Excessive sand mining can alter the river bed, force the river to change course, erode banks and lead to flooding.
  • It leads to 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.
• Damage River Biodiversity: Instream mining can have other costly effects beyond the immediate mine sites. Many hectares of fertile streamside land are lost annually, as well as valuable timber resources and wildlife habitats in the riparian areas. Degraded stream habitats result in loss of fisheries productivity, biodiversity, and recreational potential.
  • Sand Mining in Chambal has impacted the population of Gharials (National Chambal Sanctuary has been established for their conservation), a critically endangered species. The mining hurts wildlife by removing basking and egg-laying habitat.
• Alter Sediment Budget: As the amount of sand reaching Oceans changes, rivers are not able to replenish the sand on beaches and in deltas.

• Lead to poor water quality: Increased riverbed and bank erosion increases suspended solids in the water at the excavation site and downstream. Suspended solids may adversely affect water users and aquatic ecosystems.
  

Socio-Economic Impacts

• Worsen water scarcity: Sand mining transforms the riverbeds into large and deep pits; as a result, the groundwater table drops leaving the drinking water wells on the embankments of these rivers dry.
• Threat to Coastal Communities: Massive sand mining erodes river deltas, exposing coastal communities to severe land loss, and worsening the effects of climate change-induced sea level rise.
• Damage Public and Private Property: Channel incision caused by gravel mining can undermine bridge piers and expose buried pipelines and other infrastructure.

• Strengthen Policy Framework: Regulations that have been bought, have not worked properly, mainly due to lackadaisical implementation.
• Alternatives to Sand
  • M-sand - is sand made from rock by artificial processes, usually for construction purposes in cement or concrete
  • Sand segregation from overburden of coal mines
    • Import of sand

• Reducing consumption of sand
  • By optimising the use of existing buildings and infrastructure.
  • Using recycled buildings and quarry dust material as a substitute for sand.
• Reducing the negative consequences of extraction
  • By calculating the total annual bed load and restricting mining activities upto that value or less.

Sand and gravel represent the highest volume of raw material used on earth after water. Their use greatly exceeds natural renewal rates. Moreover, the amount being mined is increasing exponentially, mainly as a result of rapid economic growth. To sustain the economic growth in future, it becomes important that the resource is used judiciously.