All about Sand and its use as a construction material.

Sand has been nature’s contribution to human development. Any housing that is seen, any concrete bridge that is walked on, any steps that are climbed carry these natural blessings in abundance. Whether in the manufacture of bricks or as a base material for preparing concrete, sand is there everywhere.

For this purpose mining through sand blocks has been taking place in active collaboration between private groups and government. Like the Abhinna group, which engages in mining through Sand Blocks in West Bengal – in areas like Uttar Dinajpur, Birbhum, Purba Paschim Burdwan, Bankura, Medinipur, Purulia, Malda and Jalpaiguri District.


Here we get to know about this bountiful gift of nature :

 About Sand : What we call sand in common terms is actually a mixture of fragmented particles of decomposed rocks, shells, corals etc. Sand had been a result of fragmentation over the years. In terms of size, it is finer than gravel and coarser than silt. Though sand is a mixture of many materials,  the most common constituents of sand is silica.  Another important constituent of sand is calcium carbonate. The percentage of composition of the constituents varies from place to place, depending on natural surroundings.


Uses of Sand in Construction :  Though there have been different uses of sand – from manufacture of glasses to ingredient for polishing tools, it for construction industry that sand is most popularly used. The popularity of sand as a base material for concrete was popularized during World War I when there grew an abundant need to construct paved roads. This popularity grew through the 1920s. Then came in the late 1940s and early 1950s – an era which witnessed the boom in housing. Over the years as the concept of apartments came in, the need for sand as the base material for concrete grew.

In concrete sand is mixed with gravel, cement and water and made into a slurry. This slurry when hardened forms a rock-solid concrete structure which provides the base strength to buildings. The coarse, angular structure and the strength of the sand provides the inter molecular space for adequate binding, as well as provides strength to the concrete structure.


Different Types of natural sand that obtained :

1) Pit Sand : Pit sands are coarse sand. This type of sand  are obtained from digging deep pits where there is an abundance of supply. This is generally  red-orange in color. The coarse and angular shape of the particles makes it usable in concrete.

2) River Sand : Desert sand is obtained from river bed. Compared to pit sand it is of finer quality. It is whitish grey in color. The grains are more fine and rounded due to mutual attrition. This makes it of a very fine quality. It is much used in construction especially for plastering.

3) Sea Sand : It is obtained from sea shores. The grain is brown and rounded. However sea sand is not much used as construction material because the rounded structure makes it less resistant to molecular rearrangement.  Moreover sea sand contains salts which erodes the plastered surface and causes seepage in the long run.

4) Desert Sand : This is the type of sand one would find in the desert region formed by the erosion of rock for many million years.  Desert sand is however not suitable for construction purposes.



Responsible Sand Mining : Looking at the enormous need of sand for construction purposes, sand mining becomes an inevitable reality. Sand mining is done either through sand pits or extraction from river beds. However rampant mining is always prohibited and a few groups like the Abhinna Group- a mining company in kolkata has taken up the cause of ‘responsible sand mining’ where sand mining takes place with extreme caution and care. Extreme caution is taken to maintain the natural balance and without unending disturbance to natural topography. By this the sand is obtained but keeping the environment aspect in mind.

Does intense sand mining have a harmful impact on the ecosystem?

Sand being in high demand in the construction centers, more and more companies are engaging in this illegal trade. However, this is turning to be one of the biggest ecological disasters in the state. Sand Mining in West Bengal is also a rising terror, affecting the natural ecosystem in colossal amounts. The high levels of urbanization have led to unsustainable sand extraction, leaving back harmful impacts on the natural habitat.


Here are some of the negative effects of this procedure-


1. Causes rapid soil erosion : When a large quantity of unregulated mining of sand takes place along the beaches and riversides, the natural balance is hampered. The beaches and the rivers have thus started to retreat from excess erosion. When too much sediment is removed from these places, the river beds begin to shrink. Deltas recede because of this mining. All of these culminate in the loss of fertile lands. The ground also destabilizes, resulting in the failure of bridges, roads etc


2. Harmful to the local wildlife : The location of the beaches is just at the intersection of the land and the ocean. These beaches are home to various kind of species and living habitats like crabs, snails, turtles etc. When a large quantity of sand is mined, the wildlife surviving on the beaches are disturbed. Turtles usually lay their eggs after digging their nest on the beach sand. This is done so that the little eggs are protected from all the harmful predators. When the hatching emerge from these eggs, they run across the beach and then enter into the wild ocean waters. Lack of sand will mean a huge lack of nesting area for the turtles. This is how sand mining is responsible for destroying natural wildlife. 


This can also be noticed in the case of gharials, the fish eating crocodiles. Unfortunately, disproportionate mining of sand in West Bengal has endangered the habitat of these crocodiles. 


3.  Makes the area more flood-prone : Extracting huge amounts of sand blocks in West Bengal has made the region more prone to flooding. Sandbanks used to act as barriers for the flood. Indiscriminate sand mining is therefore very vulnerable to the natural forces. 


4. Affects the aquatic ecosystem : The ill effects of sand mining are not just confined to the beach side. The complete removal of green vegetation and the destruction of the soil profile destroys the habitat both above and below the land. They also have an impact on the underwater ecosystem. Sand mining can result in turbidity in the water. The use of machines and the disturbance caused by humans also have a negative effect on aquatic wildlife. The turbidity caused in the water creates a kind of barrier that prevents the sunlight from entering the water. This is turn becomes harmful to the corals who require sunlight in order to thrive. Fishes also die when the turbid waters cut off their oxygen supply. This is how the fishing industry suffers a huge loss.             


In stream mining also has several other costly effects which go beyond the immediate mining site. Large hectares of stream side land is annually lost due to this including valuable timber resources, and wildlife in the riparian areas. Stream habitats that are degraded slowly progress towards the loss of fisheries productivity, biodiversity with minimal chances/potential for recreation. Severely degraded channels lower the aesthetic values of the land. 


“Abhinaa Group” uses environment-friendly means to provide sand to several industrial sectors without harming the natural ecosystem.  

What Are The Methods Of Mining In Order To Create Sand Blocks In West Bengal

For the construction of building and roads and create the sand blocks in west bengal, sand is being extracted from the rivers in West Bengal. For the construction industry, the companies are dredging the rivers in order to get impure free and good quality sands. There are some of the methods of extraction of sand. These are off-channel mining and in-stream mining.

In-stream Mining

In order to lower the cost of transportation of the sand, the in-stream sand mining is often done in locations which are along the route of the transportation or close to the end markets. This type of mining is extremely damaging to the aquatic ecosystem and properties. While the flow of sediment can get hamper by the over dredging of the streams, the channels can change its course. Hence, within the sustainable limits, one can do the mining activities without harming nature. There are few recommendations which are as follows -

• Setting an elevation below which the mining is not allowed
• On the basis of annual replacement levels, one should not permit a mining scale.
• There should be a long term monitoring mechanism.
• Limiting extraction methods to bar skimming
• Between May And September, one needs to limit the mining activities

Off Channel Mining

In changing the alluvial system, floodplain extraction or off- channel mining of river sand is done. As the meandering rivers flow across the flood plains, under this system it forms a possibility that the river channel would move towards the pit. This is a situation in which the river flows through the area left between the pit and river and is known as river capture. There are some recommendations, which can lessen the harm caused by off-channel mining.

• The the walk of the channel, one should keep the maximum depth of the pit.
• Away from the main channel, the off-channel extraction should be done.
• One needs to set up a long run monitoring mechanism.
• In order to provide the brought back to support the wetland habitat, pits should be redeemed for agriculture.
• In the long term, one should establish proper responsibility and accountability.

Mining Process Of Dolomite

There is a various process of dolomite mining, which is being practiced in the dolomite minesin arunachal pradesh.They are the removal of soil and vegetation layer, cruising and blasting of dolomite and transportation.

Conclusion: The sand and dolomite mining is one of the most profitable types of mining. To know more one can go the “Abhinna Group“ and check details.